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{{Evolutionary biology}} | {{Evolutionary biology}} | ||
'''Macroevolution''' comprises the evolutionary processes and patterns which occur at and above the [[species]] level.<ref name="Saupe2021a">{{cite book |last1=Saupe |first1=Erin E. |last2=Myers |first2=Corinne E. |editor1-last=Nuño de la Rosa |editor1-first=Laura |editor2-last=Müller |editor2-first=Gerd B. |title=Chapter: Macroevolution, Book: Evolutionary Developmental Biology - A Reference Guide |date=April 1, 2021 |publisher=Springer, Cham. |isbn=978-3-319-32979-6 |pages=149–167 |edition=1 |chapter-url=https://doi.org/10.1007/978-3-319-32979-6_126 |chapter=Macroevolution|doi=10.1007/978-3-319-32979-6_126 }}</ref><ref name=":0">{{cite journal |last=Stanley|first=S. M. |date=1975-02-01 |title=A theory of evolution above the species level |journal=[[Proceedings of the National Academy of Sciences]] |language=en |volume=72 |issue=2 |pages=646–50 |doi=10.1073/pnas.72.2.646 |issn=0027-8424 |pmc=432371 |pmid=1054846 |bibcode=1975PNAS...72..646S |doi-access=free}}</ref><ref name="Gould2002a">{{cite book |last=Gould|first=Stephen Jay |title=The structure of evolutionary theory |date=2002 |publisher=Belknap Press of [[Harvard University Press]] |isbn=0-674-00613-5 |location=Cambridge, Mass. |oclc=47869352}}</ref> In contrast, [[microevolution]] is evolution occurring within the population(s) of a single species. In other words, microevolution is the scale of evolution that is limited to intraspecific (within-species) variation, while macroevolution extends to interspecific (between-species) variation.<ref name=":1">{{cite journal |last=Hautmann|first=Michael |date=2020 |title=What is macroevolution?|journal=[[Palaeontology (journal)|Palaeontology]] |language=en |volume=63 |issue=1 |pages=1–11 |doi=10.1111/pala.12465 |bibcode=2020Palgy..63....1H |issn=0031-0239 |doi-access=free}}</ref> The evolution of new species ([[speciation]]) is an example of macroevolution. This is the common definition for 'macroevolution' used by contemporary scientists.{{efn|Rolland et al. (2023)<ref name="Rolland2022a">{{cite journal |last1=Rolland |first1=J. |last2=Henao-Diaz |first2=L.F. |last3=Doebeli |first3=M.|last4=Germain |first4=Rachel |display-authors=3 |title=Conceptual and empirical bridges between micro- and macroevolution. |journal=Nature Ecology & Evolution |date=July 10, 2023 |volume=7 |issue=8 |pages=1181–1193 |doi=10.1038/s41559-023-02116-7 |pmid=37429904 |bibcode=2023NatEE...7.1181R |url=https://files.zoology.ubc.ca/mank-lab/pdf/2023NEEGaps.pdf |issn=2397-334X}}</ref> in the introduction describe | '''Macroevolution''' comprises the evolutionary processes and patterns which occur at and above the [[species]] level.<ref name="Saupe2021a">{{cite book |last1=Saupe |first1=Erin E. |last2=Myers |first2=Corinne E. |editor1-last=Nuño de la Rosa |editor1-first=Laura |editor2-last=Müller |editor2-first=Gerd B. |title=Chapter: Macroevolution, Book: Evolutionary Developmental Biology - A Reference Guide |date=April 1, 2021 |publisher=Springer, Cham. |isbn=978-3-319-32979-6 |pages=149–167 |edition=1 |chapter-url=https://doi.org/10.1007/978-3-319-32979-6_126 |chapter=Macroevolution|doi=10.1007/978-3-319-32979-6_126 }}</ref><ref name=":0">{{cite journal |last=Stanley|first=S. M. |date=1975-02-01 |title=A theory of evolution above the species level |journal=[[Proceedings of the National Academy of Sciences]] |language=en |volume=72 |issue=2 |pages=646–50 |doi=10.1073/pnas.72.2.646 |issn=0027-8424 |pmc=432371 |pmid=1054846 |bibcode=1975PNAS...72..646S |doi-access=free}}</ref><ref name="Gould2002a">{{cite book |last=Gould|first=Stephen Jay |title=The structure of evolutionary theory |date=2002 |publisher=Belknap Press of [[Harvard University Press]] |isbn=0-674-00613-5 |location=Cambridge, Mass. |oclc=47869352}}</ref> In contrast, [[microevolution]] is evolution occurring within the population(s) of a single species. In other words, microevolution is the scale of evolution that is limited to intraspecific (within-species) variation, while macroevolution extends to interspecific (between-species) variation.<ref name=":1">{{cite journal |last=Hautmann|first=Michael |date=2020 |title=What is macroevolution?|journal=[[Palaeontology (journal)|Palaeontology]] |language=en |volume=63 |issue=1 |pages=1–11 |doi=10.1111/pala.12465 |bibcode=2020Palgy..63....1H |issn=0031-0239 |doi-access=free}}</ref> The evolution of new species ([[speciation]]) is an example of macroevolution. This is the common definition for 'macroevolution' used by contemporary scientists.{{efn|Rolland et al. (2023)<ref name="Rolland2022a">{{cite journal |last1=Rolland |first1=J. |last2=Henao-Diaz |first2=L.F. |last3=Doebeli |first3=M.|last4=Germain |first4=Rachel |display-authors=3 |title=Conceptual and empirical bridges between micro- and macroevolution. |journal=Nature Ecology & Evolution |date=July 10, 2023 |volume=7 |issue=8 |pages=1181–1193 |doi=10.1038/s41559-023-02116-7 |pmid=37429904 |bibcode=2023NatEE...7.1181R |url=https://files.zoology.ubc.ca/mank-lab/pdf/2023NEEGaps.pdf |issn=2397-334X}}</ref> in the introduction describe 'microevolution' and 'macroevolution' occurring at two different scales; below the species level and at/above the species level respectively: ''"Since the modern synthesis, many evolutionary biologists have focused their attention on evolution at one of two different timescales: microevolution, that is, the evolution of populations below the species level (in fields such as population genetics, phylogeography and quantitative genetics), or macroevolution, that is, the evolution of species or higher taxonomic levels (for example, phylogenetics, palaeobiology and biogeography)."''}}{{efn| Saupe & Myers (2021)<ref name="Saupe2021a" /> states: ''"Macroevolution is the study of patterns and processes associated with evolutionary change at and above the species level, and includes investigations of both evolutionary tempo and mode."''}}{{efn| Michael Hautmann (2019)<ref name=":1" /> discusses 3 categories of definitions that have been historically used. He argues in favor of the following definition [added clarity]: ''"Macroevolution is evolutionary change that is guided by sorting of interspecific [between-species] variation."''}}{{efn| David Jablonski (2017)<ref name="Jablosnki2017a">{{cite journal |last1=Jablonski |first1=D. |title=Approaches to Macroevolution: 1. General Concepts and Origin of Variation. |journal=Springer, Evolutionary Biology |date=June 3, 2017 |volume=44 |issue=4 |pages=427–450 |doi=10.1007/s11692-017-9420-0|pmid=29142333 |pmc=5661017 |bibcode=2017EvBio..44..427J }}</ref><ref name="Jablosnki2017b">{{cite journal |last1=Jablonski |first1=D. |title=Approaches to Macroevolution: 2. Sorting of Variation, Some Overarching Issues, and General Conclusions. |journal=Springer, Evolutionary Biology |date=October 24, 2017 |volume=44 |issue=4 |pages=451–475 |doi=10.1007/s11692-017-9434-7|pmid=29142334 |pmc=5661022 |bibcode=2017EvBio..44..451J }}</ref> states: "Macroevolution, defined broadly as evolution above the species level, is thriving as a field."}}{{efn| name="GouldM"|In his book "The Structure of Evolutionary Theory" (2002)<ref name="Gould2002a" /> page 612, Stephen J. Gould describes the species as the basic unit of macroevolution, and compares speciation and extinction to birth and death in microevolutionary processes respectively: ''"In particular, and continuing to use species as a "type" example of individuality at higher levels, all evolutionary criteria apply to the species as a basic unit of macro-evolution. Species have children by branching (in our professional jargon, we even engender these offspring as "daughter species"). Speciation surely obeys principles of hereditary, for daughters, by strong constraints of homology, originate with phenotypes and genotypes closer to those of their parent than to any other species of a collateral lineage. Species certainly vary, for the defining property of reproductive isolation demands genetic differentiation from parents and collateral relatives. Finally, species interact with the environment in a causal way that can influence rates of birth (speciation) and death (extinction)."''}}{{efn| In his paper proposing the theory of [[species selection]], Steven M. Stanly (1974)<ref name=":0" /> described macroevolution as being evolution above the species level and decoupled from microevolution: ''"In reaction to the arguments of macromutationists who opposed Neo-Darwinism, modern evolutionists have forcefully asserted that the process of natural selection is responsible for both microevolution, or evolution within species, and evolution above the species level, which is also known as macroevolution or transpecific evolution. [...] Macroevolution is decoupled from microevolution, and we must envision the process governing its course as being analogous to natural selection but operating at a higher level of biological organization. In this higher-level process species become analogous to individuals, and speciation replaces reproduction"''}}{{efn| The 'Understanding Evolution' website<ref name="BerkeleyEdu1">{{cite web |title=Evolution at different scales |url=https://evolution.berkeley.edu/evolution-at-different-scales-micro-to-macro/ |website=Understanding Evolution |publisher=UCMP, Berkely}}</ref> by [[UCMP]]: ''"Microevolution happens on a small scale (within a single population), while macroevolution happens on a scale that transcends the boundaries of a single species"''}}{{efn| Thomas Holtz's course GEOL331 lecture notes<ref name="GEOL331a">{{cite web |title=Macroevolution in the Fossil Record? |url=https://www.geol.umd.edu/~tholtz/G331/lectures/331macroevo.html |website=GEOL331 Lecture Notes |publisher=University of Maryland Department of Geology}}</ref> discusses macroevolution observed in the fossil record:''"Following these early attempted modifications of Darwinism, the rest of the 20th Century onward stayed largely within a Darwinian model. However, there were different major schools of thought. Many of these differences hinged on views of microevolution (evolutionary change within a species) and macroevolution (evolutionary change above the species level). While most agreed that the ultimate processes in macroevolution were ultimately microevolutionary, there were disagreement[s] whether the patterns produced were actually reducible to microevolutionary changes."''}}{{efn| The 'Digital Atlas of Ancient Life' website<ref name="DAOAL1">{{cite web |title=What is Macroevolution? |url=https://www.digitalatlasofancientlife.org/learn/evolution/macroevolution/ |website=Digital Atlas of Ancient Life |publisher=PRI}}</ref> by [[Paleontological Research Institution|PRI]] provides a very detailed historical overview for the definition of 'macroevolution': "The meaning of the term "macroevolution" has shifted over time. Indeed, early definitions do to not necessarily make much sense in light of our current understanding of evolution, yet are still worth considering to show how the field itself has evolved. Here we will consider usage of the term macroevolution in a few key works, as well as present a definition of macroevolution that we endorse. [...] Lieberman and Eldredge (2014) defined macroevolution as "the patterns and processes pertaining to the birth, death, and persistence of species" and we adopt this definition here."}} However, the exact usage of the term has varied throughout history.<ref name=":1" /><ref name="DAOAL1" /><ref name=":2">{{cite book |last=Filipchenko|first=J. |title=Variabilität und Variation |publisher=[[Gebrüder Borntraeger Verlagsbuchhandlung|Borntraeger]] |year=1927 |location=Berlin}}</ref> | ||
and biogeography). | |||
Macroevolution addresses the evolution of species and higher taxonomic groups ([[genera]], [[ | Macroevolution addresses the evolution of species and higher taxonomic groups ([[genera]], [[Family (biology)|families]], [[Order (biology)|orders]], etc) and uses evidence from [[phylogenetics]],<ref name="Rolland2022a" /> the fossil record,<ref name="GEOL331a" /> and molecular biology to answer how different taxonomic groups exhibit different [[species diversity]] and/or [[Phenotypic disparity|morphological disparity]].<ref name="Gregory2008a">{{cite journal |last1=Gregory |first1=T.R. |title=Evolutionary Trends |journal=Evo Edu Outreach |date=June 25, 2008 |volume=1 |issue=3 |pages=259–273 |doi=10.1007/s12052-008-0055-6 |issn=1936-6434|doi-access=free }}</ref> | ||
== Origin and changing meaning of the term == | == Origin and changing meaning of the term == | ||
After [[Charles Darwin]] published his book ''On the Origin of Species''<ref>{{Cite book|last=Darwin|first=C.|title=On the origin of species by means of natural selection|publisher=John Murray|year=1859|location=London}}</ref> in 1859, evolution was widely accepted to be real phenomenon. However, many scientists still disagreed with Darwin that [[natural selection]] was the primary mechanism to explain evolution. Prior to the [[Modern synthesis (20th century)|modern synthesis]], during the period between the 1880s to the 1930s (dubbed the | After [[Charles Darwin]] published his book ''On the Origin of Species''<ref>{{Cite book|last=Darwin|first=C.|title=On the origin of species by means of natural selection|publisher=John Murray|year=1859|location=London}}</ref> in 1859, evolution was widely accepted to be real phenomenon. However, many scientists still disagreed with Darwin that [[natural selection]] was the primary mechanism to explain evolution. Prior to the [[Modern synthesis (20th century)|modern synthesis]], during the period between the 1880s to the 1930s (dubbed the '[[Eclipse of Darwinism]]') many scientists argued in favor of alternative explanations. These included '[[orthogenesis]]', and among its proponents was the Russian entomologist [[Yuri Filipchenko|Yuri A. Filipchenko]]. | ||
Filipchenko appears to have been the one who coined the term | Filipchenko appears to have been the one who coined the term 'macroevolution' in his book ''Variabilität und Variation'' (1927).<ref name=":2" /> While introducing the concept, he claimed that the field of genetics is insufficient to explain ''"the origin of higher systematic units"'' above the species level. | ||
{{Text and translation | {{Text and translation | ||
| Auf die Weise hebt die heutige Genetik zweifellos den Schleier von der Evolution der Biotypen, Jordanone und Linneone (eine Art Mikroevolution), dagegen jene Evolution der höheren systematischen Gruppen, welche von jeher die Geister besonders für sich in Anspruch genommen hat (eine Art Makroevolution), liegt gänzlich außerhalb ihres Gesichtsfeldes, und dieser Umstand scheint uns die von uns oben angeführten Erwägungen über das Fehlen einer inneren Beziehung zwischen der Genetik und der Deszendenzlehre, die sich ja hauptsächlich mit der Makroevolution befaßt, nur zu unterstreichen. | | Auf die Weise hebt die heutige Genetik zweifellos den Schleier von der Evolution der Biotypen, Jordanone und Linneone (eine Art Mikroevolution), dagegen jene Evolution der höheren systematischen Gruppen, welche von jeher die Geister besonders für sich in Anspruch genommen hat (eine Art Makroevolution), liegt gänzlich außerhalb ihres Gesichtsfeldes, und dieser Umstand scheint uns die von uns oben angeführten Erwägungen über das Fehlen einer inneren Beziehung zwischen der Genetik und der Deszendenzlehre, die sich ja hauptsächlich mit der Makroevolution befaßt, nur zu unterstreichen. Bei einer solchen Sachlage muß zugegeben werden, daß die Entscheidung der Frage über die Faktoren der größeren Züge der Evolution, d. h. dessen, was wir Makroevolution nennen, unabhängig von den Ergebnissen der gegenwärtigen Genetik geschehen muß. So vorteilhaft es für uns auch wäre, uns auch in dieser Frage auf die exakten Resultate der Genetik zu stützen, so sind sie doch, unserer Meinung nach, zu diesem Zweck ganz unbrauchbar, da die Frage über die Entstehung der höheren systematischen Einheiten ganz außerhalb des Forschungsgebietes der Genetik liegt. Infolgedessen ist letztere auch eine exakte Wissenschaft, während die Dezendenzlehre heute, ebenso wie auch in XIX. Jahrhundert, einen einen spekulativen Charakter trägt.| In this way, modern genetics undoubtedly lifts the veil from the evolution of biotypes, Jordanones and Linneones [i.e. variations within a species]{{efn|name="BiotJordLinn" | The terms ('biotypes', 'Jordanone', and 'Linneone') used here by Filipchenko were/are rarely used among non-Russian speaking scientists. According to Krasil'nikov (1958),<ref name="Krasil1958a">{{cite book |last1=Krasilʹnikov |first1=Nikolaĭ Aleksandrovich |title=Soil microorganisms and higher plants |date=1958 |publisher=Academy of Sciences of the USSR |location=Moscow |url=https://www.soilandhealth.org/wp-content/uploads/01aglibrary/010112.krasilnikov.pdf}}</ref> these terms were used to describe the variety of forms observed within a single species: ''"With the development of genetics the concept of species widened according to the ideas of variability and heredity of organisms. New terms were introduced for the determination of species subdivision, such as "biotype", "pure line", "jardanon", "linneon", etc. ["Jardanon"--a simple means of classification of lower organisms. "Linneon"--the complex of "jardanons"--according to the Russian concept, the inner species variety of forms does not exceed the limits of qualitative unity of the species.]"''}} (a kind of microevolution), but that evolution of the higher systematic groups, which has always particularly occupied the minds of men (a kind of macroevolution), lies entirely outside its field of vision, and this circumstance seems to us only to emphasize the considerations we have given above about the lack of an inner relationship between genetics and the theory of descent, which is mainly concerned with macroevolution. In such a state of affairs, it must be admitted that the decision of the question depends on the factors of the larger features of evolution, of what we call macroevolution, must occur independently of the results of current genetics. As advantageous as it would be for us to rely on the exact results of genetics in this question, they are, in our opinion, completely useless for this purpose, since the question about the origin of the higher systematic units lies entirely outside the field research area of genetics. As a result, the latter is also an exact science, while the doctrine of descent today, as well as in the 19th century, has a speculative character.| Yuri Filipchenko, ''Variabilität und Variation'' (1927), pages 93-94<ref name=":2" /> | ||
Bei einer solchen Sachlage muß zugegeben werden, daß die Entscheidung der Frage über die Faktoren der größeren Züge der Evolution, d. h. dessen, was wir Makroevolution nennen, unabhängig von den Ergebnissen der gegenwärtigen Genetik geschehen muß. So vorteilhaft es für uns auch wäre, uns auch in dieser Frage auf die exakten Resultate der Genetik zu stützen, so sind sie doch, unserer Meinung nach, zu diesem Zweck ganz unbrauchbar, da die Frage über die Entstehung der höheren systematischen Einheiten ganz außerhalb des Forschungsgebietes der Genetik liegt. Infolgedessen ist letztere auch eine exakte Wissenschaft, während die | |||
In such a state of affairs, it must be admitted that the decision of the question depends on the factors of the larger features of evolution, of what we call macroevolution, must occur independently of the results of current genetics. As advantageous as it would be for us to rely on the exact results of genetics in this question, they are, in our opinion, completely useless for this purpose, since the question about the origin of the higher systematic units lies entirely outside the field research area of genetics. As a result, the latter is also an exact science, while the doctrine of descent today, as well as in the 19th century, has a speculative character. | |||
}} | }} | ||
Filipchenko's also claimed that a new taxon cannot evolve from an older one with a lower rank; e.g. a species cannot evolve into a family. It must originate from a preceding family. Furthermore, the evolution of a new family must require the sudden appearance of new traits which are different in greater magnitude compared to the new traits required for the evolution of a genus or species. | |||
{{Text and translation | {{Text and translation | Hier scheint uns ein wesentliches Mißverständnis obzuwalten. Davon schon gar nicht zu reden, daß es kaum richtig ist, in den Jardanonen Spaltungsprodukte eines Linneone zu sehen, ist es noch unrichtiger anzunehmen, daß nach den heutigen Anschauungen ein Jordanon sich im Evolutionsprozeß in ein neues Linneon verwandeln kann oder muß. Im Gegenteil, uns scheint, daß sich bei der Evolution die verschiedenen taxonomischen Einheiten so verhalten, daß Gleiches Gleiches erzeugt. Aus einem Biotyp entsteht durch Mutation ein neuer Biotypus, aus einem Jordanon bildet sich - durch eine Neugruppierung der ihn bildenden Biotypen, sowie durch das Auftreten einiger neuer - ein zweites Jordanon; endlich zerfällt ein aus mehreren Jordanonen bestehendes Linneon infolge des Verschwindens einiger von ihnen in zwei selbständige Linneone. Es ist vollkommen richtig, daß niemand eine Umwandlung der Rassen in eine Art beobachtet hat, aber das braucht auch nicht zu sein, da im Prozeß der Evolution eine neue Art oder Arten gewöhnlich aus einer alten Art, eine neue Gattung aus einer anderen Gattung usw. entstehen. | There seems to be a fundamental misunderstanding here. Not to mention that it is hardly correct to see the Jardanones{{efn|name="BiotJordLinn"}} as products of the fission of a Linneone,{{efn|name="BiotJordLinn"}} it is even more incorrect to assume that, according to modern views, a Jordanone can or must transform into a new Linneone in the process of evolution. On the contrary, it seems to us that in evolution the various taxonomic units behave in such a way that like produces like. A new biotype{{efn|name="BiotJordLinn"}} arises from one biotype through mutation; a Jordanone forms a second Jordanone through a regrouping of the biotypes that make up it and the appearance of some new ones; finally, a Linneone consisting of several Jordanones splits into two independent Linneones as a result of the disappearance of some of them. It is quite true that no one has observed a transformation of the races into a species, but that need not be the case, since in the process of evolution a new species or species usually arise from an old species, a new genus from another genus, etc.| Yuri Filipchenko, ''Variabilität und Variation'' (1927), page 89 <ref name=":2" />}} | ||
}} | |||
Filipchenko | However, Filipchenko's views are not consistent with contemporary understanding of evolution. Furthermore, the [[Taxonomic rank#Significance and problems|Linnaean ranks]] of 'genus' (and higher) are not real entities but arbitrary concepts. These traditional taxonomic concepts [[Taxonomic_boundary_paradox|break down]] when they are applied to common ancestry.<ref name="Hendricks2014a">{{cite journal |last1=Hendricks |first1=Jonathan R. |last2=Saupe |first2=Erin E |last3=Myers |first3=Corinne E. |last4=Hermsen |first4=Elizabeth J. |last5=Allmon |first5=Warren D. |title=he generification of the fossil record. |journal=Paleobiology |date=2014 |volume=40 |issue=4 |pages=511–528 |doi=10.1666/13076}}</ref><ref name="DAOAL1"/> | ||
Nevertheless, Filipchenko’s distinction between microevolution and macroevolution had a major | Nevertheless, Filipchenko’s distinction between microevolution and macroevolution had a major influence on evolutionary biology. The term ''macroevolution'' was adopted by Filipchenko's protégé [[Theodosius Dobzhansky]] in his book ''<nowiki />'Genetics und the Origin of Species'<nowiki />'' (1937), a seminal piece that contributed to the development of the Modern Synthesis. The term was also used by critics of the Modern Synthesis. A good example of this is the book ''The Material Basis of Evolution'' (1940) by the geneticist [[Richard Goldschmidt]], a close friend of Filipchenko.<ref name="Adams1990a" /> Goldschmidt suggested [[Saltational evolution|saltational evolutionary changes]]<ref>{{Cite journal|last=Goldschmidt|first=R.|title=Some aspects of evolution|journal=Science|year=1933|volume=78|issue=2033|pages=539–547|doi=10.1126/science.78.2033.539|pmid=17811930|bibcode=1933Sci....78..539G}}</ref><ref>{{Cite book|last=Goldschmidt|first=R.|title=The material basis of evolution|publisher=Yale University Press|year=1940}}</ref> which found a moderate revival in the 'hopeful monster' concept of [[evolutionary developmental biology]] (or evo-devo).<ref>{{Cite journal|last=Theißen|first=Günter|date=March 2009|title=Saltational evolution: hopeful monsters are here to stay|journal=Theory in Biosciences|language=en|volume=128|issue=1|pages=43–51|doi=10.1007/s12064-009-0058-z|pmid=19224263|s2cid=4983539|issn=1431-7613}}</ref><ref>{{Cite book|last=Rieppel, Olivier|title=Turtles as hopeful monsters: origins and evolution|date=13 March 2017|isbn=978-0-253-02507-4|location=Bloomington, Indiana|oclc=962141060}}</ref> Occasionally such dramatic changes can lead to novel features that survive. | ||
As an alternative to saltational evolution, [[Dobzhansky]]<ref>{{Cite book|last=Dobzhanski|first=T.|title=Genetics and the origin of species.|publisher=Columbia University Press|year=1937}}</ref> suggested that the difference between macroevolution and microevolution reflects essentially a difference in time-scales, and that macroevolutionary changes were simply the sum of microevolutionary changes over geologic time. This view became broadly accepted | As an alternative to saltational evolution, [[Dobzhansky]]<ref>{{Cite book|last=Dobzhanski|first=T.|title=Genetics and the origin of species.|publisher=Columbia University Press|year=1937}}</ref> suggested that the difference between macroevolution and microevolution reflects essentially a difference in time-scales, and that macroevolutionary changes were simply the sum of microevolutionary changes over geologic time. This view became broadly accepted in the middle of the last century but it has been challenged by a number of scientists who claim that microevolution is necessary but not sufficient to explain macroevolution. This is the decoupled view (see below).<ref name="Gould2002a" /><ref name=":0" /><ref name=":1" /> | ||
== Microevolution vs Macroevolution == | == Microevolution vs Macroevolution == | ||
Micro- and macroevolution are both supported by [[Evidence_of_common_descent|overwhelming evidence]]. This fact remains uncontroversial within the [[Level_of_support_for_evolution#Scientific|scientific community]]. However, there has been considerable debate regarding the connection between microevolution and macroevolution.<ref name="Saupe2021a" /> | |||
The ''' | Broadly speaking, there are two views regarding this issue. The '''<nowiki />'Extrapolation'<nowiki />''' view holds that macroevolution is merely cumulative microevolution. The '''<nowiki />'Decoupled'<nowiki />''' view holds that there are separate macroevolutionary processes that cannot be sufficiently explained by microevolutionary processes alone. Most scientists who adopt the second viewpoint are not claiming that macroevolution is incompatible with microevolution. Rather, they see macroevolution as an autonomous field of study regarding the deep history of life. For this reason, a full understanding of macroevolution requires insights that are not limited to microevolution.<ref name="Gould2002a" /><ref>{{cite book |last=Ayala Francisco J |date=1983|name-list-style= and |editor-last1 = Asquith | editor-first1= Peter D| editor-last2=Nickles|editor-first2= Thomas |title=PSA 1982 |volume=2|publisher=Philosophy of Science Association |pages=118–132 |chapter=Beyond Darwinism? The Challenge of Macroevolution to the Synthetic Theory of Evolution |isbn=}}</ref><ref name="Levinton2001">{{cite book | vauthors = Levinton Jeffrey S | date = 2001 | title = Genetics, Paleontology, and Macroevolution 2nd edition | publisher = Cambridge University Press | place = Cambridge, UK | isbn = 0-521-80317-9}}</ref><ref name="Rolland2022a" /><ref name="Simons2002a">{{cite journal |last1=Simons |first1=Andrew M. |title=The continuity of microevolution and macroevolution |journal=Journal of Evolutionary Biology |date=August 21, 2002 |volume=15 |issue=5 |pages=688–701 |doi=10.1046/j.1420-9101.2002.00437.x}}</ref><ref name="Erwin2001a">{{cite journal |last1=Erwin |first1=Douglas H. |title=Macroevolution is more than repeated rounds of microevolution |journal=Evolution & Development |date=December 24, 2001 |volume=2 |issue=2 |pages=78–84 |doi=10.1046/j.1525-142x.2000.00045.x|pmid=11258393 }}</ref><ref name="Adams1990a">{{cite journal |last1=Adams |first1=Mark B |title=Filipchenko [Philiptschenko], Iurii Aleksandrovich. |journal=Dictionary of Scientific Biography |date=1990 |volume=17 |issue=297–303 |url=https://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/filipchenko-philiptschenko-iurii-aleksandrovich}}</ref><ref name="DAOAL1" /><ref name="Moran2022a">{{cite web |last1=Moran |first1=Laurence A. |title=Macroevolution |url=https://sandwalk.blogspot.com/2022/10/macroevolution.html |website=Sandwalk Blog |date=October 13, 2022}}</ref> An example of this argument has been made by Francisco J. Ayala. | ||
{{Quote|text="...macroevolutionary processes are underlain by microevolutionary phenomena and are compatible with microevolutionary theories, but macroevolutionary studies require the formulation of autonomous hypotheses and models (which must be tested using macroevolutionary evidence). In this (epistemologically) very important sense, macroevolution is decoupled from microevolution: macroevolution is an autonomous field of evolutionary study."|sign= Francisco J. Ayala (1983)<ref name="AyalaFrancisco">{{cite journal |last1=Ayala |first1=Francisco J. |title="Beyond Darwinism? The Challenge of Macroevolution to the Synthetic Theory of Evolution". |journal=Philosophy of Science Association. |date=1982 |volume=2 |pages=118–132}}</ref>}} | |||
Microevolution is characterized by the evolutionary process of changing heritable characteristics (phenotypes) and changes in allele frequencies (genotypes) within populations. This involves mechanisms such as [[mutation]], [[natural selection]], and [[genetic drift]] as studied in the field of [[population genetics]].<ref name=":0" /> In contrast, macroevolution concerns how species and | |||
* How different species are related to each other is | and higher taxonomic groups ([[genera]], [[Family (biology)|families]], [[Order (biology)|orders]], etc) have evolved across geography and vast spans of [[geological time]]. For example, whether [[speciation]] is [[sympatric]] or [[allopatric]]; and whether the common mode of macroevolution is better described in terms of [[phyletic gradualism]] or [[punctuated equilibrium]].<ref name="Saupe2021a" /> These and other important questions and topics are researched within various scientific fields, which makes the study of macroevolution highly interdisciplinary. Examples of these include: | ||
* The rates of evolutionary change and across time in the [[fossil record]].<ref name="Rolland2022a" | * How different species are related to each other is researched in [[phylogenetics]]). | ||
* [[Mass extinctions]] and [[adaptive radiation|evolutionary diversifications]],<ref name="GEOL331a" | * The rates of evolutionary change and across time in the [[fossil record]].<ref name="Rolland2022a" /> For example, some groups appear to experience a lot of change while others remain morphologically stable, which are often referred to as ''[[living fossils]]''. However, that term has been criticized for wrongfully implying that such organisms have not evolved at all. <ref name="Kin2014a">{{Cite journal|last1=Kin|first1=Adrian|last2=Błażejowski|first2=Błażej|date=2014-10-02|title=The Horseshoe Crab of the Genus Limulus: Living Fossil or Stabilomorph?|journal=PLOS ONE|language=en|volume=9|issue=10|article-number=e108036|doi=10.1371/journal.pone.0108036|issn=1932-6203|pmc=4183490|pmid=25275563|bibcode=2014PLoSO...9j8036K|doi-access=free}}</ref> | ||
* | * Why different taxonomic groups (even those with similar ages) exhibit different survival/extinction rates, [[species diversity]], and/or [[Phenotypic disparity|morphological disparity]]. | ||
* Long-term trends in evolution | * The causes and impacts of [[Mass extinctions]] and [[adaptive radiation|evolutionary diversifications]],<ref name="GEOL331a" /> e.g. the [[Permian-Triassic]] and [[End Cretaceous|Cretaceous-Paleogene]] events, the [[Cambrian Explosion]] and [[Cretaceous Terrestrial Revolution]]. | ||
* How | * Does natural selection also operate at the species level (see [[Group selection|Group Selection]])? | ||
* Long-term trends in evolution, e.g. trends towards complexity or simplicity and whether these trends are directional or passive.<ref name="Gregory2008a"/> | |||
* How distinctive and complex traits have evolved, e.g. [[gene duplication]], [[heterochrony]], [[Evolutionary developmental biology#The origins of novelty|novelty in evo-devo]], [[facilitated variation]], and [[constructive neutral evolution]]. | |||
==Macroevolutionary processes== | ==Macroevolutionary processes== | ||
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=== Speciation === | === Speciation === | ||
{{Main|speciation}} | {{Main|speciation}} | ||
According to | According to Hautmann<ref name=":1" />, speciation has both micro- and macroevolutionary aspects. Specifically, speciation also involves the classic process of descent with modification, i.e. morphological transformation observed across many generations. This is microevolutionary. In contrast, the species variation produced by speciation, and the rate at which it successfully occurs, is macroevolutionary.<ref name=":0" /> Stephen J. Gould also saw species as the basic unit of macroevolution.{{efn| name="GouldM"|}} | ||
Speciation is the process in which populations within one species change to an extent at which they become [[Reproductive isolation|reproductively isolated]], that is, they cannot interbreed anymore. However, this classical concept has been challenged and more recently, a phylogenetic or evolutionary [[species]] concept has been adopted. Their main criteria for new species is to be diagnosable and [[Monophyly|monophyletic]], that is, they form a clearly defined lineage.<ref>{{Cite journal |last=Luckow |first=Melissa |date=1995 |title=Species Concepts: Assumptions, Methods, and Applications | Speciation is the process in which populations within one species change to an extent at which they become [[Reproductive isolation|reproductively isolated]], that is, they cannot interbreed anymore. However, this classical concept has been challenged and more recently, a phylogenetic or evolutionary [[species]] concept has been adopted. Their main criteria for new species is to be diagnosable and [[Monophyly|monophyletic]], that is, they form a clearly defined lineage.<ref>{{Cite journal |last=Luckow |first=Melissa |date=1995 |title=Species Concepts: Assumptions, Methods, and Applications |journal=Systematic Botany |volume=20 |issue=4 |pages=589–605 |doi=10.2307/2419812 |jstor=2419812 |issn=0363-6445}}</ref><ref>{{Cite journal |last1=Frost |first1=Darrel R. |last2=Hillis |first2=David M. |date=1990 |title=Species in Concept and Practice: Herpetological Applications |journal=Herpetologica |volume=46 |issue=1 |pages=86–104 |jstor=3892607 |issn=0018-0831}}</ref> | ||
[[Charles Darwin]] first discovered that speciation can be extrapolated so that species not only evolve into new species, but also into new [[Genus|genera]], families and other groups | [[Charles Darwin]] first discovered that speciation can be extrapolated so that species not only evolve into new species, but also into new [[Genus|genera]], families and other groups of animals. In other words, macroevolution is reducible to microevolution through selection of traits over long periods of time.<ref>{{Cite journal|last=Greenwood|first=P. H.|title=Macroevolution - myth or reality ?|journal=Biological Journal of the Linnean Society|year=1979|volume=12|issue=4|pages=293–304|doi=10.1111/j.1095-8312.1979.tb00061.x}}</ref> In addition, some scholars have argued that selection at the species level is important as well.<ref>{{Cite journal|last=Grantham|first=T A|date=November 1995|title=Hierarchical Approaches to Macroevolution: Recent Work on Species Selection and the "Effect Hypothesis"|journal=Annual Review of Ecology and Systematics|language=en|volume=26|issue=1|pages=301–321|doi=10.1146/annurev.es.26.110195.001505|bibcode=1995AnRES..26..301G |issn=0066-4162}}</ref> The advent of genome sequencing enabled the discovery of gradual genetic changes both during speciation but also across higher taxa. For instance, the evolution of humans from ancestral primates or other mammals can be traced to numerous but individual mutations.<ref>{{Cite journal |last1=Foley |first1=Nicole M. |last2=Mason |first2=Victor C. |last3=Harris |first3=Andrew J. |last4=Bredemeyer |first4=Kevin R. |last5=Damas |first5=Joana |last6=Lewin |first6=Harris A. |last7=Eizirik |first7=Eduardo |last8=Gatesy |first8=John |last9=Karlsson |first9=Elinor K. |last10=Lindblad-Toh |first10=Kerstin |last11=Zoonomia Consortium‡ |last12=Springer |first12=Mark S. |last13=Murphy |first13=William J. |last14=Andrews |first14=Gregory |last15=Armstrong |first15=Joel C. |date=2023-04-28 |title=A genomic timescale for placental mammal evolution |journal=Science |language=en |volume=380 |issue=6643 |article-number=eabl8189 |doi=10.1126/science.abl8189 |issn=0036-8075 |pmc=10233747 |pmid=37104581}}</ref> | ||
According to the [[Resource-use hypothesis]], the diversification of terrestrial species is closely related to global climatic changes, particularly the [[Cenozoic]] alternation of warming and cooling episodes. Global analysis of terrestrial mammals supports the view that these physical environmental changes have shaped macroevolutionary patterns by promoting biome specialisation. This specialization leads to significantly higher rates of vicariance and speciation in biome specialist (stenobiomic) lineages compared to generalist lineages.<ref name="Hernández Fernández, M. et al. 2022">{{Cite journal| last1=Hernández Fernández |first1=Manuel | last2=Pelegrin|first2= Jonathan S. | last3=Gómez Cano|first3= Ana R. | last4=García Yelo|first4= Blanca A. | last5=Moreno-Bofarull|first5= Ana | last6=Sánchez-Fontela|first6= Noelia | last7=Rodríguez-Ruiz|first7= Claudia | last8=Ramiro Camacho|first8=Alejandro | last9=Domingo|first9= Laura | last10=Menéndez|first10= Iris | last11=Martín-Perea|first11= David M. | last12=Bazán|first12= Carla M. | last13=Alcalde|first13= Gema M. | last14=Domingo|first14= M. Soledad | last15=Luna|first15= Belén | last16=Peinado Cortés|first16= María del Mar | last17=Arias|first17= Antón | last18=González Couturier|first18= Gabriela | last19=Márquez Villena|first19= Ana| last20=Anaya|first20= Noelia| last21=Blanco|first21= Fernando | last22=Galli|first22= Emilia | last23=Gamboa|first23= Sara | last24=Quesada|first24= Álvaro | last25=Sanz-Pérez|first25= Dánae | last26=Varela |first26=Sara | last27=Cantalapiedra|first27= Juan L. | title = Macroevolution and climate changes: A global multi-family test supports the resource-use hypothesis in terrestrial mammals | journal = Historical Biology | volume = 34 | pages = 1471–1479 | year = 2022| doi = 10.1080/08912963.2022.2042807}}</ref> | |||
=== Evolution of new organs and tissues === | === Evolution of new organs and tissues === | ||
One of the main questions in evolutionary biology is how new structures evolve, such as new [[Organ (biology)|organs]]. Macroevolution is often thought to require the evolution of structures that are 'completely new'. However, fundamentally novel structures are not necessary for dramatic evolutionary change. As can be seen in [[Vertebrate|vertebrate evolution]], most "new" organs are actually not new—they are simply modifications of previously existing organs. For instance, the evolution of [[mammal]] diversity in the past 100 million years has not required any major innovation.<ref>{{Cite journal |last1=Meredith |first1=R. W. |last2=Janecka |first2=J. E. |last3=Gatesy |first3=J. |last4=Ryder |first4=O. A. |last5=Fisher |first5=C. A. |last6=Teeling |first6=E. C. |last7=Goodbla |first7=A. |last8=Eizirik |first8=E. |last9=Simao |first9=T. L. L. |last10=Stadler |first10=T. |last11=Rabosky |first11=D. L. |last12=Honeycutt |first12=R. L. |last13=Flynn |first13=J. J. |last14=Ingram |first14=C. M. |last15=Steiner |first15=C. |date=2011-10-28 |title=Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification |url=https://www.sciencemag.org/lookup/doi/10.1126/science.1211028 |journal=Science |language=en |volume=334 |issue=6055 |pages=521–524 |doi=10.1126/science.1211028 |pmid=21940861 |bibcode=2011Sci...334..521M |s2cid=38120449 |issn=0036-8075|url-access=subscription }}</ref> All of this diversity can be explained by modification of existing organs, such as the evolution of [[Tusk|elephant tusks]] from [[ | One of the main questions in evolutionary biology is how new structures evolve, such as new [[Organ (biology)|organs]]. Macroevolution is often thought to require the evolution of structures that are 'completely new'. However, fundamentally novel structures are not necessary for dramatic evolutionary change. As can be seen in [[Vertebrate|vertebrate evolution]], most "new" organs are actually not new—they are simply modifications of previously existing organs. For instance, the evolution of [[mammal]] diversity in the past 100 million years has not required any major innovation.<ref>{{Cite journal |last1=Meredith |first1=R. W. |last2=Janecka |first2=J. E. |last3=Gatesy |first3=J. |last4=Ryder |first4=O. A. |last5=Fisher |first5=C. A. |last6=Teeling |first6=E. C. |last7=Goodbla |first7=A. |last8=Eizirik |first8=E. |last9=Simao |first9=T. L. L. |last10=Stadler |first10=T. |last11=Rabosky |first11=D. L. |last12=Honeycutt |first12=R. L. |last13=Flynn |first13=J. J. |last14=Ingram |first14=C. M. |last15=Steiner |first15=C. |date=2011-10-28 |title=Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification |url=https://www.sciencemag.org/lookup/doi/10.1126/science.1211028 |journal=Science |language=en |volume=334 |issue=6055 |pages=521–524 |doi=10.1126/science.1211028 |pmid=21940861 |bibcode=2011Sci...334..521M |s2cid=38120449 |issn=0036-8075|url-access=subscription }}</ref> All of this diversity can be explained by modification of existing organs, such as the evolution of [[Tusk|elephant tusks]] from [[incisor]]s. Other examples include [[Bird wing|wings]] (modified limbs), [[feather]]s (modified [[reptile scale]]s),<ref>{{Cite journal |last1=Wu |first1=Ping |last2=Yan |first2=Jie |last3=Lai |first3=Yung-Chih |last4=Ng |first4=Chen Siang |last5=Li |first5=Ang |last6=Jiang |first6=Xueyuan |last7=Elsey |first7=Ruth M |last8=Widelitz |first8=Randall |last9=Bajpai |first9=Ruchi |last10=Li |first10=Wen-Hsiung |last11=Chuong |first11=Cheng-Ming |date=2017-11-21 |title=Multiple Regulatory Modules Are Required for Scale-to-Feather Conversion |url=|journal=Molecular Biology and Evolution |volume=35 |issue=2 |pages=417–430 |doi=10.1093/molbev/msx295 |issn=0737-4038 |pmc=5850302 |pmid=29177513}}</ref> [[lung]]s (modified [[swim bladder]]s, e.g. found in [[fish]]),<ref>{{Cite journal |last=Brainerd |first=E. L. |date=1999-12-01 |title=New perspectives on the evolution of lung ventilation mechanisms in vertebrates |url=|journal=Experimental Biology Online |language=en |volume=4 |issue=2 |pages=1–28 |doi=10.1007/s00898-999-0002-1 |bibcode=1999EvBO....4b...1B |s2cid=35368264 |issn=1430-3418}}</ref><ref>{{Cite journal |last1=Hoffman |first1=M. |last2=Taylor |first2=B. E. |last3=Harris |first3=M. B. |date=2016-04-01 |title=Evolution of lung breathing from a lungless primitive vertebrate |journal=Respiratory Physiology & Neurobiology |series=Physiology of respiratory networks of non-mammalian vertebrates |language=en |volume=224 |pages=11–16 |doi=10.1016/j.resp.2015.09.016 |issn=1569-9048 |pmc=5138057 |pmid=26476056}}</ref> or even the [[heart]] (a muscularized segment of a [[vein]]).<ref>{{Cite journal |last1=Jensen |first1=Bjarke |last2=Wang |first2=Tobias |last3=Christoffels |first3=Vincent M. |last4=Moorman |first4=Antoon F. M. |date=2013-04-01 |title=Evolution and development of the building plan of the vertebrate heart |journal=Biochimica et Biophysica Acta (BBA) - Molecular Cell Research |series=Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction |language=en |volume=1833 |issue=4 |pages=783–794 |doi=10.1016/j.bbamcr.2012.10.004 |pmid=23063530 |s2cid=28787569 |issn=0167-4889|doi-access=free }}</ref> | ||
The same concept applies to the evolution of "novel" tissues. Even fundamental tissues such as [[bone]] can evolve from combining existing [[protein]]s ([[collagen]]) with calcium phosphate (specifically, [[Hydroxyapatite|hydroxy-apatite]]). This probably happened when certain cells that make collagen also accumulated calcium phosphate to get a proto-bone cell.<ref>{{Cite journal |last1=Wagner |first1=Darja Obradovic |last2=Aspenberg |first2=Per |date=2011-08-01 |title=Where did bone come from? |url=|journal=Acta Orthopaedica |volume=82 |issue=4 |pages=393–398 |doi=10.3109/17453674.2011.588861 |issn=1745-3674 |pmc=3237026 |pmid=21657973}}</ref> | The same concept applies to the evolution of "novel" tissues. Even fundamental tissues such as [[bone]] can evolve from combining existing [[protein]]s ([[collagen]]) with calcium phosphate (specifically, [[Hydroxyapatite|hydroxy-apatite]]). This probably happened when certain cells that make collagen also accumulated calcium phosphate to get a proto-bone cell.<ref>{{Cite journal |last1=Wagner |first1=Darja Obradovic |last2=Aspenberg |first2=Per |date=2011-08-01 |title=Where did bone come from? |url=|journal=Acta Orthopaedica |volume=82 |issue=4 |pages=393–398 |doi=10.3109/17453674.2011.588861 |issn=1745-3674 |pmc=3237026 |pmid=21657973}}</ref> | ||
==Examples== | ==Examples== | ||
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=== Stanley's rule === | === Stanley's rule === | ||
Macroevolution is driven by differences between species in origination and extinction rates. Remarkably, these two factors are generally positively correlated: taxa that have typically high diversification rates also have high extinction rates. This observation has been described first by [[Steven M. Stanley|Steven Stanley]], who attributed it to a variety of ecological factors.<ref>{{Cite book|last=Stanley, Steven M.|title=Macroevolution, pattern and process|date=1979|publisher=W.H. Freeman|isbn=0-7167-1092-7|location=San Francisco|oclc=5101557}}</ref> Yet, a positive correlation of origination and extinction rates is also a prediction of the [[Red Queen hypothesis]], which postulates that evolutionary progress (increase in fitness) of any given species causes a decrease in fitness of other species, ultimately driving to extinction those species that do not adapt rapidly enough.<ref>{{Cite journal|last=Van Valen|first=L.|date=1973|title=A new evolutionary law|journal=Evolutionary Theory|volume=1|pages=1–30}}</ref> High rates of origination must therefore correlate with high rates of extinction.<ref name=":1" /> Stanley's rule, which applies to almost all taxa and geologic ages, is therefore an indication for a dominant role of biotic interactions in macroevolution. | Macroevolution is driven by differences between species in origination and extinction rates. Remarkably, these two factors are generally positively correlated: taxa that have typically high diversification rates also have high extinction rates. This observation has been described first by [[Steven M. Stanley|Steven Stanley]], who attributed it to a variety of ecological factors.<ref>{{Cite book|last=Stanley, Steven M.|title=Macroevolution, pattern and process|date=1979|publisher=W.H. Freeman|isbn=0-7167-1092-7|location=San Francisco|oclc=5101557}}</ref> Yet, a positive correlation of origination and extinction rates is also a prediction of the [[Red Queen hypothesis]], which postulates that evolutionary progress (increase in fitness) of any given species causes a decrease in fitness of other species, ultimately driving to extinction those species that do not adapt rapidly enough.<ref>{{Cite journal|last=Van Valen|first=L.|date=1973|title=A new evolutionary law|journal=Evolutionary Theory|volume=1|pages=1–30}}</ref> High rates of origination must therefore correlate with high rates of extinction.<ref name=":1" /> Stanley's rule, which applies to almost all taxa and geologic ages, is therefore an indication for a dominant role of biotic interactions in macroevolution. | ||
=== Evolution of multicellularity === | === Evolution of multicellularity === | ||
{{Main|Multicellular organism}} | {{Main|Multicellular organism}} | ||
The evolution of multicellular organisms is one of the major breakthroughs in evolution. The first step of converting a unicellular organism into a [[Animal|metazoan]] (a multicellular organism) is to allow cells to attach to each other. This can be achieved by one or a few [[mutation]]s. In fact, many [[bacteria]] form multicellular assemblies, e.g. [[cyanobacteria]] or [[myxobacteria]]. Another species of bacteria, ''Jeongeupia sacculi'', form well-ordered sheets of cells, which ultimately develop into a bulbous structure.<ref>{{Cite journal |last1=Datta |first1=Sayantan |last2=Ratcliff |first2=William C |date=2022-10-11 |title=Illuminating a new path to multicellularity |journal=eLife |volume=11 | | The evolution of multicellular organisms is one of the major breakthroughs in evolution. The first step of converting a unicellular organism into a [[Animal|metazoan]] (a multicellular organism) is to allow cells to attach to each other. This can be achieved by one or a few [[mutation]]s. In fact, many [[bacteria]] form multicellular assemblies, e.g. [[cyanobacteria]] or [[myxobacteria]]. Another species of bacteria, ''Jeongeupia sacculi'', form well-ordered sheets of cells, which ultimately develop into a bulbous structure.<ref>{{Cite journal |last1=Datta |first1=Sayantan |last2=Ratcliff |first2=William C |date=2022-10-11 |title=Illuminating a new path to multicellularity |journal=eLife |volume=11 |article-number=e83296 |doi=10.7554/eLife.83296 |pmid=36217823 |issn=2050-084X |pmc=9553208 |doi-access=free }}</ref><ref>{{Cite journal |last1=Mizuno |first1=Kouhei |last2=Maree |first2=Mais |last3=Nagamura |first3=Toshihiko |last4=Koga |first4=Akihiro |last5=Hirayama |first5=Satoru |last6=Furukawa |first6=Soichi |last7=Tanaka |first7=Kenji |last8=Morikawa |first8=Kazuya |date=2022-10-11 |editor-last=Goldstein |editor-first=Raymond E |editor2-last=Weigel |editor2-first=Detlef |title=Novel multicellular prokaryote discovered next to an underground stream |journal=eLife |volume=11 |article-number=e71920 |doi=10.7554/eLife.71920 |pmid=36217817 |pmc=9555858 |issn=2050-084X |doi-access=free }}</ref> Similarly, unicellular yeast cells can become multicellular by a single mutation in the ACE2 gene, which causes the cells to form a branched multicellular form.<ref>{{Cite journal |last1=Ratcliff |first1=William C. |last2=Fankhauser |first2=Johnathon D. |last3=Rogers |first3=David W. |last4=Greig |first4=Duncan |last5=Travisano |first5=Michael |date=May 2015 |title=Origins of multicellular evolvability in snowflake yeast |journal=Nature Communications |language=en |volume=6 |issue=1 |page=6102 |doi=10.1038/ncomms7102 |issn=2041-1723 |pmc=4309424 |pmid=25600558|bibcode=2015NatCo...6.6102R }}</ref> | ||
=== Evolution of bat wings === | === Evolution of bat wings === | ||
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{{main|Limbless vertebrates}} | {{main|Limbless vertebrates}} | ||
[[File:Vine-thicket Fine-lined Slider (Lerista cinerea).jpg|thumb|Limbloss in lizards can be observed in the genus ''[[Lerista]]'' which shows many intermediary steps with increasing loss of digits and toes. The species shown here, ''[[Lerista cinerea]]'', has no digits and only 1 toe left.]] | [[File:Vine-thicket Fine-lined Slider (Lerista cinerea).jpg|thumb|Limbloss in lizards can be observed in the genus ''[[Lerista]]'' which shows many intermediary steps with increasing loss of digits and toes. The species shown here, ''[[Lerista cinerea]]'', has no digits and only 1 toe left.]] | ||
[[Snake]]s evolved from [[lizard]]s. [[Phylogenetics|Phylogenetic]] analysis shows that snakes are actually nested within the [[phylogenetic tree]] of lizards, demonstrating that they have a common ancestor.<ref>{{Cite journal |last1=Streicher |first1=Jeffrey W. |last2=Wiens |first2=John J. |date=2017-09-30 |title=Phylogenomic analyses of more than 4000 nuclear loci resolve the origin of snakes among lizard families |journal=Biology Letters |volume=13 |issue=9 | | [[Snake]]s evolved from [[lizard]]s. [[Phylogenetics|Phylogenetic]] analysis shows that snakes are actually nested within the [[phylogenetic tree]] of lizards, demonstrating that they have a common ancestor.<ref>{{Cite journal |last1=Streicher |first1=Jeffrey W. |last2=Wiens |first2=John J. |date=2017-09-30 |title=Phylogenomic analyses of more than 4000 nuclear loci resolve the origin of snakes among lizard families |journal=Biology Letters |volume=13 |issue=9 |article-number=20170393 |doi=10.1098/rsbl.2017.0393 |pmc=5627172 |pmid=28904179}}</ref> This split happened about 180 million years ago and several intermediary [[fossil]]s are known to document the origin. In fact, limbs have been lost in numerous clades of [[reptile]]s, and there are cases of recent [[Limbless vertebrate|limb loss]]. For instance, the [[skink]] genus ''[[Lerista]]'' has lost limbs in multiple cases, with all possible intermediary steps, that is, there are species which have fully developed limbs, shorter limbs with 5, 4, 3, 2, 1 or no toes at all.<ref>{{Cite journal |last1=Skinner |first1=Adam |last2=Lee |first2=Michael SY |last3=Hutchinson |first3=Mark N |date=2008 |title=Rapid and repeated limb loss in a clade of scincid lizards |journal=BMC Evolutionary Biology |language=en |volume=8 |issue=1 |page=310 |doi=10.1186/1471-2148-8-310 |issn=1471-2148 |pmc=2596130 |pmid=19014443 |doi-access=free |bibcode=2008BMCEE...8..310S }}</ref> | ||
=== Human evolution === | === Human evolution === | ||
While human evolution from their primate ancestors did not require massive morphological changes, our brain has sufficiently changed to allow human consciousness and intelligence. While the latter involves relatively minor morphological changes it did result in dramatic changes to [[Brain|brain function]].<ref>{{Cite book | While human evolution from their primate ancestors did not require massive morphological changes, our brain has sufficiently changed to allow human consciousness and intelligence. While the latter involves relatively minor morphological changes it did result in dramatic changes to [[Brain|brain function]].<ref>{{Cite book |title=Macroevolution: explanation, interpretation and evidence |date=2015 |first1=Emanuele |last1=Serrelli |first2=Nathalie |last2=Gontier |isbn=978-3-319-15045-1 |location=Cham |oclc=903489046}}</ref> Thus, macroevolution does not have to be morphological, it can also be functional. | ||
The study of human (brain) evolution benefits from the fact that [[Human genome|human]] and [[ape]] genomes are available so that [[Ancestral sequence reconstruction|the genomes of our common ancestor can be reconstructed]].<ref>{{Cite journal |last1=Hara |first1=Yuichiro |last2=Imanishi |first2=Tadashi |last3=Satta |first3=Yoko |date=2012 |title=Reconstructing the demographic history of the human lineage using whole-genome sequences from human and three great apes |journal=Genome Biology and Evolution |volume=4 |issue=11 |pages=1133–1145 |doi=10.1093/gbe/evs075 |issn=1759-6653 |pmc=3752010 |pmid=22975719}}</ref> Even though the precise genetic mechanisms that shaped the human brain are not known, the mutations involved in human brain evolution are largely known, given that the genes expressed in the brain are relatively well understood.<ref>{{Cite journal |last1=Naumova |first1=Oksana Yu |last2=Lee |first2=Maria |last3=Rychkov |first3=Sergei Yu |last4=Vlasova |first4=Natalia V. |last5=Grigorenko |first5=Elena L. |date=2013 |title=Gene expression in the human brain: the current state of the study of specificity and spatiotemporal dynamics |journal=Child Development |volume=84 |issue=1 |pages=76–88 |doi=10.1111/cdev.12014 |issn=1467-8624 |pmc=3557706 |pmid=23145569}}</ref> | |||
=== Evolution of viviparity in lizards === | === Evolution of viviparity in lizards === | ||
[[File:Zootoca vivipara. 3epo.Post.jpg|thumb|The European Common Lizard (''[[Viviparous lizard|Zootoca vivipara]]'') consists of populations that are egg-laying or live-bearing, demonstrating that this dramatic difference can even evolve within a species.]] | [[File:Zootoca vivipara. 3epo.Post.jpg|thumb|The European Common Lizard (''[[Viviparous lizard|Zootoca vivipara]]'') consists of populations that are egg-laying or live-bearing, demonstrating that this dramatic difference can even evolve within a species.]] | ||
Most lizards are egg-laying and thus need an environment that is warm enough to incubate their eggs. However, some species have evolved [[viviparity]], that is, they give birth to live young, as almost all [[mammal]]s do. In several clades of lizards, egg-laying (oviparous) species have evolved into live-bearing ones, apparently with very little genetic change. For instance, a European common lizard, [[Viviparous lizard|''Zootoca vivipara'']], is viviparous throughout most of its range, but oviparous in the extreme southwest portion.<ref>{{Cite journal |last=Heulin |first=Benoît |date=1990-05-01 |title=Étude comparative de la membrane coquillère chez les souches ovipare et vivipare du lézard Lacerta vivipara |url=http://www.nrcresearchpress.com/doi/10.1139/z90-147 |journal=Canadian Journal of Zoology |language=en |volume=68 |issue=5 |pages=1015–1019 |doi=10.1139/z90-147 |bibcode=1990CaJZ...68.1015H |issn=0008-4301|url-access=subscription }}</ref><ref>{{Cite journal |last1=Arrayago |first1=Maria-Jesus |last2=Bea |first2=Antonio |last3=Heulin |first3=Benoit |date=1996 |title=Hybridization Experiment between Oviparous and Viviparous Strains of Lacerta vivipara: A New Insight into the Evolution of Viviparity in Reptiles | Most lizards are egg-laying and thus need an environment that is warm enough to incubate their eggs. However, some species have evolved [[viviparity]], that is, they give birth to live young, as almost all [[mammal]]s do. In several clades of lizards, egg-laying (oviparous) species have evolved into live-bearing ones, apparently with very little genetic change. For instance, a European common lizard, [[Viviparous lizard|''Zootoca vivipara'']], is viviparous throughout most of its range, but oviparous in the extreme southwest portion.<ref>{{Cite journal |last=Heulin |first=Benoît |date=1990-05-01 |title=Étude comparative de la membrane coquillère chez les souches ovipare et vivipare du lézard Lacerta vivipara |url=http://www.nrcresearchpress.com/doi/10.1139/z90-147 |journal=Canadian Journal of Zoology |language=en |volume=68 |issue=5 |pages=1015–1019 |doi=10.1139/z90-147 |bibcode=1990CaJZ...68.1015H |issn=0008-4301|url-access=subscription }}</ref><ref>{{Cite journal |last1=Arrayago |first1=Maria-Jesus |last2=Bea |first2=Antonio |last3=Heulin |first3=Benoit |date=1996 |title=Hybridization Experiment between Oviparous and Viviparous Strains of Lacerta vivipara: A New Insight into the Evolution of Viviparity in Reptiles |journal=Herpetologica |volume=52 |issue=3 |pages=333–342 |jstor=3892653 |issn=0018-0831}}</ref> That is, within a single species, a radical change in reproductive behavior has happened. Similar cases are known from South American lizards of the genus ''[[Liolaemus]]'' which have egg-laying species at lower altitudes, but closely related viviparous species at higher altitudes, suggesting that the switch from oviparous to viviparous reproduction does not require many genetic changes.<ref>{{Cite journal |last1=Ii |first1=James A. Schulte |last2=Macey |first2=J. Robert |last3=Espinoza |first3=Robert E. |last4=Larson |first4=Allan |date=January 2000 |title=Phylogenetic relationships in the iguanid lizard genus Liolaemus: multiple origins of viviparous reproduction and evidence for recurring Andean vicariance and dispersal |journal=Biological Journal of the Linnean Society |language=en |volume=69 |issue=1 |pages=75–102 |doi=10.1111/j.1095-8312.2000.tb01670.x|doi-access=free }}</ref> | ||
==Research topics== | ==Research topics== | ||
| Line 144: | Line 114: | ||
==Notes== | ==Notes== | ||
{{notelist}} | {{notelist}} | ||
==References== | ==References== | ||
| Line 151: | Line 120: | ||
==Further reading== | ==Further reading== | ||
* What is marcroevolution? (pdf) https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12465 | * What is marcroevolution? (pdf) https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12465 | ||
* {{cite web|last=AAAS |first=American Association for the Advancement of Science |author-link=American Association for the Advancement of Science |date=16 February 2006 |title=Statement on the Teaching of Evolution |publisher=aaas.org |url=http://www.aaas.org/news/releases/2006/pdf/0219boardstatement.pdf |access-date=2007-01-14 | * {{cite web|last=AAAS |first=American Association for the Advancement of Science |author-link=American Association for the Advancement of Science |date=16 February 2006 |title=Statement on the Teaching of Evolution |publisher=aaas.org |url=http://www.aaas.org/news/releases/2006/pdf/0219boardstatement.pdf |access-date=2007-01-14 |archive-url=https://web.archive.org/web/20060221125539/http://www.aaas.org/news/releases/2006/pdf/0219boardstatement.pdf |archive-date=21 February 2006}} | ||
* {{cite book|last=IAP |first=Interacademy Panel |date=2006-06-21 |title=IAP Statement on the Teaching of Evolution |publisher=interacademies.net |url=http://www.interacademies.net/Object.File/Master/6/150/Evolution%20statement.pdf |access-date=2007-01-14 | * {{cite book|last=IAP |first=Interacademy Panel |date=2006-06-21 |title=IAP Statement on the Teaching of Evolution |publisher=interacademies.net |url=http://www.interacademies.net/Object.File/Master/6/150/Evolution%20statement.pdf |access-date=2007-01-14 |archive-url=https://web.archive.org/web/20060705140010/http://www.interacademies.net/Object.File/Master/6/150/Evolution%20statement.pdf |archive-date=5 July 2006}} | ||
* {{cite journal |last=Myers |first=P.Z. |author-link=PZ Myers |date=2006-06-18 |title=Ann Coulter: No Evidence for Evolution? |journal=[[Pharyngula (blog)|Pharyngula]] |publisher=[[ScienceBlogs]] |url=http://scienceblogs.com/pharyngula/2006/06/ann_coulter_no_evidence_for_ev.php |access-date=2007-09-12 | * {{cite journal |last=Myers |first=P.Z. |author-link=PZ Myers |date=2006-06-18 |title=Ann Coulter: No Evidence for Evolution? |journal=[[Pharyngula (blog)|Pharyngula]] |publisher=[[ScienceBlogs]] |url=http://scienceblogs.com/pharyngula/2006/06/ann_coulter_no_evidence_for_ev.php |access-date=2007-09-12 |archive-url=https://web.archive.org/web/20060622031856/http://scienceblogs.com/pharyngula/2006/06/ann_coulter_no_evidence_for_ev.php |archive-date=22 June 2006 }} | ||
* {{Cite web |last=NSTA |first=National Science Teachers Association |author-link=National Science Teachers Association |year=2007 |title=An NSTA Evolution Q&A |url=http://www.nsta.org/publications/evolution.aspx |access-date=2008-02-01 | * {{Cite web |last=NSTA |first=National Science Teachers Association |author-link=National Science Teachers Association |year=2007 |title=An NSTA Evolution Q&A |url=http://www.nsta.org/publications/evolution.aspx |access-date=2008-02-01 |archive-url=https://web.archive.org/web/20080202043206/http://www.nsta.org/publications/evolution.aspx |archive-date=2 February 2008 }} | ||
* {{cite web |last=Pinholster |first=Ginger |date=19 February 2006 |title=AAAS Denounces Anti-Evolution Laws as Hundreds of K-12 Teachers Convene for 'Front Line' Event |publisher=aaas.org |url=http://www.aaas.org/news/releases/2006/0219boardstatement.shtml |access-date=2007-01-14 |archive-date=19 October 2013 |archive-url=https://web.archive.org/web/20131019171834/http://www.aaas.org/news/releases/2006/0219boardstatement.shtml | * {{cite web |last=Pinholster |first=Ginger |date=19 February 2006 |title=AAAS Denounces Anti-Evolution Laws as Hundreds of K-12 Teachers Convene for 'Front Line' Event |publisher=aaas.org |url=http://www.aaas.org/news/releases/2006/0219boardstatement.shtml |access-date=2007-01-14 |archive-date=19 October 2013 |archive-url=https://web.archive.org/web/20131019171834/http://www.aaas.org/news/releases/2006/0219boardstatement.shtml }} | ||
==External links== | ==External links== | ||
Latest revision as of 10:21, 23 December 2025
Template:Short description Template:Use dmy dates Template:Sidebar with collapsible lists
Macroevolution comprises the evolutionary processes and patterns which occur at and above the species level.[1][2][3] In contrast, microevolution is evolution occurring within the population(s) of a single species. In other words, microevolution is the scale of evolution that is limited to intraspecific (within-species) variation, while macroevolution extends to interspecific (between-species) variation.[4] The evolution of new species (speciation) is an example of macroevolution. This is the common definition for 'macroevolution' used by contemporary scientists.Template:EfnTemplate:EfnTemplate:EfnTemplate:EfnTemplate:EfnTemplate:EfnTemplate:EfnTemplate:EfnTemplate:Efn However, the exact usage of the term has varied throughout history.[4][5][6]
Macroevolution addresses the evolution of species and higher taxonomic groups (genera, families, orders, etc) and uses evidence from phylogenetics,[7] the fossil record,[8] and molecular biology to answer how different taxonomic groups exhibit different species diversity and/or morphological disparity.[9]
Origin and changing meaning of the term
After Charles Darwin published his book On the Origin of Species[10] in 1859, evolution was widely accepted to be real phenomenon. However, many scientists still disagreed with Darwin that natural selection was the primary mechanism to explain evolution. Prior to the modern synthesis, during the period between the 1880s to the 1930s (dubbed the 'Eclipse of Darwinism') many scientists argued in favor of alternative explanations. These included 'orthogenesis', and among its proponents was the Russian entomologist Yuri A. Filipchenko.
Filipchenko appears to have been the one who coined the term 'macroevolution' in his book Variabilität und Variation (1927).[6] While introducing the concept, he claimed that the field of genetics is insufficient to explain "the origin of higher systematic units" above the species level.
Filipchenko's also claimed that a new taxon cannot evolve from an older one with a lower rank; e.g. a species cannot evolve into a family. It must originate from a preceding family. Furthermore, the evolution of a new family must require the sudden appearance of new traits which are different in greater magnitude compared to the new traits required for the evolution of a genus or species.
However, Filipchenko's views are not consistent with contemporary understanding of evolution. Furthermore, the Linnaean ranks of 'genus' (and higher) are not real entities but arbitrary concepts. These traditional taxonomic concepts break down when they are applied to common ancestry.[11][5]
Nevertheless, Filipchenko’s distinction between microevolution and macroevolution had a major influence on evolutionary biology. The term macroevolution was adopted by Filipchenko's protégé Theodosius Dobzhansky in his book 'Genetics und the Origin of Species' (1937), a seminal piece that contributed to the development of the Modern Synthesis. The term was also used by critics of the Modern Synthesis. A good example of this is the book The Material Basis of Evolution (1940) by the geneticist Richard Goldschmidt, a close friend of Filipchenko.[12] Goldschmidt suggested saltational evolutionary changes[13][14] which found a moderate revival in the 'hopeful monster' concept of evolutionary developmental biology (or evo-devo).[15][16] Occasionally such dramatic changes can lead to novel features that survive.
As an alternative to saltational evolution, Dobzhansky[17] suggested that the difference between macroevolution and microevolution reflects essentially a difference in time-scales, and that macroevolutionary changes were simply the sum of microevolutionary changes over geologic time. This view became broadly accepted in the middle of the last century but it has been challenged by a number of scientists who claim that microevolution is necessary but not sufficient to explain macroevolution. This is the decoupled view (see below).[3][2][4]
Microevolution vs Macroevolution
Micro- and macroevolution are both supported by overwhelming evidence. This fact remains uncontroversial within the scientific community. However, there has been considerable debate regarding the connection between microevolution and macroevolution.[1]
Broadly speaking, there are two views regarding this issue. The 'Extrapolation' view holds that macroevolution is merely cumulative microevolution. The 'Decoupled' view holds that there are separate macroevolutionary processes that cannot be sufficiently explained by microevolutionary processes alone. Most scientists who adopt the second viewpoint are not claiming that macroevolution is incompatible with microevolution. Rather, they see macroevolution as an autonomous field of study regarding the deep history of life. For this reason, a full understanding of macroevolution requires insights that are not limited to microevolution.[3][18][19][7][20][21][12][5][22] An example of this argument has been made by Francisco J. Ayala.
Microevolution is characterized by the evolutionary process of changing heritable characteristics (phenotypes) and changes in allele frequencies (genotypes) within populations. This involves mechanisms such as mutation, natural selection, and genetic drift as studied in the field of population genetics.[2] In contrast, macroevolution concerns how species and and higher taxonomic groups (genera, families, orders, etc) have evolved across geography and vast spans of geological time. For example, whether speciation is sympatric or allopatric; and whether the common mode of macroevolution is better described in terms of phyletic gradualism or punctuated equilibrium.[1] These and other important questions and topics are researched within various scientific fields, which makes the study of macroevolution highly interdisciplinary. Examples of these include:
- How different species are related to each other is researched in phylogenetics).
- The rates of evolutionary change and across time in the fossil record.[7] For example, some groups appear to experience a lot of change while others remain morphologically stable, which are often referred to as living fossils. However, that term has been criticized for wrongfully implying that such organisms have not evolved at all. [23]
- Why different taxonomic groups (even those with similar ages) exhibit different survival/extinction rates, species diversity, and/or morphological disparity.
- The causes and impacts of Mass extinctions and evolutionary diversifications,[8] e.g. the Permian-Triassic and Cretaceous-Paleogene events, the Cambrian Explosion and Cretaceous Terrestrial Revolution.
- Does natural selection also operate at the species level (see Group Selection)?
- Long-term trends in evolution, e.g. trends towards complexity or simplicity and whether these trends are directional or passive.[9]
- How distinctive and complex traits have evolved, e.g. gene duplication, heterochrony, novelty in evo-devo, facilitated variation, and constructive neutral evolution.
Macroevolutionary processes
Speciation
Script error: No such module "Labelled list hatnote". According to Hautmann[4], speciation has both micro- and macroevolutionary aspects. Specifically, speciation also involves the classic process of descent with modification, i.e. morphological transformation observed across many generations. This is microevolutionary. In contrast, the species variation produced by speciation, and the rate at which it successfully occurs, is macroevolutionary.[2] Stephen J. Gould also saw species as the basic unit of macroevolution.Template:Efn
Speciation is the process in which populations within one species change to an extent at which they become reproductively isolated, that is, they cannot interbreed anymore. However, this classical concept has been challenged and more recently, a phylogenetic or evolutionary species concept has been adopted. Their main criteria for new species is to be diagnosable and monophyletic, that is, they form a clearly defined lineage.[24][25]
Charles Darwin first discovered that speciation can be extrapolated so that species not only evolve into new species, but also into new genera, families and other groups of animals. In other words, macroevolution is reducible to microevolution through selection of traits over long periods of time.[26] In addition, some scholars have argued that selection at the species level is important as well.[27] The advent of genome sequencing enabled the discovery of gradual genetic changes both during speciation but also across higher taxa. For instance, the evolution of humans from ancestral primates or other mammals can be traced to numerous but individual mutations.[28]
According to the Resource-use hypothesis, the diversification of terrestrial species is closely related to global climatic changes, particularly the Cenozoic alternation of warming and cooling episodes. Global analysis of terrestrial mammals supports the view that these physical environmental changes have shaped macroevolutionary patterns by promoting biome specialisation. This specialization leads to significantly higher rates of vicariance and speciation in biome specialist (stenobiomic) lineages compared to generalist lineages.[29]
Evolution of new organs and tissues
One of the main questions in evolutionary biology is how new structures evolve, such as new organs. Macroevolution is often thought to require the evolution of structures that are 'completely new'. However, fundamentally novel structures are not necessary for dramatic evolutionary change. As can be seen in vertebrate evolution, most "new" organs are actually not new—they are simply modifications of previously existing organs. For instance, the evolution of mammal diversity in the past 100 million years has not required any major innovation.[30] All of this diversity can be explained by modification of existing organs, such as the evolution of elephant tusks from incisors. Other examples include wings (modified limbs), feathers (modified reptile scales),[31] lungs (modified swim bladders, e.g. found in fish),[32][33] or even the heart (a muscularized segment of a vein).[34]
The same concept applies to the evolution of "novel" tissues. Even fundamental tissues such as bone can evolve from combining existing proteins (collagen) with calcium phosphate (specifically, hydroxy-apatite). This probably happened when certain cells that make collagen also accumulated calcium phosphate to get a proto-bone cell.[35]
Examples
Evolutionary faunas
A macroevolutionary benchmark study is Sepkoski's[36][37] work on marine animal diversity through the Phanerozoic. His iconic diagram of the numbers of marine families from the Cambrian to the Recent illustrates the successive expansion and dwindling of three "evolutionary faunas" that were characterized by differences in origination rates and carrying capacities. Long-term ecological changes and major geological events are postulated to have played crucial roles in shaping these evolutionary faunas.[38]
Stanley's rule
Macroevolution is driven by differences between species in origination and extinction rates. Remarkably, these two factors are generally positively correlated: taxa that have typically high diversification rates also have high extinction rates. This observation has been described first by Steven Stanley, who attributed it to a variety of ecological factors.[39] Yet, a positive correlation of origination and extinction rates is also a prediction of the Red Queen hypothesis, which postulates that evolutionary progress (increase in fitness) of any given species causes a decrease in fitness of other species, ultimately driving to extinction those species that do not adapt rapidly enough.[40] High rates of origination must therefore correlate with high rates of extinction.[4] Stanley's rule, which applies to almost all taxa and geologic ages, is therefore an indication for a dominant role of biotic interactions in macroevolution.
Evolution of multicellularity
Script error: No such module "Labelled list hatnote". The evolution of multicellular organisms is one of the major breakthroughs in evolution. The first step of converting a unicellular organism into a metazoan (a multicellular organism) is to allow cells to attach to each other. This can be achieved by one or a few mutations. In fact, many bacteria form multicellular assemblies, e.g. cyanobacteria or myxobacteria. Another species of bacteria, Jeongeupia sacculi, form well-ordered sheets of cells, which ultimately develop into a bulbous structure.[41][42] Similarly, unicellular yeast cells can become multicellular by a single mutation in the ACE2 gene, which causes the cells to form a branched multicellular form.[43]
Evolution of bat wings
The wings of bats have the same structural elements (bones) as any other five-fingered mammal (see periodicity in limb development). However, the finger bones in bats are dramatically elongated, so the question is how these bones became so long. It has been shown that certain growth factors such as bone morphogenetic proteins (specifically Bmp2) is over expressed so that it stimulates an elongation of certain bones. Genetic changes in the bat genome identified the changes that lead to this phenotype and it has been recapitulated in mice: when specific bat DNA is inserted in the mouse genome, recapitulating these mutations, the bones of mice grow longer.[44]
Limb loss in lizards and snakes
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Snakes evolved from lizards. Phylogenetic analysis shows that snakes are actually nested within the phylogenetic tree of lizards, demonstrating that they have a common ancestor.[45] This split happened about 180 million years ago and several intermediary fossils are known to document the origin. In fact, limbs have been lost in numerous clades of reptiles, and there are cases of recent limb loss. For instance, the skink genus Lerista has lost limbs in multiple cases, with all possible intermediary steps, that is, there are species which have fully developed limbs, shorter limbs with 5, 4, 3, 2, 1 or no toes at all.[46]
Human evolution
While human evolution from their primate ancestors did not require massive morphological changes, our brain has sufficiently changed to allow human consciousness and intelligence. While the latter involves relatively minor morphological changes it did result in dramatic changes to brain function.[47] Thus, macroevolution does not have to be morphological, it can also be functional.
The study of human (brain) evolution benefits from the fact that human and ape genomes are available so that the genomes of our common ancestor can be reconstructed.[48] Even though the precise genetic mechanisms that shaped the human brain are not known, the mutations involved in human brain evolution are largely known, given that the genes expressed in the brain are relatively well understood.[49]
Evolution of viviparity in lizards
Most lizards are egg-laying and thus need an environment that is warm enough to incubate their eggs. However, some species have evolved viviparity, that is, they give birth to live young, as almost all mammals do. In several clades of lizards, egg-laying (oviparous) species have evolved into live-bearing ones, apparently with very little genetic change. For instance, a European common lizard, Zootoca vivipara, is viviparous throughout most of its range, but oviparous in the extreme southwest portion.[50][51] That is, within a single species, a radical change in reproductive behavior has happened. Similar cases are known from South American lizards of the genus Liolaemus which have egg-laying species at lower altitudes, but closely related viviparous species at higher altitudes, suggesting that the switch from oviparous to viviparous reproduction does not require many genetic changes.[52]
Research topics
Subjects studied within macroevolution include:[53]
- Adaptive radiations such as the Cambrian Explosion.
- Changes in biodiversity through time.
- Evo-devo (the connection between evolution and developmental biology)
- Genome evolution, like horizontal gene transfer, genome fusions in endosymbioses, and adaptive changes in genome size.
- Mass extinctions.
- Estimating diversification rates, including rates of speciation and extinction.
- The debate between punctuated equilibrium and gradualism.
- The role of development in shaping evolution, particularly such topics as heterochrony and phenotypic plasticity.
See also
- Extinction event
- Interspecific competition
- Microevolution
- Molecular evolution
- Punctuated equilibrium
- Red Queen hypothesis
- Speciation
- Transitional fossil
- Unit of selection
Notes
References
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- ↑ Grinin, L., Markov, A. V., Korotayev, A. Aromorphoses in Biological and Social Evolution: Some General Rules for Biological and Social Forms of Macroevolution / Social evolution & History, vol.8, num. 2, 2009 [1]
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Further reading
- What is marcroevolution? (pdf) https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12465
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External links
- Introduction to macroevolution
- Macroevolution as the common descent of all life
- Macroevolution in the 21st century Macroevolution as an independent discipline.
- Macroevolution FAQ
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