View source for Human evolution

{{Redirect|Anthropogeny|the study of humans|Anthropology}}
{{Short description|Evolutionary process leading to anatomically modern humans}}
{{Use mdy dates|cs1-dates=ll|date=July 2024}}
[[File:Ape skeletons.png|thumb|upright=1.5|The [[hominoid]]s are descendants of a [[common ancestor]].]]
''[[Homo sapiens]]'' is a distinct species of the [[hominid]] family of [[primates]], which also includes all the [[great ape]]s.<ref>{{Cite encyclopedia |date=June 8, 2024 |title=Human evolution |url=https://www.britannica.com/science/human-evolution |encyclopedia=Encyclopædia Britannica}}</ref> Over their [[evolution]]ary history, humans gradually developed traits such as [[Human skeletal changes due to bipedalism|bipedalism]], [[dexterity]], and [[complex language]],<ref name="HallHallgrímsson2011c">{{cite book |last1=Hall |first1=Brian K. |author1-link=Brian K. Hall |last2=Hallgrímsson |first2=Benedikt |title=Strickberger's Evolution |url=https://books.google.com/books?id=CrJsNQ5wX8oC&pg=PA488 |date=2011 |publisher=Jones & Bartlett |isbn=978-1-4496-6390-2 |page=488}}</ref> as well as interbreeding with other [[hominins]] (a tribe of the [[Homininae|African hominid]] subfamily),<ref name=":3" /> indicating that human evolution was not linear but weblike.<ref name="Ackermann 2015" /><ref name="Denisovans & Neandertals">{{cite web |url= https://www.livinganthropologically.com/biological-anthropology/denisovans-neandertals-human-races/ |title=Denisovans and Neandertals: Rethinking Species Boundaries |website=Living Anthropologically |last=Antrosio |first=Jason |date=August 23, 2018 |access-date=August 25, 2018 |archive-date=August 1, 2020 |archive-url=https://web.archive.org/web/20200801180554/https://www.livinganthropologically.com/biological-anthropology/denisovans-neandertals-human-races/ |url-status=live}}</ref><ref name="Human Hybrids">{{cite magazine |last=Hammer |first=Michael F. |title=Human Hybrids |magazine=[[Scientific American]] |date=May 2013 |url= http://www.grochbiology.org/EarlyHominidInterbreeding.pdf |archive-url= https://web.archive.org/web/20180824034550/http://www.grochbiology.org/EarlyHominidInterbreeding.pdf |archive-date=August 24, 2018}}</ref><ref name="Mosaic humans, the hybrid species">{{cite magazine |last=Yong |first=Ed |title=Mosaic humans, the hybrid species |magazine=[[New Scientist]] |date=July 2011 |volume=211 |issue=2823 |pages=34–38 |doi=10.1016/S0262-4079(11)61839-3 |bibcode=2011NewSc.211...34Y |doi-access=free|issn=0262-4079}}</ref> The study of the origins of humans involves [[Interdisciplinary|several]] scientific disciplines, including [[Biological anthropology|physical]] and [[evolutionary anthropology]], [[paleontology]], and [[genetics]]; the field is also known by the terms '''anthropogeny''', '''anthropogenesis''', and '''anthropogony'''<ref>{{cite journal |last=Heng |first=Henry H. Q. |date=May 2009 |title=The genome-centric concept: Resynthesis of evolutionary theory |journal=[[BioEssays]] |volume=31 |issue=5 |pages=512–525 |doi=10.1002/bies.200800182 |issn=0265-9247 |pmid=19334004 |s2cid=1336952}}</ref><ref name="Marlowe 54–67">{{Cite journal |last=Marlowe |first=Frank W. |date=April 13, 2005 |title=Hunter-gatherers and human evolution |journal=Evolutionary Anthropology: Issues, News, and Reviews |volume=14 |issue=2 |pages=54–67 |doi=10.1002/evan.20046 |s2cid=53489209}}</ref>—with the latter two sometimes used to refer to the related subject of [[hominization]].

[[Primate evolution|Primates diverged]] from other [[mammal]]s about {{Mya|85}} ([[Myr|mya]]), in the [[Late Cretaceous]] period, with their earliest fossils appearing over 55&nbsp;mya, during the [[Paleocene]].<ref>{{cite web |last=Tyson |first=Peter |date=July 1, 2008 |title=Meet Your Ancestors |work=[[Nova ScienceNow]] |publisher=[[WGBH Educational Foundation]] |url= https://www.pbs.org/wgbh/nova/evolution/meet-your-ancestors.html |access-date=April 18, 2015 |archive-date=March 8, 2021 |archive-url= https://web.archive.org/web/20210308195934/https://www.pbs.org/wgbh/nova/evolution/meet-your-ancestors.html |url-status=live}}</ref> Primates produced successive clades leading to the [[ape]] superfamily, which gave rise to the hominid and the [[gibbon]] families; these diverged some 15–20&nbsp;mya. African and [[Ponginae|Asian hominids]] (including [[orangutan]]s) diverged about 14&nbsp;mya. [[Hominini|Hominins]] (including the [[Australopithecine]] and [[Panina]] subtribes) parted from the [[Gorillini]] tribe between 8 and 9&nbsp;mya; Australopithecine (including the extinct biped ancestors of humans) separated from the ''Pan'' genus (containing [[chimpanzee]]s and [[bonobo]]s) 4–7&nbsp;mya.<ref name=":4">{{cite news |url= https://www.science.org/content/article/bonobos-join-chimps-closest-human-relatives-rev2 |title=Bonobos Join Chimps as Closest Human Relatives |work=[[TimeTree]] |access-date=May 19, 2018 |date=June 13, 2012 |last=Gibbons |first=Ann |archive-date=September 13, 2021 |archive-url= https://web.archive.org/web/20210913223232/https://www.science.org/content/article/bonobos-join-chimps-closest-human-relatives-rev2 |url-status=live}}</ref> The ''[[Homo]]'' genus is evidenced by the appearance of ''[[H.&nbsp;habilis]]'' over 2&nbsp;mya,{{efn|name=habilis}} while [[anatomically modern human]]s emerged in Africa approximately 300,000&nbsp;years ago.
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== Before ''Homo'' ==
{{For| evolutionary history before primates|Evolution of mammals|History of life|Timeline of human evolution}}

=== Early evolution of primates ===
{{See also|Evolution of primates}}
The evolutionary history of primates can be traced back 65&nbsp;million years.{{sfn|Maxwell|1984|p=296}}<ref>{{cite journal |last1=Zhang |first1=Rui |last2=Wang |first2=Yin-Qiu |last3=Su |first3=Bing |date=July 2008 |title=Molecular Evolution of a Primate-Specific microRNA Family |journal=Molecular Biology and Evolution |volume=25 |issue=7 |pages=1493–1502 |doi=10.1093/molbev/msn094 |issn=0737-4038 |pmid=18417486 |doi-access=free}}</ref><ref>{{cite journal |last=Willoughby |first=Pamela R. |date=2005 |title=Palaeoanthropology and the Evolutionary Place of Humans in Nature |url= http://escholarship.org/uc/item/92w669xb |journal=International Journal of Comparative Psychology |volume=18 |issue=1 |pages=60–91 |doi=10.46867/IJCP.2005.18.01.02 |issn=0889-3667 |access-date=April 27, 2015 |archive-date=January 17, 2012 |archive-url= https://web.archive.org/web/20120117154844/http://escholarship.org/uc/item/92w669xb |url-status=live |doi-access=free}}</ref>{{sfn|Martin|2001|pp=12032–12038}}<ref>{{cite journal |last1=Tavaré |first1=Simon |author1-link=Simon Tavaré |last2=Marshall |first2=Charles R. |last3=Will |first3=Oliver |last4=Soligo |first4=Christophe |last5=Martin |first5=Robert D. |author4-link=Robert D. Martin |display-authors=3 |date=April 18, 2002 |title=Using the fossil record to estimate the age of the last common ancestor of extant primates |journal=[[Nature (journal)|Nature]] |volume=416 |issue=6882 |pages=726–729 |doi=10.1038/416726a |issn=0028-0836 |pmid=11961552 |bibcode=2002Natur.416..726T |s2cid=4368374}}</ref> One of the oldest known primate-like mammal species, the ''[[Plesiadapis]]'', came from North America;<ref>{{cite journal |last=Rose |first=Kenneth D. |date=1994 |title=The earliest primates |journal=Evolutionary Anthropology: Issues, News, and Reviews |volume=3 |issue=5 |pages=159–173 |doi=10.1002/evan.1360030505 |s2cid=85035753 |issn=1060-1538}}</ref><ref>{{cite web |url= http://alltheworldsprimates.org/John_Fleagle_Public.aspx |title=Primate Evolution |last1=Fleagle |first1=John |author1-link=John G. Fleagle |last2=Gilbert |first2=Chris |date=2011 |editor1-last=Rowe |editor1-first=Noel |editor2-last=Myers |editor2-first=Marc |website=All The World's Primates |publisher=Primate Conservation |location=Charlestown, Rhode Island |access-date=April 27, 2015 |archive-date=May 12, 2015 |archive-url= https://web.archive.org/web/20150512013618/http://www.alltheworldsprimates.org/john_fleagle_public.aspx |url-status=live}}</ref><ref>{{cite news |last=Roach |first=John |date=March 3, 2008 |title=Oldest Primate Fossil in North America Discovered |url= http://news.nationalgeographic.com/news/2008/03/080303-american-primate.html |work=National Geographic News |location=Washington, DC |publisher=[[National Geographic Society]] |access-date=April 27, 2015 |archive-date=October 16, 2012 |archive-url= https://web.archive.org/web/20121016193314/http://news.nationalgeographic.com/news/2008/03/080303-american-primate.html |url-status=dead}}</ref><ref>{{cite news |last=McMains |first=Vanessa |date=December 5, 2011 |title=Found in Wyoming: New fossils of oldest American primate |url= http://gazette.jhu.edu/2011/12/05/found-in-wyoming-new-fossils-of-oldest-american-primate/ |newspaper=The Gazette |location=Baltimore |publisher=[[Johns Hopkins University]] |access-date=April 27, 2015 |archive-date=January 16, 2019 |archive-url= https://web.archive.org/web/20190116200750/https://gazette.jhu.edu/2011/12/05/found-in-wyoming-new-fossils-of-oldest-american-primate/ |url-status=live}}</ref><ref>{{cite news |last=Caldwell |first=Sara B. |date=May 19, 2009 |title=Missing link found, early primate fossil 47 million years old |location=Toronto |work=Digital Journal |url= http://www.digitaljournal.com/article/272808 |access-date=April 27, 2015 |archive-date=July 22, 2015 |archive-url= https://web.archive.org/web/20150722061001/http://www.digitaljournal.com/article/272808 |url-status=live}}</ref><ref>{{cite news |last=Watts |first=Alex |date=May 20, 2009 |title=Scientists Unveil Missing Link In Evolution |url= http://news.sky.com/home/world-news/article/15284582 |access-date=April 27, 2015 |work=[[Sky News]] Online |location=London |publisher=[[Sky (United Kingdom)|BSkyB]] |archive-url= https://web.archive.org/web/20110728005247/http://news.sky.com/home/world-news/article/15284582 |archive-date=July 28, 2011}}</ref> another, ''[[Archicebus]]'', came from [[China]].<ref name="NYT-20130605">{{cite news |last=Wilford |first=J. N. |title=Palm-size fossil resets primates' clock, scientists say |url= https://www.nytimes.com/2013/06/06/science/palm-size-fossil-resets-primates-clock-scientists-say.html |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2013/06/06/science/palm-size-fossil-resets-primates-clock-scientists-say.html |archive-date=January 1, 2022 |url-access=limited |date=June 5, 2013 |work=[[The New York Times]] |access-date=June 5, 2013}}{{cbignore}}</ref> Other similar basal primates were widespread in Eurasia and Africa during the tropical conditions of the Paleocene and [[Eocene]].

[[File:Notharctus tenebrosus AMNH.jpg|thumb|''[[Notharctus tenebrosus]]'', [[American Museum of Natural History]], New York]]

David R. Begun<ref name="Kordos-p17">{{cite journal |last1=Kordos |first1=László |last2=Begun |first2=David R. |date=January 2001 |title=Primates from Rudabánya: Allocation of specimens to individuals, sex and age categories |journal=Journal of Human Evolution |volume=40 |issue=1 |pages=17–39 |doi=10.1006/jhev.2000.0437 |issn=0047-2484 |pmid=11139358 |bibcode=2001JHumE..40...17K}}</ref> concluded that early primates flourished in Eurasia and that a lineage leading to the African apes and humans, including to ''[[Dryopithecus]]'', migrated south from Europe or Western Asia into Africa. The surviving tropical population of primates—which is seen most completely in the Upper Eocene and lowermost [[Oligocene]] fossil beds of the [[Faiyum]] depression southwest of [[Cairo]]—gave rise to all extant primate species, including the [[lemur]]s of [[Madagascar]], [[loris]]es of Southeast Asia, [[galago]]s or "bush babies" of Africa, and to the [[Simian|anthropoids]], which are the [[New World monkey|Platyrrhines]] or New World monkeys, the [[Catarrhines]] or Old World monkeys, and the great apes, including humans and other hominids.

The earliest known catarrhine is ''[[Kamoyapithecus]]'' from the uppermost Oligocene at Eragaleit in the northern [[Great Rift Valley, Kenya|Great Rift Valley]] in Kenya, dated to 24&nbsp;million years ago.{{sfn|Cameron|2004|p=[https://books.google.com/books?id=fnqzb4_UVfkC&pg=PA76 76]}} Its ancestry is thought to be species related to ''[[Aegyptopithecus]]'', ''[[Propliopithecus]]'', and ''[[Parapithecus]]'' from the Faiyum, at around 35&nbsp;mya.{{sfn|Wallace|2004|p=[https://books.google.com/books?id=YoyQQEOKGVQC&pg=PA240 240]}} In 2010, ''[[Saadanius]]'' was described as a close relative of the last common ancestor of the [[Crown group|crown]] catarrhines, and tentatively dated to 29–28&nbsp;mya, helping to fill an 11-million-year gap in the fossil record.<ref name="2010Zalmout">{{cite journal |last1=Zalmout |first1=Iyad S. |last2=Sanders |first2=William J. |author2-link=William J. Sanders |last3=MacLatchy |first3=Laura M. |last4=Gunnell |first4=Gregg F. |last5=Al-Mufarreh |first5=Yahya A. |last6=Ali |first6=Mohammad A. |last7=Nasser |first7=Abdul-Azziz H. |last8=Al-Masari |first8=Abdu M. |last9=Al-Sobhi |first9=Salih A. |last10=Nadhra |first10=Ayman O. |last11=Matari |first11=Adel H. |last12=Wilson |first12=Jeffrey A. |last13=Gingerich |first13=Philip D. |date=July 15, 2010 |title=New Oligocene primate from Saudi Arabia and the divergence of apes and Old World monkeys |journal=[[Nature (journal)|Nature]] |volume=466 |issue=7304 |pages=360–364 |bibcode=2010Natur.466..360Z |doi=10.1038/nature09094 |issn=0028-0836 |pmid=20631798 |s2cid=205220837 |display-authors=3}}</ref>

[[File:Proconsul skeleton reconstitution (University of Zurich).JPG|thumb|Reconstructed tailless ''[[Proconsul (mammal)|Proconsul]]'' skeleton]]

In the [[Early Miocene]], about 22&nbsp;million years ago, the many kinds of [[Arboreal locomotion|arboreally]]-adapted (tree-dwelling) primitive catarrhines from East Africa suggest a long history of prior diversification. [[Fossil|Fossils]] at 20&nbsp;million years ago include fragments attributed to ''[[Victoriapithecus]]'', the earliest Old World monkey. Among the genera thought to be in the [[ape]] lineage leading up to 13&nbsp;million years ago are ''[[Proconsul (mammal)|Proconsul]]'', ''[[Rangwapithecus]]'', ''[[Dendropithecus]]'', ''[[Limnopithecus]]'', ''[[Nacholapithecus]]'', ''[[Equatorius]]'', ''[[Nyanzapithecus pickfordi|Nyanzapithecus]]'', ''[[Afropithecus]]'', ''Heliopithecus'', and ''[[Kenyapithecus]]'', all from East Africa.

The presence of other generalized non-cercopithecids of [[Middle Miocene]] from sites far distant, such as ''[[Otavipithecus]]'' from cave deposits in Namibia, and ''[[Pierolapithecus]]'' and ''[[Dryopithecus]]'' from France, Spain and Austria, is evidence of a wide diversity of forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the Early and Middle Miocene. The youngest of the [[Miocene]] hominoids, ''[[Oreopithecus]]'', is from coal beds in Italy that have been dated to 9&nbsp;million years ago.

Molecular evidence indicates that the lineage of gibbons diverged from the line of great apes some 18–12&nbsp;mya, and that of orangutans (subfamily [[Ponginae]]){{efn|Not to be confused with [[Pongidae]], an obsolete family which grouped together [[orangutan]]s, [[gorilla]]s and [[chimpanzee]]s to separate them from humans}} diverged from the other great apes at about 12&nbsp;million years; there are no fossils that clearly document the ancestry of gibbons, which may have originated in a so-far-unknown Southeast Asian hominoid population, but fossil proto-orangutans may be represented by ''[[Sivapithecus]]'' from India and ''[[Griphopithecus]]'' from Turkey, dated to around 10&nbsp;mya.{{sfn|Srivastava|2009|p=[https://books.google.com/books?id=kCerOsM8XMwC&pg=PA87 87]}}

Hominidae subfamily [[Homininae]] (African hominids) diverged from Ponginae (orangutans) about 14&nbsp;mya. Hominins (including humans and the Australopithecine and [[Panina]] subtribes) parted from the [[Gorillini]] tribe (gorillas) between 8 and 9&nbsp;mya; Australopithecine (including the extinct biped ancestors of humans) separated from the ''Pan'' genus (containing chimpanzees and bonobos) 4–7&nbsp;mya.<ref name=":4" /> The ''Homo'' genus is evidenced by the appearance of ''H.&nbsp;habilis'' over 2&nbsp;mya,{{efn|name=habilis}} while anatomically modern humans emerged in Africa approximately 300,000 years ago.

=== Divergence of the human clade from other great apes ===
[[File:016 Alpha male chimpanzee walking at Kibale forest National Park Photo by Giles Laurent.jpg|thumb|upright|Genetic data suggest that [[chimpanzee]]s and humans may have diverged from a common ancestor between 9 and 7 million years ago.<ref>{{cite news |title=Scientists observe chimpanzees using human-like warfare tactic |url=https://www.reuters.com/science/scientists-observe-chimpanzees-using-human-like-warfare-tactic-2023-11-02/ |work=Reuters |date=3 November 2023}}</ref>]]
Species close to the last common ancestor of gorillas, chimpanzees and humans may be represented by ''[[Nakalipithecus]]'' fossils found in Kenya and ''[[Ouranopithecus]]'' found in Greece. Molecular evidence suggests that between 8 and 4&nbsp;million years ago, first the gorillas, and then the chimpanzees (genus ''Pan'') split off from the line leading to the humans. Human DNA is approximately 98.4% identical to that of chimpanzees when comparing single nucleotide polymorphisms (see [[human evolutionary genetics]]). The fossil record, however, of gorillas and chimpanzees is limited; both poor preservation – rain forest soils tend to be acidic and dissolve bone – and [[sampling bias]] probably contribute to this problem.

Other hominins probably adapted to the drier environments outside the equatorial belt; and there they encountered antelope, hyenas, dogs, pigs, elephants, horses, and others. The equatorial belt contracted after about 8&nbsp;million years ago, and there is very little fossil evidence for the split—thought to have occurred around that time—of the hominin lineage from the lineages of gorillas and chimpanzees. The earliest fossils argued by some to belong to the human lineage are ''Sahelanthropus tchadensis'' (7 Ma) and ''Orrorin tugenensis'' (6 Ma), followed by ''Ardipithecus'' (5.5–4.4 Ma), with species ''Ar. kadabba'' and ''[[Ar. ramidus]]''.

It has been argued in a study of the life history of ''Ar. ramidus'' that the species provides evidence for a suite of anatomical and behavioral adaptations in very early hominins unlike any species of extant great ape.<ref name="aramidus">{{Cite journal |last1=Clark |first1=G. |last2=Henneberg |first2=M. |title=The life history of Ardipithecus ramidus: A heterochronic model of sexual and social maturation |journal=[[Anthropological Review]] |volume=78 |issue=2 |pages=109–132 |date=June 2015 |doi=10.1515/anre-2015-0009 |s2cid=54900467 |doi-access=free}}</ref> This study demonstrated affinities between the skull morphology of ''Ar. ramidus'' and that of infant and juvenile chimpanzees, suggesting the species evolved a juvenalised or [[paedomorphic]] craniofacial morphology via [[Heterochrony|heterochronic]] dissociation of growth trajectories. It was also argued that the species provides support for the notion that very early hominins, akin to bonobos (''Pan paniscus'') the less aggressive species of the genus ''Pan'', may have evolved via the process of [[self-domestication]]. Consequently, arguing against the so-called "chimpanzee referential model"<ref name="sayers" /> the authors suggest it is no longer tenable to use chimpanzee (''Pan troglodytes'') social and mating behaviors in models of early hominin social evolution. When commenting on the absence of aggressive canine morphology in ''Ar. ramidus'' and the implications this has for the evolution of hominin social psychology, they wrote:

{{blockquote|Of course ''Ar. ramidus'' differs significantly from bonobos, bonobos having retained a functional canine honing complex. However, the fact that ''Ar. ramidus'' shares with bonobos reduced sexual dimorphism, and a more paedomorphic form relative to chimpanzees, suggests that the developmental and social adaptations evident in bonobos may be of assistance in future reconstructions of early hominin social and sexual psychology. In fact the trend towards increased maternal care, female mate selection and self-domestication may have been stronger and more refined in ''Ar. ramidus'' than what we see in bonobos.{{r|aramidus|page1=128}}}}

The authors argue that many of the basic human adaptations evolved in the ancient forest and woodland ecosystems of late [[Miocene]] and early [[Pliocene]] Africa. Consequently, they argue that humans may not represent evolution from a chimpanzee-like ancestor as has traditionally been supposed. This suggests many modern human adaptations represent [[Phylogeny|phylogenetically]] deep traits and that the behavior and morphology of chimpanzees may have evolved subsequent to the split with the common ancestor they share with humans.

=== Genus ''Australopithecus'' ===
{{Main|Australopithecus}}
[[File:Bienvenida al Museo de Lucy.jpg|thumb|upright|Reconstruction of "[[Lucy (Australopithecus)|Lucy]]"]]
The genus ''[[Australopithecus]]'' evolved in eastern Africa around 4&nbsp;million years ago before spreading throughout the continent and eventually becoming extinct 2&nbsp;million years ago. During this time period various forms of australopiths existed, including ''[[Australopithecus anamensis]]'', ''[[Australopithecus afarensis|A. afarensis]]'', ''[[Australopithecus sediba|A. sediba]]'', and ''[[Australopithecus africanus|A. africanus]]''. There is still some debate among academics whether certain African hominid species of this time, such as ''[[Australopithecus robustus|A. robustus]]'' and ''[[Australopithecus boisei|A. boisei]]'', constitute members of the same genus; if so, they would be considered to be "robust australopiths" while the others would be considered "gracile australopiths". However, if these species do indeed constitute their own genus, then they may be given their own name, ''Paranthropus''.
* ''[[Australopithecus]]'' (4–1.8 Ma), with species ''[[Australopithecus anamensis|A. anamensis]]'', ''[[Australopithecus afarensis|A. afarensis]]'', ''[[Australopithecus africanus|A. africanus]]'', ''[[Australopithecus bahrelghazali|A. bahrelghazali]]'', ''[[Australopithecus garhi|A. garhi]]'', and ''[[Australopithecus sediba|A. sediba]]'';
* ''[[Kenyanthropus]]'' (3–2.7 Ma), with species ''[[Kenyanthropus|K. platyops]]'';
* ''[[Paranthropus]]'' (3–1.2 Ma), with species ''[[Paranthropus aethiopicus|P. aethiopicus]]'', ''[[Paranthropus boisei|P. boisei]]'', and ''[[Paranthropus robustus|P. robustus]]''
A new proposed species ''[[Australopithecus deyiremeda]]'' is claimed to have been discovered living at the same time period of ''[[Australopithecus afarensis|A. afarensis]]''. There is debate whether ''[[Australopithecus deyiremeda|A. deyiremeda]]'' is a new species or is ''[[Australopithecus afarensis|A. afarensis]]''.<ref>{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |date=May 27, 2015 |title=The Human Family Tree Bristles With New Branches |url= https://www.nytimes.com/2015/06/02/science/adding-branches-to-the-human-family-tree.html |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2015/06/02/science/adding-branches-to-the-human-family-tree.html |archive-date=January 1, 2022 |url-access=limited |newspaper=The New York Times |access-date=May 30, 2015}}{{cbignore}}</ref> ''Australopithecus prometheus'', otherwise known as [[Little Foot]] has recently been dated at 3.67&nbsp;million years old through a new dating technique, making the genus ''Australopithecus'' as old as ''afarensis''.<ref>Gardner., Elizabeth K.; Purdue University (April 1, 2015). "New instrument dates old skeleton before 'Lucy'; 'Little Foot' 3.67 million years old". Science Daily. Retrieved April 3, 2015.</ref> Given the opposable big toe found on Little Foot, it seems that the specimen was a good climber. It is thought given the night predators of the region that he built a nesting platform at night in the trees in a similar fashion to chimpanzees and gorillas.
[[File:Chimp's Nest.jpg|thumb|Chimpanzee nest. Later [[hominin]]s may have developed [[Niche construction|niche creating]] shelter-building traditions from such earlier [[Nest-building in primates|nest-building practices]].]]

== Evolution of genus ''Homo'' ==
{{Main|Homo}}
{{Human timeline}}
The earliest documented representative of the genus ''Homo'' is ''[[Homo habilis]]'', which evolved around {{Mya|2.8}},<ref name="autogenerated1">{{cite news |last=Ghosh |first=Pallab |author-link=Pallab Ghosh |date=March 4, 2015 |title='First human' discovered in Ethiopia |url= https://www.bbc.com/news/science-environment-31718336 |work=BBC News |location=London |access-date=April 19, 2015 |archive-date=April 18, 2015 |archive-url= https://web.archive.org/web/20150418032919/http://www.bbc.com/news/science-environment-31718336 |url-status=live}}</ref> and is arguably the earliest species for which there is positive evidence of the use of stone tools. The brains of these early hominins were about the same size as that of a chimpanzee, although it has been suggested that this was the time in which the human [[SRGAP2]] [[gene]] doubled, producing a more rapid wiring of the frontal cortex. During the next million years a process of rapid [[encephalization]] occurred, and with the arrival of ''[[Homo erectus]]'' and ''[[Homo ergaster]]'' in the [[fossil#Dating|fossil record]], cranial capacity had doubled to 850&nbsp;cm<sup>3</sup>.{{sfn|Swisher|Curtis|Lewin|2001}} (Such an increase in human brain size is equivalent to each generation having 125,000 more [[neuron]]s than their parents.) It is believed that ''H.&nbsp;erectus'' and ''H.&nbsp;ergaster'' were the first to use fire and complex tools, and were the first of the hominin line to leave Africa, spreading throughout Africa, Asia, and Europe between {{Mya|1.3|1.8}}.
According to the recent African origin theory, modern humans evolved in Africa possibly from ''[[H.&nbsp;heidelbergensis]]'', ''[[H.&nbsp;rhodesiensis]]'' or ''[[H.&nbsp;antecessor]]'' and migrated out of the continent some 50,000 to 100,000 years ago, gradually replacing local populations of ''H.&nbsp;erectus'', [[Denisova hominin]]s, ''[[H.&nbsp;floresiensis]]'', ''[[H.&nbsp;luzonensis]]'' and ''[[H.&nbsp;neanderthalensis]]'', whose ancestors had left Africa in earlier migrations.{{sfn|Stringer|1994|p=242}}{{sfn|McHenry|2009|p=265}}<ref>{{cite journal |title=Out of Africa Revisited |date=May 13, 2005 |journal=[[Science (journal)|Science]] |type=This Week in ''Science'' |volume=308 |issue=5724 |page=921 |doi=10.1126/science.2005.308.5724.twis |doi-access=free |s2cid=220100436 |issn=0036-8075}}</ref><ref>{{cite journal |last=Stringer |first=Chris |author-link=Chris Stringer |date=June 12, 2003 |title=Human evolution: Out of Ethiopia |journal=[[Nature (journal)|Nature]] |volume=423 |issue=6941 |pages=692–695 |doi=10.1038/423692a |issn=0028-0836 |pmid=12802315 |bibcode=2003Natur.423..692S |s2cid=26693109}}</ref><ref>{{cite web |url= http://www.actionbioscience.org/evolution/johanson.html |title=Origins of Modern Humans: Multiregional or Out of Africa? |last=Johanson |first=Donald |author-link=Donald Johanson |date=May 2001 |website=[[actionbioscience]] |publisher=[[American Institute of Biological Sciences]] |location=Washington, DC |access-date=November 23, 2009 |archive-date=November 14, 2010 |archive-url= https://web.archive.org/web/20101114081543/http://www.actionbioscience.org/evolution/johanson.html}}</ref> [[Archaic humans|Archaic ''Homo sapiens'']], the forerunner of [[anatomically modern humans]], evolved in the [[Middle Paleolithic]] between 400,000 and 250,000 years ago.<ref>{{cite press release |last1=Mixon |first1=Bobbie |last2=Ehardt |first2=Carolyn |last3=Hammer |first3=Michael |date=September 6, 2011 |title=Evolution's Past Is Modern Human's Present |url= https://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=121603&preview=false |publisher=[[National Science Foundation]] |id=Press Release 11-181 |access-date=April 20, 2015 |archive-date=December 17, 2014 |archive-url= https://web.archive.org/web/20141217084326/http://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=121603&preview=false |url-status=live}}</ref><ref>{{cite web |url= http://anthro.palomar.edu/homo2/mod_homo_4.htm |title=Early Modern ''Homo sapiens'' |last=O'Neil |first=Dennis |website=Evolution of Modern Humans: A Survey of the Biological and Cultural Evolution of Archaic and Modern Homo sapiens |publisher=[[Palomar College]] |location=San Marcos, California |type=Tutorial |access-date=April 20, 2015 |archive-date=April 30, 2015 |archive-url= https://web.archive.org/web/20150430142627/http://anthro.palomar.edu/homo2/mod_homo_4.htm}}</ref><ref>{{cite journal |title=Fossil Reanalysis Pushes Back Origin of ''Homo sapiens'' |url= http://www.scientificamerican.com/article/fossil-reanalysis-pushes/ |date=February 17, 2005 |journal=[[Scientific American]] |issn=0036-8733 |access-date=April 20, 2015 |archive-date=January 15, 2016 |archive-url= https://web.archive.org/web/20160115000603/http://www.scientificamerican.com/article/fossil-reanalysis-pushes/ |url-status=live}}</ref> Recent [[DNA]] evidence suggests that several [[haplotype]]s of [[Neanderthal]] origin are present among all non-African populations, and Neanderthals and other hominins, such as Denisovans, may have contributed up to 6% of their [[genome]] to present-day humans, suggestive of a [[Interbreeding between archaic and modern humans|limited interbreeding between these species]].<ref name="pmid21179161">{{cite journal |last1=Reich |first1=David |author1-link=David Reich (geneticist) |last2=Green |first2=Richard E. |last3=Kircher |first3=Martin |last4=Krause |first4=Johannes |last5=Patterson |first5=Nick |last6=Durand |first6=Eric Y. |last7=Viola |first7=Bence |last8=Briggs |first8=Adrian W. |last9=Stenzel |first9=Udo |last10=Johnson |first10=Philip L. F. |last11=Maricic |first11=Tomislav |last12=Good |first12=Jeffrey M. |last13=Marques-Bonet |first13=Tomas |last14=Alkan |first14=Can |last15=Fu |first15=Qiaomei |last16=Mallick |first16=Swapan |last17=Li |first17=Heng |last18=Meyer |first18=Matthias |last19=Eichler |first19=Evan E. |last20=Stoneking |first20=Mark |last21=Richards |first21=Michael |last22=Talamo |first22=Sahra |last23=Shunkov |first23=Michael V. |last24=Derevianko |first24=Anatoli P. |last25=Hublin |first25=Jean-Jacques |last26=Kelso |first26=Janet |last27=Slatkin |first27=Montgomery |last28=Pääbo |first28=Svante |author28-link=Svante Pääbo |display-authors=3 |date=December 23, 2010 |title=Genetic history of an archaic hominin group from Denisova Cave in Siberia |journal=[[Nature (journal)|Nature]] |volume=468 |issue=7327 |pages=1053–1060 |bibcode=2010Natur.468.1053R |doi=10.1038/nature09710 |issn=0028-0836 |pmid=21179161 |pmc=4306417 |hdl=10230/25596}}</ref><ref name="pmid20439435">{{cite journal |last=Noonan |first=James P. |date=May 2010 |title=Neanderthal genomics and the evolution of modern humans |journal=[[Genome Research]] |volume=20 |issue=5 |pages=547–553 |doi=10.1101/gr.076000.108 |issn=1088-9051 |pmc=2860157 |pmid=20439435}}</ref><ref name="10.1126/science.1209202">{{cite journal |last1=Abi-Rached |first1=Laurent |last2=Jobin |first2=Matthew J. |last3=Kulkarni |first3=Subhash |last4=McWhinnie |first4=A. |last5=Dalva |first5=K. |last6=Gragert |first6=L. |last7=Babrzadeh |first7=F. |last8=Gharizadeh |first8=B. |last9=Luo |first9=M. |last10=Plummer |first10=F. A. |last11=Kimani |first11=J. |last12=Carrington |first12=M. |last13=Middleton |first13=D. |last14=Rajalingam |first14=R. |last15=Beksac |first15=M. |last16=Marsh |first16=S. G. E. |last17=Maiers |first17=M. |last18=Guethlein |first18=L. A. |last19=Tavoularis |first19=S. |last20=Little |first20=A.-M. |last21=Green |first21=R. E. |last22=Norman |first22=P. J. |last23=Parham |first23=P. |display-authors=3 |date=October 7, 2011 |title=The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans |journal=[[Science (journal)|Science]] |volume=334 |issue=6052 |pages=89–94 |bibcode=2011Sci...334...89A |doi=10.1126/science.1209202 |issn=0036-8075 |pmc=3677943 |pmid=21868630}}</ref> According to some anthropologists, the transition to [[behavioral modernity]] with the development of symbolic culture, language, and specialized [[lithic technology]] happened around 50,000 years ago (beginning of the [[Upper Paleolithic]]),<ref>{{cite journal |last=Mellars |author-link=Paul Mellars |first=Paul |date=June 20, 2006 |title=Why did modern human populations disperse from Africa ca. 60,000 years ago? A new model |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=103 |issue=25 |pages=9381–9386 |bibcode=2006PNAS..103.9381M |doi=10.1073/pnas.0510792103 |issn=0027-8424 |pmc=1480416 |pmid=16772383 |doi-access=free}}</ref> although others point to evidence of a gradual change over a longer time span during the Middle Paleolithic.<ref name="Mcbrearty_Brooks">{{cite journal |last1=McBrearty |first1=Sally |last2=Brooks |first2=Alison S. |date=November 2000 |title=The revolution that wasn't: A new interpretation of the origin of modern human behavior |journal=[[Journal of Human Evolution]] |volume=39 |issue=5 |pages=453–563 |doi=10.1006/jhev.2000.0435 |issn=0047-2484 |pmid=11102266 |bibcode=2000JHumE..39..453M |s2cid=42968840}}</ref>[[File:Homo-Stammbaum, Version Stringer-en.svg|thumb|left|upright=1.35|A model of the phylogeny of ''H. sapiens'' during the [[Middle Paleolithic]]. The horizontal axis represents geographic location; the vertical axis represents time in [[Year#Abbreviations yr and ya|millions of years ago]] (Mya).<ref>based on
{{cite journal |doi=10.1126/science.aao6266 |pmid=28971970 |volume=358 |title=Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago |date=2017 |journal=[[Science (journal)|Science]] |pages=652–655 |last1=Schlebusch |first1=C. M. |last2=Malmström |first2=H. |last3=Günther |first3=T. |last4=Sjödin |first4=P. |last5=Coutinho |first5=A. |last6=Edlund |first6=H. |last7=Munters |first7=A. R. |last8=Vicente |first8=M. |last9=Steyn |first9=M. |last10=Soodyall |first10=H. |last11=Lombard |first11=M. |last12=Jakobsson |first12=M. |issue=6363 |bibcode=2017Sci...358..652S |s2cid=206663925 |doi-access=free}}, [https://d2ufo47lrtsv5s.cloudfront.net/content/sci/early/2017/09/27/science.aao6266/F3.large.jpg Fig. 3] {{Webarchive|url= https://web.archive.org/web/20180114130711/https://d2ufo47lrtsv5s.cloudfront.net/content/sci/early/2017/09/27/science.aao6266/F3.large.jpg |date=January 14, 2018}} (''H.&nbsp;sapiens'' divergence times) and
{{cite journal |last=Stringer |first=C. |title=What makes a modern human |journal=[[Nature (journal)|Nature]] |date=2012 |volume=485 |issue=7396 |pages=33–35 |doi=10.1038/485033a |pmid=22552077 |bibcode=2012Natur.485...33S |s2cid=4420496 |doi-access=free}} (archaic admixture).</ref>
''Homo Erectus'' is shown spreading across Eurasia starting around 1.8 Mya. ''Homo heidelbergensis'' is shown diverging into Neanderthals, Denisovans and ''H.&nbsp;sapiens''. With the expansion of ''H.&nbsp;sapiens'' after 0.2 Mya, Neanderthals, Denisovans and unspecified archaic African hominins are shown as [[Interbreeding between archaic and modern humans|again subsumed]] into the ''H.&nbsp;sapiens'' lineage. Admixture events in modern African populations are also indicated.]]

''Homo sapiens'' is the only [[extant species]] of its genus, ''Homo''. While some (extinct) ''Homo'' species might have been ancestors of ''Homo sapiens'', many, perhaps most, were likely "cousins", having [[speciate]]d away from the ancestral hominin line.<ref>{{cite journal |last1=Strait |first1=David S. |last2=Grine |first2=Frederick E. |author2-link=Frederick E. Grine |last3=Moniz |first3=Marc A. |date=January 1997 |title=A reappraisal of early hominid phylogeny |journal=Journal of Human Evolution |volume=32 |issue=1 |pages=17–82 |doi=10.1006/jhev.1996.0097 |issn=0047-2484 |pmid=9034954 |bibcode=1997JHumE..32...17S |s2cid=37754799}}</ref>{{sfn|Bryson|2004|pp=522–543}} There is yet no consensus as to which of these groups should be considered a separate species and which should be subspecies; this may be due to the dearth of fossils or to the slight differences used to classify species in the genus ''Homo''.{{sfn|Bryson|2004|pp=522–543}} The [[Sahara pump theory]] (describing an occasionally passable [[Wet Sahara|"wet" Sahara]] desert) provides one possible explanation of the intermittent migration and speciation in the genus ''Homo''.

Based on archaeological and paleontological evidence, it has been possible to infer, to some extent, the ancient dietary practices<ref name="NYT-20150813" /> of various ''Homo'' species and to study the role of diet in physical and behavioral evolution within ''Homo''.<ref name="Leonard_2007" />{{sfn|Walker|2007|pp=[https://books.google.com/books?id=6mxZ1hNBHgkC&pg=PA3 3–10]}}{{sfn|Ungar|Teaford|2002}}{{sfn|Bogin|1997|pp=[https://web.archive.org/web/20031203003838/http://citd.scar.utoronto.ca/ANTAO1/Projects/Bogin.html 96–142]}}<ref>{{cite journal |last=Barnicot |first=Nigel A. |date=April–June 2005 |title=Human nutrition: Evolutionary perspectives |journal=Integrative Physiological & Behavioral Science |volume=40 |issue=2 |pages=114–117 |doi=10.1007/BF02734246 |issn=1932-4502 |pmid=17393680 |s2cid=39549910}}</ref>

Some anthropologists and archaeologists subscribe to the [[Toba catastrophe theory]], which posits that the [[supereruption]] of [[Lake Toba]] on Sumatra in Indonesia some 70,000 years ago caused global starvation,<ref>{{cite news |title=The new batch – 150,000 years ago |url= http://www.bbc.co.uk/sn/prehistoric_life/human/human_evolution/new_batch1.shtml |work=The evolution of man |location=London |publisher=BBC Science & Nature |archive-url= https://web.archive.org/web/20060118155703/http://www.bbc.co.uk/sn/prehistoric_life/human/human_evolution/new_batch1.shtml |archive-date=January 18, 2006 |access-date=April 28, 2015}}</ref> killing the majority of humans and creating a [[population bottleneck]] that affected the genetic inheritance of all humans today.<ref>{{cite news |last=Whitehouse |first=David |date=June 9, 2003 |title=When humans faced extinction |url= http://news.bbc.co.uk/2/hi/science/nature/2975862.stm |work=BBC News |location=London |publisher=BBC |access-date=January 5, 2007 |archive-date=September 4, 2010 |archive-url= https://web.archive.org/web/20100904071921/http://news.bbc.co.uk/2/hi/science/nature/2975862.stm |url-status=live}}</ref> The genetic and archaeological evidence for this remains in question however.<ref>{{Cite web |url= https://www.sciencedaily.com/releases/2018/03/180312132956.htm |title=Modern humans flourished through ancient supervolcano eruption 74,000 years ago: Modern humans flourished through ancient supervolcano eruption |website=ScienceDaily |access-date=January 24, 2019 |archive-date=January 24, 2019 |archive-url= https://web.archive.org/web/20190124152235/https://www.sciencedaily.com/releases/2018/03/180312132956.htm |url-status=live}}</ref> A 2023 genetic study suggests that a similar human [[population bottleneck]] of between 1,000 and 100,000 survivors occurred "around 930,000 and 813,000 years ago ... lasted for about 117,000 years and brought human ancestors close to extinction."<ref name="NYT-20230831">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Humanity's Ancestors Nearly Died Out, Genetic Study Suggests - The population crashed following climate change about 930,000 years ago, scientists concluded. Other experts aren't convinced by the analysis. |url= https://www.nytimes.com/2023/08/31/science/human-survival-bottleneck.html |date=August 31, 2023 |work=[[the New York Times]] |archive-url= https://archive.today/20230831182259/https://www.nytimes.com/2023/08/31/science/human-survival-bottleneck.html |archive-date=August 31, 2023 |access-date=September 2, 2023}}</ref><ref name="SCI-20230831">{{cite journal |last=Hu |first=Wangjie |display-authors=etal |title=Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition |url= http://www.science.org/doi/10.1126/science.abq7487 |date=August 31, 2023 |journal=[[Science (journal)|Science]] |volume=381 |issue=6661 |pages=979–984 |doi=10.1126/science.abq7487 |pmid=37651513 |bibcode=2023Sci...381..979H |s2cid=261396309 |archive-url= https://archive.today/20230901024052/https://www.science.org/doi/10.1126/science.abq7487 |archive-date=September 1, 2023 |access-date=September 2, 2023}}</ref>

=== ''H. habilis'' and ''H. gautengensis'' ===
''Homo habilis'' lived from about 2.8<ref name="autogenerated1" /> to 1.4 Ma. The species evolved in South and East Africa in the [[Piacenzian|Late Pliocene]] or [[Early Pleistocene]], 2.5–2 Ma, when it diverged from the australopithecines with the development of smaller molars and larger brains. One of the first known hominins, it made [[stone tool|tools from stone]] and perhaps animal bones, leading to its name ''homo'' ''habilis'' (Latin 'handy man') bestowed by discoverer [[Louis Leakey]]. Some scientists have proposed moving this species from ''Homo'' into ''Australopithecus'' due to the morphology of its skeleton being more adapted to [[Arboreal locomotion|living in trees]] rather than [[Bipedalism|walking on two legs]] like later hominins.<ref>{{cite journal |last1=Wood |first1=Bernard |last2=Collard |first2=Mark |date=1999 |title=The changing face of Genus ''Homo'' |journal=Evolutionary Anthropology: Issues, News, and Reviews |volume=8 |issue=6 |pages=195–207 |doi=10.1002/(SICI)1520-6505(1999)8:6<195::AID-EVAN1>3.0.CO;2-2 |s2cid=86768101 |issn=1060-1538}}</ref>

In May 2010, a new species, ''[[Homo gautengensis]]'', was discovered in South Africa.<ref name="toothy">{{cite news |last=Viegas |first=Jennifer |date=May 21, 2010 |title=Toothy Tree-Swinger May Be Earliest Human |url= http://news.discovery.com/human/evolution/human-ancestor-tree-swinger.htm |work=[[Discovery Channel|Discovery News]] |location=Silver Spring, Maryland |publisher=[[Discovery Communications]] |access-date=April 28, 2015 |archive-date=May 9, 2015 |archive-url= https://web.archive.org/web/20150509101320/http://news.discovery.com/human/evolution/human-ancestor-tree-swinger.htm}}</ref>

=== ''H. rudolfensis'' and ''H. georgicus'' ===
These are proposed species names for fossils from about 1.9–1.6 Ma, whose relation to ''Homo habilis'' is not yet clear.
* ''Homo rudolfensis'' refers to a single, incomplete skull from Kenya. Scientists have suggested that this was a specimen of ''Homo habilis'', but this has not been confirmed.<ref>{{cite journal |last=Wood |first=Bernard A. |date=January 1999 |title=''Homo rudolfensis'' Alexeev, 1986 – fact or phantom? |journal=Journal of Human Evolution |volume=36 |issue=1 |pages=115–118 |doi=10.1006/jhev.1998.0246 |issn=0047-2484 |pmid=9924136 |bibcode=1999JHumE..36..115W}}</ref>
* ''[[Homo georgicus]]'', from [[Georgia (country)|Georgia]], may be an intermediate form between ''Homo habilis'' and ''Homo erectus'',<ref>{{cite journal |last1=Gabounia |first1=Léo |last2=de Lumley |first2=Marie-Antoinette |last3=Vekua |first3=Abesalom |last4=Lordkipanidze |first4=David |last5=de Lumley |first5=Henry |date=September 2002 |title=Découverte d'un nouvel hominidé à Dmanissi (Transcaucasie, Géorgie) |trans-title=Discovery of a new hominid at Dmanisi (Transcaucasia, Georgia) |journal=Comptes Rendus Palevol |language=fr |volume=1 |issue=4 |pages=243–253 |doi=10.1016/S1631-0683(02)00032-5 |bibcode=2002CRPal...1..243G |issn=1631-0683 |display-authors=3}}</ref> or a subspecies of ''Homo erectus''.<ref>{{cite journal |last1=Lordkipanidze |first1=David |author1-link=David Lordkipanidze |last2=Vekua |first2=Abesalom |last3=Ferring |first3=Reid |last4=Rightmire |first4=G. Philip |last5=Zollikofer |first5=Christoph P. E. |last6=Ponce de León |first6=Marcia S. |last7=Agusti |first7=Jordi |last8=Kiladze |first8=Gocha |last9=Mouskhelishvili |first9=Alexander |last10=Nioradze |first10=Medea |last11=Tappen |first11=Martha |date=November 2006 |title=A fourth hominin skull from Dmanisi, Georgia |journal=The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology |volume=288A |issue=11 |pages=1146–1157 |doi=10.1002/ar.a.20379 |issn=1552-4884 |pmid=17031841 |display-authors=3 |doi-access=free}}</ref>

=== ''H. ergaster'' and ''H. erectus'' ===
[[File:Homo-erectus Turkana-Boy (Ausschnitt) Fundort Nariokotome, Kenia, Rekonstruktion im Neanderthal Museum.jpg|thumb|right|230px|Reconstruction of [[Turkana Boy]] who lived 1.5 to 1.6 million years ago]]
The first fossils of ''Homo erectus'' were discovered by Dutch physician [[Eugene Dubois]] in 1891 on the Indonesian island of Java. He originally named the material ''[[Anthropopithecus]] erectus'' (1892–1893, considered at this point as a chimpanzee-like fossil primate) and ''[[Pithecanthropus]] erectus'' (1893–1894, changing his mind as of based on its morphology, which he considered to be intermediate between that of humans and apes).<ref>{{cite journal |last=Turner |first=William |author-link=William Turner Thiselton-Dyer |date=April 1895 |title=On M. Dubois' Description of Remains recently found in Java, named by him ''Pithecanthropus erectus''. With Remarks on so-called Transitional Forms between Apes and Man |journal=Journal of Anatomy and Physiology |volume=29 |issue=Pt 3 |pages=424–445 |pmc=1328414 |pmid=17232143}}</ref> Years later, in the 20th century, the German physician and [[paleoanthropologist]] [[Franz Weidenreich]] (1873–1948) compared in detail the characters of Dubois' [[Java Man]], then named ''Pithecanthropus erectus'', with the characters of the [[Peking Man]], then named ''Sinanthropus pekinensis''. Weidenreich concluded in 1940 that because of their anatomical similarity with modern humans it was necessary to gather all these specimens of Java and China in a single species of the genus ''Homo'', the species ''H.&nbsp;erectus''.<ref>{{Cite journal |last=Weidenreich |first=Franz |date=July 1940 |title=Some Problems Dealing with Ancient Man |journal=American Anthropologist |volume=42 |issue=3 |pages=375–383 |doi=10.1525/aa.1940.42.3.02a00010 |issn=0002-7294 |doi-access=free}}</ref><ref>{{Citation |last1=Grine |first1=Frederick E. |date=2009 |pages=197–207 |publisher=Springer Netherlands |isbn=978-1-4020-9979-3 |last2=Fleagle |first2=John G. |title=The First Humans – Origin and Early Evolution of the Genus ''Homo'' |chapter=The First Humans: A Summary Perspective on the Origin and Early Evolution of the Genus ''Homo'' |series="Vertebrate Paleobiology and Paleoanthropology" series |doi=10.1007/978-1-4020-9980-9_17}}</ref>

''Homo erectus'' lived from about 1.8 Ma to about 70,000 years ago – which would indicate that they were probably wiped out by the Toba catastrophe; however, nearby ''[[H.&nbsp;floresiensis]]'' survived it. The early phase of ''H.&nbsp;erectus'', from 1.8 to 1.25 Ma, is considered by some to be a separate species, ''H.&nbsp;ergaster'', or as ''H.&nbsp;erectus ergaster'', a subspecies of ''H.&nbsp;erectus''. Many paleoanthropologists now use the term ''Homo ergaster'' for the non-Asian forms of this group, and reserve ''H.&nbsp;erectus'' only for those fossils that are found in Asia and meet certain skeletal and dental requirements which differ slightly from ''H.&nbsp;ergaster''.

In Africa in the Early Pleistocene, 1.5–1 Ma, some populations of ''Homo habilis'' are thought to have evolved larger brains and to have made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, ''Homo erectus''—in Africa.<ref>{{cite journal |last1=Spoor |first1=Fred |last2=Wood |first2=Bernard A. |last3=Zonneveld |first3=Frans |date=June 23, 1994 |title=Implications of early hominid labyrinthine morphology for evolution of human bipedal locomotion |journal=[[Nature (journal)|Nature]] |volume=369 |issue=6482 |pages=645–648 |bibcode=1994Natur.369..645S |doi=10.1038/369645a0 |issn=0028-0836 |pmid=8208290 |s2cid=4344784}}</ref> This species also may have used fire to cook meat. [[Catching Fire: How Cooking Made Us Human|Richard Wrangham]]  notes that ''Homo'' seems to have been ground dwelling, with reduced intestinal length, smaller dentition, and "brains [swollen] to their current, horrendously fuel-inefficient size",<ref>{{Cite news |last=Ings |first=Simon |url= https://www.telegraph.co.uk/culture/books/6250132/Catching-Fire-How-Cooking-Made-Us-Human-by-Richard-Wrangham-review.html |archive-url= https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/culture/books/6250132/Catching-Fire-How-Cooking-Made-Us-Human-by-Richard-Wrangham-review.html |archive-date=January 11, 2022 |url-access=subscription |url-status=live |title=''Catching Fire: How Cooking Made Us Human'' by Richard Wrangham: Review |access-date=February 23, 2016 |date=October 4, 2009}}{{cbignore}}</ref> and hypothesizes that control of fire and cooking, which released increased nutritional value, was the key adaptation that separated ''Homo'' from tree-sleeping Australopithecines.<ref>{{cite book |last=Wrangham |first=Richard |date=2011 |title=Catching Fire: How cooking made us human}}{{page needed|date=December 2021}}</ref>
{{See also|Control of fire by early humans}}

=== ''H. cepranensis'' and ''H. antecessor'' ===
These are proposed as species intermediate between ''H.&nbsp;erectus'' and ''H.&nbsp;heidelbergensis''.
* ''H. antecessor'' is known from fossils from Spain and England that are dated 1.2 Ma–500 [[Year#SI prefix multipliers|ka]].<ref>{{cite journal |last1=Bermúdez de Castro |first1=José María |last2=Arsuaga |first2=Juan Luis |author2-link=Juan Luis Arsuaga |last3=Carbonell |first3=Eudald |author3-link=Eudald Carbonell |last4=Rosas |first4=Antonio |last5=Martínez |first5=I. |last6=Mosquera |first6=Marina |date=May 30, 1997 |title=A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans |journal=[[Science (journal)|Science]] |volume=276 |issue=5317 |pages=1392–1395 |doi=10.1126/science.276.5317.1392 |issn=0036-8075 |pmid=9162001 |display-authors=3}}</ref><ref>{{cite journal |last1=Carbonell |first1=Eudald |last2=Bermúdez de Castro |first2=José María |last3=Parés |first3=Josep M. |last4=Pérez-González |first4=A. |last5=Cuenca-Bescós |first5=G. |last6=Ollé |first6=A. |last7=Mosquera |first7=M. |last8=Huguet |first8=R. |last9=Van Der Made |first9=J. |last10=Rosas |first10=A. |last11=Sala |first11=R. |last12=Vallverdú |first12=J. |last13=García |first13=N. |last14=Granger |first14=D. E. |last15=Martinón-Torres |first15=M. |last16=Rodríguez |first16=X. P. |last17=Stock |first17=G. M. |last18=Vergès |first18=J. M. |last19=Allué |first19=E. |last20=Burjachs |first20=F. |last21=Cáceres |first21=I. |last22=Canals |first22=A. |last23=Benito |first23=A. |last24=Díez |first24=C. |last25=Lozano |first25=M. |last26=Mateos |first26=A. |last27=Navazo |first27=M. |last28=Rodríguez |first28=J. |last29=Rosell |first29=J. |last30=Arsuaga |first30=J. L. |date=March 27, 2008 |title=The first hominin of Europe |journal=[[Nature (journal)|Nature]] |volume=452 |issue=7186 |pages=465–469 |bibcode=2008Natur.452..465C |doi=10.1038/nature06815 |issn=0028-0836 |pmid=18368116 |display-authors=3 |hdl=2027.42/62855 |s2cid=4401629 |hdl-access=free}}</ref>
* ''[[Homo cepranensis|H. cepranensis]]'' refers to a single skull cap from Italy, estimated to be about 800,000 years old.<ref>{{cite journal |last1=Manzi |first1=Giorgio |last2=Mallegni |first2=Francesco |author2-link=Francesco Mallegni |last3=Ascenzi |first3=Antonio |date=August 14, 2001 |title=A cranium for the earliest Europeans: Phylogenetic position of the hominid from Ceprano, Italy |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=98 |issue=17 |pages=10011–10016 |bibcode=2001PNAS...9810011M |doi=10.1073/pnas.151259998 |issn=0027-8424 |pmc=55569 |pmid=11504953 |doi-access=free}}</ref>

=== ''H. heidelbergensis'' ===
{{Main|Homo heidelbergensis}}
''H. heidelbergensis'' ("Heidelberg Man") lived from about 800,000 to about 300,000 years ago. Also proposed as ''Homo sapiens heidelbergensis'' or ''Homo sapiens paleohungaricus''.<ref>{{cite journal |last1=Czarnetzki |first1=Alfred |last2=Jakob |first2=Tina |last3=Pusch |first3=Carsten M. |date=April 2003 |title=Palaeopathological and variant conditions of the ''Homo heidelbergensis'' type specimen (Mauer, Germany) |journal=Journal of Human Evolution |volume=44 |issue=4 |pages=479–495 |doi=10.1016/S0047-2484(03)00029-0 |issn=0047-2484 |pmid=12727464 |bibcode=2003JHumE..44..479C}}</ref>

=== ''H. rhodesiensis'', and the Gawis cranium ===
* ''H. rhodesiensis'', estimated to be 300,000–125,000 years old. Most current researchers place Rhodesian Man within the group of ''Homo heidelbergensis'', though other designations such as archaic ''Homo sapiens'' and ''Homo sapiens rhodesiensis'' have been proposed.
* In February 2006 a fossil, the [[Gawis cranium]], was found which might possibly be a species intermediate between ''H.&nbsp;erectus'' and ''H.&nbsp;sapiens'' or one of many evolutionary dead ends. The skull from Gawis, Ethiopia, is believed to be 500,000–250,000 years old. Only summary details are known, and the finders have not yet released a peer-reviewed study. Gawis man's facial features suggest that it is either an intermediate species or an example of a "Bodo man" female.<ref>{{cite press release |last1=Semaw |first1=Sileshi |last2=Toth |first2=Nicholas |last3=Schick |first3=Kathy |last4=Simpson |first4=Scott |last5=Quade |first5=Jay |last6=Rogers |first6=Michael J. |date=March 27, 2006 |title=Scientists discover hominid cranium in Ethiopia |url= http://newsinfo.iu.edu/news/page/normal/3142.html |location=Bloomington |publisher=[[Indiana University]] |access-date=November 26, 2006 |display-authors=3 |archive-date=November 15, 2006 |archive-url= https://web.archive.org/web/20061115161617/http://newsinfo.iu.edu/news/page/normal/3142.html |url-status=live}}</ref>

=== Neanderthal and Denisovan ===
{{Main|Neanderthal|Denisovan}}
[[File:Homo sapiens neanderthalensis-Mr. N.jpg|thumb|upright|Reconstruction of an elderly Neanderthal man]]
''Homo neanderthalensis'', alternatively designated as ''Homo sapiens neanderthalensis'',<ref>{{cite journal |last=Harvati |first=Katerina |date=January 2003 |title=The Neanderthal taxonomic position: Models of intra- and inter-specific craniofacial variation |journal=Journal of Human Evolution |volume=44 |issue=1 |pages=107–132 |doi=10.1016/S0047-2484(02)00208-7 |issn=0047-2484 |pmid=12604307 |bibcode=2003JHumE..44..107H}}</ref> lived in Europe and Asia from 400,000<ref>{{Cite journal |last1=Herrera |first1=K. J. |last2=Somarelli |first2=J. A. |last3=Lowery |first3=R. K. |last4=Herrera |first4=R. J. |title=To what extent did Neanderthals and modern humans interact? |date=2009 |journal=Biological Reviews |volume=84 |issue=2 |pages=245–257 |doi=10.1111/j.1469-185X.2008.00071.x |pmid=19391204 |s2cid=25787484}}</ref> to about 28,000 years ago.<ref>{{cite journal |doi=10.1038/nature05195 |pmid=16971951 |title=Late survival of Neanderthals at the southernmost extreme of Europe |journal=[[Nature (journal)|Nature]] |volume=443 |issue=7113 |pages=850–853 |date=2006 |last1=Finlayson |first1=C. |last2=Giles Pacheco |first2=F. |last3=Rodríguez-Vidal |first3=J. |last4=Fa |first4=D. A. |last5=Gutiérrez López |first5=J. M. |last6=Santiago Pérez |first6=A. |last7=Finlayson |first7=G. |last8=Allué |first8=E. |last9=Baena Preysler |first9=J. |last10=Cáceres |first10=I. |last11=Carrión |first11=J. S. |last12=Fernández-Jalvo |first12=Y. |last13=Gleed-Owen |first13=C. P. |last14=Jiménez-Espejo |first14=F. J. |last15=López Martínez |first15=P. |last16=López Sáez |first16=J. A. |last17=Riquelme Cantal |first17=J. A. |last18=Sánchez Marco |first18=A. |last19=Giles Guzmán |first19=F. |last20=Brown |first20=K. |last21=Fuentes |first21=N. |last22=Valarino |first22=C. A. |last23=Villalpando |first23=A. |last24=Stringer |first24=C. B. |last25=Martínez Ruíz |first25=F. C. |last26=Sakamoto |first26=T. |display-authors=3 |bibcode=2006Natur.443..850F |hdl=10261/18685 |s2cid=4411186}}{{collapsible list |title=Full list of authors |bullets=true |Clive Finlayson |Francisco Giles Pacheco |Joaquín Rodríguez-Vidal |Darren A. Fa |José María Gutierrez López |Antonio Santiago Pérez |Geraldine Finlayson |Ethel Allue |Javier Baena Preysler |Isabel Cáceres |José S. Carrión |Yolanda Fernández-Jalvo |Christopher P. Gleed-Owen |Francisco J. Jimenez-Espejo |Pilar López Martínez |José Antonio López Sáez |José Antonio Riquelme Cantal |Antonio Sánchez Marco |Francisco Giles Guzman |Kimberly Brown |Noemí Fuentes |Claire A. Valarino |Antonio Villalpando |Christopher B. Stringer |Francisca Martinez Ruiz |Tatsuhiko Sakamoto}}</ref>
There are a number of clear anatomical differences between [[anatomically modern humans]] (AMH) and Neanderthal specimens, many relating to the superior Neanderthal adaptation to cold environments. Neanderthal [[surface to volume ratio]] was even lower than that among modern [[Inuit]] populations, indicating superior retention of body heat.

Neanderthals also had significantly larger brains, as shown from brain endocasts, casting doubt on their intellectual inferiority to modern humans. However, the higher body mass of Neanderthals may have required larger brain mass for body control.<ref name="dunbar">{{Cite journal |last1=Pearce |first1=Eiluned |last2=Stringer |first2=Chris |last3=Dunbar |first3=R. I. M. |date=2013 |title=New insights into differences in brain organization between Neanderthals and anatomically modern humans |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=280 |issue=1758 |page=20130168 |doi=10.1098/rspb.2013.0168 |pmc=3619466 |pmid=23486442}}</ref> Also, recent research by Pearce, [[Chris Stringer|Stringer]], and Dunbar has shown important differences in brain architecture. The larger size of the Neanderthal orbital chamber and [[occipital lobe]] suggests that they had a better visual acuity than modern humans, useful in the dimmer light of glacial Europe.

Neanderthals may have had less [[Dunbar's number|brain capacity available for social functions]]. Inferring social group size from endocranial volume (minus occipital lobe size) suggests that Neanderthal groups may have been limited to 120 individuals, compared to 144{{cn|date=January 2024}}<ref>{{Cite journal |last1=Bocquet-Appel |first1=Jean-Pierre |last2=Degioanni |first2=Anna |date=December 2013 |title=Neanderthal Demographic Estimates |url= https://www.journals.uchicago.edu/doi/full/10.1086/673725# |journal=The University of Chicago Press Journals |volume=54 |issue=S8 |pages=S202–S213 |doi=10.1086/673725|url-access=subscription }}</ref> possible relationships for modern humans. Larger social groups could imply that modern humans had less risk of inbreeding within their clan, trade over larger areas (confirmed in the distribution of stone tools), and faster spread of social and technological innovations. All these may have all contributed to modern ''Homo sapiens'' replacing Neanderthal populations by 28,000 BP.<ref name="dunbar" />

Earlier evidence from sequencing mitochondrial DNA suggested that no significant gene flow occurred between ''H. neanderthalensis'' and ''H. sapiens'', and that the two were separate species that shared a common ancestor about 660,000 years ago.<ref>{{cite journal |last1=Krings |first1=Matthias |last2=Stone |first2=Anne |last3=Schmitz |first3=Ralf W. |last4=Krainitzki |first4=Heike |last5=Stoneking |first5=Mark |last6=Pääbo |first6=Svante |date=July 11, 1997 |title=Neandertal DNA sequences and the origin of modern humans |journal=[[Cell (journal)|Cell]] |volume=90 |issue=1 |pages=19–30 |doi=10.1016/S0092-8674(00)80310-4 |issn=0092-8674 |pmid=9230299 |hdl=11858/00-001M-0000-0025-0960-8 |s2cid=13581775 |display-authors=3 |hdl-access=free}}</ref><ref>{{cite journal |last1=Green |first1=Richard E. |last2=Malaspinas |first2=Anna-Sapfo |last3=Krause |first3=Johannes |last4=Briggs |first4=Adrian W. |last5=Johnson |first5=Philip L.F. |last6=Uhler |first6=Caroline |last7=Meyer |first7=Matthias |last8=Good |first8=Jeffrey M. |last9=Maricic |first9=Tomislav |last10=Stenzel |first10=Udo |last11=Prüfer |first11=Kay |last12=Siebauer |first12=Michael |last13=Burbano |first13=Hernán A. |last14=Ronan |first14=Michael |last15=Rothberg |first15=Jonathan M. |last16=Egholm |first16=Michael |last17=Rudan |first17=Pavao |last18=Brajković |first18=Dejana |last19=Kućan |first19=Željko |last20=Gušić |first20=Ivan |last21=Wikström |first21=Mårten |last22=Laakkonen |first22=Liisa |last23=Kelso |first23=Janet |last24=Slatkin |first24=Montgomery |last25=Pääbo |first25=Svante |date=August 8, 2008 |title=A Complete Neandertal Mitochondrial Genome Sequence Determined by High-Throughput Sequencing |journal=Cell |volume=134 |issue=3 |pages=416–426 |doi=10.1016/j.cell.2008.06.021 |issn=0092-8674 |pmc=2602844 |pmid=18692465 |display-authors=3}}</ref><ref>{{cite journal |last1=Serre |first1=David |last2=Langaney |first2=André |last3=Chech |first3=Mario |last4=Teschler-Nicola |last5=Paunovic |last6=Mennecier |last7=Hofreiter |last8=Possnert |last9=Pääbo |date=March 2004 |title=No Evidence of Neandertal mtDNA Contribution to Early Modern Humans |journal=PLOS Biology |volume=2 |issue=3 |page=e57 |doi=10.1371/journal.pbio.0020057 |issn=1545-7885 |pmc=368159 |pmid=15024415 |display-authors=3 |doi-access=free}}</ref> However, a sequencing of the Neanderthal genome in 2010 indicated that Neanderthals did indeed interbreed with anatomically modern humans c. 45,000-80,000 years ago, around the time modern humans migrated out from Africa, but before they dispersed throughout Europe, Asia and elsewhere.<ref name="neandersequence">{{cite news |last=Viegas |first=Jennifer |date=May 6, 2010 |title=Neanderthals, Humans Interbred, DNA Proves |url= http://news.discovery.com/human/evolution/neanderthal-human-interbreed-dna.htm |work=Discovery News |location=Silver Spring, Maryland |publisher=[[Discovery Communications]] |access-date=April 30, 2015 |archive-url= https://web.archive.org/web/20150508221757/http://news.discovery.com/human/evolution/neanderthal-human-interbreed-dna.htm |archive-date=May 8, 2015}}</ref> The genetic sequencing of a 40,000-year-old [[Peștera cu Oase|human skeleton from Romania]] showed that 11% of its genome was Neanderthal, implying the individual had a Neanderthal ancestor 4–6 generations previously,<ref>{{cite journal |last=Calloway |first=Ewan |title=Early European may have had Neanderthal great-great-grandparent |journal=[[Nature (journal)|Nature]] |date=May 13, 2015 |url= https://www.nature.com/news/early-european-may-have-had-neanderthal-great-great-grandparent-1.17534 |doi=10.1038/nature.2015.17534 |s2cid=181973496 |access-date=January 23, 2019 |archive-date=January 15, 2019 |archive-url= https://web.archive.org/web/20190115110342/http://www.nature.com/news/early-european-may-have-had-neanderthal-great-great-grandparent-1.17534 |url-status=live|url-access=subscription }}</ref> in addition to a contribution from earlier interbreeding in the Middle East. Though this interbred Romanian population seems not to have been ancestral to modern humans, the finding indicates that interbreeding happened repeatedly.<ref>{{cite news |last=Sample |first=Ian |title=My Neanderthal sex secret: Modern European's great-great grandparent link |newspaper=[[The Guardian]] |date=June 22, 2015 |access-date=July 27, 2018 |url= https://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link |archive-date=September 23, 2016 |archive-url= https://web.archive.org/web/20160923235758/https://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link |url-status=live}}</ref>

All modern non-African humans have about 1% to 4% (or 1.5% to 2.6% by more recent data) of their DNA derived from Neanderthals.<ref name="greenetal" /><ref name="neandersequence" /><ref name="A high-coverage Neandertal genome f" /> This finding is consistent with recent studies indicating that the divergence of some human alleles dates to one Ma, although this interpretation has been questioned.<ref>{{cite journal |last1=Gutiérrez |first1=Gabriel |last2=Sánchez |first2=Diego |last3=Marín |first3=Antonio |date=August 2002 |title=A Reanalysis of the Ancient Mitochondrial DNA Sequences Recovered from Neandertal Bones |journal=Molecular Biology and Evolution |volume=19 |issue=8 |pages=1359–1366 |doi=10.1093/oxfordjournals.molbev.a004197 |issn=0737-4038 |pmid=12140248 |doi-access=free}}</ref><ref>{{cite journal |last1=Hebsgaard |first1=M. B. |last2=Wiuf |first2=C. |last3=Gilbert |first3=M. T. |last4=Glenner |first4=H. |last5=Willerslev |first5=E. |date=January 2007 |title=Evaluating Neanderthal Genetics and Phylogeny |journal=Journal of Molecular Evolution |volume=64 |issue=1 |pages=50–60 |doi=10.1007/s00239-006-0017-y |issn=0022-2844 |pmid=17146600 |s2cid=2746487 |url= http://www.birc.au.dk/%7Ewiuf/journalWiuf/jMolEvol64.pdf |archive-url= https://wayback.archive-it.org/all/20110401041826/http://www.birc.au.dk/~wiuf/journalWiuf/jMolEvol64.pdf |archive-date=April 1, 2011 |access-date=October 24, 2017 |citeseerx=10.1.1.174.8969 |bibcode=2007JMolE..64...50H}}</ref> Neanderthals and AMH ''Homo sapiens'' could have co-existed in Europe for as long as 10,000 years, during which AMH populations exploded, vastly outnumbering Neanderthals, possibly outcompeting them by sheer numbers.<ref>{{cite journal |last1=Mellars |first1=Paul |last2=French |first2=Jennifer C. |date=July 29, 2011 |title=Tenfold Population Increase in Western Europe at the Neandertal–to–Modern Human Transition Paul |journal=[[Science (journal)|Science]] |volume=333 |issue=6042 |pages=623–627 |bibcode=2011Sci...333..623M |doi=10.1126/science.1206930 |issn=0036-8075 |pmid=21798948 |s2cid=28256970}}</ref>

In 2008, archaeologists working at the site of [[Denisova Cave]] in the [[Altai Mountains]] of [[Siberia]] uncovered a small bone fragment from the fifth finger of a juvenile member of another human species, the Denisovans.<ref>{{cite journal |last=Brown |first=Terence A. |date=April 8, 2010 |title=Human evolution: Stranger from Siberia |journal=[[Nature (journal)|Nature]] |volume=464 |issue=7290 |pages=838–839 |bibcode=2010Natur.464..838B |doi=10.1038/464838a |issn=0028-0836 |pmid=20376137 |s2cid=4320406 |doi-access=free}}</ref> Artifacts, including a bracelet, excavated in the cave at the same level were [[Radiocarbon dating|carbon dated]] to around 40,000 BP. As DNA had survived in the fossil fragment due to the cool climate of the Denisova Cave, both mtDNA and nuclear DNA were sequenced.<ref name="pmid21179161" /><ref name="Pääbo et al.">{{cite journal |last1=Krause |first1=Johannes |author1-link=Johannes Krause |last2=Fu |first2=Qiaomei |last3=Good |first3=Jeffrey M. |last4=Viola |first4=Bence |last5=Shunkov |first5=Michael V. |last6=Derevianko |first6=Anatoli P. |last7=Pääbo |first7=Svante |author7-link=Svante Pääbo |display-authors=3 |date=April 8, 2010 |title=The complete mitochondrial DNA genome of an unknown hominin from southern Siberia |journal=[[Nature (journal)|Nature]] |volume=464 |issue=7290 |pages=894–897 |bibcode=2010Natur.464..894K |doi=10.1038/nature08976 |issn=0028-0836 |pmid=20336068 |pmc=10152974 |s2cid=4415601 |doi-access=free}}</ref>

While the divergence point of the mtDNA was unexpectedly deep in time,<ref name="The Scientist">{{cite news |last=Katsnelson |first=Alla |date=March 24, 2010 |title=New hominin found via mtDNA |url= http://www.the-scientist.com/?articles.view/articleNo/28876/title/New-hominin-found-via-mtDNA/#ixzz0j820ioz1 |work=The Nutshell |type=Blog |location=Philadelphia |publisher=[[The Scientist (magazine)|The Scientist]] |issn=0890-3670 |access-date=May 1, 2015 |archive-date=July 2, 2015 |archive-url= https://web.archive.org/web/20150702154449/http://www.the-scientist.com/?articles.view/articleNo/28876/title/New-hominin-found-via-mtDNA/#ixzz0j820ioz1 |url-status=live}}</ref> the full genomic sequence suggested the Denisovans belonged to the same lineage as Neanderthals, with the two diverging shortly after their line split from the lineage that gave rise to modern humans.<ref name="pmid21179161" /> Modern humans are known to have overlapped with Neanderthals in Europe and the Near East for possibly more than 40,000 years,<ref>"Kaufman, Danial (2002), "Comparisons and the Case for Interaction among Neanderthals and Early Modern Humans in the Levant" (Oxford Journal of Anthropology)</ref> and the discovery raises the possibility that Neanderthals, Denisovans, and modern humans may have co-existed and interbred. The existence of this distant branch creates a much more complex picture of humankind during the [[Late Pleistocene]] than previously thought.<ref name="Pääbo et al." /><ref>{{cite journal |last1=Bokma |first1=Folmer |last2=van den Brink |first2=Valentijn |last3=Stadler |first3=Tanja |date=September 2012 |title=Unexpectedly many extinct hominins |journal=[[Evolution (journal)|Evolution]] |volume=66 |issue=9 |pages=2969–2974 |doi=10.1111/j.1558-5646.2012.01660.x |issn=0014-3820 |pmid=22946817 |s2cid=13145359 |doi-access=free}}</ref> Evidence has also been found that as much as 6% of the DNA of some modern [[Melanesians]] derive from Denisovans, indicating limited interbreeding in Southeast Asia.<ref name="Reich_2011" /><ref>{{cite journal |last1=Martinón-Torres |first1=María |last2=Dennell |first2=Robin |last3=Bermúdez de Castro |first3=José María |date=February 2011 |title=The Denisova hominin need not be an out of Africa story |journal=Journal of Human Evolution |volume=60 |issue=2 |pages=251–255 |doi=10.1016/j.jhevol.2010.10.005 |issn=0047-2484 |pmid=21129766 |bibcode=2011JHumE..60..251M}}</ref>

Alleles thought to have originated in Neanderthals and Denisovans have been identified at several genetic loci in the genomes of modern humans outside Africa. [[Human leukocyte antigen]] (HLA) haplotypes from Denisovans and Neanderthal represent more than half the HLA alleles of modern Eurasians,<ref name="10.1126/science.1209202" /> indicating strong positive selection for these [[introgressed]] alleles. Corinne Simoneti at Vanderbilt University, in Nashville and her team have found from medical records of 28,000 people of European descent that the presence of Neanderthal DNA segments may be associated with a higher rate of depression.<ref>{{Cite journal |doi=10.1126/science.aad2149 |pmid=26912863 |pmc=4849557 |title=The phenotypic legacy of admixture between modern humans and Neandertals |journal=[[Science (journal)|Science]] |volume=351 |issue=6274 |pages=737–741 |date=2016 |last1=Simonti |first1=C. N. |last2=Vernot |first2=B. |last3=Bastarache |first3=L. |last4=Bottinger |first4=E. |last5=Carrell |first5=D. S. |last6=Chisholm |first6=R. L. |last7=Crosslin |first7=D. R. |last8=Hebbring |first8=S. J. |last9=Jarvik |first9=G. P.| last10=Kullo| first10=I. J. |last11=Li |first11=R. |last12=Pathak |first12=J. |last13=Ritchie |first13=M. D. |last14=Roden |first14=D. M. |last15=Verma |first15=S. S. |last16=Tromp |first16=G. |last17=Prato |first17=J. D. |last18=Bush |first18=W. S. |last19=Akey |first19=J. M. |last20=Denny |first20=J. C. |last21=Capra |first21=J. A. |bibcode=2016Sci...351..737S}}</ref>

The flow of genes from Neanderthal populations to modern humans was not all one way. Sergi Castellano of the Max Planck Institute for [[Evolutionary Anthropology]] reported in 2016 that while Denisovan and Neanderthal genomes are more related to each other than they are to us, Siberian Neanderthal genomes show more similarity to modern human genes than do European Neanderthal populations. This suggests Neanderthal populations interbred with modern humans around 100,000 years ago, probably somewhere in the Near East.<ref>{{cite journal |volume=530 |issue=7591 |title=Ancient gene flow from early modern humans into Eastern Neanderthals |journal=[[Nature (journal)|Nature]] |pages=429–433 |pmid=26886800 |pmc=4933530 |last1=Kuhlwilm |first1=M. |last2=Gronau |first2=I. |last3=Hubisz |first3=M. J. |last4=de Filippo |first4=C. |last5=Prado-Martinez |first5=J. |last6=Kircher |first6=M. |last7=Fu |first7=Q. |last8=Burbano |first8=H. A. |last9=Lalueza-Fox |first9=C. |last10=de la Rasilla |first10=M. |last11=Rosas |first11=A. |last12=Rudan |first12=P. |last13=Brajkovic |first13=D. |last14=Kucan |first14=Ž. |last15=Gušic |first15=I. |last16=Marques-Bonet |first16=T. |last17=Andrés |first17=A. M. |last18=Viola |first18=B. |last19=Pääbo |first19=S. |author19-link=Svante Pääbo |last20=Meyer |first20=M. |last21=Siepel |first21=A. |last22=Castellano |first22=S. |doi=10.1038/nature16544 |bibcode=2016Natur.530..429K |date=2016}}</ref>

Studies of a Neanderthal child at Gibraltar show from brain development and tooth eruption that Neanderthal children may have matured more rapidly than ''Homo sapiens''.<ref>Dean, MC, Stringer, CB et al, (1986) "Age at death of the Neanderthal child from Devil's Tower, Gibraltar and the implications for studies of general growth and development in Neanderthals" (American Journal of Physical Anthropology, Vol 70 Issue 3, July 1986)</ref>

=== ''H. floresiensis'' ===
{{Main|Homo floresiensis}}
[[File:Homo floresiensis v 2-0.jpg|thumb|200px|A facial reconstruction of ''Homo floresiensis''|left]]
''H. floresiensis'', which lived from approximately 190,000 to 50,000 years [[before present]] (BP), has been nicknamed the ''[[hobbit]]'' for its small size, possibly a result of [[insular dwarfism]].<ref name=":0">{{cite journal |last1=Brown |first1=P. |last2=Sutikna |first2=T. |last3=Morwood |first3=M. J. |last4=Soejono |first4=R. P. |last5=Jatmiko |first5=A. |last6=Wayhu |first6=S. E. |last7=Awe Due |first7=R. |author3-link=Mike Morwood |author4-link=Raden Panji Soejono |date=October 28, 2004 |title=A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia |journal=[[Nature (journal)|Nature]] |volume=431 |issue=7012 |pages=1055–1061 |bibcode=2004Natur.431.1055B |doi=10.1038/nature02999 |issn=0028-0836 |pmid=15514638 |s2cid=26441 |url= http://doc.rero.ch/record/15287/files/PAL_E2586.pdf |access-date=January 3, 2023 |archive-date=January 3, 2023 |archive-url= https://web.archive.org/web/20230103195019/http://doc.rero.ch/record/15287/files/PAL_E2586.pdf |url-status=live}}</ref> ''H. floresiensis'' is intriguing both for its size and its age, being an example of a recent species of the genus ''Homo'' that exhibits derived traits not shared with modern humans. In other words, ''H. floresiensis'' shares a common ancestor with modern humans, but split from the modern human lineage and followed a distinct evolutionary path. The main find was a skeleton believed to be a woman of about 30 years of age. Found in 2003, it has been dated to approximately 18,000 years old. The living woman was estimated to be one meter in height, with a brain volume of just 380&nbsp;cm<sup>3</sup> (considered small for a chimpanzee and less than a third of the ''H.&nbsp;sapiens'' average of 1400&nbsp;cm<sup>3</sup>).<ref name=":0" />

However, there is an ongoing debate over whether ''H.&nbsp;floresiensis'' is indeed a separate species.<ref name=":1">{{cite journal |last1=Argue |first1=Debbie |last2=Donlon |first2=Denise |last3=Groves |first3=Colin |author3-link=Colin Groves |last4=Wright |first4=Richard |date=October 2006 |title=''Homo floresiensis'': Microcephalic, pygmoid, ''Australopithecus'', or ''Homo''? |journal=Journal of Human Evolution |volume=51 |issue=4 |pages=360–374 |doi=10.1016/j.jhevol.2006.04.013 |issn=0047-2484 |pmid=16919706 |bibcode=2006JHumE..51..360A}}</ref> Some scientists hold that ''H. floresiensis'' was a modern ''H. sapiens'' with pathological dwarfism.<ref name="Martin">{{cite journal |last1=Martin |first1=Robert D. |author1-link=Robert D. Martin |last2=Maclarnon |first2=Ann M. |last3=Phillips |first3=James L. |last4=Dobyns |first4=William B. |date=November 2006 |title=Flores hominid: New species or microcephalic dwarf? |journal=The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology |volume=288A |issue=11 |pages=1123–1145 |doi=10.1002/ar.a.20389 |issn=1552-4884 |pmid=17031806 |doi-access=free}}</ref> This hypothesis is supported in part, because some modern humans who live on [[Flores]], the Indonesian island where the skeleton was found, are [[Pygmy peoples|pygmies]]. This, coupled with pathological dwarfism, could have resulted in a significantly diminutive human. The other major attack on ''H. floresiensis'' as a separate species is that it was found with tools only associated with ''H. sapiens''.<ref name="Martin" />

The hypothesis of pathological dwarfism, however, fails to explain additional [[Homo floresiensis#Anatomy|anatomical features]] that are unlike those of modern humans (diseased or not) but much like those of ancient members of our genus. Aside from cranial features, these features include the form of bones in the wrist, forearm, shoulder, knees, and feet. Additionally, this hypothesis fails to explain the find of multiple examples of individuals with these same characteristics, indicating they were common to a large population, and not limited to one individual.<ref name=":1" />

In 2016, fossil teeth and a partial jaw from hominins assumed to be ancestral to ''H.&nbsp;floresiensis'' were discovered<ref name="Callaway2016b">{{cite journal |last=Callaway |first=E. |title='Hobbit' relatives found after ten-year hunt |journal=[[Nature (journal)|Nature]] |volume=534 |issue=7606 |date=June 8, 2016 |pages=164–165 |doi=10.1038/534164a |pmid=27279191 |bibcode=2016Natur.534Q.164C |doi-access=free}}</ref> at [[Mata Menge]], about {{cvt|74|km}} from Liang Bua. They date to about 700,000 years ago<ref name="Brumm2016">{{cite journal |last1=Brumm |first1=A. |last2=van den Bergh |first2=G. D. |last3=Storey |first3=M. |last4=Kurniawan |first4=I. |last5=Alloway |first5=B. V. |last6=Setiawan |first6=R. |last7=Setiyabudi |first7=E. |last8=Grün |first8=R. |last9=Moore |first9=M. W. |last10=Yurnaldi |first10=D. |last11=Puspaningrum |first11=M. R. |last12=Wibowo |first12=U. P. |last13=Insani |first13=H. |last14=Sutisna |first14=I. |last15=Westgate |first15=J. A. |last16=Pearce |first16=N. J. G. |last17=Duval |first17=M. |last18=Meijer |first18=H. J. M. |last19=Aziz |first19=F. |last20=Sutikna |first20=T. |last21=van der Kaars |first21=S. |last22=Flude |first22=S. |last23=Morwood |first23=M. J. |display-authors=4 |title=Age and context of the oldest known hominin fossils from Flores |journal=[[Nature (journal)|Nature]] |volume=534 |issue=7606 |date=June 8, 2016 |pages=249–253 |pmid=27279222 |doi=10.1038/nature17663 |bibcode=2016Natur.534..249B |s2cid=28608179 |url= http://pure.aber.ac.uk/ws/files/9400924/Brumm_et_al_2016_Age_stratigraphic_context_hominin_fossils_Flores_NAture_DRAFT_MS.pdf |access-date=November 11, 2021 |archive-date=March 6, 2020 |archive-url= https://web.archive.org/web/20200306112537/http://pure.aber.ac.uk/ws/files/9400924/Brumm_et_al_2016_Age_stratigraphic_context_hominin_fossils_Flores_NAture_DRAFT_MS.pdf |url-status=live}}{{collapsible list |title=Full list of authors |bullets=true |Adam Brumm |Gerrit D. van den Bergh |Michael Storey |Iwan Kurniawan |Brent V. Alloway |Ruly Setiawan |Erick Setiyabudi |Rainer Grün |Mark W. Moore |Dida Yurnaldi |Mika R. Puspaningrum |Unggul P. Wibowo |Halmi Insani |Indra Sutisna |John A. Westgate |Nick J. G. Pearce |Mathieu Duval |Hanneke J. M. Meijer |Fachroel Aziz |Thomas Sutikna |Sander van der Kaars |Stephanie Flude |Michael J. Morwood}}</ref> and are noted by Australian archaeologist Gerrit van den Bergh for being even smaller than the later fossils.<ref>{{cite journal |last1=van den Bergh |first1=G. D. |last2=Kaifu |first2=Y. |last3=Kurniawan |first3=I. |last4=Kono |first4=R. T. |last5=Brumm |first5=A. |last6=Setiyabudi |first6=E. |last7=Aziz |first7=F. |last8=Morwood |first8=M. J. |title=''Homo floresiensis''-like fossils from the early Middle Pleistocene of Flores |journal=[[Nature (journal)|Nature]] |volume=534 |issue=7606 |date=June 8, 2016 |pages=245–248 |doi=10.1038/nature17999 |pmid=27279221 |bibcode=2016Natur.534..245V |s2cid=205249218}}</ref>

=== ''H. luzonensis'' ===
{{Main|Homo luzonensis}}
A small number of specimens from the island of [[Luzon]], dated 50,000 to 67,000 years ago, have recently been assigned by their discoverers, based on dental characteristics, to a novel human species, ''H. luzonensis''.<ref>{{cite journal |last1=Détroit |first1=F. |last2=Mijares |first2=A. S. |last3=Corny |first3=J. |last4=Daver |first4=G. |last5=Zanolli |first5=C. |last6=Dizon |first6=E. |last7=Robles |first7=E. |last8=Grün |first8=R. |last9=Piper |first9=P. J. |name-list-style=amp |date=2019 |title=A new species of ''Homo'' from the Late Pleistocene of the Philippines |journal=[[Nature (journal)|Nature]] |volume=568 |issue=7751 |pages=181–186 |doi=10.1038/s41586-019-1067-9 |pmid=30971845 |bibcode=2019Natur.568..181D |s2cid=106411053 |url= https://hal.archives-ouvertes.fr/hal-02296712/file/Detroit_%26_al_2019_Nature_postprint.pdf |access-date=May 11, 2021 |archive-date=October 13, 2022 |archive-url= https://web.archive.org/web/20221013114830/https://hal.archives-ouvertes.fr/hal-02296712/file/Detroit_%26_al_2019_Nature_postprint.pdf |url-status=live}}</ref>

=== ''H. sapiens'' ===
{{Main|Archaic humans|Early modern human|Interbreeding between archaic and modern humans|Human#Evolution}}
[[File:Homo sapiens sapiens (Fundort Jebel Irhoud Marokko).jpg|thumb|200px|Reconstruction of early ''Homo sapiens'' from [[Jebel Irhoud]], Morocco {{c.|315 000 years BP}}]]
''H. sapiens'' (the adjective ''[[wikt:sapiens|sapiens]]'' is Latin for "wise" or "intelligent") emerged in Africa around 300,000 years ago, likely derived from ''[[H.&nbsp;heidelbergensis]]'' or a related lineage.<ref name="Schlebusch2017">{{cite journal |doi=10.1126/science.aao6266 |pmid=28971970 |title=Southern African ancient genomes estimate modern human divergence to 350,000 to 260,000 years ago |journal=[[Science (journal)|Science]] |volume=358 |issue=6363 |pages=652–655 |date=2017 |last1=Schlebusch |first1=Carina M. |last2=Malmström |first2=Helena |last3=Günther |first3=Torsten |last4=Sjödin |first4=Per |last5=Coutinho |first5=Alexandra |last6=Edlund |first6=Hanna |last7=Munters |first7=Arielle R. |last8=Vicente |first8=Mário |last9=Steyn |first9=Maryna |last10=Soodyall |first10=Himla |last11=Lombard |first11=Marlize |last12=Jakobsson |first12=Mattias |bibcode=2017Sci...358..652S |s2cid=206663925 |doi-access=free}}</ref><ref name="Guardian">{{cite news |url= https://www.theguardian.com/science/2017/jun/07/oldest-homo-sapiens-bones-ever-found-shake-foundations-of-the-human-story |title=Oldest ''Homo sapiens'' bones ever found shake foundations of the human story |last=Sample |first=Ian |work=[[The Guardian]] |date=June 7, 2017 |access-date=June 7, 2017 |archive-date=October 31, 2019 |archive-url= https://web.archive.org/web/20191031005024/https://www.theguardian.com/science/2017/jun/07/oldest-homo-sapiens-bones-ever-found-shake-foundations-of-the-human-story |url-status=live}}</ref> In September 2019, scientists reported the computerized determination, based on 260 [[CT scan]]s, of a virtual [[Human skull|skull shape]] of the last common human ancestor to [[modern human]]s (''H. sapiens''), representative of the earliest modern humans, and suggested that modern humans arose between 260,000 and 350,000 years ago through a merging of populations in [[East Africa|East]] and South Africa.<ref name="NYT-20190910">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Scientists Find the Skull of Humanity's Ancestor — on a Computer: By comparing fossils and CT scans, researchers say they have reconstructed the skull of the last common forebear of modern humans |url= https://www.nytimes.com/2019/09/10/science/human-ancestor-skull-computer.html |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2019/09/10/science/human-ancestor-skull-computer.html |archive-date=January 1, 2022 |url-access=limited |date=September 10, 2019 |work=[[The New York Times]] |access-date=September 10, 2019}}{{cbignore}}</ref><ref name="NAT-20190910">{{cite journal |last1=Mounier |first1=Aurélien |last2=Lahr |first2=Marta |title=Deciphering African late middle Pleistocene hominin diversity and the origin of our species |journal=[[Nature Communications]] |volume=10 |issue=1 |page=3406 |doi=10.1038/s41467-019-11213-w |pmid=31506422 |pmc=6736881 |date=2019 |bibcode=2019NatCo..10.3406M}}</ref>

Between 400,000 years ago and the second interglacial period in the [[Middle Pleistocene]], around 250,000 years ago, the trend in [[Brain size#Cranial capacity|intra-cranial volume expansion]] and the elaboration of stone tool technologies developed, providing evidence for a transition from ''H.&nbsp;erectus'' to ''H.&nbsp;sapiens''. The direct evidence suggests there was a migration of ''H.&nbsp;erectus'' [[Recent African origin of modern humans|out of Africa]], then a further speciation of ''H.&nbsp;sapiens'' from ''H.&nbsp;erectus'' in Africa. A subsequent migration (both within and out of Africa) eventually replaced the earlier dispersed ''H.&nbsp;erectus''. This migration and origin theory is usually referred to as the "recent single-origin hypothesis" or "out of Africa" theory. ''H.&nbsp;sapiens'' [[Archaic human admixture with modern humans|interbred with archaic humans]] both in Africa and in Eurasia, in Eurasia notably with Neanderthals and Denisovans.<ref name="pmid21179161" /><ref name="Reich_2011" />

The [[Toba catastrophe theory]], which postulates a [[population bottleneck]] for ''H. sapiens'' about 70,000 years ago,<ref name="ambrose1998">{{cite journal |last=Ambrose |first=Stanley H. |date=June 1998 |title=Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans |journal=Journal of Human Evolution |volume=34 |issue=6 |pages=623–651 |doi=10.1006/jhev.1998.0219 |issn=0047-2484 |pmid=9650103 |bibcode=1998JHumE..34..623A |s2cid=33122717}}</ref> was controversial from its first proposal in the 1990s and by the 2010s had very little support.<ref>{{Cite journal |doi=10.1073/pnas.0909000107 |ref=CITEREFHuffothers2010 |first1=Chad D. |last1=Huff |first2=Jinchuan |last2=Xing |first3=Alan R. |last3=Rogers |first4=David |last4=Witherspoon |first5=Lynn B. |last5=Jorde |title=Mobile Elements Reveal Small Population Size in the Ancient Ancestors of ''Homo sapiens'' |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=107 |issue=5 |pages=2147–2152 |date=January 19, 2010 |pmc=2836654 |pmid=20133859 |url= http://www.pnas.org/content/early/2010/01/06/0909000107.full.pdf+html |bibcode=2010PNAS..107.2147H |doi-access=free}}</ref> Distinctive [[human genetic variability]] has arisen as the result of the [[founder effect]], by [[Archaic human admixture with modern humans|archaic admixture]] and by [[Recent human evolution|recent evolutionary pressures]].

== Anatomical changes ==
Since ''[[Homo sapiens]]'' separated from its [[Chimpanzee–human last common ancestor|last common ancestor]] shared with [[chimpanzee]]s, human evolution is characterized by a number of [[Morphology (biology)|morphological]], [[Human development (biology)|developmental]], [[Human physiology|physiological]], [[Human behavior|behavioral]], and environmental changes.<ref name="Marlowe 54–67" /> Environmental (cultural) evolution discovered much later during the [[Pleistocene]] played a significant role in human evolution observed via human transitions between subsistence systems.<ref>{{Cite journal |last=Clark |first=Jamie L. |date=September 2011 |title=The evolution of human culture during the later Pleistocene: Using fauna to test models on the emergence and nature of "modern" human behavior |url= https://linkinghub.elsevier.com/retrieve/pii/S0278416511000225 |journal=Journal of Anthropological Archaeology |volume=30 |issue=3 |pages=273–291 |doi=10.1016/j.jaa.2011.04.002 |access-date=October 27, 2021 |archive-date=May 25, 2021 |archive-url= https://web.archive.org/web/20210525182055/https://linkinghub.elsevier.com/retrieve/pii/S0278416511000225 |url-status=live|url-access=subscription }}</ref><ref name="Marlowe 54–67" /> The most significant of these adaptations are bipedalism, increased brain size, lengthened [[ontogeny]] (gestation and infancy), and decreased [[sexual dimorphism]]. The relationship between these changes is the subject of ongoing debate.{{sfn|Boyd|Silk|2003|p={{Page needed|date=February 2015}}}} Other significant morphological changes included the evolution of a [[Thumb#Grips|power and precision grip]], a change first occurring in ''[[H.&nbsp;erectus]]''.{{sfn|Brues|Snow|1965|pp=[https://books.google.com/books?id=9WemAAAAIAAJ&pg=PA1 1–39]}}

=== Bipedalism ===
[[File:Akha cropped.png|thumb|upright|Bipedalism shown by a man and a woman]]

[[Bipedalism]] (walking on two legs) is the basic adaptation of the hominid and is considered the main cause behind a suite of skeletal changes shared by all bipedal hominids. The earliest hominin, of presumably primitive bipedalism, is considered to be either ''[[Sahelanthropus]]''<ref name="Brunet2002">{{cite journal |last1=Brunet |first1=M. |last2=Guy |first2=F. |last3=Pilbeam |first3=D. |last4=Mackaye |first4=H. |last5=Likius |first5=A. |last6=Ahounta |first6=D. |last7=Beauvilain |first7=A. |last8=Blondel |first8=C. |last9=Bocherens |first9=H. |last10=Boisserie |first10=J. |last11=De Bonis |first11=L. |last12=Coppens |first12=Y. |last13=Dejax |first13=J. |last14=Denys |first14=C. |last15=Duringer |first15=P. |last16=Eisenmann |first16=V. |last17=Fanone |first17=G. |last18=Fronty |first18=P. |last19=Geraads |first19=D. |last20=Lehmann |first20=T. |last21=Lihoreau |first21=F. |last22=Louchart |first22=A. |last23=Mahamat |first23=A. |last24=Merceron |first24=G. |last25=Mouchelin |first25=G. |last26=Otero |first26=O. |last27=Pelaez Campomanes |first27=P. |last28=Ponce De Leon |first28=M. |last29=Rage |first29=J. |last30=Sapanet |first30=M. |last31=Schuster |first31=M. |last32=Sudre |first32=J. |last33=Tassy |first33=P. |last34=Valentin |first34=X. |last35=Vignaud |first35=P. |last36=Viriot |first36=L. |last37=Zazzo |first37=A. |last38=Zollikofer |first38=C. |display-authors=6 |author1-link=Michel Brunet (paleontologist) |author3-link=David Pilbeam |date=July 11, 2002 |title=A new hominid from the Upper Miocene of Chad, Central Africa |journal=[[Nature (journal)|Nature]] |volume=418 |issue=6894 |pages=145–151 |doi=10.1038/nature00879 |issn=0028-0836 |pmid=12110880 |bibcode=2002Natur.418..145B |s2cid=1316969 |url= http://doc.rero.ch/record/13388/files/PAL_E190.pdf |access-date=February 20, 2023 |archive-date=February 25, 2023 |archive-url= https://web.archive.org/web/20230225204437/https://doc.rero.ch/record/13388/files/PAL_E190.pdf |url-status=live}}}{{collapsible list |title=Full list of authors |bullets=true |Michel Brunet |Franck Guy |David Pilbeam |Hassane Taisso Mackaye |Andossa Likius |Djimdoumalbaye Ahounta |Alain Beauvilain |Cécile Blondel |Hervé Bocherens |Jean-Renaud Boisserie |Louis De Bonis |Yves Coppens |Jean Dejax |Christiane Denys |Philippe Duringer |Véra Eisenmann |Gongdibé Fanone |Pierre Fronty |Denis Geraads |Thomas Lehmann |Fabrice Lihoreau |Antoine Louchart |Adoum Mahamat |Gildas Merceron |Guy Mouchelin |Olga Otero |Pablo Pelaez Campomanes |Marcia Ponce De Leon |Jean-Claude Rage |Michel Sapanet |Mathieu Schuster |Jean Sudre |Pascal Tassy |Xavier Valentin |Patrick Vignaud |Laurent Viriot |Antoine Zazzo |Christoph Zollikofer}}</ref> or ''[[Orrorin]]'', both of which arose some 6 to 7&nbsp;million years ago. The non-bipedal knuckle-walkers, the [[gorilla]]s and chimpanzees, diverged from the hominin line over a period covering the same time, so either ''Sahelanthropus'' or ''Orrorin'' may be our last shared ancestor. ''[[Ardipithecus]]'', a full biped, arose approximately 5.6&nbsp;million years ago.<ref>{{cite journal |title=Ardipithecus ramidus and the Paleobiology of Early Hominids |journal=[[Science (journal)|Science]] |volume=326 |issue=5949 |pages=75–86 |date=2009 |last1=White |first1=T. D. |last2=Asfaw |first2=B. |last3=Beyene |first3=Y. |last4=Haile-Selassie |first4=Y. |last5=Lovejoy |first5=C. O. |last6=Suwa |first6=G. |last7=Woldegabriel |first7=G. |pmid=19810190 |bibcode=2009Sci...326...75W |s2cid=20189444 |doi=10.1126/science.1175802}}</ref>

The early bipeds eventually evolved into the australopithecines and still later into the genus ''[[Homo]]''. There are several theories of the adaptation value of bipedalism. It is possible that bipedalism was favored because it freed the hands for reaching and carrying food, saved energy during locomotion,<ref name="Kwang Hyun 2015 929–934">{{Cite journal |last=Kwang Hyun |first=Ko |date=2015 |title=Origins of Bipedalism |journal=Brazilian Archives of Biology and Technology |doi=10.1590/S1516-89132015060399 |volume=58 |issue=6 |pages=929–934 |arxiv=1508.02739 |bibcode=2015arXiv150802739K |s2cid=761213}}</ref> enabled long-distance running and hunting, provided an enhanced field of vision, and helped avoid hyperthermia by reducing the surface area exposed to direct sun; features all advantageous for thriving in the new savanna and woodland environment created as a result of the East African Rift Valley uplift versus the previous closed forest habitat.<ref name="Kwang Hyun 2015 929–934" />{{sfn|DeSalle|Tattersall|2008|p=[https://books.google.com/books?id=Bf4Sitw7YaIC&pg=PA146 146]}}{{sfn|Curry|2008|pp=106–109}} A 2007 study provides support for the hypothesis that bipedalism evolved because it used less energy than quadrupedal knuckle-walking.<ref>{{cite news |date=July 17, 2007 |title=Study Identifies Energy Efficiency as Reason for Evolution of Upright Walking |work=[[ScienceDaily]] |url= https://www.sciencedaily.com/releases/2007/07/070716191140.htm |access-date=April 9, 2015 |archive-date=May 4, 2015 |archive-url= https://web.archive.org/web/20150504174649/http://www.sciencedaily.com/releases/2007/07/070716191140.htm |url-status=live}}<br />{{cite web |url= http://uanews.org/story/study-identifies-energy-efficiency-reason-evolution-upright-walking |title=Study identifies energy efficiency as reason for evolution of upright walking |date=July 16, 2007 |website=UANews |publisher=[[University of Arizona]] |location=Tucson |access-date=April 23, 2015 |archive-date=July 3, 2022 |archive-url= https://web.archive.org/web/20220703195556/http://uanews.org/story/study-identifies-energy-efficiency-reason-evolution-upright-walking |url-status=usurped}}</ref><ref>{{cite journal |last1=Sockol |first1=Michael D. |last2=Raichlen |first2=David A. |last3=Pontzer |first3=Herman |date=July 24, 2007 |title=Chimpanzee locomotor energetics and the origin of human bipedalism |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=104 |issue=30 |pages=12265–12269 |doi=10.1073/pnas.0703267104 |issn=0027-8424 |pmc=1941460 |pmid=17636134 |bibcode=2007PNAS..10412265S |doi-access=free}}</ref> However, recent studies suggest that bipedality without the [[Control of fire by early humans|ability to use fire]] would not have allowed global dispersal.<ref>{{cite journal |last1=David-Barrett |first1=T. |last2=Dunbar |first2=R. I. M. |date=2016 |title=Bipedality and Hair-loss Revisited: The Impact of Altitude and Activity Scheduling |journal=Journal of Human Evolution |volume=94 |pages=72–82 |pmid=27178459 |pmc=4874949 |doi=10.1016/j.jhevol.2016.02.006}}</ref> This change in gait saw a lengthening of the legs proportionately when compared to the length of the arms, which were shortened through the removal of the need for [[brachiation]]. Another change is the shape of the big toe. Recent studies suggest that australopithecines still lived part of the time in trees as a result of maintaining a grasping big toe. This was progressively lost in habilines.

Anatomically, the evolution of bipedalism has been accompanied by a large number of skeletal changes, not just to the legs and pelvis, but also to the [[Human vertebral column|vertebral column]], feet and ankles, and skull.{{sfn|Aiello|Dean|1990}} The [[femur]] evolved into a slightly more angular position to move the center of gravity toward the geometric center of the body. The knee and ankle joints became increasingly robust to better support increased weight. To support the increased weight on each vertebra in the upright position, the human vertebral column became S-shaped and the [[lumbar vertebrae]] became shorter and wider. In the feet the big toe moved into alignment with the other toes to help in forward locomotion. The arms and forearms shortened relative to the legs making it easier to run. The [[foramen magnum]] migrated under the skull and more anterior.{{sfn|Kondo|1985}}

The most significant changes occurred in the pelvic region, where the long downward facing [[Ilium (bone)|iliac blade]] was shortened and widened as a requirement for keeping the center of gravity stable while walking;{{sfn|Srivastava|2009|p=[https://books.google.com/books?id=kCerOsM8XMwC&pg=PA87 87]}} bipedal hominids have a shorter but broader, bowl-like pelvis due to this. A drawback is that the birth canal of bipedal apes is smaller than in knuckle-walking apes, though there has been a widening of it in comparison to that of australopithecine and modern humans, thus permitting the passage of newborns due to the increase in cranial size. This is limited to the upper portion, since further increase can hinder normal bipedal movement.{{sfn|Strickberger|2000|pp=[https://books.google.com/books?id=feMItLo5gwgC&pg=PA476 475–476]}}

The shortening of the pelvis and smaller birth canal evolved as a requirement for bipedalism and had significant effects on the process of human birth, which is much more difficult in modern humans than in other primates. During human birth, because of the variation in size of the pelvic region, the fetal head must be in a transverse position (compared to the mother) during entry into the birth canal and rotate about 90 degrees upon exit.{{sfn|Trevathan|2011|p=[https://books.google.com/books?id=Potlqpl-jxgC&pg=PA20 20]}} The smaller birth canal became a limiting factor to brain size increases in early humans and prompted a shorter gestation period leading to the relative immaturity of human offspring, who are unable to walk much before 12 months and have greater [[neoteny]], compared to other primates, who are mobile at a much earlier age.{{sfn|Curry|2008|pp=106–109}} The increased brain growth after birth and the increased dependency of children on mothers had a major effect upon the female reproductive cycle,<ref>{{cite book |last=Zuk |first=Marlene |date=2014 |title=Paleofantasy: What Evolution Really Tells Us About Sex, Diet, and How We Live |publisher=W.W. Norton & Company |isbn=978-0-393-34792-0 |oclc=846889455}}{{page needed|date=December 2021}}</ref> and the more frequent appearance of [[alloparenting]] in humans when compared with other hominids.<ref>{{cite book |last=Hrdy |first=Sarah Blaffer |date=2011 |title=Mothers and Others: The Evolutionary Origins of Mutual Understanding |publisher=Harvard University Press |isbn=978-0-674-06032-6 |oclc=940575388}}{{page needed|date=December 2021}}</ref> Delayed human sexual maturity also led to the evolution of [[menopause]] with one explanation, the [[grandmother hypothesis]], providing that elderly women could better pass on their genes by taking care of their daughter's offspring, as compared to having more children of their own.<ref>{{cite journal |last=Wayman |first=Erin |date=August 19, 2013 |title=Killer whales, grandmas and what men want: Evolutionary biologists consider menopause |url= https://www.sciencenews.org/article/killer-whales-grandmas-and-what-men-want-evolutionary-biologists-consider-menopause |journal=[[Science News]] |issn=0036-8423 |access-date=April 24, 2015 |archive-date=November 6, 2014 |archive-url= https://web.archive.org/web/20141106194849/https://www.sciencenews.org/article/killer-whales-grandmas-and-what-men-want-evolutionary-biologists-consider-menopause |url-status=live}}</ref><ref>{{Cite journal |last=Blell |first=Mwenza |date=September 29, 2017 |title=Grandmother Hypothesis, Grandmother Effect, and Residence Patterns |journal=The International Encyclopedia of Anthropology |pages=1–5 |doi=10.1002/9781118924396.wbiea2162 |isbn=978-1-118-92439-6 |doi-access=free}}</ref>

=== Encephalization ===
[[File:Skull evolution.png|center|thumb|920px|Skulls of successive (or near-successive, depending on the source) human evolutionary ancestors,{{efn|There is no general agreement on the line of [[species|special]] descent of ''H. sapiens'' from ''H. erectus''. Some of the species depicted in the image may not actually represent a direct evolutionary ancestor to ''H. sapiens'', and may not directly derive from one another, namely:

* ''H. heidelbergensis'' likely did not descend from ''H. antecessor''.<ref name="Welker2020">{{Cite journal |doi=10.1038/s41586-020-2153-8 |issn=1476-4687 |volume=580 |issue=7802 |pages=235–238 |last1=Welker |first1=F. |last2=Ramos-Madrigal |first2=J. |last3=Gutenbrunner |first3=P. |display-authors=etal |title=The dental proteome of ''Homo antecessor'' |journal=[[Nature (journal)|Nature]] |date=April 1, 2020 |pmid=32269345 |pmc=7582224 |bibcode=2020Natur.580..235W |s2cid=214736611 |url= http://eprints.whiterose.ac.uk/159068/1/Welker_etal_Hominin1_AAM.docx |access-date=November 10, 2021 |archive-date=November 10, 2021 |archive-url= https://web.archive.org/web/20211110200345/https://eprints.whiterose.ac.uk/159068/1/Welker_etal_Hominin1_AAM.docx |url-status=live}}{{collapsible list |title=Full list of authors |bullets=true |Frido Welker |Jazmín Ramos-Madrigal |Petra Gutenbrunner |Meaghan Mackie |Shivani Tiwary |Rosa Rakownikow Jersie-Christensen |Cristina Chiva |Marc R. Dickinson |Martin Kuhlwilm |Marc de Manuel |Pere Gelabert |María Martinón-Torres |Ann Margvelashvili |Juan Luis Arsuaga |Eudald Carbonell |Tomas Marques-Bonet |Kirsty Penkman |Eduard Sabidó |Jürgen Cox |Jesper V. Olsen |David Lordkipanidze |Fernando Racimo |Carles Lalueza-Fox |José María Bermúdez de Castro |Eske Willerslev |Enrico Cappellini}}</ref>
* ''H. heidelbergensis'' is likely not an ancestor to ''H. sapiens'', nor is ''H. antecessor''.<ref name="Welker2020" />
* ''H. ergaster'' is often considered the next evolutionary ancestor to ''H. sapiens'' following ''H. erectus'', however, there is considerable uncertainty as to the accuracy of classifying it as a separate species from ''H. erectus'' at all.<ref>{{Cite journal |last1=Dennell |first1=Robin |last2=Roebroeks |first2=Wil |date=2005 |title=An Asian perspective on early human dispersal from Africa |journal=[[Nature (journal)|Nature]] |volume=438 |issue=7071 |pages=1099–1104 |doi=10.1038/nature04259 |pmid=16371999 |bibcode=2005Natur.438.1099D |s2cid=4405913 |url= https://www.nature.com/articles/nature04259 |access-date=November 10, 2021 |archive-date=October 31, 2021 |archive-url= https://web.archive.org/web/20211031154723/https://www.nature.com/articles/nature04259 |url-status=live|url-access=subscription }}</ref>}} up until 'modern' ''Homo sapiens''<br /> * [[Mya (unit)|Mya]] – million years ago, [[kya (unit)|kya]] – thousand years ago]]
[[File:Brain size and tooth size in hominins.jpg|thumb|upright=1.5|Brain size and tooth size in hominins]]
The human species eventually developed a much larger brain than that of other primates—typically {{convert|1330|cm3|abbr=on}} in modern humans, nearly three times the size of a chimpanzee or gorilla brain.<ref name="Schoeneman">{{cite journal |last=Schoenemann |first=P. Thomas |date=October 2006 |title=Evolution of the Size and Functional Areas of the Human Brain |journal=[[Annual Review of Anthropology]] |volume=35 |pages=379–406 |doi=10.1146/annurev.anthro.35.081705.123210 |s2cid=7611321 |issn=0084-6570}}</ref> After a period of stasis with ''Australopithecus anamensis'' and ''Ardipithecus'', species which had smaller brains as a result of their bipedal locomotion,<ref>{{cite web |last1=Brown |first1=Graham |last2=Fairfax |first2=Stephanie |last3=Sarao |first3=Nidhi |title=Tree of Life Web Project: Human Evolution |url= http://tolweb.org/treehouses/?treehouse_id=3710 |website=www.tolweb.org |access-date=August 24, 2015 |archive-date=June 6, 2020 |archive-url= https://web.archive.org/web/20200606091921/http://tolweb.org/treehouses/?treehouse_id=3710 |url-status=live}}</ref> the pattern of [[encephalization]] started with ''Homo habilis'', whose {{convert|600|cm3|abbr=on}} brain was slightly larger than that of chimpanzees. This evolution continued in ''Homo erectus'' with {{convert|800–1,100|cm3|abbr=on}}, and reached a maximum in Neanderthals with {{convert|1200–1,900|cm3|abbr=on}}, larger even than modern ''Homo sapiens''. This brain increase manifested during postnatal [[neural development|brain growth]], far exceeding that of other apes ([[heterochrony]]). It also allowed for extended periods of [[Observational learning|social learning]] and [[language acquisition]] in juvenile humans, beginning as much as 2&nbsp;million years ago. Encephalization may be due to a dependency on calorie-dense, difficult-to-acquire food.<ref>{{Cite journal |last1=Kaplan |first1=Hillard |last2=Hill |first2=Kim |last3=Lancaster |first3=Jane |last4=Hurtado |first4=Magdelena |date=August 16, 2000 |title=A Theory of Human Life History Evolution: Diet, Intelligence, and Longevity |url= https://www.unm.edu/~hkaplan/KaplanHillLancasterHurtado_2000_LHEvolution.pdf |journal=Evolutionary Anthropology |volume=9 |issue=4 |pages=156–185 |doi=10.1002/1520-6505(2000)9:4<156::AID-EVAN5>3.0.CO;2-7 |s2cid=2363289 |access-date=September 20, 2019 |archive-date=February 15, 2020 |archive-url= https://web.archive.org/web/20200215120245/http://www.unm.edu/~hkaplan/KaplanHillLancasterHurtado_2000_LHEvolution.pdf |url-status=live}}</ref>

Furthermore, the changes in the structure of [[human brain]]s may be even more significant than the increase in size.<ref name="Park2007">{{cite journal |last1=Park |first1=M. S. |last2=Nguyen |first2=A. D. |last3=Aryan |first3=H. E. |last4=U |first4=H. S. |last5=Levy |first5=M. L. |last6=Semendeferi |first6=K. |date=March 2007 |title=Evolution of the human brain: Changing brain size and the fossil record |journal=[[Neurosurgery (journal)|Neurosurgery]] |volume=60 |issue=3 |pages=555–562 |issn=0148-396X |pmid=17327801 |s2cid=19610624 |doi=10.1227/01.NEU.0000249284.54137.32}}</ref><ref name="Bruner2007">{{cite journal |last=Bruner |first=Emiliano |date=December 2007 |title=Cranial shape and size variation in human evolution: Structural and functional perspectives |citeseerx=10.1.1.391.288 |journal=Child's Nervous System |volume=23 |issue=12 |pages=1357–1365 |doi=10.1007/s00381-007-0434-2 |issn=0256-7040 |pmid=17680251 |s2cid=16163137}}</ref><ref>{{cite journal |last=Potts |first=Richard |author-link=Rick Potts |date=October 2012 |title=Evolution and Environmental Change in Early Human Prehistory |journal=Annual Review of Anthropology |volume=41 |pages=151–167 |doi=10.1146/annurev-anthro-092611-145754 |issn=0084-6570}}</ref><ref name="Leonard_2007">{{cite journal |last1=Leonard |first1=William R. |last2=Snodgrass |first2=J. Josh |last3=Robertson |first3=Marcia L. |date=August 2007 |title=Effects of brain evolution on human nutrition and metabolism |journal=[[Annual Review of Nutrition]] |volume=27 |pages=311–327 |doi=10.1146/annurev.nutr.27.061406.093659 |issn=0199-9885 |pmid=17439362 |s2cid=18869516}}</ref> Fossilized skulls shows the brain size in early humans fell within the range of modern humans 300,000 years ago, but only got its present-day brain shape between 100,000 and 35,000 years ago.<ref>{{Cite journal |title=The evolution of modern human brain shape - Science |journal=Science Advances |date=January 5, 2018 |volume=4 |issue=1 |doi=10.1126/sciadv.aao5961 |last1=Neubauer |first1=Simon |last2=Hublin |first2=Jean-Jacques |last3=Gunz |first3=Philipp |pages=eaao5961 |pmid=29376123 |pmc=5783678 |bibcode=2018SciA....4.5961N}}</ref> [[File:Students explore hominid evolution.jpg|alt=Three students hold three different skulls in front of their faces, to show the difference in size and shape compared to the modern head|left|thumb|The size and shape of the skull changed over time. The leftmost, and largest, is a replica of a modern human skull.]] The [[temporal lobe]]s, which contain centers for language processing, have increased disproportionately, as has the [[prefrontal cortex]], which has been related to complex decision-making and moderating social behavior.<ref name="Schoeneman" /> Encephalization has been tied to increased starches<ref name="NYT-20150813">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |date=August 13, 2015 |title=For Evolving Brains, a 'Paleo' Diet Full of Carbs |work=The New York Times |url= https://www.nytimes.com/2015/08/13/science/for-evolving-brains-a-paleo-diet-full-of-carbs.html |url-access=limited |access-date=August 14, 2015 |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2015/08/13/science/for-evolving-brains-a-paleo-diet-full-of-carbs.html |archive-date=January 1, 2022}}{{cbignore}}</ref> and meat<ref>{{cite journal |last=Mann |first=Neil |date=September 2007 |title=Meat in the human diet: An anthropological perspective |journal=Nutrition & Dietetics |volume=64 |issue=Supplement 4 |pages=S102–S107 |doi=10.1111/j.1747-0080.2007.00194.x |issn=1747-0080 |doi-access=free}}</ref><ref>{{cite press release |last=McBroom |first=Patricia |date=June 14, 1999 |title=Meat-eating was essential for human evolution, says UC Berkeley anthropologist specializing in diet |location=Berkeley |publisher=[[University of California Press]] |url= http://www.berkeley.edu/news/media/releases/99legacy/6-14-1999a.html |access-date=April 25, 2015 |archive-date=April 20, 2015 |archive-url= https://web.archive.org/web/20150420060844/http://www.berkeley.edu/news/media/releases/99legacy/6-14-1999a.html |url-status=live}}</ref> in the diet, however a 2022 meta study called into question the role of meat.<ref>{{Cite journal |last1=Barr |first1=W. Andrew |last2=Pobiner |first2=Briana |last3=Rowan |first3=John |last4=Du |first4=Andrew |last5=Faith |first5=J. Tyler |date=February 1, 2022 |title=No sustained increase in zooarchaeological evidence for carnivory after the appearance of ''Homo erectus'' |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=119 |issue=5 |doi=10.1073/pnas.2115540119 |doi-access=free |issn=0027-8424 |pmid=35074877 |pmc=8812535 |bibcode=2022PNAS..11915540B}}</ref> Other factors are the development of cooking,<ref name="Organ_2011">{{cite journal |last1=Organ |first1=Chris |last2=Nunn |first2=Charles L. |last3=Machanda |first3=Zarin |last4=Wrangham |first4=Richard W. |author4-link=Richard Wrangham |date=August 30, 2011 |title=Phylogenetic rate shifts in feeding time during the evolution of ''Homo'' |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=108 |issue=35 |pages=14555–14559 |doi=10.1073/pnas.1107806108 |issn=0027-8424 |pmc=3167533 |pmid=21873223 |bibcode=2011PNAS..10814555O |doi-access=free}}</ref> and it has been proposed that intelligence increased as a response to an increased necessity for [[Dunbar's number|solving social problems]] as human society became more complex.<ref name="David-Barrett">{{cite journal |last1=David-Barrett |first1=T. |last2=Dunbar |first2=R. I. M. |date=2013 |title=Processing Power Limits Social Group Size: Computational Evidence for the Cognitive Costs of Sociality |journal=Proceedings of the Royal Society of London B: Biological Sciences |volume=280 |issue=1765 |page=20131151 |doi=10.1098/rspb.2013.1151 |pmid=23804623 |pmc=3712454}}</ref> Changes in skull morphology, such as smaller mandibles and mandible muscle attachments, allowed more room for the brain to grow.{{sfn|Bown|Rose|1987}}

The increase in volume of the [[neocortex]] also included a rapid increase in size of the [[cerebellum]]. Its function has traditionally been associated with balance and fine motor control, but more recently with [[speech]] and [[cognition]]. The great apes, including hominids, had a more pronounced cerebellum relative to the neocortex than other primates. It has been suggested that because of its function of sensory-motor control and learning complex muscular actions, the cerebellum may have underpinned human technological adaptations, including the preconditions of speech.<ref>{{cite journal |last1=Barton |first1=Robert A. |last2=Venditti |first2=Chris |date=October 20, 2014 |title=Rapid Evolution of the Cerebellum in Humans and Other Great Apes |journal=[[Current Biology]] |volume=24 |issue=20 |pages=2440–2444 |issn=0960-9822 |doi=10.1016/j.cub.2014.08.056 |pmid=25283776 |s2cid=5041106 |doi-access=free |bibcode=2014CBio...24.2440B}}</ref><ref>{{cite journal |last1=Starowicz-Filip |first1=Anna |last2=Milczarek |first2=Olga |last3=Kwiatkowski |first3=Stanisław |last4=Bętkowska-Korpała |first4=Barbara |last5=Prochwicz |first5=Katarzyna |date=2013 |title=Cerebellar cognitive affective syndrome CCAS – a case report |journal=Archives of Psychiatry and Psychotherapy |volume=15 |issue=3 |pages=57–64 |doi=10.12740/APP/18666 |doi-access=free}}</ref><ref>{{cite journal |last1=Yu |first1=Feng |last2=Jiang |first2=Qing-jun |last3=Sun |first3=Xi-yan |last4=Zhang |first4=Rong-wei |date=August 22, 2014 |title=A new case of complete primary cerebellar agenesis: Clinical and imaging findings in a living patient |journal=[[Brain (journal)|Brain]] |doi=10.1093/brain/awu239 |issn=1460-2156 |pmid=25149410 |volume=138 |issue=Pt 6 |pages=e353 |pmc=4614135}}</ref><ref>{{cite journal |last=Weaver |first=Anne H. |date=March 8, 2005 |title=Reciprocal evolution of the cerebellum and neocortex in fossil humans |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=102 |issue=10 |pages=3576–3580 |doi=10.1073/pnas.0500692102 |issn=0027-8424 |pmc=553338 |pmid=15731345 |bibcode=2005PNAS..102.3576W |doi-access=free}}</ref>

The immediate survival advantage of encephalization is difficult to discern, as the major brain changes from ''Homo erectus'' to ''Homo heidelbergensis'' were not accompanied by major changes in technology. It has been suggested that the changes were mainly social and behavioural, including increased empathic abilities,<ref>{{cite book |last=Klein |first=Stefan |date=2014 |title=Survival of the Nicest |isbn=978-1-61519-090-4 |publisher=The Experiment}}</ref><ref>{{Cite journal |title=Social Network Size Affects Neural Circuits in Macaques |journal=[[Science (journal)|Science]] |date=November 4, 2011 |issn=0036-8075 |pmid=22053054 |pages=697–700 |volume=334 |issue=6056 |doi=10.1126/science.1210027 |last1=Sallet |first1=J. |last2=Mars |first2=R. B. |last3=Noonan |first3=M. P. |last4=Andersson |first4=J. L. |last5=O'Reilly |first5=J. K. |last6=Jbabdi |first6=S. |last7=Croxson |first7=P. L. |last8=Jenkinson |first8=M. |last9=Miller |first9=K. L. |bibcode=2011Sci...334..697S |s2cid=206536017}}</ref> increases in size of social groups,<ref name="David-Barrett" /><ref>{{cite journal |last1=Dunbar |first1=R. I. M. |date=1992 |title=Neocortex size as a constraint on group size in primates |journal=Journal of Human Evolution |volume=22 |issue=6 |pages=469–493 |doi=10.1016/0047-2484(92)90081-j |doi-access=free |bibcode=1992JHumE..22..469D}}</ref><ref>{{Cite journal |title=Encephalization is not a universal macroevolutionary phenomenon in mammals but is associated with sociality |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |date=December 14, 2010 |issn=0027-8424 |pmc=3003036 |pmid=21098277 |pages=21582–21586 |volume=107 |issue=50 |doi=10.1073/pnas.1005246107 |first1=Susanne |last1=Shultz |first2=Robin |last2=Dunbar |bibcode=2010PNAS..10721582S |doi-access=free}}</ref> and increased behavioral plasticity.<ref>{{Cite journal |last=Richard |first=Potts |date=1998 |title=Environmental Hypotheses of Hominin Evolution |journal=American Journal of Physical Anthropology |volume=107 |issue=S27 |pages=93–136 |doi=10.1002/(sici)1096-8644(1998)107:27+<93::aid-ajpa5>3.0.co;2-x |pmid=9881524}}</ref> Humans are unique in the ability to acquire information through social transmission and adapt that information.<ref>{{Cite book |last=Richerson |first=Peter J. |title=Not by Genes Alone: How Culture Transformed Human Evolution |date=2006 |publisher=[[University of Chicago Press]] |isbn=0-226-71212-5 |oclc=642503808}}</ref> The emerging field of [[cultural evolution]] studies human sociocultural change from an evolutionary perspective.<ref>{{Cite journal |last1=Mesoudi |first1=Alex |last2=Whiten |first2=Andrew |last3=Laland |first3=Kevin N. |date=August 2006 |title=Towards a unified science of cultural evolution |journal=Behavioral and Brain Sciences |volume=29 |issue=4 |pages=329–347 |doi=10.1017/s0140525x06009083 |pmid=17094820 |issn=0140-525X}}</ref>

[[File:Homo skull changes.png|center|thumb|750px|Evolution of the shape, size, and contours of the human (''Homo'') skull<ref>{{cite journal |last1=Berger |first1=L. R. |last2=Hawks |first2=J. |last3=Dirks |first3=P. H. |last4=Elliott |first4=M. |last5=Roberts |first5=E. M. |title=''Homo naledi'' and Pleistocene hominin evolution in subequatorial Africa |journal=eLife |volume=6 |date=May 9, 2017 |pmid=28483041 |pmc=5423770 |doi=10.7554/elife.24234 |doi-access=free}}</ref><ref>{{cite book |url= https://www.researchgate.net/publication/278682043 |title=Analyzing Hominin Hominin Phylogeny: Cladistic Approach |last1=Strait |first1=David |last2=Grine |first2=Frederick |last3=Fleagle |first3=John |name-list-style=vanc |date=2015 |isbn=978-3-642-39978-7 |pages=1989–2014 (cladogram p. 2006) |publisher=Springer}}.</ref><!--ref name="Saylor 2015 483–488" /-->{{efn|name=habilis|The conventional estimate on the age of ''H. habilis'' is at roughly 2.1 to 2.3 million years.{{sfn|Stringer|1994|p=242}}<ref>{{cite book |last1=Schrenk |first1=F. |last2=Kullmer |first2=O. |last3=Bromage |first3=T. |chapter=Chapter 9: The Earliest Putative ''Homo'' Fossils |editor1-last=Henke |editor1-first=W. |editor2-last=Tattersall |editor2-first=I. |title=Handbook of Paleoanthropology |date=2007 |pages=1611–1631 |doi=10.1007/978-3-540-33761-4_52}}</ref> Suggestions for pushing back the age to 2.8 Mya were made in 2015 based on the discovery of [[LD 350-1|a jawbone]].<ref>{{cite journal |last1=Spoor |first1=F. |last2=Gunz |first2=P. |last3=Neubauer |first3=S. |last4=Stelzer |first4=S. |last5=Scott |first5=N. |last6=Kwekason |first6=A. |last7=Dean |first7=M. C. |title=Reconstructed ''Homo habilis'' type OH 7 suggests deep-rooted species diversity in early ''Homo'' |journal=[[Nature (journal)|Nature]] |volume=519 |issue=7541 |pages=83–6 |date=March 2015 |pmid=25739632 |doi=10.1038/nature14224 |bibcode=2015Natur.519...83S |s2cid=4470282}}</ref>}}<ref>{{cite journal |last=Schuster |first=A. M. |date=1997 |title=Earliest Remains of Genus ''Homo'' |url= http://archive.archaeology.org/9701/newsbriefs/homo.html |journal=Archaeology |volume=50 |access-date=March 5, 2015 |number=1 |archive-date=March 17, 2015 |archive-url= https://web.archive.org/web/20150317002614/http://archive.archaeology.org/9701/newsbriefs/homo.html |url-status=live}} The line to the earliest members of ''Homo'' was derived from ''[[Australopithecus]]'', a genus which had separated from the Chimpanzee–human last common ancestor by late [[Miocene]] or early [[Pliocene]] times.
<!--Why is so much of the [[Chimpanzee–human last common ancestor]] article reproduced in this footnote?
with date estimates by several specialists ranging from  13 million years ago to more recently than six million years ago.
* {{cite journal |last1=Arnason |first1=U. |last2=Gullberg |first2=A. |last3=Janke |first3=A. |title=Molecular timing of primate divergences as estimated by two nonprimate calibration points |journal=Journal of Molecular Evolution |volume=47 |issue=6 |pages=718–27 |date=December 1998 |pmid=9847414 |doi=10.1007/PL00006431 |bibcode=1998JMolE..47..718A}}
* {{cite journal |last1=Patterson |first1=N. |last2=Richter |first2=D. J. |last3=Gnerre |first3=S. |last4=Lander |first4=E. S. |last5=Reich |first5=D. |title=Genetic evidence for complex speciation of humans and chimpanzees |journal=[[Nature (journal)|Nature]] |volume=441 |issue=7097 |pages=1103–1108 |date=June 2006 |pmid=16710306 |doi=10.1038/nature04789 |bibcode=2006Natur.441.1103P}}
* {{cite journal |last=Wakeley |first=J. |title=Complex speciation of humans and chimpanzees |journal=[[Nature (journal)|Nature]] |volume=452 |issue=7184 |pages=E3-4; discussion E4 |date=March 2008 |pmid=18337768 |doi=10.1038/nature06805 |bibcode=2008Natur.452....3W}}
"Patterson et al. suggest that the apparently short divergence time between humans and chimpanzees on the X chromosome is explained by a massive interspecific hybridization event in the ancestry of these two species. However, Patterson et al. do not statistically test their own null model of simple speciation before concluding that speciation was complex, and—even if the null model could be rejected—they do not consider other explanations of a short divergence time on the X chromosome. These include natural selection on the X chromosome in the common ancestor of humans and chimpanzees, changes in the ratio of male-to-female mutation rates over time, and less extreme versions of divergence with gene flow. I therefore believe that their claim of hybridization is unwarranted." see [[CHLCA#Current estimates|current estimates regarding complex speciation]].
--></ref>{{efn|''H. erectus'' in the narrow sense (the Asian species) was extinct by 140,000 years ago, ''[[Homo erectus soloensis]]'', found in [[Java (island)|Java]], is considered the latest known survival of ''H. erectus''. Formerly dated to as late as 50,000 to 40,000 years ago, a 2011 study pushed back the date of its extinction of ''H. e. soloensis'' to 143,000 years ago at the latest, more likely before 550,000 years ago.<ref>{{cite journal |last1=Indriati |first1=E. |last2=Swisher |first2=C. C. |last3=Lepre |first3=C. |last4=Quinn |first4=R. L. |last5=Suriyanto |first5=R. A. |last6=Hascaryo |first6=A. T. |last7=Grün |first7=R. |last8=Feibel |first8=C. S. |last9=Pobiner |first9=B. L. |last10=Aubert |first10=M. |last11=Lees |first11=W. |last12=Antón |first12=S. C. |display-authors=5 |title=The age of the 20 meter Solo River terrace, Java, Indonesia and the survival of ''Homo erectus'' in Asia |journal=[[PLoS One]] |volume=6 |issue=6 |pages=e21562 |date=2011 |pmid=21738710 |pmc=3126814 |doi=10.1371/journal.pone.0021562 |bibcode=2011PLoSO...621562I |doi-access=free}}{{collapsible list |title=Full list of authors |bullets=true |Etty Indriati |Carl C. Swisher III |Christopher Lepre |Rhonda L. Quinn |Rusyad A. Suriyanto |Agus T. Hascaryo |Rainer Grün |Craig S. Feibel |Briana L. Pobiner |Maxime Aubert |Wendy Lees |Susan C. Antón}}</ref>}}<ref name=":3">{{cite journal |last1=Mondal |first1=M. |last2=Bertranpetit |first2=J. |last3=Lao |first3=O. |title=Approximate Bayesian computation with deep learning supports a third archaic introgression in Asia and Oceania |journal=Nature Communications |volume=10 |issue=1 |page=246 |date=January 2019 |pmid=30651539 |pmc=6335398 |doi=10.1038/s41467-018-08089-7 |bibcode=2019NatCo..10..246M}}</ref><ref name="Zeitoun 2003 148–156">{{cite journal |last=Zeitoun |first=V. |title=High occurrence of a basicranial feature in ''Homo erectus'': Anatomical description of the preglenoid tubercle |journal=The Anatomical Record Part B: The New Anatomist |volume=274 |issue=1 |pages=148–56 |date=September 2003 |pmid=12964205 |doi=10.1002/ar.b.10028 |doi-access=free}}</ref><ref name="Proceedings 2015">{{cite journal |last1=Dembo |first1=M. |last2=Matzke |first2=N. J. |last3=Mooers |first3=A. Ø. |last4=Collard |first4=M. |title=Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships |journal=Proceedings. Biological Sciences |volume=282 |issue=1812 |page=20150943 |date=August 2015 |pmid=26202999 |pmc=4528516 |doi=10.1098/rspb.2015.0943}}</ref><ref name=":2">{{cite journal |last1=Dembo |first1=M. |last2=Radovčić |first2=D. |last3=Garvin |first3=H. M. |last4=Laird |first4=M. F. |last5=Schroeder |first5=L. |last6=Scott |first6=J. E. |last7=Brophy |first7=J. |last8=Ackermann |first8=R. R. |last9=Musiba |first9=C. M. |last10=de Ruiter |first10=D. J. |last11=Mooers |first11=A. Ø. |last12=Collard |first12=M. |display-authors=2 |title=The evolutionary relationships and age of ''Homo naledi'': An assessment using dated Bayesian phylogenetic methods |journal=Journal of Human Evolution |volume=97 |pages=17–26 |date=August 2016 |pmid=27457542 |doi=10.1016/j.jhevol.2016.04.008 |bibcode=2016JHumE..97...17D |hdl-access=free |hdl=2164/8796}}{{collapsible list |title=Full list of authors |bullets=true |Mana Dembo |Davorka Radovčić |Heather M. Garvinc |Myra F. Laird |Lauren Schroeder |Jill E. Scott |Juliet Brophy |Rebecca R. Ackermann |Chares M. Musiba |Darryl J. de Ruiter |Arne Ø. Mooers |Mark Collard}}</ref><ref>{{cite journal |last1=Mounier |first1=A. |last2=Caparros |first2=M. |date=2015 |title=The phylogenetic status of ''Homo heidelbergensis'' – a cladistic study of Middle Pleistocene hominins |journal=BMSAP |language=fr |volume=27 |issue=3–4 |pages=110–134 |doi=10.1007/s13219-015-0127-4 |s2cid=17449909 |issn=0037-8984}}</ref><ref name=":1" /><ref>{{cite book |url= https://books.google.com/books?id=bL2XDwAAQBAJ&q=Sahelanthropus+tchadensis&pg=PA7 |title=The Origins of Europeans and Their Pre-Historic Innovations from 6 Million to 10,000 BCE: From 6 Million to 10,000 BCE |last=Harrison |first=N. |date=May 1, 2019 |publisher=Algora Publishing |isbn=978-1-62894-379-5}}</ref><ref>{{cite journal |last1=Rogers |first1=A. R. |last2=Harris |first2=N. S. |last3=Achenbach |first3=A. A. |title=Neanderthal-Denisovan ancestors interbred with a distantly related hominin |journal=Science Advances |volume=6 |issue=8 |pages=eaay5483 |date=February 2020 |pmid=32128408 |pmc=7032934 |doi=10.1126/sciadv.aay5483 |doi-access=free |bibcode=2020SciA....6.5483R}}</ref>]]

=== Sexual dimorphism ===
The reduced degree of [[sexual dimorphism in humans]] is visible primarily in the reduction of the male [[canine tooth]] relative to other ape species (except gibbons) and reduced brow ridges and general robustness of males. Another important physiological change related to [[sexuality]] in humans was the evolution of [[Concealed ovulation|hidden estrus]]. Humans are the only hominoids in which the female is fertile year round and in which no special signals of fertility are produced by the body (such as genital swelling or overt changes in proceptivity during estrus).<ref>{{cite book |last=Tanner |first=Nancy Makepeace |title=On Becoming Human |url= https://books.google.com/books?id=_j45AAAAIAAJ |date=1981 |publisher=CUP Archive |isbn=978-0-521-28028-0 |page=[https://books.google.com/books?id=_j45AAAAIAAJ&pg=PA202 202]}}</ref>

Nonetheless, humans retain a degree of sexual dimorphism in the distribution of body hair and subcutaneous fat, and in the overall size, males being around 15% larger than females.<ref>{{Cite journal |last1=Reno |first1=Philip L. |last2=Lovejoy |first2=C. Owen |date=April 28, 2015 |title=From Lucy to Kadanuumuu: Balanced analyses of ''Australopithecus afarensis'' assemblages confirm only moderate skeletal dimorphism |journal=PeerJ |volume=3 |page=e925 |doi=10.7717/peerj.925 |pmid=25945314 |pmc=4419524 |issn=2167-8359 |doi-access=free}}</ref> These changes taken together have been interpreted as a result of an increased emphasis on [[pair bond]]ing as a possible solution to the requirement for increased parental investment due to the prolonged infancy of offspring.<ref>{{Cite journal |last=Lovejoy |first=C. Owen |date=October 2, 2009 |title=Reexamining Human Origins in Light of Ardipithecus ramidus |journal=[[Science (journal)|Science]] |volume=326 |issue=5949 |pages=74–74e8 |doi=10.1126/science.1175834 |issn=0036-8075 |bibcode=2009Sci...326...74L |url= http://doc.rero.ch/record/211449/files/PAL_E4439.pdf |pmid=19810200 |s2cid=42790876 |access-date=December 6, 2019 |archive-date=February 24, 2021 |archive-url= https://web.archive.org/web/20210224110943/http://doc.rero.ch/record/211449/files/PAL_E4439.pdf |url-status=live}}</ref>

=== Ulnar opposition ===
[[File:Erpurua eta hatz txikia.jpg|thumb|120px|Only the human is able to touch the little finger with the thumb.]]
The ulnar opposition—the contact between the thumb and the tip of the [[little finger]] of the same hand—is unique to the [[Homo|genus ''Homo'']],<ref>{{Cite journal |last=Young |first=Richard W. |date=January 2003 |title=Evolution of the human hand: The role of throwing and clubbing |journal=Journal of Anatomy |volume=202 |issue=1 |pages=165–174 |doi=10.1046/j.1469-7580.2003.00144.x |issn=0021-8782 |pmc=1571064 |pmid=12587931}}</ref> including Neanderthals, the [[Atapuerca Mountains|Sima de los Huesos]] [[Hominini|hominins]] and [[Homo sapiens|anatomically modern humans]].<ref name="Miriam">{{cite book |last=Ittyerah |first=Miriam |title=Hand Preference and Hand Ability: Evidence from studies in Haptic Cognition |publisher=[[John Benjamins Publishing]] |date=2013 |pages=37–38 |isbn=978-90-272-7164-8}}</ref><ref>{{cite web |last=Wilson |first=Frank R. |url= https://www.nytimes.com/books/first/w/wilson-hand.html |title=The Hand How Its Use Shapes the Brain, Language, and Human Culture |work=The New York Times |access-date=July 2, 2017 |archive-date=August 28, 2017 |archive-url= https://web.archive.org/web/20170828024550/http://www.nytimes.com/books/first/w/wilson-hand.html |url-status=live}}</ref> In other primates, the thumb is short and unable to touch the little finger.<ref name="Miriam" /> The ulnar opposition facilitates the precision grip and power grip of the human hand, underlying all the skilled manipulations.

=== Other changes ===
A number of other changes have also characterized the evolution of humans, among them an increased reliance on vision rather than smell (highly reduced [[olfactory bulb]]); a longer juvenile developmental period and higher infant dependency;<ref name="Kuzawa2014">{{cite journal |last1=Kuzawa |first1=Christopher W. |last2=Chugani |first2=Harry T. |last3=Grossman |first3=Lawrence I. |last4=Lipovich |first4=Leonard |last5=Muzik |first5=Otto |last6=Hof |first6=Patrick R. |last7=Wildman |first7=Derek E. |last8=Sherwood |first8=Chet C. |last9=Leonard |first9=William R. |last10=Lange |first10=Nicholas |date=August 25, 2014 |title=Metabolic costs and evolutionary implications of human brain development |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=111 |issue=36 |pages=13010–13015 |doi=10.1073/pnas.1323099111 |pmid=25157149 |pmc=4246958 |bibcode=2014PNAS..11113010K |doi-access=free}}</ref> a smaller gut and small, misaligned teeth; faster basal metabolism;<ref name="Pontzer2016">{{Cite journal |last1=Pontzer |first1=Herman |last2=Brown |first2=Mary H. |last3=Raichlen |first3=David A. |last4=Dunsworth |first4=Holly |last5=Hare |first5=Brian |last6=Walker |first6=Kara |last7=Luke |first7=Amy |last8=Dugas |first8=Lara R. |last9=Durazo-Arvizu |first9=Ramon |last10=Schoeller |first10=Dale |last11=Plange-Rhule |first11=Jacob |last12=Bovet |first12=Pascal |last13=Forrester |first13=Terrence E. |last14=Lambert |first14=Estelle V. |last15=Thompson |first15=Melissa Emery |last16=Shumaker |first16=Robert W. |last17=Ross |first17=Stephen P. |date=May 4, 2016 |title=Metabolic acceleration and the evolution of human brain size and life history |journal=[[Nature (journal)|Nature]] |volume=533 |issue=7603 |pages=390–392 |bibcode=2016Natur.533..390P |doi=10.1038/nature17654 |pmid=27144364 |pmc=4942851}}</ref> loss of body hair;<ref name="MarkusJRantala2007">{{cite journal |last1=Rantala |first1=Markus J. |date=August 20, 2007 |title=Evolution of nakedness in ''Homo sapiens'' |url= https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7998.2007.00295.x |journal=[[Journal of Zoology]] |volume=273 |issue=1 |pages=1–7 |doi=10.1111/j.1469-7998.2007.00295.x |access-date=November 5, 2022 |archive-date=November 5, 2022 |archive-url= https://web.archive.org/web/20221105183758/https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7998.2007.00295.x |url-status=live|url-access=subscription }}</ref> an increase in
[[eccrine sweat gland]] density that is ten times higher than any other [[catarrhini]]an primates,<ref>[https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1010614 Differential modularity of the mammalian Engrailed 1 enhancer network directs sweat gland development]</ref> yet humans use 30% to 50% less water per day compared to chimps and gorillas;<ref>[https://today.duke.edu/2021/03/humans-evolved-be-water-saving-ape Humans Evolved to Be the Water-Saving Ape | Duke Today]</ref> more [[Rapid eye movement sleep|REM sleep]] but less sleep in total;<ref>[https://www.smithsonianmag.com/science-nature/why-humans-sleep-less-than-their-primate-relatives-180980018/ Why Humans Sleep Less Than Their Primate Relatives]</ref> a change in the shape of the dental arcade from u-shaped to parabolic; development of a [[chin]] (found in ''Homo sapiens'' alone); [[Temporal styloid process|styloid processes]]; and a descended [[larynx]]. As the human hand and arms adapted to the making of tools and were used less for climbing, the shoulder blades changed too. As a side effect, it allowed human ancestors to throw objects with greater force, speed and accuracy.<ref>{{Cite web |last=Potter |first=Lisa Marie |title=Shouldering the Burden of Evolution |work=UCSF News Center |publisher=[[University of California San Francisco]] |date=September 8, 2015 |url= https://www.ucsf.edu/news/2015/09/131526/shouldering-burden-evolution |url-status=live |access-date=May 8, 2023 |archive-url= https://web.archive.org/web/20230508132136/https://www.ucsf.edu/news/2015/09/131526/shouldering-burden-evolution |archive-date=May 8, 2023}}</ref>

== Use of tools ==
[[File:Pierre taillée Melka Kunture Éthiopie fond.jpg|thumb|"A sharp rock", an [[Oldowan]] pebble tool, the most basic of human stone tools]]
[[File:Small bonfire.JPG|thumb|The harnessing of fire was a pivotal milestone in human history.]]
[[File:Acheuleanhandaxes.jpg|thumb|upright|[[Acheulean]] hand-axes from [[Kent]]. ''H.&nbsp;erectus'' [[flint]] work. The types shown are (clockwise from top) cordate, ficron and ovate.]]
[[File:Venus of Willendorf frontview retouched 2.jpg|thumb|upright|[[Venus of Willendorf]], an example of [[Paleolithic]] art, dated circa 30,000 years ago<ref name="PHYS">{{cite journal |last1=Weber |first1=G.W. |last2=Lukeneder |first2=A. |last3=Harzhauser |first3=M. |date=February 28, 2022 |title=The microstructure and origin of the Venus of Willendorf |journal=[[Scientific Reports]] |publisher=[[Nature (journal)|Nature]] |volume=12 |issue=2926 |page=2926 |doi=10.1038/s41598-022-06799-z |pmc=8885675 |pmid=35228605 |doi-access=free}}</ref>]]
{{See also|Hunting hypothesis}}

The use of tools has been interpreted as a sign of intelligence, and it has been theorized that tool use may have stimulated certain aspects of human evolution, especially the continued expansion of the human brain.<ref name="auto">{{cite journal |last=Ko |first=Kwang Hyun |title=Origins of human intelligence: The chain of tool-making and brain evolution |journal=Anthropological Notebooks |date=2016 |volume=22 |issue=1 |pages=5–22 |url= http://www.drustvo-antropologov.si/AN/PDF/2016_1/Anthropological_Notebooks_XXII_1_Ko.pdf |access-date=August 8, 2016 |archive-date=August 17, 2016 |archive-url= https://web.archive.org/web/20160817210720/http://www.drustvo-antropologov.si/AN/PDF/2016_1/Anthropological_Notebooks_XXII_1_Ko.pdf |url-status=live}}</ref> Paleontology has yet to explain the expansion of this organ over millions of years despite being extremely demanding in terms of energy consumption. The brain of a modern human consumes, on average, about 13 watts (260 kilocalories per day), a fifth of the body's resting power consumption.<ref>{{cite journal |last=Jabr |first=Ferris |date=July 18, 2012 |title=Does Thinking Really Hard Burn More Calories? |url= http://www.scientificamerican.com/article/thinking-hard-calories/ |journal=Scientific American |issn=0036-8733 |access-date=May 3, 2015 |archive-date=May 3, 2015 |archive-url= https://web.archive.org/web/20150503113428/http://www.scientificamerican.com/article/thinking-hard-calories/ |url-status=live}}</ref> Increased tool use would allow hunting for energy-rich meat products, and would enable processing more energy-rich plant products. Researchers have suggested that early hominins were thus under evolutionary pressure to increase their capacity to create and use tools.<ref>{{cite journal |last=Gibbons |first=Ann |date=May 29, 1998 |title=Solving the Brain's Energy Crisis |journal=[[Science (journal)|Science]] |volume=280 |issue=5368 |pages=1345–1347 |doi=10.1126/science.280.5368.1345 |issn=0036-8075 |pmid=9634409 |s2cid=28464775}}</ref>

Precisely when early humans started to use tools is difficult to determine, because the more primitive these tools are (for example, sharp-edged stones) the more difficult it is to decide whether they are natural objects or human artifacts.<ref name="auto" /> There is some evidence that the australopithecines (4 Ma) [[Osteodontokeratic culture|may have used broken bones as tools]], but this is debated.{{sfn|Robinson|2008|p=[https://books.google.com/books?id=-kOvkb-xbU8C&pg=PA398 398]}}

[[Tool use by animals|Many species make and use tools]], but it is the human genus that dominates the areas of making and using more complex tools. The oldest known tools are flakes from West Turkana, Kenya, which date to 3.3&nbsp;million years ago.<ref name="Harmand 310–315">{{Cite journal |last1=Harmand |first1=Sonia |last2=Lewis |first2=Jason E. |last3=Feibel |first3=Craig S. |last4=Lepre |first4=Christopher J. |last5=Prat |first5=Sandrine |last6=Lenoble |first6=Arnaud |last7=Boës |first7=Xavier |last8=Quinn |first8=Rhonda L. |last9=Brenet |first9=Michel |date=May 20, 2015 |title=3.3-million-year-old stone tools from Lomekwi 3, West Turkana, Kenya |journal=[[Nature (journal)|Nature]] |volume=521 |issue=7552 |pages=310–315 |doi=10.1038/nature14464 |pmid=25993961 |issn=0028-0836 |bibcode=2015Natur.521..310H |s2cid=1207285}}</ref> The next oldest stone tools are from [[Gona, Ethiopia]], and are considered the beginning of the Oldowan technology. These tools date to about 2.6&nbsp;million years ago.<ref>{{Cite journal |last1=Semaw |first1=Sileshi |last2=Rogers |first2=Michael J. |last3=Quade |first3=Jay |last4=Renne |first4=Paul R. |last5=Butler |first5=Robert F. |last6=Dominguez-Rodrigo |first6=Manuel |last7=Stout |first7=Dietrich |last8=Hart |first8=William S. |last9=Pickering |first9=Travis |last10=Simpson |first10=Scott W. |date=August 1, 2003 |title=2.6-Million-year-old stone tools and associated bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia |journal=Journal of Human Evolution |volume=45 |issue=2 |pages=169–177 |doi=10.1016/S0047-2484(03)00093-9 |pmid=14529651 |issn=0047-2484 |bibcode=2003JHumE..45..169S}}</ref> A ''Homo'' fossil was found near some [[Oldowan]] tools, and its age was noted at 2.3&nbsp;million years old, suggesting that maybe the ''Homo'' species did indeed create and use these tools. It is a possibility but does not yet represent solid evidence.{{sfn|Freeman|Herron|2007|pp=786–788}} The [[third metacarpal styloid process]] enables the hand bone to lock into the wrist bones, allowing for greater amounts of pressure to be applied to the wrist and hand from a grasping thumb and fingers. It allows humans the dexterity and strength to make and use complex tools. This unique anatomical feature separates humans from other apes and other nonhuman primates, and is not seen in human fossils older than 1.8&nbsp;million years.<ref>{{cite journal |last1=Ward |first1=Carol V. |last2=Tocheri |first2=Matthew W. |last3=Plavcan |first3=J. Michael |last4=Brown |first4=Francis H. |last5=Manthi |first5=Fredrick Kyalo |date=January 7, 2014 |title=Early Pleistocene third metacarpal from Kenya and the evolution of modern human-like hand morphology |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=111 |issue=1 |pages=121–124 |doi=10.1073/pnas.1316014110 |issn=0027-8424 |pmc=3890866 |pmid=24344276 |display-authors=3 |bibcode=2014PNAS..111..121W |doi-access=free}}</ref>

Bernard Wood noted that ''Paranthropus'' co-existed with the early ''Homo'' species in the area of the "Oldowan Industrial Complex" over roughly the same span of time. Although there is no direct evidence which identifies ''Paranthropus'' as the tool makers, their anatomy lends to indirect evidence of their capabilities in this area. Most paleoanthropologists agree that the early ''Homo'' species were indeed responsible for most of the Oldowan tools found. They argue that when most of the Oldowan tools were found in association with human fossils, ''Homo'' was always present, but ''Paranthropus'' was not.{{sfn|Freeman|Herron|2007|pp=786–788}}

In 1994, Randall Susman used the anatomy of opposable thumbs as the basis for his argument that both the ''Homo'' and ''Paranthropus'' species were toolmakers. He compared bones and muscles of human and chimpanzee thumbs, finding that humans have 3 muscles which are lacking in chimpanzees. Humans also have thicker metacarpals with broader heads, allowing more precise grasping than the chimpanzee hand can perform. Susman posited that modern anatomy of the human opposable thumb is an evolutionary response to the requirements associated with making and handling tools and that both species were indeed toolmakers.{{sfn|Freeman|Herron|2007|pp=786–788}}

{{anchor|Modern humans and the "Great Leap Forward" debate}}

== Transition to behavioral modernity ==
{{Further|Behavioral modernity}}

Anthropologists describe [[modern human behavior]] to include cultural and behavioral traits such as specialization of tools, use of jewellery and images (such as cave drawings), organization of living space, rituals (such as grave gifts), specialized hunting techniques, exploration of less hospitable geographical areas, and [[barter]] trade networks, as well as more general traits such as language and complex symbolic thinking. Debate continues as to whether a "revolution" led to modern humans ("big bang of human consciousness"), or whether the evolution was more gradual.<ref name="Mcbrearty_Brooks" />

Until about 50,000–40,000 years ago, the use of stone tools seems to have progressed stepwise. Each phase (''H.&nbsp;habilis'', ''H.&nbsp;ergaster'', ''H.&nbsp;neanderthalensis'') marked a new technology, followed by very slow development until the next phase. Currently paleoanthropologists are debating whether these ''Homo'' species possessed some or many modern human behaviors. They seem to have been culturally conservative, maintaining the same technologies and foraging patterns over very long periods.

Around 50,000 [[Before Present|BP]], human culture started to evolve more rapidly. The transition to behavioral modernity has been characterized by some as a "'''Great Leap Forward'''",{{sfn|Diamond|1999|p=39}} or as the "Upper Palaeolithic Revolution",<ref>{{cite journal |last=Bar-Yosef |first=Ofer |author-link=Ofer Bar-Yosef |date=October 2002 |title=The Upper Paleolithic Revolution |journal=Annual Review of Anthropology |volume=31 |pages=363–393 |doi=10.1146/annurev.anthro.31.040402.085416 |issn=0084-6570}}</ref> due to the sudden appearance in the archaeological record of distinctive signs of modern behavior and [[big game hunting]].<ref name="oppenheimer" /> Evidence of behavioral modernity significantly earlier also exists from Africa, with older evidence of abstract imagery, widened subsistence strategies, more sophisticated tools and weapons, and other "modern" behaviors, and many scholars have recently argued that the transition to modernity occurred sooner than previously believed.<ref name="Mcbrearty_Brooks" /><ref name="Henshilwood etal 2002" /><ref name="Henshilwood Marean 2003">{{cite journal |last1=Henshilwood |first1=Christopher |last2=Marean |first2=Curtis |date=2003 |title=The Origin of Modern Human Behavior: Critique of the Models and Their Test Implications |journal=Current Anthropology |volume=44 |issue=5 |pages=627–651 |pmid=14971366 |s2cid=11081605 |doi=10.1086/377665}}</ref><ref name="Backwell">{{cite journal |last1=Backwell |first1=L. |last2=d'Errico |first2=F. |last3=Wadley |first3=L. |date=2008 |title=Middle Stone Age bone tools from the Howiesons Poort layers, Sibudu Cave, South Africa |journal=Journal of Archaeological Science |volume=35 |issue=6 |pages=1566–1580 |doi=10.1016/j.jas.2007.11.006 |bibcode=2008JArSc..35.1566B}}</ref>

Other scholars consider the transition to have been more gradual, noting that some features had already appeared among archaic African ''Homo sapiens'' 300,000–200,000 years ago.<ref>{{cite journal |last=Nowell |first=April |date=October 2010 |title=Defining Behavioral Modernity in the Context of Neandertal and Anatomically Modern Human Populations |journal=Annual Review of Anthropology |volume=39 |pages=437–452 |issn=0084-6570 |doi=10.1146/annurev.anthro.012809.105113}}</ref><ref>{{cite journal |last1=d'Errico |first1=Francesco |last2=Stringer |first2=Chris B. |date=April 12, 2011 |title=Evolution, revolution or saltation scenario for the emergence of modern cultures? |journal=[[Philosophical Transactions of the Royal Society B]] |volume=366 |issue=1567 |pages=1060–1069 |doi=10.1098/rstb.2010.0340 |issn=0962-8436 |pmc=3049097 |pmid=21357228}}</ref><ref>{{cite news |last=Chatterjee |first=Rhitu |title=Scientists Are Amazed By Stone Age Tools They Dug Up In Kenya |date=March 15, 2018 |work=[[NPR]] |url= https://www.npr.org/sections/goatsandsoda/2018/03/15/593591796/scientists-are-amazed-by-stone-age-tools-they-dug-up-in-kenya |access-date=March 15, 2018 |archive-date=March 15, 2018 |archive-url= https://web.archive.org/web/20180315193655/https://www.npr.org/sections/goatsandsoda/2018/03/15/593591796/scientists-are-amazed-by-stone-age-tools-they-dug-up-in-kenya |url-status=live}}</ref><ref name="The Atlantic-555674">{{cite news |last=Yong |first=Ed |author-link=Ed Yong |title=A Cultural Leap at the Dawn of Humanity – New finds from Kenya suggest that humans used long-distance trade networks, sophisticated tools, and symbolic pigments right from the dawn of our species |date=March 15, 2018 |work=[[The Atlantic]] |url= https://www.theatlantic.com/science/archive/2018/03/a-deeper-origin-of-complex-human-cultures/555674/ |access-date=March 15, 2018 |archive-date=November 17, 2020 |archive-url= https://web.archive.org/web/20201117002023/https://www.theatlantic.com/science/archive/2018/03/a-deeper-origin-of-complex-human-cultures/555674/ |url-status=live}}</ref><ref name="Brooks">{{Cite journal |title=Long-distance stone transport and pigment use in the earliest Middle Stone Age |journal=[[Science (journal)|Science]] |volume=360 |issue=6384 |pages=90–94 |date=2018 |pmid=29545508 |doi=10.1126/science.aao2646 |last1=Brooks |first1=A. S. |last2=Yellen |first2=J. E. |last3=Potts |first3=R. |last4=Behrensmeyer |first4=A. K. |last5=Deino |first5=A. L. |last6=Leslie |first6=D. E. |last7=Ambrose |first7=S. H. |last8=Ferguson |first8=J. R. |last9=d'Errico |first9=F. |last10=Zipkin |first10=A. M. |last11=Whittaker |first11=S. |last12=Post |first12=J. |last13=Veatch |first13=E. G. |last14=Foecke |first14=K. |last15=Clark |first15=J. B. |bibcode=2018Sci...360...90B |s2cid=14051717 |doi-access=free}}</ref> Recent evidence suggests that the Australian Aboriginal population separated from the African population 75,000 years ago, and that they made a {{convert|160|km|abbr=on}} sea journey 60,000 years ago, which may diminish the significance of the Upper Paleolithic Revolution.<ref>{{cite journal |first1=Morten |last1=Rasmussen |first2=Xiaosen |last2=Guo |first3=Yong |last3=Wang |first4=Kirk E. |last4=Lohmueller |first5=Simon |last5=Rasmussen |first6=Anders |last6=Albrechtsen |first7=Line |last7=Skotte |first8=Stinus |last8=Lindgreen |first9=Mait |last9=Metspalu|first10=Thibaut |last10=Jombart |first11=Toomas |last11=Kivisild |first12=Weiwei |last12=Zhai |first13=Anders |last13=Eriksson |first14=Andrea |last14=Manica |first15=Ludovic |last15=Orlando |first16=Francisco M. |last16=De La Vega |first17=Silvana |last17=Tridico |first18=Ene |last18=Metspalu |first19=Kasper |last19=Nielsen |first20=María C. |last20=Ávila-Arcos |first21=J. Víctor |last21=Moreno-Mayar |first22=Craig |last22=Muller |first23=Joe |last23=Dortch |first24=M. Thomas P. |last24=Gilbert |first25=Ole |last25=Lund |first26=Agata |last26=Wesolowska |first27=Monika |last27=Karmin |first28=Lucy A. |last28=Weinert |first29=Bo |last29=Wang|first30=Jun |last30=Li |first31=Shuaishuai |last31=Tai |first32=Fei |last32=Xiao |first33=Tsunehiko |last33=Hanihara |first34=George |last34=van Driem |first35=Aashish R. |last35=Jha |first36=François-Xavier |last36=Ricaut |first37=Peter |last37=de Knijff |first38=Andrea B. |last38=Migliano |first39=Irene |last39=Gallego Romero|first40=Karsten |last40=Kristiansen |first41=David M. |last41=Lambert |first42=Søren |last42=Brunak |first43=Peter |last43=Forster |first44=Bernd |last44=Brinkmann |first45=Olaf |last45=Nehlich |first46=Michael |last46=Bunce |first47=Michael |last47=Richards |first48=Ramneek |last48=Gupta |first49=Carlos D. |last49=Bustamante|first50=Anders |last50=Krogh |first51=Robert A. |last51=Foley |first52=Marta M. |last52=Lahr |first53=Francois |last53=Balloux |first54=Thomas |last54=Sicheritz-Pontén |first55=Richard |last55=Villems |first56=Rasmus |last56=Nielsen |first57=Jun |last57=Wang |first58=Eske |last58=Willerslev |display-authors=6 |title=An Aboriginal Australian Genome Reveals Separate Human Dispersals into Asia |journal=[[Science (journal)|Science]] |volume=334 |issue=6052 |pages=94–98 |date=2011 |doi=10.1126/science.1211177 |pmid=21940856 |pmc=3991479  |bibcode=2011Sci...334...94R}}</ref>

Modern humans started burying their dead, making clothing from animal hides, hunting with more sophisticated techniques (such as using [[trapping pit|pit traps]] or driving animals off cliffs), and [[cave painting]].<ref>{{cite journal |last=Ambrose |first=Stanley H. |date=March 2, 2001 |title=Paleolithic Technology and Human Evolution |journal=[[Science (journal)|Science]] |volume=291 |issue=5509 |pages=1748–1753 |bibcode=2001Sci...291.1748A |doi=10.1126/science.1059487 |issn=0036-8075 |pmid=11249821 |s2cid=6170692}}</ref> As human culture advanced, different populations innovated existing technologies: artifacts such as fish hooks, buttons, and bone needles show signs of cultural variation, which had not been seen prior to 50,000 BP. Typically, the older ''H.&nbsp;neanderthalensis'' populations did not vary in their technologies, although the [[Chatelperronian]] assemblages have been found to be Neanderthal imitations of ''H.&nbsp;sapiens'' [[Aurignacian]] technologies.<ref>{{cite journal |last=Mellars |first=P. |date=2010 |title=Neanderthal symbolism and ornament manufacture: The bursting of a bubble? |journal=Proc Natl Acad Sci USA |volume=107 |issue=47 |pages=20147–20148 |doi=10.1073/pnas.1014588107 |pmid=21078972 |pmc=2996706 |bibcode=2010PNAS..10720147M |doi-access=free}}</ref>

== Recent and ongoing human evolution ==
{{Main|Recent human evolution}}
[[Anatomically modern human]] populations continue to evolve, as they are affected by both natural selection and [[genetic drift]]. Although [[selection pressure]] on some traits, such as resistance to smallpox, has decreased in the modern age, humans are still undergoing natural selection for many other traits. Some of these are due to specific environmental pressures, while others are related to lifestyle changes since the development of agriculture (10,000 years ago), urbanization (5,000), and industrialization (250 years ago). It has been argued that human evolution has accelerated since the development of agriculture 10,000 years ago and civilization some 5,000 years ago, resulting, it is claimed, in substantial genetic differences between different current human populations,{{sfn|Cochran|Harpending|2009}} and more recent research indicates that for some traits, the developments and innovations of human culture have driven a new form of selection that coexists with, and in some cases has largely replaced, natural selection.<ref>{{Cite journal |last=Bender |first=Andrea |date=August 8, 2019 |title=The Role of Culture and Evolution for Human Cognition |journal=Topics in Cognitive Science |volume=12 |issue=4 |pages=1403–1420 |doi=10.1111/tops.12449 |pmid=31392845 |issn=1756-8757 |doi-access=free |hdl=1956/22031 |hdl-access=free}}</ref>

[[File:Homo sapiens sapiens, Oase, Rumänien (Daniela Hitzemann).jpg|thumb|180px|Reconstruction of the [[Initial Upper Paleolithic|upper Palaeolithic]] human [[Oase 2]] {{c.|40 000 years BP}}<ref>{{cite journal |last1=Fu |first1=Q. |last2=Hajdinjak |first2=M. |last3=Moldovan |first3=O. T. |last4=Constantin |first4=S. |last5=Mallick |first5=S. |last6=Skoglund |first6=Pontus |last7=Patterson |first7=N. |last8=Rohland |first8=N. |last9=Lazaridis |first9=I. |last10=Nickel |first10=B. |last11=Viola |first11=B. |last12=Prüfer |first12=Kay |last13=Meyer |first13=M. |last14=Kelso |first14=J. |last15=Reich |first15=D. |last16=Pääbo |first16=S. |author16-link=Svante Pääbo |title=An early modern human from Romania with a recent Neanderthal ancestor |journal=[[Nature (journal)|Nature]] |date=2015 |volume=524 |issue=7564 |pages=216–219 |doi=10.1038/nature14558 |pmid=26098372 |pmc=4537386 |bibcode=2015Natur.524..216F}}</ref>]]
Particularly conspicuous is variation in superficial characteristics, such as [[Afro-textured hair]], or the recent evolution of [[light skin]] and blond hair in some populations, which are attributed to differences in climate. Particularly strong selective pressures have resulted in [[high-altitude adaptation in humans]], with different ones in different isolated populations. Studies of the [[High-altitude adaptation in humans#Genetic basis|genetic basis]] show that some developed very recently, with Tibetans evolving over 3,000 years to have high proportions of an allele of [[EPAS1]] that is adaptive to high altitudes.

Other evolution is related to [[endemic disease]]s: the presence of [[malaria]] selects for [[sickle cell trait]] (the [[heterozygous]] form of sickle cell gene), while in the absence of malaria, the health effects of [[sickle-cell anemia]] select against this trait. For another example, the population at risk of the severe debilitating disease [[kuru (disease)|kuru]] has significant over-representation of an immune variant of the [[PRNP|prion protein]] gene G127V versus non-immune alleles. The frequency of this [[Mutation|genetic variant]] is due to the survival of immune persons.<ref>{{cite news |author=Medical Research Council [UK] |author-link=Medical Research Council (United Kingdom) |date=November 21, 2009 |title=Brain Disease 'Resistance Gene' evolves in Papua New Guinea community; could offer insights into CJD |url= https://www.sciencedaily.com/releases/2009/11/091120091959.htm |work=ScienceDaily |access-date=November 22, 2009 |archive-date=June 8, 2019 |archive-url= https://web.archive.org/web/20190608194846/https://www.sciencedaily.com/releases/2009/11/091120091959.htm |url-status=live}}</ref><ref>{{Cite journal |doi=10.1056/NEJMoa0809716 |pmid=19923577 |date=2009 |display-authors=3 |last1=Mead |first1=S. |last2=Whitfield |first2=J. |last3=Poulter |first3=M. |last4=Shah |first4=P. |last5=Uphill |first5=J. |last6=Campbell |first6=T. |last7=Al-Dujaily |first7=H. |last8=Hummerich |first8=H. |last9=Beck |first9=J. |last10=Mein |first10=C. A. |last11=Verzilli |first11=C. |last12=Whittaker |first12=J. |last13=Alpers |first13=M. P. |last14=Collinge |first14=J. |title=A Novel Protective Prion Protein Variant that Colocalizes with Kuru Exposure |volume=361 |issue=21 |pages=2056–2065 |journal=The New England Journal of Medicine |url= https://researchonline.lshtm.ac.uk/4514/1/nejmoa0809716.pdf |access-date=August 20, 2019 |archive-date=July 20, 2018 |archive-url= https://web.archive.org/web/20180720215808/http://researchonline.lshtm.ac.uk/4514/1/nejmoa0809716.pdf |url-status=live}}{{collapsible list |title=Full list of authors |bullets=true |Simon Mead |Jerome Whitfield |Mark Poulter |Paresh Shah |James Uphill |Tracy Campbell |Huda Al-Dujaily |Holger Hummerich |Jon Beck |Charles A. Mein |Claudio Verzilli |John Whittaker |Michael P. Alpers |John Collinge}}</ref> Some reported trends remain unexplained and the subject of ongoing research in the novel field of evolutionary medicine: [[polycystic ovary syndrome]] (PCOS) reduces fertility and thus is expected to be subject to extremely strong negative selection, but its relative commonality in human populations suggests a counteracting selection pressure. The identity of that pressure remains the subject of some debate.<ref>{{Cite journal |last1=Corbett |first1=Stephen |last2=Morin-Papunen |first2=Laure |date=July 2013 |title=The Polycystic Ovary Syndrome and recent human evolution |journal=Molecular and Cellular Endocrinology |volume=373 |issue=1–2 |pages=39–50 |pmid=23352610 |s2cid=13078403 |doi=10.1016/j.mce.2013.01.001 |url= https://linkinghub.elsevier.com/retrieve/pii/S030372071300004X |access-date=October 8, 2020 |archive-date=May 25, 2021 |archive-url= https://web.archive.org/web/20210525180722/https://linkinghub.elsevier.com/retrieve/pii/S030372071300004X |url-status=live|url-access=subscription }}</ref>

Recent human evolution related to agriculture includes genetic resistance to infectious disease that has appeared in human populations by crossing the species barrier from domesticated animals,{{sfn|Diamond|1999}} as well as changes in metabolism due to changes in diet, such as [[lactase persistence]].

Culturally-driven evolution can defy the expectations of natural selection:  while human populations experience some pressure that drives a selection for producing children at younger ages, the advent of effective contraception, higher education, and changing social norms have driven the observed selection in the opposite direction.<ref>{{Cite journal |last1=Courtiol |first1=Alexandre |last2=Tropf |first2=Felix C. |last3=Mills |first3=Melinda C. |date=July 12, 2016 |title=When genes and environment disagree: Making sense of trends in recent human evolution |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=113 |issue=28 |pages=7693–7695 |doi=10.1073/pnas.1608532113 |issn=0027-8424 |pmc=4948334 |pmid=27402758 |bibcode=2016PNAS..113.7693C |doi-access=free}}</ref> However, culturally-driven selection need not necessarily work counter or in opposition to natural selection:  some proposals to explain the high rate of recent human brain expansion indicate a kind of feedback whereupon the brain's increased social learning efficiency encourages cultural developments that in turn encourage more efficiency, which drive more complex cultural developments that demand still-greater efficiency, and so forth.<ref>{{Cite journal |last1=Markov |first1=Alexander V. |last2=Markov |first2=Mikhail A. |date=June 2020 |title=Runaway brain-culture coevolution as a reason for larger brains: Exploring the "cultural drive" hypothesis by computer modeling |journal=Ecology and Evolution |volume=10 |issue=12 |pages=6059–6077 |doi=10.1002/ece3.6350 |issn=2045-7758 |pmc=7319167 |pmid=32607213 |bibcode=2020EcoEv..10.6059M}}</ref> Culturally-driven evolution has an advantage in that in addition to the genetic effects, it can be observed also in the archaeological record:  the development of stone tools across the Palaeolithic period connects to culturally-driven cognitive development in the form of skill acquisition supported by the culture and the development of increasingly complex technologies and the cognitive ability to elaborate them.<ref>{{Cite journal |last=Stout |first=Dietrich |date=April 12, 2011 |title=Stone toolmaking and the evolution of human culture and cognition |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |volume=366 |issue=1567 |pages=1050–1059 |doi=10.1098/rstb.2010.0369 |issn=0962-8436 |pmc=3049103 |pmid=21357227}}</ref>

In contemporary times, since industrialization, some trends have been observed: for instance, menopause is evolving to occur later.<ref name="doi10.1073/pnas.0906199106" /> Other reported trends appear to include lengthening of the human reproductive period and reduction in cholesterol levels, blood glucose and blood pressure in some populations.<ref name="doi10.1073/pnas.0906199106">{{Cite journal |first1=S. G. |last1=Byars |last3=Govindaraju |first2=D. |first3=D. R. |last2=Ewbank |first4=S. C. |last4=Stearns |title=Natural selection in a contemporary human population |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |date=2009 |pmid=19858476 |pmc=2868295 |doi=10.1073/pnas.0906199106 |volume=107 |issue=suppl_1 |pages=1787–1792 |bibcode=2010PNAS..107.1787B |doi-access=free}}</ref>

== History of study ==
{{For timeline|Timeline of human evolution}}

=== Before Darwin ===
The name {{lang|la|Homo}} of the biological genus to which humans belong is [[Latin]] for 'human'.{{efn|The Latin word which refers to adult
males only is {{lang|la|vir}}}} It was chosen originally by [[Carl Linnaeus]] in his classification system.{{efn|See the [[Binomial nomenclature]] and {{lang|la|[[Systema Naturae]]}} articles.}} The English word ''human'' is from the Latin {{lang|la|humanus}}, the adjectival form of {{lang|la|homo}}. The Latin {{lang|la|homo}} derives from the [[Proto-Indo-European language|Indo-European]] root *''{{PIE|dhghem}}'', or 'earth'.<ref>{{cite book |title=More Word Histories and Mysteries: From Aardvark to Zombie |editor=((Editors of the American Heritage Dictionaries)) |date=2006 |location=Boston |publisher=[[Houghton Mifflin Harcourt|Houghton Mifflin]] |isbn=978-0-618-71681-4 |lccn=2006020835 |oclc=70199867 |url= https://archive.org/details/morewordhistorie0000unse |url-access=registration}}{{page needed|date=December 2021}}</ref> Linnaeus and other scientists of his time also considered the great apes to be the closest relatives of humans based on [[Morphology (biology)|morphological]] and [[Anatomy|anatomical]] similarities.<ref>{{cite web |title=Nested Hierarchies, the Order of Nature: Carolus Linnaeus |work=Understanding Evolution: The History of Evolutionary Thought |publisher=The University of California at Berkeley |url= https://evolution.berkeley.edu/evolibrary/article/0_0_0/history_05 |access-date=August 2, 2019 |archive-date=August 2, 2019 |archive-url= https://web.archive.org/web/20190802105432/https://evolution.berkeley.edu/evolibrary/article/0_0_0/history_05 |url-status=live}}</ref>

=== Darwin ===
The possibility of linking humans with earlier apes by descent became clear only after 1859 with the publication of [[Charles Darwin]]'s ''[[On the Origin of Species]]'', in which he argued for the idea of the evolution of new species from earlier ones. Darwin's book did not address the question of human evolution, saying only that "Light will be thrown on the origin of man and his history."{{sfn|Darwin|1859|pp=[http://darwin-online.org.uk/content/frameset?itemID=F373&viewtype=text&pageseq=506 367–404]}}

The first debates about the nature of human evolution arose between [[Thomas Henry Huxley]] and [[Richard Owen]]. Huxley argued for human evolution from apes by illustrating many of the similarities and differences between humans and other apes, and did so particularly in his 1863 book ''[[Evidence as to Man's Place in Nature]]''. Many of Darwin's early supporters (such as [[Alfred Russel Wallace]] and [[Charles Lyell]]) did not initially agree that the origin of the mental capacities and the moral sensibilities of humans could be explained by [[natural selection]], though this later changed. Darwin applied the theory of evolution and [[sexual selection]] to humans in his 1871 book ''[[The Descent of Man, and Selection in Relation to Sex]]''.{{sfn|Darwin|1981}}

=== First fossils ===
A major problem in the 19th century was the lack of [[Transitional fossil|fossil intermediaries]]. [[Neanderthal]] remains were discovered in a limestone quarry in 1856, three years before the publication of ''On the Origin of Species'', and Neanderthal fossils had been discovered in Gibraltar even earlier, but it was originally claimed that these were the remains of a modern human who had suffered some kind of illness.{{sfn|Montgomery|1988|pp=95–96}} Despite the 1891 discovery by [[Eugène Dubois]] of what is now called ''Homo erectus'' at [[Trinil]], [[Java]], it was only in the 1920s when such fossils were discovered in Africa, that intermediate species began to accumulate.<ref>{{Cite journal |last1=Shipman |first1=Pat |last2=Storm |first2=Paul |date=2002 |title=Missing links: Eugène Dubois and the origins of paleoanthropology |journal=Evolutionary Anthropology: Issues, News, and Reviews |volume=11 |issue=3 |pages=108–116 |doi=10.1002/evan.10021 |s2cid=84889438 |issn=1520-6505}}</ref> In 1925, [[Raymond Dart]] described ''[[Australopithecus africanus]]''.<ref>{{cite journal |last=Dart |first=Raymond |author-link=Raymond Dart |date=February 7, 1925 |title=''Australopithecus africanus'': The Man-Ape of South Africa |journal=[[Nature (journal)|Nature]] |volume=115 |issue=2884 |pages=195–199 |doi=10.1038/115195a0 |issn=0028-0836 |bibcode=1925Natur.115..195D |s2cid=4142569 |doi-access=free}}</ref> The [[Type (biology)|type specimen]] was the [[Taung Child]], an australopithecine infant which was discovered in a cave. The child's remains were a remarkably well-preserved tiny skull and an [[endocast]] of the brain.

Although the brain was small (410&nbsp;cm<sup>3</sup>), its shape was rounded, unlike that of chimpanzees and gorillas, and more like a modern human brain. Also, the specimen showed short [[Canine tooth|canine teeth]], and the position of the [[foramen magnum]] (the hole in the skull where the spine enters) was evidence of [[bipedal]] locomotion. All of these traits convinced Dart that the Taung Child was a bipedal human ancestor, a transitional form between apes and humans.

=== The East African fossils ===
[[File:Fossil hominids.jpg|thumb|upright|left|[[Fossil]] [[hominid]] evolution display at [[The Museum of Osteology]], [[Oklahoma City]], Oklahoma, US]]

During the 1960s and 1970s, hundreds of fossils were found in East Africa in the regions of the [[Olduvai Gorge]] and [[Lake Turkana]]. These searches were carried out by the Leakey family, with [[Louis Leakey]] and his wife [[Mary Leakey]], and later their son [[Richard Leakey|Richard]] and daughter-in-law [[Meave Leakey|Meave]], fossil hunters and paleoanthropologists. From the fossil beds of Olduvai and Lake Turkana they amassed specimens of the early hominins: the australopithecines and ''Homo'' species, and even ''H.&nbsp;erectus''.

These finds cemented Africa as the cradle of humankind. In the late 1970s and the 1980s, [[Ethiopia]] emerged as the new hot spot of paleoanthropology after [[Lucy (Australopithecus)|"Lucy"]], the most complete fossil member of the species ''[[Australopithecus afarensis]]'', was found in 1974 by [[Donald Johanson]] near [[Hadar, Ethiopia|Hadar]] in the desertic [[Afar Triangle]] region of northern Ethiopia. Although the specimen had a small brain, the pelvis and leg bones were almost identical in function to those of modern humans, showing with certainty that these hominins had walked erect.{{sfn|Johanson|Edey|1981|pp=20–22, 184–185}} Lucy was classified as a new species, ''Australopithecus afarensis'', which is thought to be more closely related to the genus ''Homo'' as a direct ancestor, or as a close relative of an unknown ancestor, than any other known hominid or hominin from this early time range.<ref>{{cite book |title=The Human Lineage |last1=Cartmill |first1=Matt |last2=Smith |first2=Fred H. |last3=Brown |first3=Kaye B. |page=[https://books.google.com/books?id=5TRHOmTUTP4C&pg=PA151 151] |date=2009 |publisher=Wiley-Blackwell |isbn=978-0-471-21491-5}}</ref> (The specimen was nicknamed "Lucy" after [[the Beatles]]' song "[[Lucy in the Sky with Diamonds]]", which was played loudly and repeatedly in the camp during the excavations.){{sfn|Johanson|Edey|1981|p=22}} The [[Afar Triangle]] area would later yield discovery of many more hominin fossils, particularly those uncovered or described by teams headed by [[Tim D. White]] in the 1990s, including ''[[Ardipithecus ramidus]]'' and ''[[Ardipithecus kadabba|A.&nbsp;kadabba]]''.<ref>{{cite journal |last=Shreeve |first=Jamie |date=July 2010 |title=The Evolutionary Road |url= http://ngm.nationalgeographic.com/2010/07/middle-awash/shreeve-text |journal=National Geographic |issn=0027-9358 |access-date=May 28, 2015 |archive-date=January 26, 2016 |archive-url= https://web.archive.org/web/20160126024510/http://ngm.nationalgeographic.com/2010/07/middle-awash/shreeve-text |url-status=dead}}</ref>

In 2013, fossil skeletons of ''[[Homo naledi]]'', an [[extinct species]] of [[hominin]] assigned (provisionally) to the genus ''Homo'', were found in the [[Rising Star Cave]] system, a site in South Africa's [[Cradle of Humankind]] region in [[Gauteng]] province near [[Johannesburg]].<ref>{{cite journal |doi=10.7554/eLife.09560 |volume=4 |title=''Homo naledi'', a new species of the genus ''Homo'' from the Dinaledi Chamber, South Africa |journal=eLife |pmid=26354291 |pmc=4559886 |date=September 10, 2015 |last1=Berger |first1=L. R. |last2=Hawks |first2=J. |last3=de Ruiter |first3=D. J. |last4=Churchill |first4=S. E. |display-authors=etal |doi-access=free}}{{collapsible list |title=Full list of authors |bullets=true |Lee R Berger |John Hawks |Darryl J de Ruiter |Steven E Churchill |Peter Schmid |Lucas K Delezene |Tracy L Kivell |Heather M Garvin |Scott A Williams |Jeremy M DeSilva |Matthew M Skinner |Charles M Musiba |Noel Cameron |Trenton W Holliday |William Harcourt-Smith |Rebecca R Ackermann |Markus Bastir |Barry Bogin |Debra Bolter |Juliet Brophy |Zachary D Cofran |Kimberly A Congdon |Andrew S Deane |Mana Dembo |Michelle Drapeau |Marina C Elliott |Elen M Feuerriegel |Daniel Garcia-Martinez |David J Green |Alia Gurtov |Joel D Irish |Ashley Kruger |Myra F Laird |Damiano Marchi |Marc R Meyer |Shahed Nalla |Enquye W Negash |Caley M Orr |Davorka Radovcic |Lauren Schroeder |Jill E Scott |Zachary Throckmorton |Matthew W Tocheri |Caroline VanSickle |Christopher S Walker |Pianpian Wei |Bernhard Zipfel}}</ref><ref name="NGS-20150910" /> {{As of|2015|9}}, fossils of at least fifteen individuals, amounting to 1,550 specimens, have been excavated from the cave.<ref name="NGS-20150910">{{cite web |last=Shreeve |first=Jamie |title=This Face Changes the Human Story. But How? |url= http://news.nationalgeographic.com/2015/09/150910-human-evolution-change/ |date=September 10, 2015 |work=[[National Geographic News]] |access-date=September 10, 2015 |archive-date=April 14, 2018 |archive-url= https://web.archive.org/web/20180414054102/https://news.nationalgeographic.com/2015/09/150910-human-evolution-change/ |url-status=dead}}</ref> The species is characterized by a body mass and stature similar to small-bodied human populations, a smaller [[Endocranium|endocranial]] volume similar to ''[[Australopithecus]]'', and a [[Skull|cranial]] [[Morphology (biology)|morphology]] (skull shape) similar to early ''Homo'' species. The skeletal anatomy combines primitive features known from [[australopithecine]]s with features known from early hominins. The individuals show signs of having been deliberately disposed of within the cave near the time of death. The fossils were dated close to 250,000 years ago,<ref>{{harvp|Dirks|Roberts|Hilbert-Wolf|Kramers|2017}}: between 335 and 236 ka. The lower limit of 236 ka is due to optically stimulated luminescence dating of sediments with U-Th and palaeomagnetic analyses of flowstones; the upper limit of 335 ka is due to U-series and electron spin resonance (US-ESR) dating of two ''H. naledi'' teeth, to {{val|253|82|70|u=ka}}, for an estimated age of the fossils of {{val|253|82|17|u=ka}}.</ref> and thus are not ancestral but contemporary with the first appearance of larger-brained [[anatomically modern humans]].<ref name="eLIFE-2017a">{{Cite journal |last1=Dirks |first1=Paul H. G. M. |first2=Eric M. |last2=Roberts |first3=Hannah |last3=Hilbert-Wolf |first4=Jan D. |last4=Kramers |first5=John |last5=Hawks |first6=Anthony |last6=Dosseto |first7=Mathieu |last7=Duval |first8=Marina |last8=Elliott |first9=Mary |last9=Evans |first10=Rainer |last10=Grün |first11=John |last11=Hellstrom |first12=Andy I. R. |last12=Herries |first13=Renaud |last13=Joannes-Boyau |first14=Tebogo V. |last14=Makhubela |first15=Christa J. |last15=Placzek |first16=Jessie |last16=Robbins |first17=Carl |last17=Spandler |first18=Jelle |last18=Wiersma |first19=Jon |last19=Woodhead |first20=Lee R. |last20=Berger |display-authors=4 |name-list-style=vanc |date=May 9, 2017 |title=The age of ''Homo naledi'' and associated sediments in the Rising Star Cave, South Africa |journal=eLife |volume=6 |pages=e24231 |pmid=28483040 |pmc=5423772 |doi=10.7554/eLife.24231 |doi-access=free}}{{collapsible list| title=Full list of authors| bullets=true| Paul H.G.M. Dirks| Eric M. Roberts| Hannah Hilbert-Wolf| Jan D. Kramers| John Hawks| Anthony Dosseto| Mathieu Duval| Marina Elliott| Mary Evans| Rainer Grün| John Hellstrom| Andy I.R. Herries| Renaud Joannes-Boyau| Tebogo V. Makhubela| Christa J. Placzek| Jessie Robbins| Carl Spandler| Jelle Wiersma| Jon Woodhead| Lee R. Berger}}</ref>

=== The genetic revolution ===

The genetic revolution in studies of human evolution started when [[Vincent Sarich]] and [[Allan Wilson (biologist)|Allan Wilson]] measured the strength of immunological cross-reactions of [[Serum (blood)|blood serum]] [[albumin]] between pairs of creatures, including humans and African apes (chimpanzees and gorillas).<ref name="MolClock">{{Cite journal |last1=Sarich |first1=V. M. |last2=Wilson |first2=A. C. |title=Immunological time scale for hominid evolution |journal=[[Science (journal)|Science]] |volume=158 |issue=3805 |pages=1200–1204 |date=1967 |pmid=4964406 |doi=10.1126/science.158.3805.1200 |bibcode=1967Sci...158.1200S |s2cid=7349579}}</ref> The strength of the reaction could be expressed numerically as an immunological distance, which was in turn proportional to the number of [[amino acid]] differences between homologous proteins in different species. By constructing a calibration curve of the ID of species' pairs with known divergence times in the fossil record, the data could be used as a [[molecular clock]] to estimate the times of divergence of pairs with poorer or unknown fossil records.

In their seminal 1967 paper in ''[[Science (journal)|Science]]'', Sarich and Wilson estimated the divergence time of humans and apes as four to five million years ago,<ref name="MolClock" /> at a time when standard interpretations of the fossil record gave this divergence as at least 10 to as much as 30&nbsp;million years. Subsequent fossil discoveries, notably "Lucy", and reinterpretation of older fossil materials, notably ''[[Sivapithecus|Ramapithecus]]'', showed the younger estimates to be correct and validated the albumin method.

Progress in [[DNA sequencing]], specifically [[mitochondrial DNA]] (mtDNA) and then [[Human Y-chromosome DNA haplogroup|Y-chromosome DNA]] (Y-DNA) advanced the understanding of human origins.{{sfn|DeSalle|Tattersall|2008|p=[https://books.google.com/books?id=Bf4Sitw7YaIC&pg=PA146 146]}}{{sfn|M'charek|2005|p=[https://books.google.com/books?id=n-K436zeUY8C&pg=PA96 96]}}{{sfn|Trent|2005|p=[https://books.google.com/books?id=772BEp8ZyMYC&pg=PA6 6]}} Application of the [[molecular clock]] principle revolutionized the study of [[molecular evolution]].

On the basis of a separation from the [[orangutan]] between 10 and 20&nbsp;million years ago, earlier studies of the molecular clock suggested that there were about 76 mutations per generation that were not inherited by human children from their parents; this evidence supported the divergence time between hominins and chimpanzees noted above. However, a 2012 study in Iceland of 78 children and their parents suggests a mutation rate of only 36 mutations per generation; this datum extends the separation between humans and chimpanzees to an earlier period greater than 7&nbsp;million years ago ([[Year#SI prefix multipliers|Ma]]). Additional research with 226 offspring of wild chimpanzee populations in eight locations suggests that chimpanzees reproduce at age 26.5 years on average; which suggests the human divergence from chimpanzees occurred between 7 and 13&nbsp;mya. And these data suggest that ''Ardipithecus'' (4.5 Ma), ''Orrorin'' (6 Ma) and ''Sahelanthropus'' (7 Ma) all may be on the hominid [[Lineage (evolution)|lineage]], and even that the separation may have occurred outside the [[East African Rift]] region.

Furthermore, analysis of the two species' genes in 2006 provides evidence that after human ancestors had started to diverge from chimpanzees, interspecies mating between "proto-human" and "proto-chimpanzees" nonetheless occurred regularly enough to change certain genes in the new [[gene pool]]:
: A new comparison of the human and chimpanzee genomes suggests that after the two lineages separated, they may have begun interbreeding... A principal finding is that the [[X chromosome]]s of humans and chimpanzees appear to have [[Genetic divergence|diverged]] about 1.2&nbsp;million years more recently than the other chromosomes.
The research suggests:
: There were in fact two splits between the human and chimpanzee lineages, with the first being followed by interbreeding between the two populations and then a second split. The suggestion of a hybridization has startled paleoanthropologists, who nonetheless are treating the new genetic data seriously.<ref>{{cite news |last=Wade |first=Nicholas |author-link=Nicholas Wade |date=May 18, 2006 |title=Two Splits Between Human and Chimp Lines Suggested |url= https://www.nytimes.com/2006/05/18/science/18evolve.html |newspaper=The New York Times |access-date=April 20, 2015 |archive-date=May 18, 2022 |archive-url= https://web.archive.org/web/20220518095858/https://www.nytimes.com/2006/05/18/science/18evolve.html |url-status=live}}</ref>

=== The quest for the earliest hominin ===
In the 1990s, several teams of paleoanthropologists were working throughout Africa looking for evidence of the earliest divergence of the hominin lineage from the great apes. In 1994, Meave Leakey discovered ''[[Australopithecus anamensis]]''. The find was overshadowed by Tim D. White's 1995 discovery of ''Ardipithecus ramidus'', which pushed back the fossil record to {{ma|4.2}}.

In 2000, [[Martin Pickford]] and [[Brigitte Senut]] discovered, in the [[Tugen Hills]] of [[Kenya]], a 6-million-year-old bipedal hominin which they named ''[[Orrorin|Orrorin tugenensis]]''. And in 2001, a team led by [[Michel Brunet (paleontologist)|Michel Brunet]] discovered the skull of ''[[Sahelanthropus|Sahelanthropus tchadensis]]'' which was dated as {{ma|7.2|million years ago}}, and which Brunet argued was a bipedal, and therefore a hominid—that is, a hominin ({{lang|la|{{abbr|cf|confer}}}} [[Hominidae]]; terms "hominids" and hominins).

=== Human dispersal ===
{{See also|Early human migrations|Recent African origin of modern humans|Multiregional origin of modern humans|Archaic humans in Southeast Asia}}
{{multiple image
| total_width       = 570
| footer            = Different models for the beginning of the present human species
| image1            = World map of prehistoric human migrations.jpg
| alt1              = Map with arrows emanating from Africa, across Eurasia, to Australia and the Americas.
| caption1          = A global mapping model of human migration, based from divergence of the [[mitochondrial DNA]] (which indicates the [[Lineage (genetic)|matrilineage]]).<ref name="Behar 2008" /><ref name="Gonder 2007" /><ref name="Tishkoff 2009" /> Timescale ([[Year#SI prefix multipliers|ka]]) indicated by colours.
| image2            = Homo trellis.jpg
| alt2              = Trellis of intermingling populations for the last two million years.
| caption2          = A "trellis" (as [[Milford H. Wolpoff]] called it) that emphasizes back-and-forth gene flow among geographic regions<ref>{{cite journal |last=Templeton |first=Alan R. |author-link=Alan Templeton |date=2005 |title=Haplotype Trees and Modern Human Origins |journal=[[American Journal of Physical Anthropology]] |volume=128 |issue=Supplement 41: Yearbook of Physical Anthropology |pages=33–59 |doi=10.1002/ajpa.20351 |issn=0002-9483 |pmid=16369961}}</ref>
}}

Anthropologists in the 1980s were divided regarding some details of reproductive barriers and migratory dispersals of the genus ''Homo''. Subsequently, genetics has been used to investigate and resolve these issues. According to the [[Sahara pump theory]] evidence suggests that the genus ''Homo'' have migrated out of Africa at least three and possibly four times (e.g. ''Homo erectus'', ''Homo heidelbergensis'' and two or three times for ''Homo sapiens''). Recent evidence suggests these dispersals are closely related to fluctuating periods of climate change.<ref>{{cite magazine |last=deMenocal |first=Peter B. |date=2016 |title=Climate Shocks |magazine=[[Scientific American]] |volume=25 |issue=4}}</ref>

Recent evidence suggests that humans may have left Africa half a million years earlier than previously thought. A joint Franco-Indian team has found human artifacts in the Siwalk Hills north of New Delhi dating back at least 2.6&nbsp;million years. This is earlier than the previous earliest finding of genus ''Homo'' at [[Dmanisi]], in [[Georgia (country)|Georgia]], dating to 1.85&nbsp;million years. Although controversial, tools found at a Chinese cave strengthen the case that humans used tools as far back as 2.48&nbsp;million years ago.<ref>{{cite magazine |last=Barras |first=Colin |title=Stone tools hint humans reached Asia much earlier |magazine=[[New Scientist]] |date=February 6, 2016}}</ref> This suggests that the Asian "Chopper" tool tradition, found in Java and northern China may have left Africa before the appearance of the [[Acheulian]] hand axe.

==== Dispersal of modern ''Homo sapiens'' ====
Up until the genetic evidence became available, there were two dominant models for the dispersal of modern humans. The [[Multiregional evolution|multiregional hypothesis]] proposed that the genus ''Homo'' contained only a single interconnected population as it does today (not separate species), and that its evolution took place worldwide continuously over the last couple of million years. This model was proposed in 1988 by [[Milford H. Wolpoff]].<ref>{{cite journal |last1=Wolpoff |first1=Milford H. |author1-link=Milford H. Wolpoff |last2=Hawks |first2=John |author2-link=John D. Hawks |last3=Caspari |first3=Rachel |date=May 2000 |title=Multiregional, Not Multiple Origins |journal=American Journal of Physical Anthropology |volume=112 |issue=1 |pages=129–136 |doi=10.1002/(SICI)1096-8644(200005)112:1<129::AID-AJPA11>3.0.CO;2-K |issn=0002-9483 |pmid=10766948 |url= http://www-personal.umich.edu/~wolpoff/Papers/Multiregional.PDF |hdl=2027.42/34270 |hdl-access=free |access-date=May 12, 2013 |archive-date=January 25, 2021 |archive-url= https://web.archive.org/web/20210125052356/http://www-personal.umich.edu/~wolpoff/Papers/Multiregional.PDF |url-status=live}}</ref><ref>{{cite journal |last1=Wolpoff |first1=M. H. |author1-link=Milford H. Wolpoff |last2=Spuhler |first2=J. N. |last3=Smith |first3=F. H. |last4=Radovcic |first4=J. |last5=Pope |first5=G. |last6=Frayer |first6=D. W. |last7=Eckhardt |first7=R. |last8=Clark |first8=G. |date=August 12, 1988 |title=Modern Human Origins |journal=[[Science (journal)|Science]] |volume=241 |issue=4867 |pages=772–774 |bibcode=1988Sci...241..772W |doi=10.1126/science.3136545 |issn=0036-8075 |pmid=3136545 |s2cid=5223638}}</ref> In contrast, the "out of Africa" model proposed that modern ''H.&nbsp;sapiens'' speciated in Africa recently (that is, approximately 200,000 years ago) and the subsequent migration through [[Eurasia]] resulted in the nearly complete replacement of other ''Homo'' species. This model has been developed by [[Chris Stringer]] and Peter Andrews.<ref>{{cite news |last=Owen |first=James |date=July 18, 2007 |url= http://news.nationalgeographic.com/news/2007/07/070718-african-origin.html |title=Modern Humans Came Out of Africa, 'Definitive' Study Says |work=National Geographic News |location=Washington, DC |publisher=[[National Geographic Society]] |access-date=May 14, 2011 |archive-date=June 27, 2018 |archive-url= https://web.archive.org/web/20180627005155/https://news.nationalgeographic.com/news/2007/07/070718-african-origin.html |url-status=dead}}</ref><ref>{{cite journal |last1=Stringer |first1=Chris B. |last2=Andrews |first2=Peter |date=March 11, 1988 |title=Genetic and fossil evidence for the origin of modern humans |journal=[[Science (journal)|Science]] |volume=239 |issue=4845 |pages=1263–1268 |issn=0036-8075 |bibcode=1988Sci...239.1263S |doi=10.1126/science.3125610 |pmid=3125610 |s2cid=39200956}}</ref>

Sequencing mtDNA and Y-DNA sampled from a wide range of indigenous populations revealed ancestral information relating to both male and female genetic heritage, and strengthened the "out of Africa" theory and weakened the views of multiregional evolutionism.{{sfn|Webster|2010|p=[https://books.google.com/books?id=cdiy1EhJVW0C&pg=PA53 53]}} Aligned in genetic tree differences were interpreted as supportive of a recent single origin.{{sfn|Ramachandran|Tang|Gutenkunst|Bustamante|2010|p=[https://books.google.com/books?id=FlfPSpBvKLgC&pg=PA606 606]}}

"Out of Africa" has thus gained much support from research using female mitochondrial DNA and the male [[Y chromosome]]. After analysing genealogy trees constructed using 133 types of mtDNA, researchers concluded that all were descended from a female African progenitor, dubbed [[Mitochondrial Eve]]. "Out of Africa" is also supported by the fact that mitochondrial genetic diversity is highest among African populations.<ref name="Cann">{{cite journal |last1=Cann |first1=Rebecca L. |author1-link=Rebecca L. Cann |last2=Stoneking |first2=Mark |author2-link=Mark Stoneking |last3=Wilson |first3=Allan C. |author3-link=Allan Wilson (biologist) |date=January 1, 1987 |title=Mitochondrial DNA and human evolution |url= http://artsci.wustl.edu/~landc/html/cann/ |journal=[[Nature (journal)|Nature]] |volume=325 |issue=6099 |pages=31–36 |bibcode=1987Natur.325...31C |doi=10.1038/325031a0 |issn=0028-0836 |pmid=3025745 |s2cid=4285418 |archive-url= https://web.archive.org/web/20100813121953/http://artsci.wustl.edu/~landc/html/cann/ |archive-date=August 13, 2010 |access-date=April 21, 2015|url-access=subscription }}</ref>

A broad study of African genetic diversity, headed by [[Sarah Tishkoff]], found the [[San people]] had the greatest genetic diversity among the 113 distinct populations sampled, making them one of 14 "ancestral population clusters". The research also located a possible origin of modern human migration in southwestern Africa, near the coastal border of [[Namibia]] and [[Angola]].<ref>{{cite news |last=Gill |first=Victoria |date=May 1, 2009 |title=Africa's genetic secrets unlocked |work=[[BBC News]] |location=London |publisher=BBC |url= http://news.bbc.co.uk/2/hi/science/nature/8027269.stm |access-date=June 8, 2011 |archive-date=May 14, 2020 |archive-url= https://web.archive.org/web/20200514095952/http://news.bbc.co.uk/2/hi/science/nature/8027269.stm |url-status=live}}</ref> The fossil evidence was insufficient for archaeologist [[Richard Leakey]] to resolve the debate about exactly where in Africa modern humans first appeared.{{sfn|Leakey|1994|pp=87–89}} Studies of [[haplogroup]]s in [[Human Y-chromosome DNA haplogroup|Y-chromosomal DNA]] and [[Human mitochondrial DNA haplogroup|mitochondrial DNA]] have largely supported a recent African origin.<ref>{{cite journal |last1=Jorde |first1=Lynn B. |last2=Bamshad |first2=Michael |last3=Rogers |first3=Alan R. |author3-link=Alan R. Rogers |date=February 1998 |title=Using mitochondrial and nuclear DNA markers to reconstruct human evolution |journal=BioEssays |volume=20 |issue=2 |pages=126–136 |doi=10.1002/(SICI)1521-1878(199802)20:2<126::AID-BIES5>3.0.CO;2-R |issn=0265-9247 |pmid=9631658 |s2cid=17203268}}</ref> All the evidence from autosomal DNA also predominantly supports a Recent African origin. However, evidence for [[Archaic human admixture with modern humans|archaic admixture in modern humans]], both in Africa and later, throughout Eurasia has recently been suggested by a number of studies.<ref>{{cite journal |last1=Wall |first1=Jeffrey D. |last2=Lohmueller |first2=Kirk E. |last3=Plagnol |first3=Vincent |date=August 2009 |title=Detecting Ancient Admixture and Estimating Demographic Parameters in Multiple Human Populations |pmid=19420049 |journal=Molecular Biology and Evolution |volume=26 |issue=8 |pages=1823–1827 |issn=0737-4038 |doi=10.1093/molbev/msp096 |pmc=2734152}}</ref>

Recent sequencing of Neanderthal<ref name="greenetal">{{cite journal |last1=Green |first1=R. E. |last2=Krause |first2=J. |last3=Briggs |first3=A. W. |last4=Maricic |first4=T. |last5=Stenzel |first5=U. |last6=Kircher |first6=M. |last7=Patterson |first7=N. |last8=Li |first8=H. |last9=Zhai |first9=W. |last10=Fritz |first10=M. H. Y. |last11=Hansen |first11=N. F. |last12=Durand |first12=E. Y. |last13=Malaspinas |first13=A. S. |last14=Jensen |first14=J. D. |last15=Marques-Bonet |first15=T. |last16=Alkan |first16=C. |last17=Prufer |first17=K. |last18=Meyer |first18=M. |last19=Burbano |first19=H. A. |last20=Good |first20=J. M. |last21=Schultz |first21=R. |last22=Aximu-Petri |first22=A. |last23=Butthof |first23=A. |last24=Höber |first24=B. |last25=Höffner |first25=B. |last26=Siegemund |first26=M. |last27=Weihmann |first27=A. |last28=Nusbaum |first28=C. |last29=Lander |first29=E. 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C. |last51=Slatkin |first51=M. |last52=Nielsen |first52=R. |last53=Kelso |first53=J. |last54=Lachmann |first54=M. |last55=Reich |first55=D. |last56=Pääbo |first56=S. |display-authors=4 |date=May 7, 2010 |title=A Draft Sequence of the Neandertal Genome |journal=[[Science (journal)|Science]] |volume=328 |issue=5979 |pages=710–722 |bibcode=2010Sci...328..710G |doi=10.1126/science.1188021 |issn=0036-8075 |pmid=20448178 |pmc=5100745}}{{collapsible list |title=Full list of authors |bullets=true |Richard E. Green |Johannes Krause |Adrian W. Briggs |Tomislav Maricic |Udo Stenzel |Martin Kircher |Nick Patterson |Heng Li |Weiwei Zhai |Markus Hsi-Yang Fritz |Nancy F. Hansen |Eric Y. Durand |Anna-Sapfo Malaspinas |Jeffrey D. Jensen |Tomas Marques-Bonet |Can Alkan |Kay Prüfer |Matthias Meyer |Hernán A. Burbano |Jeffrey M. Good |Rigo Schultz |Ayinuer Aximu-Petri |Anne Butthof |Barbara Höber |Barbara Höffner |Madlen Siegemund |Antje Weihmann |Chad Nusbaum |Eric S. Lander |Carsten Russ |Nathaniel Novod |Jason Affourtit |Michael Egholm |Christine Verna |Pavao Rudan |Dejana Brajkovic |Željko Kucan |Ivan Gušic |Vladimir B. Doronichev |Liubov V. Golovanova |Carles Lalueza-Fox |Marco de la Rasilla |Javier Fortea |Antonio Rosas |Ralf W. Schmitz |Philip L. F. Johnson |Evan E. Eichler |Daniel Falush |Ewan Birney |James C. Mullikin |Montgomery Slatkin |Rasmus Nielsen |Janet Kelso |Michael Lachmann |David Reich |[[Svante Pääbo]]}}</ref> and Denisovan<ref name="pmid21179161" /> genomes shows that some admixture with these populations has occurred. All modern human groups outside Africa have 1–4% or (according to more recent research) about 1.5–2.6% Neanderthal [[allele]]s in their genome,<ref name="A high-coverage Neandertal genome f">{{cite journal |last1=Prüfer |first1=K. |last2=de Filippo |first2=C. |last3=Grote |first3=S. |last4=Mafessoni |first4=F. |last5=Korlević |first5=P. |last6=Hajdinjak |first6=M. |title=A high-coverage Neandertal genome from Vindija Cave in Croatia |journal=[[Science (journal)|Science]] |date=2017 |doi=10.1126/science.aao1887 |pmid=28982794 |pmc=6185897 |display-authors=etal |volume=358 |issue=6363 |pages=655–658 |bibcode=2017Sci...358..655P}}</ref> and some [[Melanesians]] have an additional 4–6% of Denisovan alleles. These new results do not contradict the "out of Africa" model, except in its strictest interpretation, although they make the situation more complex. After recovery from a [[genetic bottleneck]] that some researchers speculate might be linked to the [[Toba catastrophe theory|Toba supervolcano catastrophe]], a fairly small group left Africa and interbred with Neanderthals, probably in the Middle East, on the Eurasian steppe or even in North Africa before their departure. Their still predominantly African descendants spread to populate the world. A fraction in turn interbred with Denisovans, probably in southeastern Asia, before populating Melanesia.<ref name="Reich_2011">{{cite journal |last1=Reich |first1=David |last2=Patterson |first2=Nick |last3=Kircher |first3=Martin |last4=Delfin |first4=Frederick |last5=Nandineni |first5=Madhusudan R. |last6=Pugach |first6=Irina |last7=Ko |first7=Albert Min-Shan |last8=Ko |first8=Ying-Chin |last9=Jinam |first9=Timothy A. |last10=Phipps |first10=Maude E. |last11=Saitou |first11=Naruya |last12=Wollstein |first12=Andreas |last13=Kayser |first13=Manfred |last14=Pääbo |first14=Svante |last15=Stoneking |first15=Mark |display-authors=3 |date=October 7, 2011 |title=Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania |journal=American Journal of Human Genetics |volume=89 |issue=4 |pages=516–528 |doi=10.1016/j.ajhg.2011.09.005 |issn=0002-9297 |pmc=3188841 |pmid=21944045}}</ref> [[Human leukocyte antigen|HLA]] haplotypes of Neanderthal and Denisova origin have been identified in modern Eurasian and Oceanian populations.<ref name="10.1126/science.1209202" /> The Denisovan [[EPAS1]] gene has also been found in Tibetan populations.<ref>Huertha Sanchez, Emilia et al. (2014), "Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA" (Nature Vol 512, August 14, 2014)</ref> Studies of the human genome using machine learning have identified additional genetic contributions in Eurasians from an "unknown" ancestral population potentially related to the Neanderthal-Denisovan lineage.<ref>{{Cite web |url= https://www.sciencedaily.com/releases/2019/01/190116122650.htm |title=Artificial intelligence applied to the genome identifies an unknown human ancestor |website=[[ScienceDaily]] |access-date=January 17, 2019 |archive-date=January 16, 2019 |archive-url= https://web.archive.org/web/20190116213803/https://www.sciencedaily.com/releases/2019/01/190116122650.htm |url-status=live}}</ref>

[[File:Spreading homo sapiens la.svg|thumb|upright=1.5| A map of [[early human migrations]]]]

There are still differing theories on whether there was a single exodus from Africa or several. A multiple dispersal model involves the Southern Dispersal theory,<ref name="lahr">{{cite web |url= http://www.human-evol.cam.ac.uk/Projects/sdispersal/sdispersal.htm |title=Searching for traces of the Southern Dispersal |last1=Lahr |first1=Marta Mirazón |author1-link=Marta Mirazón Lahr |last2=Petraglia |first2=Mike |last3=Stokes |first3=Stephen |last4=Duller |first4=Geoff |display-authors=3 |website=Leverhulme Centre for Human Evolutionary Studies |publisher=[[University of Cambridge]] |archive-url= https://web.archive.org/web/20120510133600/http://www.human-evol.cam.ac.uk/Projects/sdispersal/sdispersal.htm |archive-date=May 10, 2012 |access-date=April 21, 2015}}</ref><ref>Simpson, Colin. [https://www.thenational.ae/uae/science/dna-evidence-suggests-the-whole-world-is-a-little-bit-arab-1.408619 DNA evidence suggests the whole world is a little bit Arab]. [[The National (Abu Dhabi)|The National]]. 16, June 2020. Archived at [https://web.archive.org/web/20200129100200/https://www.thenational.ae/uae/science/dna-evidence-suggests-the-whole-world-is-a-little-bit-arab-1.408619 The Wayback Machine]</ref><ref>{{cite journal |last1=Fernandes |first1=V. |last2=Alshamali |first2=F. |last3=Alves |first3=M. |display-authors=etal |title=The Arabian cradle: Mitochondrial relicts of the first steps along the southern route out of Africa |journal=[[American Journal of Human Genetics]] |date=2012 |volume=90 |issue=2 |pages=347–355 |doi=10.1016/j.ajhg.2011.12.010 |pmid=22284828 |pmc=3276663 }}</ref> which has gained support in recent years from genetic, linguistic and archaeological evidence. In this theory, there was a coastal dispersal of modern humans from the [[Horn of Africa]] crossing the Bab el Mandib to Yemen at a lower sea level around 70,000 years ago. This group helped to populate Southeast Asia and Oceania, explaining the discovery of early human sites in these areas much earlier than those in the [[Levant]].<ref name="lahr" /> This group seems to have been dependent upon marine resources for their survival.

[[Stephen Oppenheimer]] has proposed a second wave of humans may have later dispersed through the Persian Gulf oases, and the Zagros mountains into the Middle East. Alternatively it may have come across the [[Sinai Peninsula]] into Asia, from shortly after 50,000 yrs BP, resulting in the bulk of the human populations of Eurasia. It has been suggested that this second group possibly possessed a more sophisticated "big game hunting" tool technology and was less dependent on coastal food sources than the original group. Much of the evidence for the first group's expansion would have been destroyed by the rising sea levels at the end of each [[glacial maximum]].<ref name="lahr" /> The multiple dispersal model is contradicted by studies indicating that the populations of Eurasia and the populations of Southeast Asia and Oceania are all descended from the same mitochondrial DNA L3 [[Lineage (genetic)|lineages]], which support a single migration out of Africa that gave rise to all non-African populations.<ref>{{cite journal |last1=Macaulay |first1=Vincent |last2=Hill |first2=Catherine |last3=Achilli |first3=Alessandro |last4=Rengo |first4=Chiara |last5=Clarke |first5=D. |last6=Meehan |first6=W. |last7=Blackburn |first7=J. |last8=Semino |first8=O. |last9=Scozzari |first9=R. |last10=Cruciani |first10=F. |last11=Taha |first11=A. |last12=Shaari |first12=N. K. |last13=Raja |first13=J. M. |last14=Ismail |first14=P. |last15=Zainuddin |first15=Z. |last16=Goodwin |first16=W. |last17=Bulbeck |first17=D. |last18=Bandelt |first18=H. J. |last19=Oppenheimer |first19=S. |last20=Torroni |first20=A. |last21=Richards |first21=M. |display-authors=3 |date=May 13, 2005 |title=Single, Rapid Coastal Settlement of Asia Revealed by Analysis of Complete Mitochondrial Genomes |journal=[[Science (journal)|Science]] |volume=308 |issue=5724 |pages=1034–1036 |bibcode=2005Sci...308.1034M |doi=10.1126/science.1109792 |issn=0036-8075 |pmid=15890885 |s2cid=31243109 |url= http://psasir.upm.edu.my/id/eprint/40255/1/Single%2C%20rapid%20coastal%20settlement%20of%20Asia%20revealed%20by%20analysis%20of%20complete%20mitochondrial%20genomes.pdf |url-status=live |access-date=August 20, 2019 |archive-url= https://web.archive.org/web/20220828110206/http://psasir.upm.edu.my/id/eprint/40255/1/Single%2C%20rapid%20coastal%20settlement%20of%20Asia%20revealed%20by%20analysis%20of%20complete%20mitochondrial%20genomes.pdf |archive-date=August 28, 2022}}</ref>

On the basis of the early date of Badoshan Iranian Aurignacian, Oppenheimer suggests that this second dispersal may have occurred with a pluvial period about 50,000 years before the present, with modern human big-game hunting cultures spreading up the Zagros Mountains, carrying modern human genomes from Oman, throughout the Persian Gulf, northward into Armenia and Anatolia, with a variant travelling south into Israel and to Cyrenicia.<ref name="oppenheimer">{{cite book |last=Oppenheimer |first=Stephen |date=2012 |title=Out of Eden: The Peopling of the World |publisher=Robinson |edition=New}}</ref>

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== Evidence ==
The evidence on which scientific accounts of human evolution are based comes from many fields of [[natural science]]. The main source of knowledge about the evolutionary process has traditionally been the fossil record, but since the development of genetics beginning in the 1970s, DNA analysis has come to occupy a place of comparable importance. The studies of ontogeny, [[Phylogenetics|phylogeny]] and especially [[evolutionary developmental biology]] of both vertebrates and invertebrates offer considerable insight into the evolution of all life, including how humans evolved. The specific study of the origin and life of humans is [[anthropology]], particularly paleoanthropology which focuses on the study of human [[prehistory]].{{sfn|Stanford|Allen|Antón|2009}}

=== Evidence from genetics ===
{{Main|Human evolutionary genetics|Human genetic variation}}
[[File:Hominidae chart.svg|upright=1.5|thumb|Family tree showing the [[Extant taxon|extant]] hominoids: humans (genus ''[[Homo]]''), [[chimpanzee]]s and bonobos (genus ''[[Pan (genus)|Pan]]''), [[gorilla]]s (genus ''Gorilla''), [[orangutan]]s (genus ''[[Pongo (genus)|Pongo]]''), and gibbons (four genera of the family [[Hylobatidae]]: ''[[Hylobates]]'', ''[[Hoolock]]'', ''[[Nomascus]]'', and ''[[Symphalangus]]''). All except gibbons are hominids.]]

The closest living relatives of humans are bonobos and chimpanzees (both genus ''Pan'') and gorillas (genus ''Gorilla'').<ref name="Wood">{{cite journal |last1=Wood |first1=Bernard A. |last2=Richmond |first2=Brian G. |date=July 2000 |title=Human evolution: Taxonomy and paleobiology |journal=Journal of Anatomy |volume=197 |issue=1 |pages=19–60 |doi=10.1046/j.1469-7580.2000.19710019.x |issn=1469-7580 |pmid=10999270 |pmc=1468107}}</ref> With the sequencing of both the human and chimpanzee genome, {{as of|2012|lc=y}} estimates of the similarity between their DNA sequences range between 95% and 99%.<ref name="Wood" /><ref>{{cite journal |last1=Ajit |first1=Varki |author1-link=Ajit Varki |last2=Nelson |first2=David L. |date=October 2007 |title=Genomic Comparisons of Humans and Chimpanzees |journal=Annual Review of Anthropology |volume=36 |pages=191–209 |doi=10.1146/annurev.anthro.36.081406.094339 |issn=0084-6570 |url= http://www.chd.ucsd.edu/_files/fall2008/Varki.2007.ARA.pdf |access-date=April 26, 2015 |quote=Sequence differences from the human genome were confirmed to be ~1% in areas that can be precisely aligned, representing ~35 million single base-pair differences. Some 45 million nucleotides of insertions and deletions unique to each lineage were also discovered, making the actual difference between the two genomes ~4%. |archive-date=September 23, 2015 |archive-url= https://web.archive.org/web/20150923202404/http://www.chd.ucsd.edu/_files/fall2008/Varki.2007.ARA.pdf |url-status=live}}</ref><ref name="sayers">{{cite journal |last1=Sayers |first1=Ken |last2=Raghanti |first2=Mary Ann |last3=Lovejoy |first3=C. Owen |author3-link=Owen Lovejoy (anthropologist) |date=October 2012 |title=Human Evolution and the Chimpanzee Referential Doctrine |journal=Annual Review of Anthropology |volume=41 |pages=119–138 |doi=10.1146/annurev-anthro-092611-145815 |issn=0084-6570}}</ref> It is also noteworthy that mice share around 97.5% of their working DNA with humans.<ref>{{Cite web |last=#author. Coghlan |first=Andy |date=May 30, 2002 |title=Just 2.5% of DNA turns mice into men |url=https://www.newscientist.com/article/dn2352-just-2-5-of-dna-turns-mice-into-men/#:~:text=Mice%20and%20men%20share%20about%2097.5%20per,mouse-human%20differences%20as%20high%20as%2015%20per. |access-date=2024-08-18 |website=New Scientist |language=en-US}}</ref>  By using the technique called the [[molecular clock]] which estimates the time required for the number of divergent mutations to accumulate between two lineages, the approximate date for the split between lineages can be calculated.

The gibbons (family Hylobatidae) and then the orangutans (genus ''Pongo'') were the first groups to split from the line leading to the hominins, including humans—followed by gorillas (genus ''Gorilla''), and, ultimately, by the chimpanzees (genus ''Pan''). The splitting date between hominin and chimpanzee lineages is placed by some between {{Mya|4|8}}, that is, during the [[Late Miocene]].{{sfn|Dawkins|2004}}<ref>{{cite web |url= http://www.timetree.org/index.php?taxon_a=Hominidae&taxon_b=Hylobatidae&submit=Search |title=Find Time of Divergence: Hominidae versus Hylobatidae |website=[[TimeTree]] |access-date=April 18, 2015 |archive-url= https://web.archive.org/web/20150418222205/http://www.timetree.org/index.php?taxon_a=Hominidae&taxon_b=Hylobatidae&submit=Search |archive-date=April 18, 2015}}</ref><ref>{{cite journal |last=Ruvolo |first=Maryellen |date=October 1997 |title=Genetic Diversity in Hominoid Primates |journal=Annual Review of Anthropology |volume=26 |pages=515–540 |doi=10.1146/annurev.anthro.26.1.515 |issn=0084-6570}}</ref><ref name="Ruvolo1997">{{cite journal |last=Ruvolo |first=Maryellen |date=March 1997 |title=Molecular Phylogeny of the Hominoids: Inferences from Multiple Independent DNA Sequence Data Sets |journal=Molecular Biology and Evolution |volume=14 |issue=3 |pages=248–265 |doi=10.1093/oxfordjournals.molbev.a025761 |issn=0737-4038 |pmid=9066793 |doi-access=free}}</ref> Speciation, however, appears to have been unusually drawn out. Initial divergence occurred sometime between {{Mya|7|13}}, but ongoing hybridization blurred the separation and delayed complete separation during several millions of years. Patterson (2006) dated the final divergence at {{Mya|5|6}}.<ref>{{cite journal |last1=Patterson |first1=N. |last2=Richter |first2=D. J. |last3=Gnerre |first3=S. |last4=Lander |first4=E. S. |last5=Reich |first5=D. |date=2006 |title=Genetic evidence for complex speciation of humans and chimpanzees |journal=[[Nature (journal)|Nature]] |volume=441 |issue=7097 |pages=1103–1108 |doi=10.1038/nature04789 |pmid=16710306 |bibcode=2006Natur.441.1103P |s2cid=2325560}}</ref>

Genetic evidence has also been employed to compare species within the genus ''Homo'', investigating [[Archaic human admixture with modern humans|gene flow between early modern humans and Neanderthals]], and to enhance the understanding of the early human migration patterns and splitting dates. By comparing the parts of the genome that are [[Neutral theory of molecular evolution|not under natural selection]] and which therefore accumulate mutations at a fairly steady rate, it is possible to reconstruct a genetic tree incorporating the entire human species since the last shared ancestor.

Each time a certain mutation ([[single-nucleotide polymorphism]]) appears in an individual and is passed on to his or her descendants, a haplogroup is formed including all of the descendants of the individual who will also carry that mutation. By comparing mitochondrial [[DNA]] which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose [[genetic marker]] is found in all modern humans, the so-called [[mitochondrial Eve]], must have lived around 200,000 years ago.

Human evolutionary genetics studies how [[human genome]]s differ among individuals, the evolutionary past that gave rise to them, and their current effects. Differences between genomes have [[Anthropology|anthropological]], medical and [[Forensic science|forensic]] implications and applications. Genetic data can provide important insight into human evolution.

In May 2023, scientists reported a more complicated pathway of human evolution than previously understood. According to the studies, humans evolved from different places and times in Africa, instead of from a single location and period of time.<ref name="NYT-20230517">{{cite news |last=Zimmer |first=Carl |author-link=Carl Zimmer |title=Study Offers New Twist in How the First Humans Evolved - A new genetic analysis of 290 people suggests that humans emerged at various times and places in Africa. |url= https://www.nytimes.com/2023/05/17/science/human-origins-africa.html |date=May 17, 2023 |work=[[The New York Times]] |archive-url= https://archive.today/20230517235653/https://www.nytimes.com/2023/05/17/science/human-origins-africa.html |archive-date=May 17, 2023 |access-date=May 18, 2023}}</ref><ref name="NAT-20230517">{{cite journal |last1=Ragsdale |first1=Aaron P. |display-authors=et al. |title=A weakly structured stem for human origins in Africa |date=May 17, 2023 |journal=[[Nature (journal)|Nature]] |volume=167 |issue=7962 |pages=755–763 |doi=10.1038/s41586-023-06055-y |pmid=37198480 |pmc=10208968 |bibcode=2023Natur.617..755R}}</ref>

=== Evidence from the fossil record ===
[[File:Homo habilis-KNM ER 1813.jpg|thumb|upright|Replica of fossil skull of ''[[H.&nbsp;habilis]]''. Fossil number KNM ER 1813, found at [[Koobi Fora]], Kenya.]]
[[File:Homo ergaster.jpg|thumb|upright|Replica of fossil skull of ''[[H.&nbsp;ergaster]]'' (African ''H.&nbsp;erectus''). Fossil number Khm-Heu 3733 discovered in 1975 in Kenya.]]

There is little fossil evidence for the divergence of the gorilla, chimpanzee and hominin lineages.<ref>{{cite journal |last=Begun |first=David R. |date=October 2010 |title=Miocene Hominids and the Origins of the African Apes and Humans |journal=Annual Review of Anthropology |volume=39 |pages=67–84 |doi=10.1146/annurev.anthro.012809.105047 |issn=0084-6570}}</ref> The earliest fossils that have been proposed as members of the hominin lineage are ''Sahelanthropus tchadensis'' dating from {{mya|7}}, ''Orrorin tugenensis'' dating from {{mya|5.7}}, and ''Ardipithecus kadabba'' dating to {{mya|5.6}}. Each of these have been argued to be a [[bipedal]] ancestor of later hominins but, in each case, the claims have been contested. It is also possible that one or more of these species are ancestors of another branch of African apes, or that they represent a shared ancestor between hominins and other apes.

The question then of the relationship between these early fossil species and the hominin lineage is still to be resolved. From these early species, the australopithecines arose around {{mya|4}} and diverged into [[Paranthropus|robust]] (also called ''[[Paranthropus]]'') and [[Australopithecus|gracile]] branches, one of which (possibly ''[[Australopithecus garhi|A. garhi]]'') probably went on to become ancestors of the genus ''Homo''. The australopithecine species that is best represented in the fossil record is ''Australopithecus afarensis'' with more than 100 fossil individuals represented, found from Northern Ethiopia (such as the famous "Lucy"), to Kenya, and South Africa. Fossils of robust australopithecines such as ''A. robustus'' (or alternatively ''[[Paranthropus robustus]]'') and ''A./P. boisei'' are particularly abundant in South Africa at sites such as [[Kromdraai]] and [[Swartkrans]], and around [[Lake Turkana]] in Kenya.

The earliest member of the genus ''Homo'' is ''Homo habilis'' which evolved around {{Mya|2.8}}.<ref name="autogenerated1" /> ''H.&nbsp;habilis'' is the first species for which we have positive evidence of the use of stone tools. They developed the [[Oldowan]] lithic technology, named after the Olduvai Gorge in which the first specimens were found. Some scientists consider ''[[Homo rudolfensis]]'', a larger bodied group of fossils with similar morphology to the original ''H.&nbsp;habilis'' fossils, to be a separate species, while others consider them to be part of ''H.&nbsp;habilis''—simply representing intraspecies variation, or perhaps even [[sexual dimorphism]]. The brains of these early hominins were about the same size as that of a chimpanzee, and their main adaptation was bipedalism as an adaptation to terrestrial living.

During the next million years, a process of encephalization began and, by the arrival (about {{Mya|1.9}}) of ''H.&nbsp;erectus'' in the fossil record, cranial capacity had doubled. ''H.&nbsp;erectus'' were the first of the hominins to emigrate from Africa, and, from {{Mya|1.8|1.3}}, this species spread through Africa, Asia, and Europe. One population of ''H.&nbsp;erectus'', also sometimes classified as separate species ''H.&nbsp;ergaster'', remained in Africa and evolved into ''H.&nbsp;sapiens''. It is believed that ''H.&nbsp;erectus'' and ''H.&nbsp;ergaster'' were the first to use fire and complex tools. In Eurasia, ''H.&nbsp;erectus'' evolved into species such as ''[[H.&nbsp;antecessor]]'', ''[[H.&nbsp;heidelbergensis]]'' and ''[[H.&nbsp;neanderthalensis]]''. The earliest fossils of anatomically modern humans are from the Middle Paleolithic, about 300–200,000 years ago such as the Herto and [[Omo remains]] of Ethiopia, [[Jebel Irhoud]] remains of Morocco, and Florisbad remains of South Africa; [[Skhul and Qafzeh hominins|later fossils]] from the [[Skhul Cave]] in Israel and Southern Europe begin around 90,000 years ago ({{Mya|0.09}}).

As modern humans spread out from Africa, they encountered other hominins such as ''H.&nbsp;neanderthalensis'' and the Denisovans, who may have evolved from populations of ''H.&nbsp;erectus'' that had left Africa around {{mya|2}}. The nature of interaction between early humans and these sister species has been a long-standing source of controversy, the question being whether humans replaced these earlier species or whether they were in fact similar enough to interbreed, in which case these earlier populations may have contributed genetic material to modern humans.{{sfn|Wood|2009|pp=[https://link.springer.com/chapter/10.1007%2F978-1-4020-9980-9_3#page-1 17–27]}}<ref name="NYT-01302012">{{cite news |last=Mitchell |first=Alanna |date=January 30, 2012 |title=DNA Turning Human Story Into a Tell-All |url= https://www.nytimes.com/2012/01/31/science/gains-in-dna-are-speeding-research-into-human-origins.html |archive-url= https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2012/01/31/science/gains-in-dna-are-speeding-research-into-human-origins.html |archive-date=January 1, 2022 |url-access=limited |newspaper=The New York Times |access-date=February 13, 2012}}{{cbignore}}</ref>

This migration out of Africa is estimated to have begun about 70–50,000 years [[Before Present|BP]] and modern humans subsequently spread globally, replacing earlier hominins either through competition or hybridization. They inhabited Eurasia and Oceania by 40,000 years BP, and the Americas by at least 14,500 years BP.<ref>{{cite journal |last=Wood |first=Bernard A. |date=December 1996 |title=Human evolution |journal=BioEssays |volume=18 |issue=12 |pages=945–954 |doi=10.1002/bies.950181204 |issn=0265-9247 |pmid=8976151 |s2cid=221464189}}</ref>

=== Inter-species breeding ===
{{Further|Interbreeding between archaic and modern humans}}
[[File:Homo lineage 2017update.svg|thumb|upright=1.35|A model of the evolution of the genus ''Homo'' over the last 2&nbsp;million years (vertical axis). The rapid "[[Recent African origin of modern humans|Out of Africa]]" expansion of ''H. sapiens'' is indicated at the top of the diagram, with admixture indicated with [[Neanderthals]], [[Denisovans]], and unspecified archaic African hominins.]]
The hypothesis of interbreeding, also known as hybridization, admixture or hybrid-origin theory, has been discussed ever since the discovery of Neanderthal remains in the 19th century.<ref>{{cite book |last=Huxley |first=T. |title=Collected Essays: Volume VII, Man's Place in Nature |date=1890 |chapter=The Aryan Question and Pre-Historic Man |chapter-url= http://aleph0.clarku.edu/huxley/CE7/Aryan.html |access-date=August 25, 2018 |archive-date=July 26, 2011 |archive-url= https://web.archive.org/web/20110726231311/http://aleph0.clarku.edu/huxley/CE7/Aryan.html |url-status=live}}</ref> The linear view of human evolution began to be abandoned in the 1970s as different species of humans were discovered that made the linear concept increasingly unlikely. In the 21st century with the advent of molecular biology techniques and computerization, [[whole-genome sequencing]] of Neanderthal and human [[genome]] were performed, confirming recent admixture between different human species.<ref name="greenetal" /> In 2010, evidence based on molecular biology was published, revealing unambiguous examples of interbreeding between archaic and modern humans during the [[Middle Paleolithic]] and early [[Upper Paleolithic]]. It has been demonstrated that interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins.<ref>{{cite web |last=Coghlan |first=Andy |date=March 15, 2018 |url= https://www.newscientist.com/article/2163910-our-ancestors-mated-with-the-mystery-denisovan-people-twice/ |title=Our ancestors mated with the mystery 'Denisovan' people – twice |work=[[New Scientist]] |access-date=August 25, 2018 |url-status=live |archive-url= https://web.archive.org/web/20180805035916/https://www.newscientist.com/article/2163910-our-ancestors-mated-with-the-mystery-denisovan-people-twice |archive-date=August 5, 2018}}</ref> Today, approximately 2% of DNA from all non-African populations (including Europeans, Asians, and [[Oceanians]]) is Neanderthal,<ref name="greenetal" /> with traces of Denisovan heritage.<ref name="NG-20180822">{{cite news |last=Wei-Haas |first=Maya |date=August 22, 2018 |title=Ancient Girl's Parents Were Two Different Human Species – Born 90,000 years ago, the child is the first direct evidence of interbreeding among Neanderthals and their cousins the Denisovans |work=National Geographic |url= https://www.nationalgeographic.com/science/2018/08/news-denisovan-neanderthal-hominin-hybrid-ancient-human/ |access-date=August 22, 2018 |archive-date=June 14, 2019 |archive-url= https://web.archive.org/web/20190614092015/https://www.nationalgeographic.com/science/2018/08/news-denisovan-neanderthal-hominin-hybrid-ancient-human/ |url-status=dead}}</ref> Also, 4–6% of modern [[Melanesians|Melanesian]] genetics are Denisovan.<ref name="NG-20180822" /> Comparisons of the human genome to the genomes of Neandertals, Denisovans and apes can help identify features that set modern humans apart from other hominin species. In a 2016 [[comparative genomics]] study, a Harvard Medical School/UCLA research team made a world map on the distribution and made some predictions about where Denisovan and Neanderthal genes may be impacting modern human biology.<ref>{{cite web |url= https://www.sciencedaily.com/releases/2016/03/160328133514.htm |author=Cell Press |author-link=Cell Press |title=A world map of Neanderthal and Denisovan ancestry in modern humans |date=March 28, 2016 |website=ScienceDaily |access-date=August 25, 2018 |archive-date=August 26, 2018 |archive-url= https://web.archive.org/web/20180826005214/https://www.sciencedaily.com/releases/2016/03/160328133514.htm |url-status=live}}</ref><ref>{{cite journal |last1=Sankararaman |first1=S. |last2=Mallick |first2=S. |last3=Patterson |first3=N. |last4=Reich |first4=D. |date=March 28, 2016 |title=The Combined Landscape of Denisovan and Neanderthal Ancestry in Present-Day Humans |journal=Current Biology |volume=26 |issue=9 |pages=1241–1247 |doi=10.1016/j.cub.2016.03.037 |pmid=27032491 |pmc=4864120 |bibcode=2016CBio...26.1241S}}</ref>

For example, comparative studies in the mid-2010s found several [[Phenotypic trait|traits]] related to neurological, immunological,<ref>{{cite web |publisher=American Association for the Advancement of Science |work=the Neandertal Genome |url= http://www.sciencemag.org/site/special/neandertal/feature/genomics.html |title=Human-Neandertal Comparisons |date=2010 |archive-url= https://web.archive.org/web/20200528032345/http://www.sciencemag.org/site/special/neandertal/feature/genomics.html |archive-date=May 28, 2020}}</ref> developmental, and metabolic phenotypes, that were developed by archaic humans to European and Asian environments and inherited to modern humans through admixture with local hominins.<ref>{{cite journal |last1=Dannemann |first1=M. |last2=Andrés |first2=A. M. |last3=Kelso |first3=J. |title=Introgression of Neandertal- and Denisovan-like Haplotypes Contributes to Adaptive Variation in Human Toll-like Receptors |date=2016 |journal=[[American Journal of Human Genetics]] |volume=98 |issue=1 |pages=22–33 |doi=10.1016/j.ajhg.2015.11.015 |pmid=26748514 |pmc=4716682}}</ref><ref>{{cite journal |last1=Gittelman |first1=Rachel M. |last2=Schraiber |first2=Joshua G. |last3=Vernot |first3=Benjamin |last4=Mikacenic |first4=Carmen |last5=Wurfel |first5=Mark M. |last6=Akey |first6=Joshua M. |date=2016 |title=Archaic Hominin Admixture Facilitated Adaptation to Out-of-Africa Environments |journal=[[Current Biology]] |volume=26 |issue=24 |pages=3375–3382 |doi=10.1016/j.cub.2016.10.041 |pmid=27839976 |pmc=6764441 |bibcode=2016CBio...26.3375G}}</ref>

Although the narratives of human evolution are often contentious, several discoveries since 2010 show that human evolution should not be seen as a simple linear or branched progression, but a mix of related species.<ref name="pmid21179161" /><ref name="Denisovans & Neandertals" /><ref name="Human Hybrids" /><ref name="Mosaic humans, the hybrid species" /> In fact, genomic research has shown that hybridization between substantially diverged lineages is the rule, not the exception, in human evolution.<ref name="Ackermann 2015">{{cite journal |title=The Hybrid Origin of "Modern" Humans |first1=Rebecca |last1=Rogers Ackermann |first2=Alex |last2=Mackay |first3=Michael L. |last3=Arnold |journal=Evolutionary Biology |date=October 2015 |doi=10.1007/s11692-015-9348-1 |volume=43 |issue=1 |pages=1–11 |s2cid=14329491}}</ref> Furthermore, it is argued that hybridization was an essential creative force in the emergence of modern humans.<ref name="Ackermann 2015" />

=== Stone tools ===
{{Main|Stone tool}}
Stone tools are first attested around 2.6&nbsp;million years ago, when hominins in Eastern Africa used so-called core [[Oldowan|tools]], [[Chopper (archaeology)|choppers]] made out of round cores that had been split by simple strikes.<ref name="Plummer">{{cite journal |last=Plummer |first=Thomas |date=2004 |title=Flaked stones and old bones: Biological and cultural evolution at the dawn of technology |journal=American Journal of Physical Anthropology |volume=125 |issue=Supplement 39: Yearbook of Physical Anthropology |pages=118–164 |doi=10.1002/ajpa.20157 |issn=0002-9483 |pmid=15605391 |doi-access=free}}</ref> This marks the beginning of the [[Paleolithic]], or Old [[Stone Age]]; its end is taken to be the end of the last [[Last glacial period|Ice Age]], around 10,000 years ago. The Paleolithic is subdivided into the [[Lower Paleolithic]] (Early Stone Age), ending around 350,000–300,000 years ago, the [[Middle Paleolithic]] (Middle Stone Age), until 50,000–30,000 years ago, and the [[Upper Paleolithic]], (Late Stone Age), 50,000–10,000 years ago.

Archaeologists working in the Great Rift Valley in Kenya have discovered the oldest known stone tools in the world. Dated to around 3.3&nbsp;million years ago, the implements are some 700,000 years older than stone tools from Ethiopia that previously held this distinction.<ref name="Harmand 310–315" /><ref>{{cite journal |last=Wong |first=Kate |date=April 15, 2015 |title=Archaeologists Take Wrong Turn, Find World's Oldest Stone Tools |url= http://blogs.scientificamerican.com/observations/2015/04/15/archaeologists-take-wrong-turn-find-worlds-oldest-stone-tools/ |journal=Scientific American |type=Blog |issn=0036-8733 |access-date=May 3, 2015 |archive-date=May 8, 2015 |archive-url= https://web.archive.org/web/20150508034444/http://blogs.scientificamerican.com/observations/2015/04/15/archaeologists-take-wrong-turn-find-worlds-oldest-stone-tools/ |url-status=live}}</ref><ref>{{cite journal |last=Balter |first=Michael |date=April 14, 2015 |title=World's oldest stone tools discovered in Kenya |url= https://www.science.org/content/article/world-s-oldest-stone-tools-discovered-kenya |journal=[[Science (journal)|Science]] |type=News |doi=10.1126/science.aab2487 |issn=0036-8075 |access-date=May 3, 2015 |archive-date=October 20, 2021 |archive-url= https://web.archive.org/web/20211020055503/https://www.science.org/content/article/world-s-oldest-stone-tools-discovered-kenya |url-status=live|url-access=subscription }}</ref><ref>{{cite news |last=Drake |first=Nadia |author-link=Nadia Drake |date=April 16, 2015 |title=Oldest Stone Tools Discovered in Kenya |url= http://news.nationalgeographic.com/2015/04/150416-oil-fish-hearts-spill-tuna-gulf-bp-deepwater-exxon-alaska/150416-oldest-stone-tools-archaeology-kenya-human-origins-evolution/ |work=National Geographic News |location=Washington, DC |publisher=[[National Geographic Society]] |access-date=May 3, 2015 |archive-date=April 23, 2015 |archive-url= https://web.archive.org/web/20150423222706/http://news.nationalgeographic.com/2015/04/150416-oil-fish-hearts-spill-tuna-gulf-bp-deepwater-exxon-alaska/150416-oldest-stone-tools-archaeology-kenya-human-origins-evolution/ |url-status=dead}}</ref>

The period from 700,000 to 300,000 years ago is also known as the [[Acheulean]], when ''H.&nbsp;ergaster'' (or ''erectus'') made large stone [[hand axe]]s out of [[flint]] and [[quartzite]], at first quite rough (Early Acheulian), later "[[retouch (lithics)|retouched]]" by additional, more-subtle strikes at the sides of the [[Lithic flake|flakes]]. After 350,000 BP the more refined so-called [[Levallois technique]] was developed, a series of consecutive strikes, by which scrapers, slicers ("racloirs"), needles, and flattened needles were made.<ref name="Plummer" /> Finally, after about 50,000 BP, ever more refined and specialized flint tools were made by the Neanderthals and the immigrant [[Cro-Magnon]]s (knives, blades, skimmers). Bone tools were also made by ''H. sapiens'' in Africa by 90,000–70,000 years ago<ref name="Henshilwood etal 2002">{{cite journal |last1=Henshilwood |first1=C. S. |last2=d'Errico |first2=F. |last3=Yates |first3=R. |last4=Jacobs |first4=Z. |last5=Tribolo |first5=C. |last6=Duller |first6=G. A. T. |last7=Mercier |first7=N. |last8=Sealy |first8=J. C. |last9=Valladas |first9=H. |last10=Watts |first10=I. |last11=Wintle |first11=A. G. |author-link=Christopher Henshilwood |display-authors=3 |date=2002 |title=Emergence of Modern Human Behavior: Middle Stone Age Engravings from South Africa |journal=[[Science (journal)|Science]] |volume=295 |issue=5558 |pages=1278–1280 |doi=10.1126/science.1067575 |pmid=11786608 |s2cid=31169551 |bibcode=2002Sci...295.1278H}}</ref><ref>{{cite journal |title=A middle stone age worked bone industry from Katanda, Upper Semliki Valley, Zaire |date=April 28, 1995 |last1=Yellen |first1=J. E. |last2=Brooks |first2=A. S. |last3=Cornelissen |first3=E. |last4=Mehlman |first4=M. J. |last5=Stewart |first5=K. |journal=[[Science (journal)|Science]] |volume=268 |pages=553–556 |issue=5210 |doi=10.1126/science.7725100 |pmid=7725100 |bibcode=1995Sci...268..553Y}}</ref> and are also known from early ''H. sapiens'' sites in Eurasia by about 50,000 years ago.

== Species list ==
{{See also|Template:Homo|l1=List of ''Homo'' species}}
This list is in [[chronological]] order across the table by '''''[[genus]]'''''. Some species/subspecies names are well-established, and some are less established – especially in genus ''Homo''. Please see articles for more information.
{| class="wikitable"
!''[[Sahelanthropus]]''
!''[[Homo]]'' (humans)
|-
|''S. tchadensis''
|''[[Homo gautengensis|H. gautengensis]]''
|-
!''[[Orrorin]]''
|''[[Homo habilis|H. habilis]]''
|-
|''O. tugenensis''
|''[[Homo rudolfensis|H. rudolfensis]]''
|-
!''[[Ardipithecus]]''
|''[[Homo floresiensis|H. floresiensis]]''
|-
|''[[Ardipithecus#Ardipithecus kadabba|A. kadabba]]''
|''[[Homo ergaster|H. ergaster]]''
|-
|''[[Ardipithecus#Ardipithecus ramidus|A. ramidus]]''
|''[[Homo erectus|H. erectus]]''
|-
!''[[Australopithecus]]''
|• ''[[H. e. georgicus]]''
|-
|''[[Australopithecus anamensis|A. anamensis]]''
|''[[Homo cepranensis|H. cepranensis]]''
|-
|''[[Australopithecus afarensis|A. afarensis]]''
|''[[Homo antecessor|H. antecessor]]''
|-
|''[[Australopithecus bahrelghazali|A. bahrelghazali]]''{{pad|5em}}
|''[[Homo heidelbergensis|H. heidelbergensis]]''
|-
|''[[Australopithecus africanus|A. africanus]]''
|''[[Homo rhodesiensis|H. rhodesiensis]]''
|-
|''[[Australopithecus garhi|A. garhi]]''
|''[[Homo naledi|H. naledi]]''
|-
|''[[Australopithecus sediba|A. sediba]]''
|''[[Florisbad Skull|H. helmei]]''
|-
!''[[Kenyanthropus]]''
|''[[Neanderthal|H. neanderthalensis]]''
|-
|''K. platyops''
|''[[H. sapiens]]''
|-
!''[[Paranthropus]]''
|• ''[[Homo sapiens idaltu|H. s. idaltu]]''
|-
|''[[Paranthropus aethiopicus|P. aethiopicus]]''
|• ''[[Cro-Magnon|H. s. sapiens]]'' (early)
|-
|''[[Paranthropus boisei|P. boisei]]''
|• ''[[H. s. sapiens]]'' (modern)
|-
|''[[Paranthropus robustus|P. robustus]]''
|
|}

== See also ==
{{div col|colwidth=20em}}
* [[Adaptive evolution in the human genome]]
* [[Amity–enmity complex]]
* [[Archaeogenetics]]
* [[Dual inheritance theory]]
* [[Evolution of human intelligence]]
* [[Evolution of morality]]
* [[Evolutionary medicine]]
* [[Evolutionary neuroscience]]
* [[Evolutionary origin of religion]]
* [[Evolutionary psychology]]
* [[Human behavioral ecology]]
* [[Human origins (disambiguation)|Human origins]]
* [[Human vestigiality]]
* [[List of human evolution fossils]]
* [[Molecular paleontology]]
* [[Obstetrical dilemma]]
* [[Origin of language]]
* [[Origin of speech]]
* [[Prehistory of nakedness and clothing]]
* [[Sexual selection in humans]]
* [[Transgenerational trauma]]
*[[Timeline of human evolution]]
{{div col end}}

== Notes ==
{{Notelist}}

== References ==
{{Reflist|refs=
<ref name="Behar 2008">{{cite journal |last1=Behar |first1=D. M. |last2=Villems |first2=R. |last3=Soodyall |first3=H. |last4=Blue-Smith |first4=J. |last5=Pereira |first5=L. |last6=Metspalu |first6=E. |last7=Scozzari |first7=R. |last8=Makkan |first8=H. |last9=Tzur |first9=S. |last10=Comas |first10=D. |last11=Bertranpetit |first11=J. |last12=Quintana-Murci |first12=L. |last13=Tyler-Smith |first13=C. |last14=Wells |first14=R. S. |last15=Rosset |first15=S. |author16=Genographic Consortium |author3-link=Himla Soodyall |display-authors=3 |date=May 9, 2008 |title=The Dawn of Human Matrilineal Diversity |journal=[[American Journal of Human Genetics]] |volume=82 |issue=5 |pages=1130–1140 |doi=10.1016/j.ajhg.2008.04.002 |issn=0002-9297 |pmc=2427203 |pmid=18439549}}{{collapsible list |title=Full list of authors |bullets=true |Doron M. Behar |Richard Villems |Himla Soodyall |Jason Blue-Smith |Luisa Pereira |Ene Metspalu |Rosaria Scozzari |Heeran Makkan |Shay Tzur |David Comas |Jaume Bertranpetit |Lluis Quintana-Murci |Chris Tyler-Smith |R. Spencer Wells |Saharon Rosset |The Genographic Consortium}}</ref>

<ref name="Gonder 2007">{{cite journal |last1=Gonder |first1=M. K. |last2=Mortensen |first2=H. M. |last3=Reed |first3=F. A. |last4=de Sousa |first4=A. |last5=Tishkoff |first5=S. A. |date=March 2007 |title=Whole-mtDNA Genome Sequence Analysis of Ancient African Lineages |journal=[[Molecular Biology and Evolution]] |volume=24 |issue=3 |pages=757–768 |doi=10.1093/molbev/msl209 |issn=0737-4038 |pmid=17194802 |doi-access=free}}</ref>

<ref name="Tishkoff 2009">{{cite journal |last1=Tishkoff |first1=S. A. |last2=Reed |first2=F. A. |last3=Friedlaender |first3=F. R. |author1-link=Sarah Tishkoff |display-authors=etal |title=The Genetic Structure and History of Africans and African Americans |publication-date=May 22, 2009 |journal=[[Science (journal)|Science]] |date=2009 |volume=324 |issue=5930 |pages=1035–1044 |doi=10.1126/science.1172257 |pmc=2947357 |pmid=19407144 |bibcode=2009Sci...324.1035T}}{{collapsible list |title=Full list of authors |bullets=true |Sarah A. Tishkoff |Floyd A. Reed |Françoise R. Friedlaender |Christopher Ehret |Alessia Ranciaro |Alain Froment |Jibril B. Hirbo |Agnes A. Awomoyi |Jean-Marie Bodo |Ogobara Doumbo |Muntaser Ibrahim |Abdalla T. Juma |Maritha J. Kotze |Godfrey Lema |Jason H. Moore |Holly Mortensen |Thomas B. Nyambo |Sabah A. Omar |Kweli Powell |Gideon S. Pretorius |Michael W. Smith |Mahamadou A. Thera |Charles Wambebe |James L. Weber |Scott M. Williams}}</ref>
}}

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* {{cite book |last=Webster |first=Donovan |author-link=Donovan Webster |date=2010 |title=Meeting the Family: One Man's Journey Through His Human Ancestry |others=Foreword by [[Spencer Wells]] |location=Washington, DC |publisher=[[National Geographic Society]] |isbn=978-1-4262-0573-6 |lccn=2009050471 |oclc=429022321}}
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{{Refend}}

== Further reading ==
{{refbegin}}
* {{cite book |last=Alexander |first=Richard D. |author-link=Richard D. Alexander |date=1990 |title=How Did Humans Evolve? Reflections on the Uniquely Unique Species |url= http://qcpages.qc.edu/Biology/LahtiSites/RDAlexander/Pubs/Alexander90.pdf |series=Special Publication |issue=1 |location=Ann Arbor |publisher=[[List of museums and collections at the University of Michigan#Museum of Zoology|Museum of Zoology, University of Michigan]] |pages=1–38 |lccn=90623893 |oclc=22860997 |access-date=May 6, 2015 |archive-date=March 4, 2016 |archive-url= https://web.archive.org/web/20160304185713/http://qcpages.qc.edu/Biology/LahtiSites/RDAlexander/Pubs/Alexander90.pdf}}
* {{cite book |last1=Barton |first1=Nicholas H. |author1-link=Nick Barton |last2=Briggs |first2=Derek E. G. |author2-link=Derek Briggs |last3=Eisen |first3=Jonathan A. |author3-link=Jonathan Eisen |last4=Goldstein |first4=David B. |last5=Patel |first5=Nipan H. |date=2007 |title=Evolution |publisher=[[Cold Spring Harbor Laboratory]] Press |isbn=978-0-87969-684-9 |lccn=2007010767 |oclc=86090399 |display-authors=3}}
* {{cite journal |last1=Enard |first1=Wolfgang |last2=Przeworski |first2=Molly |last3=Fisher |first3=Simon E. |author3-link=Simon Fisher |last4=Lai |first4=Cecilia S. L. |last5=Wiebe |first5=Victor |last6=Kitano |first6=Takashi |last7=Monaco |first7=Anthony P. |last8=Pääbo |first8=Svante |date=August 22, 2002 |title=Molecular evolution of ''FOXP2'', a gene involved in speech and language |journal=[[Nature (journal)|Nature]] |volume=418 |issue=6900 |pages=869–872 |doi=10.1038/nature01025 |issn=0028-0836 |pmid=12192408 |display-authors=3 |bibcode=2002Natur.418..869E |s2cid=4416233 |hdl=11858/00-001M-0000-0012-CB89-A |hdl-access=free}}
* {{cite journal |last1=Flinn |first1=Mark V. |last2=Geary |first2=David C. |author2-link=David C. Geary |last3=Ward |first3=Carol V. |date=2005 |title=Ecological dominance, social competition, and coalitionary arms races: Why humans evolved extraordinary intelligence |url= http://web.missouri.edu/~gearyd/Flinnetal2005.pdf |journal=Evolution and Human Behavior |volume=26 |issue=1 |pages=10–46 |doi=10.1016/j.evolhumbehav.2004.08.005 |bibcode=2005EHumB..26...10F |issn=1090-5138 |access-date=May 5, 2015 |archive-date=June 4, 2007 |archive-url= https://web.archive.org/web/20070604224126/http://web.missouri.edu/~gearyd/Flinnetal2005.pdf |url-status=live}}
* {{cite book |last=Galinon-Melenec |first=Béatrice |chapter=From "Traces" and "Human Trace" to "Human–Trace Paradigm" |editor1-last=Parrend |editor1-first=Pierre |editor2-last=Bourgine |editor2-first=Paul |editor3-last=Collet |editor3-first=Pierre |date=2015 |title=First Complex systems Digital Campus World E-Conference |publisher=[[Springer Nature|Springer]] |location=Tempe, Arizona}}
* {{cite book |last=Gibbons |first=Ann |date=2006 |title=The First Human: The Race to Discover our Earliest Ancestors |location=New York |publisher=[[Doubleday (publisher)|Doubleday]] |isbn=978-0-385-51226-8 |lccn=2005053780 |oclc=61652817 |url= https://archive.org/details/firsthumanraceto00gibb}}
* {{cite book |editor-last=Hartwig |editor-first=Walter C. |editor-link=Walter Hartwig |date=2002 |title=The Primate Fossil Record |series=Cambridge Studies in Biological and Evolutionary Anthropology |volume=33 |publisher=[[Cambridge University Press]] |isbn=978-0-521-66315-1 |lccn=2001037847 |oclc=47254191}}
* {{cite journal |last1=Heizmann |first1=Elmar P. J. |last2=Begun |first2=David R. |date=November 2001 |title=The oldest Eurasian hominoid |journal=Journal of Human Evolution |volume=41 |issue=5 |doi=10.1006/jhev.2001.0495 |pages=463–481 |issn=0047-2484 |pmid=11681862 |bibcode=2001JHumE..41..463H |s2cid=21230992 |url= http://doc.rero.ch/record/13528/files/PAL_E351.pdf}}
* {{cite journal |last1=Hill |first1=Andrew |last2=Ward |first2=Steven |date=1988 |title=Origin of the hominidae: The record of African large hominoid evolution between 14 my and 4 my |journal=American Journal of Physical Anthropology |volume=31 |issue=59 |pages=49–83 |doi=10.1002/ajpa.1330310505 |issn=0002-9483 |doi-access=free}}
* {{cite journal |last=Hoagland |first=Hudson |title=Science and the New Humanism |journal=[[Science (journal)|Science]] |date=1964 |volume=143 |issue=3602 |pages=111–114 |doi=10.1126/science.143.3602.111 |pmid=17781189 |bibcode=1964Sci...143..111H}}
* {{cite journal |last1=Ijdo |first1=Jacob W. |last2=Baldini |first2=Antonio |last3=Ward |first3=David C. |last4=Reeders |first4=Stephen T. |last5=Wells |first5=Richard A. |date=October 15, 1991 |title=Origin of human chromosome 2: An ancestral telomere-telomere fusion |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |volume=88 |issue=20 |pages=9051–9055 |bibcode=1991PNAS...88.9051I |doi=10.1073/pnas.88.20.9051 |issn=0027-8424 |pmc=52649 |pmid=1924367 |display-authors=3 |doi-access=free}} – two ancestral ape chromosomes fused to give rise to human chromosome 2
* {{cite book |last1=Johanson |first1=Donald |author1-link=Donald Johanson |last2=Wong |first2=Kate |date=2010 |title=Lucy's Legacy: The Quest for Human Origins |location=New York |publisher=[[Three Rivers Press]] |isbn=978-0-307-39640-2 |lccn=2010483830 |oclc=419801728}}
* {{cite book |editor1-last=Jones |editor1-first=Steve |editor2-last=Martin |editor2-first=Robert D. |editor3-last=Pilbeam |editor3-first=David |date=1994 |orig-date=1992 |title=The Cambridge Encyclopedia of Human Evolution |others=Foreword by Richard Dawkins |publisher=[[Cambridge University Press]] |isbn=978-0-521-32370-3 |lccn=92018037 |oclc=444512451 |url= https://archive.org/details/cambridgeencyclo00step}} (This book contains very useful, information-dense chapters on primate evolution in general, and human evolution in particular, including fossil history.)
* {{cite book |last1=Kawabata |first1=Hiroshi |last2=Kaifu |first2=Yousuke |date=2020 |title=Lost in Evolution: Exploring Humanity's Path in Asia |location=Tokyo |publisher=Japan Publishing Industry Foundation for Culture |isbn=978-4-86658-133-0 |url= https://www.jpicinternational.com/books/science/b78321546939314b4f3be37eeeba766ac05b6301.html |access-date=October 20, 2022 |archive-date=October 20, 2022 |archive-url= https://web.archive.org/web/20221020054826/https://www.jpicinternational.com/books/science/b78321546939314b4f3be37eeeba766ac05b6301.html |url-status=live}}
* {{cite book |last1=Leakey |first1=Richard E. |last2=Lewin |first2=Roger |date=1992 |title=Origins Reconsidered: In Search of What Makes us Human |location=New York |publisher=[[Doubleday (publisher)|Doubleday]] |isbn=978-0-385-41264-3 |lccn=92006661 |oclc=25373161}}
* {{cite book |last=Lewin |first=Roger |date=1997 |title=Bones of Contention: Controversies in the Search for Human Origins |edition=2nd |publisher=[[University of Chicago Press]] |isbn=978-0-226-47651-3 |lccn=97000972 |oclc=36181117}}
* {{cite book |last1=Morwood |first1=Mike |last2=van Oosterzee |first2=Penny |date=2007 |title=A New Human: The Startling Discovery and Strange Story of the 'Hobbits' of Flores, Indonesia |location=New York |publisher=[[Smithsonian Institution|Smithsonian]] Books / [[HarperCollins]] |isbn=978-0-06-089908-0 |lccn=2006052267 |oclc=76481584 |url= https://archive.org/details/newhumanstrange00morw}}
* {{cite book |last=Oppenheimer |first=Stephen |author-link=Stephen Oppenheimer |date=2003 |title=Out of Eden: The Peopling of the World |location=London |publisher=[[Constable & Robinson]] |isbn=978-1-84119-697-8 |lccn=2005482222 |oclc=52195607}}
* {{cite journal |last1=Ovchinnikov |first1=Igor V. |last2=Götherström |first2=Anders |last3=Romanova |first3=Galina P. |last4=Kharitonov |first4=Vitaliy M. |last5=Lidén |first5=Kerstin |last6=Goodwin |first6=William |display-authors=3 |date=March 30, 2000 |title=Molecular analysis of Neanderthal DNA from the Northern Caucasus |journal=[[Nature (journal)|Nature]] |volume=404 |issue=6777 |pages=490–493 |doi=10.1038/35006625 |issn=0028-0836 |pmid=10761915 |bibcode=2000Natur.404..490O |s2cid=3101375}}
* {{cite book |last=Roberts |first=Alice M. |author-link=Alice Roberts |date=2009 |title=The Incredible Human Journey: The Story of How We Colonised the Planet |location=London |publisher=[[Bloomsbury Publishing]] |isbn=978-0-7475-9839-8 |oclc=310156315}}
* {{cite book |last=Shreeve |first=James |date=1995 |title=The Neandertal Enigma: Solving the Mystery of Modern Human Origins |location=New York |publisher=[[William Morrow & Co.]] |isbn=978-0-688-09407-2 |lccn=95006337 |oclc=32088673 |url= https://archive.org/details/neandertalenigma00shre_0}}
* {{cite book |last=Stringer |first=Chris B. |date=2011 |title=The Origin of Our Species |location=London |publisher=[[Penguin Books|Allen Lane]] |isbn=978-1-84614-140-9 |lccn=2011489742 |oclc=689522193}}
* {{cite book |last1=Stringer |first1=Chris B. |last2=Andrews |first2=Peter |date=2005 |title=The Complete World of Human Evolution |url= https://archive.org/details/completeworldofh0000stri |url-access=registration |location=London / New York |publisher=[[Thames & Hudson]] |isbn=978-0-500-05132-0 |lccn=2004110563 |oclc=224377190}}
* {{cite book |last1=Stringer |first1=Christopher |last2=McKie |first2=Robin |date=1997 |title=African Exodus: The Origins of Modern Humanity |location=New York |publisher=[[Henry Holt & Co.]] |isbn=978-0-8050-2759-4 |lccn=96037718 |oclc=36001167 |url= https://archive.org/details/africanexodusori00stri}}
* {{cite book |last=Sykes |first=Rebecca Wragg |date=2020 |title=[[Kindred: Neanderthal Life, Love, Death and Art]] |location=London |publisher=[[Bloomsbury Publishing|Bloomsbury Sigma]] |isbn=978-1-4729-3749-0}}
* {{cite book |last=Tattersall |first=Ian |date=2008 |title=The Fossil Trail: How We Know What We Think We Know About Human Evolution |edition=2nd |publisher=[[Oxford University Press]] |isbn=978-0-19-536766-9 |lccn=2008013654 |oclc=218188644}}
* {{cite book |last=van Oosterzee |first=Penny |date=1999 |title=Dragon Bones: The Story of Peking Man |location=St Leonards, New South Wales |publisher=[[Allen & Unwin]] Australia |isbn=978-1-86508-123-6 |lccn=00300421 |oclc=45853997}}
* {{cite book |last=Wade |first=Nicholas |author-link=Nicholas Wade |date=2006 |title=Before the Dawn: Recovering the Lost History of Our Ancestors |location=New York |publisher=[[Penguin Books|Penguin]] |isbn=978-1-59420-079-3 |lccn=2005055293 |oclc=62282400 |title-link=Before the Dawn (Wade book)}}
* {{cite book |last1=Walker |first1=Alan |last2=Shipman |first2=Pat |date=1996 |title=The Wisdom of the Bones: In Search of Human Origins |location=London |publisher=[[Weidenfeld & Nicolson]] |isbn=978-0-297-81670-6 |oclc=35202130}}
* {{cite book |last1=Weiss |first1=Mark L. |last2=Mann |first2=Alan E. |date=1985 |title=Human Biology and Behavior: An Anthropological Perspective |edition=4th |location=Boston |publisher=[[Little, Brown & Co.]] |isbn=978-0-316-92894-6 |lccn=85000158 |oclc=11726796}} (This book contains very accessible descriptions of human and non-human primates, their evolution, and fossil history.)
* {{cite book |last=Wells |first=Spencer |author-link=Spencer Wells |date=2003 |orig-date=Originally published 2002; Princeton, NJ: Princeton University Press |title=The Journey of Man: A Genetic Odyssey |edition=Random House trade paperback |location=New York |publisher=[[Random House]] |isbn=978-0-8129-7146-0 |lccn=2003066679 |oclc=53287806}}
{{refend}}

== External links ==
{{Commons category|Human evolution}}
* "[https://www.scientificamerican.com/article/race-evolution-and-the-science-of-human-origins/ Race, Evolution and the Science of Human Origins]" by Allison Hopper, ''[[Scientific American]]'' (July 5, 2021).
* {{cite web |url= http://www.bbc.co.uk/sn/prehistoric_life/human/human_evolution/index.shtml |title=The evolution of man |publisher=BBC Science & Nature |access-date=May 6, 2015}}
* {{cite web |url= http://www.becominghuman.org/ |title=Becoming Human |publisher=[[Arizona State University]]'s [[Institute of Human Origins]] |access-date=May 6, 2015}}
* {{cite web |url= http://www.hhmi.org/biointeractive/bones-stones-and-genes-origin-modern-humans-0 |title=Bones, Stones and Genes: The Origin of Modern Humans |type=Video lecture series |publisher=[[Howard Hughes Medical Institute]] |access-date=May 6, 2015 |archive-url= https://web.archive.org/web/20150424155530/http://www.hhmi.org/biointeractive/bones-stones-and-genes-origin-modern-humans-0 |archive-date=April 24, 2015}}
* {{cite web |url= http://www.evolution-textbook.org/content/free/figures/ch25.html |title=''Evolution'' Figures: Chapter 25 |publisher=Cold Spring Harbor Laboratory Press |access-date=May 6, 2015}} – Illustrations from the book ''Evolution'' (2007)
* {{cite web |url= http://humanorigins.si.edu/ |title=Human Evolution |publisher=[[Smithsonian Institution]]'s Human Origins Program |access-date=June 24, 2013}}
* {{cite web |url= http://archaeologyinfo.com/human-evolution-timeline/ |title=Human Evolution Timeline |publisher=ArchaeologyInfo.com |access-date=June 24, 2013 |archive-date=June 18, 2013 |archive-url= https://web.archive.org/web/20130618121818/http://archaeologyinfo.com/human-evolution-timeline/}}
* [https://www.canal-u.tv/video/universite_du_havre/conference_mondiale_de_l_unitwin_unesco_sur_les_systemes_complexes_le_paradigme_de_l_homme_trace.20031 "Human Trace" video] (2015) [[Normandy University]] UNIHAVRE, [[Centre national de la recherche scientifique|CNRS]], IDEES, E.Laboratory on Human Trace Unitwin Complex System Digital Campus UNESCO.
* {{cite AV media |people=Lambert, Tim (Producer) |date=June 24, 2015 |title=First Peoples |url= https://www.pbs.org/first-peoples/home/ |access-date=July 18, 2015 |location=London |publisher=[[Wall to Wall (production company)|Wall to Wall Television]] |oclc=910115743}}
* [http://yalebooks.com/yupbooks/book.asp?isbn=9780300182026 Shaping Humanity Video] 2013 [[Yale University]]
* [http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive Human Timeline (Interactive)] – [[Smithsonian Institution|Smithsonian]], [[National Museum of Natural History]] (August 2016).
* [https://www.bbc.co.uk/programmes/p003hyfl Human Evolution], BBC Radio 4 discussion with Steve Jones, Fred Spoor & Margaret Clegg (''In Our Time'', February 16, 2006)
* [https://www.smithsonianmag.com/science-nature/essential-timeline-understanding-evolution-homo-sapiens-180976807/ Evolutionary Timeline of Home Sapiens] − [[Smithsonian (magazine)|Smithsonian]] (February 2021)
* [https://www.salon.com/2021/08/24/more-americans-believe-in-evolution/ History of Human Evolution in the United States] – [[Salon.com|Salon]] (August 24, 2021)

{{Human Evolution}}
{{Human genetics}}
{{Apes}}
{{Prehistoric technology}}
{{Evolutionary psychology}}
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[[Category:Human evolution| ]]
[[Category:Anthropology]]