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{{short description|German biologist, philosopher, physician, and artist (1834–1919)}}
{{about||the German general|Ernst Haeckel (general)}}
{{redirect|Haeckel}}
{{Use British English|date=April 2015}}
{{Use dmy dates|date=August 2024}}
{{Infobox scientist
| name              = Ernst Haeckel
| image             = Ernst Haeckel 5.jpg
| birth_name        = Ernst Heinrich Philipp August Haeckel
| birth_date        = {{birth date|1834|2|16|df=y}}
| birth_place       = [[Potsdam]], [[Kingdom of Prussia]]
| death_date        = {{death date and age|1919|8|9|1834|2|16|df=y}}
| death_place       = [[Jena]], [[Saxe-Weimar-Eisenach]], [[Weimar Republic|Germany]]
| workplaces        = [[University of Jena]]
| spouse            = Anna Sethe, Agnes Huschke
| education         = {{plainlist|
*[[University of Berlin]]
*[[University of Würzburg]]
*[[University of Jena]]}}
| author_abbrev_zoo = '''Haeckel'''
| author_abbrev_bot = '''Haeckel'''
| signature         = Ernst Haeckel Signature.jpg
| prizes            = {{plainlist|
*[[Linnean Medal]] {{small|(1894)}}
*{{no wrap|[[Darwin–Wallace Medal]] {{small|(Silver, 1908)}}}}}}
| citizenship       = German Empire
| fields            = {{hlist|Zoology|Natural History|Eugenics|Philosophy|Marine Biology}}
| academic_advisors = Johannes Peter Müller
| known_for         = Recapitulation theory
|works=''[[Kunstformen der Natur]]''
}}
'''Ernst Heinrich Philipp August Haeckel''' ({{IPAc-en|ˈ|h|ɛ|k|əl}};<ref>{{Cite Merriam-Webster|Haeckel}}</ref> {{IPA|de|ɛʁnst ˈhɛkl̩|lang}}; 16 February 1834 – 9 August 1919)<ref>{{Britannica|251305}}</ref> was a German [[zoologist]], [[natural history|naturalist]], [[eugenics|eugenicist]], [[Philosophy|philosopher]], physician, professor, [[marine biology|marine biologist]] and artist. He discovered, described and named thousands of new species, mapped a [[genealogical]] tree relating all life forms and coined many terms in [[biology]], including ''[[ecology]]'',<ref>{{cite book |last1=Haeckel |first1=Ernst |title=Generelle Morphologie der Organismen  |trans-title=The General Morphology of Organisms |date=1866 |publisher=Georg Reimer |location=Berlin, (Germany) |volume=2 |url=https://www.biodiversitylibrary.org/item/52177#page/454/mode/1up |language=de}}  From p. 286: ''"Unter Oecologie verstehen wir die gesammte Wissenschaft von den Beziehungen des Organismus zur umgebenden Aussenwelt, wohin wir im weiteren Sinne alle "Existenz-Bedingungen" rechnen können."'' (By "ecology" we understand the comprehensive science of the relationships of the organism to its surrounding environment, where we can include, in the broader sense, all "conditions of existence".)</ref> ''[[phylum]]'',<ref>{{cite book |last1=Haeckel |first1=Ernst |title=Generelle Morphologie der Organismen |trans-title=The General Morphology of Organisms |date=1866 |publisher=G. Reimer |location=Berlin, (Germany) |volume=1 |pages=[https://archive.org/details/generellemorphol01haec/page/28 28]–29 |url=https://archive.org/details/generellemorphol01haec |language=de}} Haeckel noted that species constantly evolved into new species that seemed to retain few consistent features among themselves and therefore few features that distinguished them as a group ("a self-contained unity").  ''"Wohl aber ist eine solche reale und vollkommen abgeschlossene Einheit die Summe aller Species, welche aus einer und derselben gemeinschaftlichen Stammform allmählig sich entwickelt haben, wie z. B. alle Wirbelthiere.  Diese Summe nennen wir Stamm (Phylon)."'' (However, perhaps such a real and completely self-contained unity is the aggregate of all species which have gradually evolved from one and the same common original form, as, for example, all vertebrates. We name this aggregate [a] ''Stamm'' [i.e., race] (''Phylon'').)</ref> ''[[phylogeny]]'',<ref>(Haeckel, 1866), [https://archive.org/details/generellemorphol01haec/page/28 vol. 1, p. 29]:  ''"Die Untersuchung der Entwicklung dieser Stämme und die Feststellung der genealogischen Verwandtschaft aller Species, die zu einem Stamm gehören, halten wir für die höchste und letzte besondere Aufgabe der organischen Morphologie.  Im sechsten Buche werden wir die Grundzüge dieser Phylogenie oder Entwicklungsgeschichte der organischen Stämme (Kreise oder "Typen") festzustellen haben."''  (The investigation of the evolution of these phyla and the identification of the genealogical kinship of all species that belong to a phylum—we deem [this] the highest and ultimately specific task of organic morphology.  In the sixth book, we will have to establish the outline of this "phylogeny" or history of the evolution of the organic phyla (groups or "types").)</ref> [[ontogeny]],<ref>{{Cite web |last=Robinson |first=Gloria |date=12 February 2022 |title=Ernst Haeckel {{!}} German embryologist {{!}} Britannica |url=https://www.britannica.com/biography/Ernst-Haeckel |access-date=2022-03-09 |website=Encyclopedia Britannica |language=en}}</ref> and ''[[Protista]].''<ref>(Haeckel, 1866), vol. 1, pp. 215 ff.  From p. 215:  ''"VII.  Character des Protistenreiches."'' (VII. Character of the kingdom of Protists.) From p. 216:  ''"VII.  B. Morphologischer Character des Protistenreiches.  Ba.  Character der protistischen Individualitäten.  Der wesentliche tectologische Character der Protisten liegt in der sehr unvollkommenen Ausbildung und Differenzirung der Individualität überhaupt, insbesondere aber derjenigen zweiter Ordnung, der Organe.  Sehr viele Protisten erheben sich niemals über den morphologischen Werth von Individuen erster Ordnung oder Plastiden."''  (VII. B. Morphological character of the kingdom of protists.  Ba. Character of the protist Individualities.  The essential [[wikt:tectology|tectological]] character of protists lies in the very incomplete formation and differentiation of individuality generally, however particularly of those of the second order, the organs.  Very many protists never rise above the morphological level of individuals of the first order or plastids.)</ref> Haeckel promoted and popularised [[Charles Darwin]]'s work in Germany<ref name="Watts et al., 2019" /> and developed the disproven but influential [[recapitulation theory]] ("ontogeny recapitulates phylogeny"), wrongly claiming that an individual organism's biological development, or [[ontogeny]], parallels and summarizes its species' evolutionary development, or [[phylogeny]], using incorrectly drawn images of human embryonic development. Whether they were intentionally falsified, or drawn poorly by accident is a matter of debate.<ref name="cam.ac.uk">{{cite web | url=https://www.cam.ac.uk/research/features/haeckels-embryos-the-images-that-would-not-go-away | title=Haeckel's embryos: The images that would not go away &#124; University of Cambridge | date=6 July 2015 }}</ref>

The published artwork of Haeckel includes over 100 detailed, multi-colour [[Biological illustration|illustrations of animals and sea creatures]], collected in his ''[[Kunstformen der Natur]]'' ("Art Forms of Nature"), a book which would go on to influence the [[Art Nouveau]] artistic movement. As a philosopher, Ernst Haeckel wrote ''Die Welträthsel'' (1895–1899; in English: ''The Riddles of the Universe'', 1900), the genesis for the term "[[world riddle]]" (''Welträtsel''); and ''Freedom in Science and Teaching''<ref>''Freedom in Science and Teaching''. German 1877, English 1879, {{ISBN|1-4102-1175-4}}.</ref> to support teaching evolution.

Haeckel promoted [[scientific racism]]<ref>Hawkins, Mike (1997). ''Social Darwinism in European and American Thought''. Cambridge: Cambridge University Press. p. 140.</ref> and embraced the idea of [[Social Darwinism]].<ref name="Watts et al., 2019" /><ref>Hawkins, Mike (1997). ''Social Darwinism in European and American Thought''. Cambridge: Cambridge University Press. p. 137.</ref> He was the first person to characterize the [[World War I|Great War]] as the "first" World War, which he did as early as 1914.

== Early life and education==
[[File:Ernst Haeckel 1860.jpg|thumb|upright|Christmas of 1860]]

Ernst Haeckel was born on 16 February 1834, in [[Potsdam]] (then part of the [[Kingdom of Prussia]]).<ref>
{{cite book
 | last1 = Di Gregorio
 | first1 = Mario A.
 | chapter = 1: Young Haeckel
 | title = From Here to Eternity: Ernst Haeckel and Scientific Faith
 | url = https://books.google.com/books?id=aZK004HREqgC
 | series = Religion, Theologie Und Naturwissenschaft/Religion, Theology, And Natural Science
 | volume = 3
 | location = Goettingen
 | publisher = Vandenhoeck & Ruprecht
 | date = 2005
 | page = 26
 | isbn = 9783525569726
 | access-date = 25 March 2019
| quote = On 16 February 1834 a son was born to Charlotte and Carl Gottlob Haeckel in Kanal 24a (later Yorkstrasse 7), Potsdam, Prussia. His name was Ernst Heinrich Phillip August, and he was destined to become one of the most influential and controversial thinkers of his time.
}}
</ref>
In 1852, Haeckel completed studies at the ''Domgymnasium'', the cathedral high-school of [[Merseburg]].<ref name=HaeckelDE>"Ernst Haeckel" (article),''German Wikipedia'', 26 October 2006, webpage: [[:de:Ernst Haeckel|DE-Wiki-Ernst-Haeckel]]: last paragraph of "Leben" (Life) section.</ref>{{Better source needed|date= November 2015|reason= [[WP:CIRCULAR]]}} He then studied medicine in Berlin and [[Würzburg]], particularly with [[Albert von Kölliker]], [[Franz Leydig]], [[Rudolf Virchow]] (with whom he later worked briefly as assistant), and with the anatomist-physiologist [[Johannes Peter Müller]] (1801–1858).<ref name=HaeckelDE /> Together with [[Hermann Steudner]] he attended [[botany]] lectures in Würzburg. In 1857 Haeckel attained a doctorate in medicine, and afterwards he received the license to practice medicine. The occupation of physician appeared less worthwhile to Haeckel after contact with suffering patients.<ref name=HaeckelDE />

==Career==
Haeckel studied under [[Carl Gegenbaur]] at the [[University of Jena]] for three years. In 1861 he earned a [[habilitation]] in [[comparative anatomy]] and became a professor of [[zoology]] at the [[University of Jena|University at Jena]], where he remained for 47 years, from 1862 to 1909. Between 1859 and 1866, Haeckel worked on many phyla, such as [[radiolarian]]s, [[poriferan]]s ([[sponge]]s) and [[annelid]]s (segmented worms).<ref name=HaeckelUCB /> During a trip to the [[Mediterranean]], Haeckel named nearly 700 new species of radiolarians.<ref name=HaeckelUCB />

From 1866 to 1867 Haeckel made an extended journey to the [[Canary Islands]] with [[Hermann Fol]]. On 17 October 1866 he arrived in London. Over the next few days he met [[Charles Lyell]], and visited [[Thomas Huxley]] and family at their home. On 21 October he visited [[Charles Darwin]] at [[Down House]] in Kent.<ref>{{cite book|first=Robert J.|last=Richards|title=The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought|url=https://books.google.com/books?id=dgSC0TLldq8C|year=2008|publisher=University of Chicago Press|isbn=978-0-226-71219-2|pages=173–174}}</ref> In 1867 he married Agnes Huschke. Their son Walter was born in 1868, their daughters Elizabeth in 1871 and Emma in 1873.<ref name=HaeckelDE /> In 1869 he traveled as a researcher to [[Norway]], in 1871 to [[Croatia]] (where he lived on the island of [[Hvar]] in a monastery),<ref>[https://timesmachine.nytimes.com/timesmachine/1914/02/22/100083143.pdf New York Times] Haeckel Again Honored in Spite of Himself on his 80th Birthday, published: 22 February 1914</ref> and in 1873 to [[Egypt]], [[Turkey]], and [[Greece]].<ref name=HaeckelDE /> In 1907 he had [[Jena Phyletisches Museum|a museum]] built in [[Jena]] to teach the public about [[evolution]]. Haeckel retired from teaching in 1909, and in 1910 he withdrew from the [[Evangelical Church of Prussia]].<ref name=HaeckelDE />

[[File:ErnstHaeckel.jpg|thumb|upright|In later life]]

On the occasion of his 80th birthday celebration he was presented with a two-volume work entitled ''Was wir Ernst Haeckel verdanken (What We Owe to Ernst Haeckel)'', edited at the request of the German Monistenbund by Heinrich Schmidt of Jena.<ref>{{cite encyclopedia |last= Felden |first= Emil |author-link=:de:Emil Felden |editor-last= Schmidt |editor-first= Heinrich |editor-link= Heinrich Schmidt (philosopher) |others= Deutscher Monistenbund |encyclopedia= Was wir Ernst Haeckel Verdanken (What We Owe to Ernst Haeckel): Ein Buch der Verehrung und Dankbarkeit|title= Felden Pastor an St. Martini Bremen |trans-title= Pastor of St. Martini Church, Bremen, Germany |url= https://books.google.com/books?id=W-AOAQAAIAAJ&pg=PA125 |language= de |year= 1914|publisher= Verlag Unesma |volume= 2 |location= Leipzig |pages= 125–128 |quote= testimony of Emil Felden in ''Was wir Ernst Haeckel Verdanken'', vol. ii, p. 125.}}</ref><ref>{{cite book|last= Carus|first=Paul|title= The Open Court|url= https://books.google.com/books?id=nLsNAQAAIAAJ&pg=PA385|year= 1914|publisher= Open Court Publishing Company|page= 385|quote= PROFESSOR Ernst Haeckel's celebration of his 80th birthday,  ...on this occasion we note a work of two stately volumes, entitled ''Was wir Ernst Haeckel verdanken'', edited at the request of the German ''Monistenbund'' by Heinrich Schmidt of Jena. (Image of p.&nbsp;385 at Google Books)}}</ref>

==Personal life and death==
In 1864, his first wife, Anna Sethe, died. Haeckel dedicated some species of jellyfish that he found beautiful (such as ''Desmonema annasethe'') to her.<ref>{{cite book|first=Ernst|last=Haeckel|title=The Art and Science of Ernst Haeckel|pages= 14, 50|url=https://www.taschen.com/pages/en/catalogue/classics/all/01157/facts.the_art_and_science_of_ernst_haeckel.htm}}</ref><ref name=Innes>{{cite journal |last1=Innes |first1=Shelley |title=From Here to Eternity: Ernst Haeckel and Scientific Faith, Religion, Theology, and Natural Science, Vol. 3 by Mario di Gregorio |journal=Journal of the History of Biology |date=2006 |volume=39 |issue=1 |pages=214–216 | doi = 10.1007/s10739-006-0001-9 |jstor=4332000|s2cid=189843968 }}</ref>

Haeckel's second wife, Agnes, died in 1915, and he became substantially frailer, breaking his leg and arm.<ref name=HaeckelDE /> He sold his "Villa Medusa" in [[Jena]] in 1918 to the [[Carl Zeiss foundation]], which preserved his library.<ref name=HaeckelDE /> 
Haeckel died on 9 August 1919.<ref>{{Cite journal|last1=Kutschera|first1=Ulrich|last2=Levit|first2=Georgy S.|last3=Hossfeld|first3=Uwe|date=1 May 2019|title=Ernst Haeckel (1834–1919): The German Darwin and his impact on modern biology|journal=Theory in Biosciences| language=en| volume=138| issue=1| pages=1–7| doi=10.1007/s12064-019-00276-4|pmid=30799517|issn=1611-7530|doi-access=free}}</ref>

=== Religious views ===
In ''Monism as Connecting Religion and Science'' (1892), he argued in favor of [[monism]] as the view most compatible with the current scientific understanding of the natural world. His perspective of monism was pantheistic and impersonal. <blockquote>The monistic idea of God, which alone is compatible with our present knowledge of nature, recognizes the divine spirit in all things. It can never recognise in God a "personal being," or, in other words, an individual of limited extension in space, or even of human form. God is everywhere.<ref>{{cite book |last1=Haeckel |first1=Ernst |title=Monism as Connecting Religion and Science |date=1892 |url=https://www.gutenberg.org/cache/epub/9199/pg9199-images.html |access-date=16 January 2023}}</ref></blockquote>
Haeckel became the most famous proponent of [[Monism]] in Germany.<ref>Weir, Todd H. ''Secularism and religion in nineteenth-century Germany. The rise of the fourth confession.'' Cambridge University Press, 2014, p. 67</ref>
In 1906 Haeckel belonged to the founders of the [[Monist League]] ([[:de:Deutscher Monistenbund|Deutscher Monistenbund]]), which took a stance against philosophical materialism and promote a "natural Weltanschauung".<ref>{{cite book |last1=Daum |first1=Andreas W. |author-link=Andreas Daum |title=Wissenschaftspopularisierung im 19. Jahrhundert: Bürgerliche Kultur, naturwissenschaftliche Bildung und die deutsche Öffentlichkeit, 1848–1914 |date=1998 |publisher=Oldenbourg |location=Munich |isbn=3-486-56337-8 |pages=215–219}}</ref> This organization lasted until 1933 and included such notable members as [[Wilhelm Ostwald]], [[Georg von Arco]] (1869–1940), [[Helene Stöcker]] and [[Walter Arthur Berendsohn]].<ref>''Health, Race and German Politics Between National Unification and Nazism'' by [[Paul Weindling]], Cambridge University Press, 1993., pp. 46, 250</ref>

=== Politics ===
Haeckel's affinity for the German [[Romanticism|Romantic movement]], coupled with his acceptance of a form of [[Lamarckism]], influenced his political beliefs. Rather than being a strict [[Natural selection|Darwinian]], Haeckel believed that the characteristics of an organism were acquired through interactions with the environment and that [[ontogeny]] reflected [[phylogeny]]. He saw the [[social science]]s as instances of "applied biology", and that phrase was picked up and used for [[Nazi propaganda]].<ref name=HaeckelUCB>"Ernst Haeckel" (biography), [[UC Berkeley]], 2004, webpage: [http://www.ucmp.berkeley.edu/history/haeckel.html BerkeleyEdu-Haeckel].</ref>

He was the first person to use the term "first world war" about [[World War I]].<ref name="Shapiro329">
{{cite book
 |title= The Yale Book of Quotations
 |editor= [[Fred R. Shapiro]] |publisher= [[Yale University Press]]
 |year= 2006 |pages= 329
 |url= https://books.google.com/books?id=w5-GR-qtgXsC&q=The+Yale+book+of+quotations
 |isbn= 978-0-300-10798-2
 |quote= There is no doubt that the course and character of the feared "European War"...will become the first world war in the full sense of the word. ''[[Indianapolis Star]]'', 20 September 1914
}}
</ref>

However, Haeckel's books were banned by the [[Nazi Party]], which refused Monism and Haeckel's freedom of thought. Moreover, it is worth mentioning that Haeckel had often overtly recognized the great contribution of educated Jews to the German culture.<ref>{{cite book|first=Ernst|last=Haeckel|title=The Art and Science of Ernst Haeckel|pages=41}}</ref>

== Research ==
[[File:Haeckel Actiniae.jpg|upright|thumb|Sea anemones from Ernst Haeckel's ''[[Kunstformen der Natur]]'' (Art forms of Nature) of 1904]]

Haeckel was a [[zoologist]], an accomplished artist and illustrator, and later a professor of [[comparative anatomy]]. Although Haeckel's ideas are important to the history of [[evolutionary theory]], and although he was a competent [[invertebrate]] [[anatomist]] most famous for his work on [[radiolaria]], many speculative concepts that he championed are now considered incorrect. For example, Haeckel described and named hypothetical ancestral [[microorganism]]s that have never been found.<ref>{{cite book|first=Ronald A.|last=Jenner|title=Ancestors in Evolutionary Biology Linear Thinking about Branching Trees|location=Cambridge|publisher=Cambridge University Press|year=2022|page=110|isbn=978-1-31622-666-7|url=https://books.google.com/books?id=aHZ6EAAAQBAJ}}</ref>

He was one of the first to consider [[psychology]] as a branch of [[physiology]]. He also proposed the kingdom ''[[Protista]]''<ref name=HaeckelDE /> in 1866. His chief interests lay in [[evolution]] and life development processes in general, including development of nonrandom form, which culminated in the beautifully illustrated ''[[Kunstformen der Natur]]'' (''Art forms of nature''). Haeckel did not support [[natural selection]], rather believing in [[Lamarckism]].<ref>Ruse, M. 1979. ''The Darwinian Revolution''. Chicago: University of Chicago Press.</ref>

[[File:Haeckel vs von Baer.svg|thumb|upright=1.7|Embryology theories of Ernst Haeckel and [[Karl Ernst von Baer]] compared]]

Haeckel advanced a version of the earlier [[recapitulation theory]] previously set out by [[Étienne Serres]] in the 1820s and supported by followers of [[Étienne Geoffroy Saint-Hilaire]] including [[Robert Edmond Grant]].<ref>{{harvnb|Desmond|1989|pp=53–53, 86–88, 337–340}}</ref> It proposed a link between [[ontogeny]] (development of form) and [[phylogeny]] (evolutionary descent), summed up by Haeckel in the phrase "[[ontogeny recapitulates phylogeny]]". His concept of recapitulation has been refuted in the form he gave it (now called "strong recapitulation"), in favour of the ideas [[Karl Ernst von Baer#Baer's laws (embryology)|first advanced by Karl Ernst von Baer]]. The strong recapitulation hypothesis views ontogeny as repeating forms of adult ancestors, while weak recapitulation means that what is repeated (and built upon) is the ancestral embryonic development process.<ref>Richardson and Keuck, (Biol. Review (2002), 77, pp. 495–528) show that it is a simplification to suppose that Haeckel held the recapitulation theory in its strong form. They quote Haeckel as saying "If [recapitulation] was always complete, it would be a very easy task to construct whole phylogeny on the basis of ontogeny.  … There is certainly, even now, a number of lower vertebrate animals (e.g. some Anthozoa and Vermes) where we are authorised to interpret each embryological form directly as the historical representation or portrait-like silhouette of an extinct ancestral form. But in a great majority of animals, including man, this is not possible because the infinitely varied conditions of existence have led the embryonic forms themselves to be changed and to partly lose their original condition (Haeckel, 1903: pp. 435–436)"</ref> Haeckel supported the theory with [[embryo drawings]] that have since been shown to be oversimplified and in part inaccurate, and the theory is now considered an oversimplification of quite complicated relationships, however comparison of embryos<ref name="Watts et al., 2019">{{cite journal |author1=Watts E |author2=Levit GS |author3=Hossfeld U |title=Ernst Haeckel's contribution to Evo-Devo and scientific debate: a re-evaluation of Haeckel's controversial illustrations in US textbooks in response to creationist accusations. | journal=Theory Biosci | year= 2019 | volume= 138 | issue= 1 | pages= 9–29 | pmid=30868433 | doi=10.1007/s12064-019-00277-3 | s2cid=76663562 | doi-access=free }}</ref> remains a powerful way to demonstrate that all animals are related. Haeckel introduced the concept of [[heterochrony]], the change in timing of [[embryonic development]] over the course of evolution.<ref name=Horder>{{cite book |author=Horder, Tim |chapter=Heterochrony |title=Encyclopedia of Life Sciences |publisher=John Wiley & Sons |date=April 2006 }}</ref><ref name="Hall 2003">{{cite journal |last1=Hall |first1=B. K. |title=Evo-Devo: evolutionary developmental mechanisms |journal=International Journal of Developmental Biology |date=2003 |volume=47 |issue=7–8 |pages=491–495 |pmid=14756324}}</ref>

[[File:Ernst Haeckel and von Miclucho-Maclay 1866.jpg|thumb|upright|Haeckel (left) with [[Nicholai Miklukho-Maklai]], his assistant, in the [[Canary Islands|Canaries]], 1866]]
[[File:Pithecanthropus Alalus.1894.jpg|left|thumb|Portrait of two <nowiki>''P. alalus''</nowiki>, speculative species]]
Haeckel was a flamboyant figure, who sometimes took great, non-scientific leaps from available evidence. For example, at the time when Darwin published ''[[On the Origin of Species by Means of Natural Selection]]'' (1859), Haeckel postulated that evidence of human evolution would be found in the [[Dutch East Indies]] (now [[Indonesia]]).  At that time, no remains of human ancestors had yet been identified.  He described these theoretical remains in great detail and even named the as-yet unfound species, ''Pithecanthropus alalus'', and instructed his students such as [[Richard Hertwig|Richard]] and [[Oskar Hertwig]] to go and find it.{{Citation needed|date=August 2019}}

One student did find some remains: a Dutchman named [[Eugène Dubois]] searched the [[East Indies]] from 1887 to 1895, discovering the remains of [[Java Man]] in 1891, consisting of a skullcap, thighbone, and a few teeth. These remains are among the oldest hominid remains ever found. Dubois classified Java Man with Haeckel's ''Pithecanthropus'' label, though they were later reclassified as ''[[Homo erectus]]''. Some scientists of the day suggested<ref>{{cite book|url=https://books.google.com/books?id=N26AAAAAMAAJ|title=The Red Ape: Orang-utans and Human Origins|first=Jeffrey H.|last=Schwartz|publisher=Houghton Mifflin|year=1987|isbn=9780395380178}}</ref> Dubois' Java Man as a potential intermediate form between modern humans and the common ancestor we share with the other [[great apes]]. The current consensus of anthropologists is that the direct ancestors of modern humans were African populations of ''[[Homo erectus]]'' (possibly ''[[Homo ergaster]]''), rather than the Asian populations exemplified by Java Man and [[Peking Man]]. (Ironically, a new human species, ''[[Homo floresiensis]]'', a dwarf human type, has recently been discovered in the island of Flores).<ref>{{Cite journal|last1=Martin|first1=Robert D.|last2=MacLarnon|first2=Ann M.|last3=Phillips|first3=James L.|last4=Dobyns|first4=William B.|date=2006|title=Flores hominid: New species or microcephalic dwarf?|journal=The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology|language=en|volume=288A|issue=11|pages=1123–1145|doi=10.1002/ar.a.20389|pmid=17031806|issn=1552-4892|doi-access=free}}</ref>

== Polygenism and racial theory ==
<!--- The article Charles Darwin links to this section. Please do not change the title of this section without adding an appropriate anchor or making appropriate amendments to all the articles which link to it.  --->
The [[creationism|creationist]] [[polygenism]] of [[Samuel George Morton]] and [[Louis Agassiz]], which presented human [[race (classification of human beings)|races]] as separately created [[species]], was rejected by [[Charles Darwin]], who argued for the [[Monogenism|monogenesis]] of the [[human]] species and the [[recent African origin of modern humans|African origin of modern humans]]. Haeckel put forward a racist<ref>{{Cite journal |last1=Levit |first1=Georgy S. |last2=Hossfeld |first2=Uwe |date=2020-05-25 |title=Ernst Haeckel, Nikolai Miklucho-Maclay and the racial controversy over the Papuans |journal=Frontiers in Zoology |volume=17 |issue=1 |pages=16 |doi=10.1186/s12983-020-00358-w |issn=1742-9994 |pmc=7247218 |pmid=32489391 |doi-access=free}}</ref> doctrine of evolutionary polygenism based on the ideas of the linguist [[August Schleicher]], in which several different language groups had arisen separately from speechless prehuman ''Urmenschen'' ({{langx|de|proto-humans}}), which themselves had evolved from simian ancestors. These separate languages had completed the transition from animals to man, and under the influence of each main branch of languages, humans had evolved – in a kind of [[Lamarckism|Lamarckian]] use-inheritance – as separate species, which could be subdivided into races. From this, Haeckel drew the implication that languages with the most potential yield the human races with the most potential, led by the Semitic and Indo-Germanic groups, with Berber, Jewish, Greco-Roman and Germanic varieties to the fore.{{sfn|Richards|2008|pages=259–260}} As Haeckel stated:<ref>''Natürliche Schöpfungsgeschichte'' (1868), p. 511; quoted after [[Robert J. Richards]], "The linguistic creation of man: Charles Darwin, August Schleicher, Ernst Haeckel, and the Missing Link in Nineteenth-Century Evolutionary Theory".[http://www.courses.fas.harvard.edu/~hsci278/Readings_on_Language/Darwin_and_language_by_Richards.htm#_ftnref62] {{Webarchive|url=https://web.archive.org/web/20040203111759/http://www.courses.fas.harvard.edu/~hsci278/Readings_on_Language/Darwin_and_language_by_Richards.htm#_ftnref62|date=3 February 2004}}</ref>

{{blockquote|We must mention here one of the most important results of the comparative study of languages, which for the Stammbaum of the species of men is of the highest significance, namely that human languages probably had a multiple or polyphyletic origin. Human language as such probably developed only after the species of speechless ''Urmenschen'' or ''Affenmenschen'' ({{langx|de|ape-men}}) had split into several species or kinds. With each of these human species, language developed on its own and independently of the others. At least this is the view of Schleicher, one of the foremost authorities on this subject.&nbsp;... If one views the origin of the branches of language as the special and principal act of becoming human, and the species of humankind as distinguished according to their language stem, then one can say that the different species of men arose independently of one another.}}

Haeckel's view can be seen as a forerunner of the views of [[Carleton S. Coon|Carleton Coon]], who also believed that human races evolved independently and in parallel with each other. These ideas eventually fell from favour.<ref>{{cite book|first=C. Loring |last=Brace|title=Evolution in an Anthropological View|location=Walnut Creek, CA|publisher=AltaMira Press|year=2000|page=237|isbn=978-0-74250-263-5|url=https://books.google.com/books?id=SsRFuisbUk4C}}</ref>

Haeckel also applied the hypothesis of polygenism to the modern diversity of human groups. He became a key figure in [[social darwinism]] and leading proponent of [[scientific racism]], stating for instance:<ref>''The History of Creation'', 6th edition (1914), volume 2, page 429.</ref>

{{blockquote|The Caucasian, or Mediterranean man (''Homo Mediterraneus''), has from time immemorial been placed at the head of all the races of men, as the most highly developed and perfect. It is generally called the Caucasian race, but as, among all the varieties of the species, the Caucasian branch is the least important, we prefer the much more suitable appellation proposed by [[Friedrich Müller (linguist)|Friedrich Müller]], namely, that of ''Mediterranese''. For the most important varieties of this species, which are moreover the most eminent actors in what is called "Universal History", first rose to a flourishing condition on the shores of the Mediterranean.&nbsp;... This species alone (with the exception of the Mongolian) has had an actual history; it alone has attained to that degree of civilisation which seems to raise men above the rest of nature.}}

Haeckel divided human beings into ten races, of which the [[Caucasian race|Caucasian]] was the highest and the primitives were doomed to extinction.<ref>John P. Jackson and Nadine M. Weidman. ''[https://books.google.com/books?id=G-crlAYsZ-MC Race, Racism, and Science: Social Impact and Interaction]'', Rutgers University Press, 2005, p. 87</ref> In his view, 'Negroes' were savages and Whites were the most civilised: for instance, he claimed that '[t]he Negro' had stronger and more freely movable toes than any other race, which, he argued, was evidence of their being less evolved, and which led him to compare them to {{'"}}four-handed" Apes'.<ref name="Jahoda">[[Gustav Jahoda]], ''Images of Savages: Ancient Roots of Modern Prejudice in Western Culture'', 1999, p. 83</ref>

In his ''[[Ontogeny and Phylogeny (book)|Ontogeny and Phylogeny]]'' Harvard paleontologist [[Stephen Jay Gould]] wrote: "[Haeckel's] evolutionary racism; his call to the German people for racial purity and unflinching devotion to a 'just' state; his belief that harsh, inexorable laws of evolution ruled human civilization and nature alike, conferring upon favored races the right to dominate others&nbsp;... all contributed to the rise of [[Nazism]]."<ref>Gould, S.J. ''Ontogeny and Phylogeny''. Cambridge MA: Belknap Press of Harvard University Press pp. 77–78</ref>

In his introduction to the [[Nazi Party]] ideologue [[Alfred Rosenberg]]'s 1930 book ''The Myth of the Twentieth Century'' Peter Peel affirms that Rosenberg had indeed read Haeckel.<ref>{{Cite web |url=http://www.nommeraadio.ee/meedia/pdf/RRS/Alfred%20Rosenberg%20-%20The%20Myth%20of%20the%2020th%20Century.pdf |title=The Myth of the 20th Century |last=Rosenberg |first=Alfred |author-link=Alfred Rosenberg |date=1930 |access-date=1 February 2018}}</ref>

In the same line of thought, historian [[Daniel Gasman]] states that Haeckel's ideology stimulated the birth of [[Fascist]] ideology in Italy and France.<ref>Daniel Gasman (1998). "Haeckel's Monism and the Birth of Fascist Ideology". ''Studies in Modern European History'' 33. Peter Lang Pub Incorporated. {{ISSN|0893-6897}}. {{ISBN|978-0-8204-4108-5}}</ref>

However, in 2009 [[Robert J. Richards]] noted: "Haeckel, on his travels to Ceylon and Indonesia, often formed closer and more intimate relations with natives, even members of the untouchable classes, than with the European colonials." and says the Nazis rejected Haeckel, since he opposed antisemitism, while supporting ideas they disliked (for instance atheism, feminism, internationalism, pacifism etc.).<ref>Robert J. Richards, "Myth 19: That Darwin and Haeckel Were Complicit in Nazi Biology", in [[Ronald L. Numbers]], ed., ''Galileo Goes to Jail and Other Myths About Science and Religion'', Harvard University Press, 2009, p. 174.</ref>

The [[Jena Declaration]], published by the [[German Zoological Society]], rejects the idea of human "[[Race (biology)|races]]" and distances itself from the [[Scientific racism|racial theories]] of Ernst Haeckel and other 20th century scientists. It claims that [[genetic variation]] between [[World population|human populations]] is smaller than within them, demonstrating that the biological concept of "races" is invalid. The statement highlights that there are no specific [[gene]]s or [[genetic marker]]s that match with conventional racial [[categorization]]s. It also indicates that the idea of "races" is based on [[racism]] rather than any [[Science|scientific]] factuality.<ref>{{Cite web |last=Max Planck Institute of Geoanthropology |date=10 September 2019 |title=Jenaer Erklärung |url=https://www.shh.mpg.de/1464654/jenaer-erklaerung |access-date=17 November 2023 |website=www.shh.mpg.de |language=en}}</ref><ref>{{Cite web |last=Nachrichten Informationsdienst Wissenschaft |date=10 September 2019 |title='Human races' do not exist |url=https://nachrichten.idw-online.de/2019/09/10/human-races-do-not-exist |access-date=17 November 2023 |website=nachrichten.idw-online.de |language=de-DE}}</ref>

=== Asia hypothesis ===
[[File:Haeckel_1882.jpg|thumb|Haeckel in Ceylon, 1882]]
Haeckel claimed the origin of humanity was to be found in Asia: he believed that [[Hindustan]] (Indian subcontinent) was the actual location where the first humans had evolved. Haeckel argued that humans were closely related to the [[primate]]s of Southeast Asia and rejected Darwin's hypothesis of Africa.<ref>Douglas Palmer, ''Prehistoric past: The four billion year history of life on earth'', p. 43</ref><ref>Brian Regal, ''Human evolution: a guide to the debates'', pp. 73–75</ref>

Haeckel later claimed that the [[Transitional fossil#Missing links|missing link]] was to be found on the lost continent of [[Lemuria (continent)|Lemuria]] located in the Indian Ocean. He believed that Lemuria was the home of the first humans and that Asia was the home of many of the earliest [[primate]]s; he thus supported that Asia was the cradle of hominid evolution. Haeckel also claimed that Lemuria connected Asia and Africa, which allowed the [[Human migration|migration of humans]] to the rest of the world.<ref>Christopher J Norton and David R Braun. ''Asian Paleoanthropology: From Africa to China and beyond''. p. 4</ref><ref>Mario A. Di Gregorio. ''From here to Eternity: Ernst Haeckel and the scientific faith''. p. 480</ref>

In Haeckel's book ''The History of Creation'' (1884) he included [[Human migration|migration]] routes which he thought the first humans had used outside of Lemuria.<ref>{{cite book |last1=Haeckel |first1=Ernest |title=THE HISTORY OF CREATION, Vol. II |date=1884 |page=Frontispiece |url=https://www.gutenberg.org/files/40473/40473-h/40473-h.htm#plxv |access-date=23 October 2022 |ref=40473-h.htm}}</ref>

== Embryology and recapitulation theory ==
{{further|Recapitulation theory}}
[[File:Haeckel-embryos-weeks4-6.jpg|thumb|right|Illustrations of dog and human embryos, looking almost identical at 4 weeks then differing at 6 weeks, shown above a 6-week turtle embryo and 8-day hen embryo, presented by Haeckel in 1868 as convincing proof of evolution. The pictures of the earliest embryonic stages are now considered inaccurate.<ref>{{cite journal |last1=Richardson |first1=M. K. |last2=Hanken |first2=J. |last3=Selwood |first3=L. |author-link3=Lynne Selwood |last4=Wright |first4=G. M. |last5=Richards |first5=R. J. |last6=Pieau |first6=C. |last7=Raynaud |first7=A. |year=1998 |title=Letters |journal=Science |volume=280 |issue=5366 |pages=983, 985–6 |doi=10.1126/science.280.5366.983c |pmid=9616084 |s2cid=2497289}}</ref>]]

When Haeckel was a student in the 1850s he showed great interest in [[embryology]], attending the rather unpopular lectures twice and in his notes sketched the visual aids: textbooks had few illustrations, and large format plates were used to show students how to see the tiny forms under a reflecting microscope, with the translucent tissues seen against a black background. Developmental series were used to show stages within a species, but inconsistent views and stages made it even more difficult to compare different species. It was agreed by all European evolutionists that all [[vertebrate]]s looked very similar at an early stage, in what was thought of as a common ideal type, but there was a continuing debate from the 1820s between the Romantic [[recapitulation theory]] that human embryos developed through stages of the forms of all the major groups of adult animals, literally manifesting a sequence of organisms on a [[great chain of being|linear chain of being]], and [[Karl Ernst von Baer]]'s opposing view, stated in [[von Baer's laws (embryology)|von Baer's laws of embryology]], that the early general forms diverged into four major groups of specialised forms without ever resembling the adult of another species, showing affinity to an [[archetype]] but no relation to other types or any [[transmutation of species]]. By the time Haeckel was teaching he was able to use a textbook with woodcut illustrations written by his own teacher [[Albert von Kölliker]], which purported to explain human development while also using other mammalian embryos to claim a coherent sequence. Despite the significance to ideas of transformism, this was not really polite enough for the new popular science writing, and was a matter for medical institutions and for experts who could make their own comparisons.<ref name=hopwood2006 />{{rp|264–267}}<ref>{{harvnb|Darwin|Costa|2011|p=450}}</ref>

=== Darwin, Naturphilosophie and Lamarck ===

Darwin's ''[[On the Origin of Species]]'', which made a powerful impression on Haeckel when he read it in 1864, was very cautious about the possibility of ever reconstructing the history of life, but did include a section reinterpreting von Baer's embryology and revolutionising the field of study, concluding that "Embryology rises greatly in interest, when we thus look at the embryo as a picture, more or less obscured, of the common parent-form of each great class of animals." It mentioned von Baer's 1828 anecdote (misattributing it to [[Louis Agassiz]]) that at an early stage embryos were so similar that it could be impossible to tell whether an unlabelled specimen was of a mammal, a bird, or of a reptile, and Darwin's own research using embryonic stages of [[barnacle]]s to show that they are [[crustacean]]s, while cautioning against the idea that one organism or embryonic stage is "higher" or "lower", or more or less evolved.<ref>{{harvnb|Darwin|1859|pp=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F373&pageseq=457 439–450]}}<br />{{harvnb|Darwin|Costa|2011|pp=439–450}}</ref> Haeckel disregarded such caution, and in a year wrote his massive and ambitious ''Generelle Morphologie'', published in 1866, presenting a revolutionary new synthesis of Darwin's ideas with the German tradition of ''[[Naturphilosophie]]'' going back to [[Johann Wolfgang von Goethe|Goethe]] and with the progressive evolutionism of [[Lamarckism|Lamarck]] in what he called ''Darwinismus''. He used [[morphology (biology)|morphology]] to reconstruct the [[evolutionary history of life]], in the absence of fossil evidence using embryology as evidence of ancestral relationships. He invented new terms, including [[ontogeny]] and [[phylogeny]], to present his evolutionised recapitulation theory that "ontogeny recapitulated phylogeny". The two massive volumes sold poorly, and were heavy going: with his limited understanding of German, Darwin found them impossible to read. Haeckel's publisher turned down a proposal for a "strictly scholarly and objective" second edition.<ref name=hopwood2006 />{{rp|269–270}}

=== Embryological drawings ===
[[File:Tree of life by Haeckel.jpg|upright|thumb|Haeckel's [[tree of life (biology)|tree of life]]]]

Haeckel's aim was a reformed morphology with evolution as the organising principle of a cosmic synthesis unifying science, religion, and art. He was giving successful "popular lectures" on his ideas to students and townspeople in [[Jena]], in an approach pioneered by his teacher [[Rudolf Virchow]]. To meet his publisher's need for a popular work he used a student's transcript of his lectures as the basis of his ''Natürliche Schöpfungsgeschichte'' of 1868, presenting a comprehensive presentation of evolution. In the Spring of that year he drew figures for the book, synthesising his views of specimens in Jena and published pictures to represent types. After publication he told a colleague that the images "are completely exact, partly copied from nature, partly assembled from all illustrations of these early stages that have hitherto become known". There were various styles of [[embryological drawings]] at that time, ranging from more schematic representations to "naturalistic" illustrations of specific specimens. Haeckel believed privately that his figures were both exact and synthetic, and in public asserted that they were schematic like most figures used in teaching. The images were reworked to match in size and orientation, and though displaying Haeckel's own views of essential features, they support von Baer's concept that vertebrate embryos begin similarly and then diverge. Relating different images on a grid conveyed a powerful evolutionary message. As a book for the general public, it followed the common practice of not citing sources.<ref name=hopwood2006 />{{rp|270–274}}

[[File:Embryo - copies.jpg|thumb|left|In 1868 Haeckel illustrated von Baer's observation that early embryos of different species could not be told apart by using the same woodcut three times as dog, chick and turtle embryos: he changed this in the next edition.]]
The book sold very well, and while some anatomical experts hostile to Haeckel's evolutionary views expressed some private concerns that certain figures had been drawn rather freely, the figures showed what they already knew about similarities in embryos. The first published concerns came from [[Ludwig Rütimeyer]], a professor of zoology and comparative anatomy at the [[University of Basel]] who had placed fossil mammals in an evolutionary lineage early in the 1860s and had been sent a complimentary copy. At the end of 1868 his review in the ''Archiv für Anthropologie'' wondered about the claim that the work was "popular and scholarly", doubting whether the second was true, and expressed horror about such public discussion of man's place in nature with illustrations such as the evolutionary trees being shown to non-experts. Though he made no suggestion that embryo illustrations should be directly based on specimens, to him the subject demanded the utmost "scrupulosity and conscientiousness" and an artist must "not arbitrarily model or generalise his originals for speculative purposes" which he considered proved by comparison with works by other authors. In particular, "one and the same, moreover incorrectly interpreted woodcut, is presented to the reader three times in a row and with three different captions as [the] embryo of the dog, the chick, [and] the turtle". He accused Haeckel of "playing fast and loose with the public and with science", and failing to live up to the obligation to the truth of every serious researcher. Haeckel responded with angry accusations of bowing to religious prejudice, but in the second (1870) edition changed the duplicated embryo images to a single image captioned "embryo of a mammal or bird". Duplication using galvanoplastic stereotypes ([[Stereotype (printing)|clichés]]) was a common technique in textbooks, but not on the same page to represent different eggs or embryos. In 1891 Haeckel made the excuse that this "extremely rash foolishness" had occurred in undue haste but was "bona fide", and since repetition of incidental details was obvious on close inspection, it is unlikely to have been intentional deception.<ref name=hopwood2006 />{{rp|275–276;282–286}}

The revised 1870 second edition of 1,500 copies attracted more attention, being quickly followed by further revised editions with larger print runs as the book became a prominent part of the optimistic, nationalist, anticlerical "culture of progress" in [[Otto von Bismarck]]'s new [[German Empire]]. The similarity of early vertebrate embryos became common knowledge, and the illustrations were praised by experts such as [[Michael Foster (physiologist)|Michael Foster]] of the [[University of Cambridge]]. In the introduction to his 1871 ''[[The Descent of Man, and Selection in Relation to Sex]]'', Darwin gave particular praise to Haeckel, writing that if ''Natürliche Schöpfungsgeschichte'' "had appeared before my essay had been written, I should probably never have completed it". The first chapter included an illustration: "As some of my readers may never have seen a drawing of an embryo, I have given one of man and another of a dog, at about the same early stage of development, carefully copied from two works of undoubted accuracy" with a footnote citing the sources and noting that "Häckel has also given analogous drawings in his ''Schöpfungsgeschichte.''" The fifth edition of Haeckel's book appeared in 1874, with its frontispiece a heroic portrait of Haeckel himself, replacing the previous controversial image of the heads of apes and humans.<ref name=hopwood2006 />{{rp|285–288}}<ref>{{harvnb|Darwin|1871|pp=[http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F937.1&pageseq=17 4], [http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=F937.1&pageseq=27 14–17]}}</ref>

[[File:Haeckel Anthropogenie 1874.jpg|thumb|right|1874 illustration from ''Anthropogenie'' showing "very early", "somewhat later" and "still later" stages of embryos of fish (F), salamander (A), turtle (T), chick (H), pig (S), cow (R), rabbit (K), and human (M)]]

=== Controversy ===
Later in 1874, Haeckel's simplified embryology textbook ''Anthropogenie'' made the subject into a battleground over Darwinism aligned with Bismarck's ''[[Kulturkampf]]'' ("culture struggle") against the Catholic Church. Haeckel took particular care over the illustrations, changing to the leading zoological publisher Wilhelm Engelmann of Leipzig and obtaining from them use of illustrations from their other textbooks as well as preparing his own drawings including a dramatic double page illustration showing "early", "somewhat later" and "still later" stages of 8 different vertebrates. Though Haeckel's views had attracted continuing controversy, there had been little dispute about the embryos and he had many expert supporters, but [[Wilhelm His Sr.|Wilhelm His]] revived the earlier criticisms and introduced new attacks on the 1874 illustrations.<ref>Wilhelm His. ''Unsere Körperform und das physiologische Problem ihrer Entstehung''. F. C. W. Vogel, Leipzig 1875.</ref> 

Expert anatomists were critical of Haeckel's work. Catholic priests also opposed Haeckel's views. Specifically, Haeckel's critics accused him of manipulating the embryo drawings to make the early stages of different species look more similar. They claimed that the drawings of four-week dog and human embryos had been copied without attribution from other sources, and changed by expanding dog's head and reducing the human head, moving the eye, and exaggerating the size of the human tail.  Haeckel himself considered the drawings stylized and illustrative, but his detractors considered them forgery and fraud.<ref name=hopwood2006 />{{rp|270-271,288–296,299}}

While it has been widely claimed that Haeckel was charged with fraud by five professors and convicted by a university court at Jena, there does not appear to be an independently verifiable source for this claim.<ref>{{citation|last=Richards|first=Robert J.|author-link=Robert J. Richards|title=Ernst Haeckel and the Struggles over Evolution and Religion|url=https://books.google.com/books?id=byJk8Ea0WSQC&pg=PA89|access-date=22 February 2016|volume=10|year=2005|publisher=Universitätsverlag Göttingen|isbn=978-3-938616-39-0|pages=89–115|journal=Annals of the History and Philosophy of Biology}}</ref> Recent analyses (Richardson 1998, Richardson and Keuck 2002) have found that some of the criticisms of Haeckel's embryo drawings were legitimate,{{citation needed|date=March 2025}} but others were unfounded.<ref>Michael K. Richardson. 1998. "Haeckel's embryos continued". ''Science'' 281:1289, quoted in NaturalScience.com webpage [http://naturalscience.com/ns/letters/ns_let17.html Re: ''Ontogeny and phylogeny''] {{webarchive|url=https://web.archive.org/web/20061114003612/http://naturalscience.com/ns/letters/ns_let17.html |date=14 November 2006 }}: A Letter from Richard Bassetti; Editor's note.</ref><ref>"While some criticisms of the drawings are legitimate, others are more tendentious", Richardson and Keuck "Haeckel's ABC of evolution and development", ''Biol. Rev.'' (2002), '''77''', pp. 495–528. Quoted from p. 495.</ref> There were multiple versions of the embryo drawings, and Haeckel rejected the claims of fraud. It was later said that "there is evidence of sleight of hand" on both sides of the feud between Haeckel and [[Wilhelm His Sr.|Wilhelm His]].<ref>Richardson & Keuck 2001. See for example, their Fig. 7, showing His's drawing of the forelimb of a deer embryo developing a clef, compared with a similar drawing (Sakurai, 1906) showing the forelimb initially developing as a digital plate with rays. Richardson and Keuck say "Unfortunately His's embryos are mostly at later stages than the nearly identical early stage embryos illustrated by Haeckel [top row of Haeckel's drawing]. Thus they do not inform the debate and may themselves be disingenuous." p. 518.</ref> [[Robert J. Richards]], in a paper published in 2008, defends the case for Haeckel, shedding doubt against the fraud accusations based on the material used for comparison with what Haeckel could access at the time.<ref>{{Cite journal|title=Haeckel's embryos: fraud not proven |first=Robert J. | last=Richards |journal=Biology & Philosophy |year=2009 |volume=24 |pages=147–154 |doi=10.1007/s10539-008-9140-z |citeseerx=10.1.1.591.9350 |s2cid=13416916 |url=http://home.uchicago.edu/~rjr6/articles/Haeckel--fraud%20not%20proven.pdf}}</ref>

== Assessments of potential influence on Nazism ==
Some historians have seen Haeckel's social Darwinism as a forerunner to [[Nazism|Nazi]] ideology.<ref>{{cite book |last1=Gould |first1=Stephen Jay |title=Ontogeny and Phylogeny |url=https://archive.org/details/ontogenyphylogen00goul |url-access=registration |date=1977 |publisher=Harvard University Press |location=Cambridge, Mass. |page=[https://archive.org/details/ontogenyphylogen00goul/page/77 77-78]|isbn=9780674639409 }}</ref><ref>{{cite book |last1=Gasman |first1=Daniel |title=The Scientific Origins of National Socialism: Social Darwinism in Ernst Haeckel and the German Monist League |date=1971 |publisher=MacDonald & co. |location=New Brunswick |page=xiv}}</ref><ref>{{cite book |last1=Weikart |first1=Richard |title=From Darwin to Hitler |date=2004 |publisher=Palgrave MacMillan |location=New York|isbn=1403965021}}</ref>{{Page needed|date=May 2021}} Others have denied the relationship altogether.<ref>{{cite book |last1=Kelly |first1=Alfred |title=The Descent of Darwin: The Popularization of Darwinism in Germany, 1860–1914 |url=https://archive.org/details/descentofdarwinp0000kell |url-access=registration |date=1981 |publisher=University of North Carolina Press |location=Chapel Hill, North Carolina |page=[https://archive.org/details/descentofdarwinp0000kell/page/121 121]|isbn=9780807814604 }}</ref>{{sfn|Richards|2008|pages=448–453}}<ref>{{cite book |last1=Di Gregorio |first1=Mario A. |title=From Here to Eternity: Ernst Haeckel and Scientific Faith |date=2005 |publisher=Vandenhoeck & Ruprecht |page=569}}</ref>

The evidence is in some respects ambiguous. On one hand, Haeckel was an advocate of [[scientific racism]]. He held that evolutionary biology had definitively proven that races were unequal in intelligence and ability, and that their lives were also of unequal value, e.g., "These lower races (such as the Veddahs or Australian negroes) are psychologically nearer to the mammals (apes or dogs) than to civilised Europeans; we must therefore, assign a totally different value to their lives."<ref>{{cite book |last1=Haeckel |first1=Ernst |title=The Wonders of Life |date=1904 |publisher=Watts & Co. |location=London |page=[https://archive.org/details/in.ernet.dli.2015.22567/page/n422 82, 406]–407 |url=https://archive.org/details/in.ernet.dli.2015.22567 |access-date=15 May 2019}}</ref> As a result of the "struggle for existence", it followed that the "lower" races would eventually be exterminated.<ref>{{cite book |last1=Hawkins |first1=Mike |title=Social Darwinism in European and American Thought |url=https://archive.org/details/socialdarwinisme00hawk |url-access=limited |date=1997 |publisher=Cambridge University Press |location=Cambridge |page=[https://archive.org/details/socialdarwinisme00hawk/page/n149 140]}}</ref> He was also a social Darwinist who believed that "survival of the fittest" was a natural law, and that struggle led to improvement of the race.<ref>{{cite book |last1=Hawkins |first1=Mike |title=Social Darwinism in European and American Thought |url=https://archive.org/details/socialdarwinisme00hawk |url-access=limited |date=1997 |publisher=Cambridge University Press |location=Cambridge |page=[https://archive.org/details/socialdarwinisme00hawk/page/n146 137]}}</ref> As an advocate of eugenics, he also believed that about 200,000 [[Mental illness|mentally]] and [[Genetic disorder|congenitally ill]] should be killed by a medical control board.<ref>{{cite book |last1=Haeckel |first1=Ernst |title=The Wonders of Life |date=1904 |publisher=Watts & Co. |location=London |page=[https://archive.org/details/in.ernet.dli.2015.22567/page/n138 122]–124 |url=https://archive.org/details/in.ernet.dli.2015.22567 |access-date=15 May 2019}}</ref> This idea was later put into practice by [[Nazi Germany]], as part of the [[Aktion T4]] program.<ref>{{cite book |last1=Gregorio |first1=Mario A Di |title=From Here to Eternity: Ernst Haeckel and Scientific Faith |date=2005 |publisher=Vandenhoeck & Ruprecht |page=571}}</ref> 

[[Alfred Ploetz]], founder of the [[German Society for Racial Hygiene]], praised Haeckel repeatedly, and invited him to become an honorary member. Haeckel accepted the invitation.<ref>{{cite book |last1=Weikart |first1=Richard |title=From Darwin to Hitler |date=2004 |publisher=Palgrave MacMillan |location=New York |isbn=1403965021|page=15}}</ref> Haeckel also believed that Germany should be governed by an authoritarian political system, and that inequalities both within and between societies were an inevitable product of evolutionary law.<ref>{{cite book |last1=Hawkins |first1=Mike |title=Social Darwinism in European and American Thought |url=https://archive.org/details/socialdarwinisme00hawk |url-access=limited |date=1997 |publisher=Cambridge University Press |location=Cambridge |page=[https://archive.org/details/socialdarwinisme00hawk/page/n148 139]}}</ref> Haeckel was also an extreme German nationalist who believed strongly in the superiority of German culture.<ref>{{cite book |last1=Gregorio |first1=Mario A Di |title=From Here to Eternity: Ernst Haeckel and Scientific Faith |date=2005 |publisher=Vandenhoeck & Ruprecht |page=568}}</ref>

On the other hand, Haeckel was not an anti-Semite. In the racial hierarchies he constructed Jews tended to appear closer to the top, rather than closer to the bottom as in [[Nazism and race|Nazi racial thought]].{{sfn|Richards|2008|pages=273–275}} He was also a pacifist until the First World War, when he wrote propaganda in favor of the war.{{sfn|Richards|2008|pages=432–433}} The principal arguments of historians who deny a meaningful connection between Haeckel and Nazism are that Haeckel's ideas were very common at the time, that Nazis were much more strongly influenced by other thinkers, and that Haeckel is properly classified as a 19th-century German liberal, rather than a forerunner to Nazism.{{sfn|Richards|2008|pages=270–271}}<ref>{{cite book |last1=Gregorio |first1=Mario A Di |title=From Here to Eternity: Ernst Haeckel and Scientific Faith |date=2005 |publisher=Vandenhoeck & Ruprecht |page=506}}</ref> They also point to incompatibilities between evolutionary biology and Nazi ideology.<ref>{{cite book |last1=Kelly |first1=Alfred |title=The Descent of Darwin: The Popularization of Darwinism in Germany, 1860–1914 |url=https://archive.org/details/descentofdarwinp0000kell |url-access=registration |date=1981 |publisher=University of North Carolina Press |location=Chapel Hill, North Carolina |page=[https://archive.org/details/descentofdarwinp0000kell/page/121 121]|isbn=9780807814604 }}</ref>

Nazis themselves divided on the question of whether Haeckel should be counted as a pioneer of their ideology. [[Schutzstaffel|SS]] captain and biologist [[Heinz Brücher]] wrote a biography of Haeckel in 1936, in which he praised Haeckel as a "pioneer in biological state thinking".<ref>{{cite book |last1=Deichmann |first1=Ute |title=Biologists Under Hitler |date=1996 |publisher=Harvard University Press |pages=259–260}}</ref> This opinion was also shared by the scholarly journal, ''Der Biologe'', which celebrated Haeckel's 100th birthday, in 1934, with several essays acclaiming him as a pioneering thinker of Nazism.<ref>{{cite book |last1=Deichmann |first1=Ute |title=Biologists Under Hitler |date=1996 |publisher=Harvard University Press |location=Cambridge, Massachusetts |pages=269–270}}</ref> Other Nazis kept their distance from Haeckel. Nazi propaganda guidelines issued in 1935 listed books which popularized Darwin and evolution on an "expunged list". Haeckel was included by name as a forbidden author.<ref>{{cite book |last1=Kelly |first1=Alfred |title=The Descent of Darwin: The Popularization of Darwinism in Germany, 1860–1914 |url=https://archive.org/details/descentofdarwinp0000kell |url-access=registration |date=1981 |publisher=University of North Carolina |location=Chapel Hill |page=[https://archive.org/details/descentofdarwinp0000kell/page/121 121–122]|isbn=9780807814604 }}</ref> Gunther Hecht, a member of the Nazi Department of Race Politics, also issued a memorandum rejecting Haeckel as a forerunner of Nazism.{{sfn|Richards|2008|page=446}} Kurt Hildebrandt, a Nazi political philosopher, also rejected Haeckel.{{sfn|Richards|2008|page=446}} Eventually Haeckel was rejected by Nazi bureaucrats.{{sfn|Richards|2008|page=445}}

== Awards and honors ==
Haeckel was elected as a member to the [[American Philosophical Society]] in 1885.<ref>{{Cite web|title=APS Member History|url=https://search.amphilsoc.org/memhist/search?creator=&title=&subject=&subdiv=&mem=&year=1885&year-max=&dead=&keyword=&smode=advanced|access-date=21 May 2021|website=search.amphilsoc.org}}</ref> He was awarded the title of Excellency by Kaiser [[Wilhelm II, German Emperor|Wilhelm II]] in 1907<ref>{{cite news|access-date=15 July 2012|url=https://newspaperarchive.com/singleviewer.aspx?pdfid=56797786|archive-url=https://archive.today/20130130040215/http://newspaperarchive.com/singleviewer.aspx?pdfid=56797786|url-status=dead|archive-date=30 January 2013|title=Kaiser Honors Haeckel|work=The New York Times|date=9 March 1907}}</ref> and the [[Linnean Society of London]]'s prestigious [[Darwin-Wallace Medal]] in 1908. In the United States, ''[[Mount Haeckel]]'', a {{convert|13418|ft|m|abbr=on}} summit in the Eastern [[Sierra Nevada (U.S.)|Sierra Nevada]], overlooking the Evolution Basin, is named in his honour, as is another ''Mount Haeckel'', a {{convert|2941|m|ft|abbr=on}} summit in [[List of mountains of New Zealand by height|New Zealand]]; and the [[asteroid]] [[12323 Haeckel]].<ref>{{Cite web|url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=12323|title=JPL Small-Body Database Browser|website=ssd.jpl.nasa.gov|access-date=16 January 2020}}</ref><ref>{{Cite book |title=The Story of Mount Cook National Park : a handbook to help you enjoy the park |date=1986 |publisher=Dept. of Lands and Survey; Auckland, N.Z |isbn=9780477061360 |edition=6th |location=New Zealand |pages=152}}</ref>

In Jena he is remembered with a monument at Herrenberg (erected in 1969),<ref>{{cite web| url = https://commons.wikimedia.org/wiki/File:Monument_to_Ernst_Haeckel,_evolutionary_biologist,_at_Herrenberg_Jena.jpg| title = Wikimedia - Monument to Ernst Haeckel| date = 10 February 2014}}</ref> an exhibition at [[Ernst-Haeckel-Haus]],<ref>{{cite web| url = https://www.visit-jena.de/en/arts-entertainment/museums/ernst-haeckel-haus/| title = Visit Jena - Ernst Haeckel Haus| access-date = 18 April 2019| archive-date = 18 April 2019| archive-url = https://web.archive.org/web/20190418161315/https://www.visit-jena.de/en/arts-entertainment/museums/ernst-haeckel-haus/| url-status = dead}}</ref> and at the [[Jena Phyletic Museum]], which continues to teach about evolution and share his work to this day.<ref>{{cite web| url = http://www.phyletisches-museum.de/exhibition-information.html| title = Phyletisches Museum Jena}}</ref>

The ratfish, ''[[Harriotta haeckeli]]'' is named in his honor.<ref>{{Cite web|url = http://www.etyfish.org/chimaeriformes/|title = Order CHIMAERIFORMES|date = 13 January 2013|access-date = 3 February 2021|archive-date = 12 May 2016|archive-url = https://web.archive.org/web/20160512162931/http://www.etyfish.org/chimaeriformes/|url-status = dead}}</ref>

The research vessel ''Ernst Haeckel'' is named in his honor.<ref>{{Cite web|url=http://soviet-trawler.narod.ru/pages/gdr/ernst_haeckel.html|title = Research trawler "Ernst Haeckel"}}</ref>

In 1981, a botanical journal called ''Ernstia'' was started being published in the city of [[Maracay]], Venezuela.<ref>{{cite web |title=Ernstia. Maracay {{!}} International Plant Names Index |url=https://www.ipni.org/p/1281-2 |website=www.ipni.org |access-date=30 November 2021}}</ref>

In 2013, ''[[Ernstia]]'', a [[genus]] of [[calcareous sponges]] in the family [[Clathrinidae]]. The genus was erected to contain five species previously assigned to ''[[Clathrina]]''. The genus name honors Ernst Haeckel for his contributions towards sponge taxonomy and phylogeny.<ref name=Klautauetal2013>{{cite journal|last=Klautau|first=M.|author2=Azevedo, F. |author3=Condor-Lujan, B. |author4=Rapp, H. T. |author5=Collins, A. |author6= Russo, C. A. d. M. |title=A Molecular Phylogeny for the Order Clathrinida Rekindles and Refines Haeckel's Taxonomic Proposal for Calcareous Sponges|journal=Integrative and Comparative Biology|date=2013|volume=53|issue=3|pages=447–461|doi=10.1093/icb/ict039|url=https://www.researchgate.net/publication/236909245 |pmid=23704365|doi-access=free}}</ref><ref>{{cite web| url = http://www.marinespecies.org/aphia.php?p=taxdetails&id=732171| title = World Register of Marine Species entry}}</ref>

== Publications ==
[[File:Haeckel Muscinae.jpg|thumb|upright|''Kunstformen'' – plate 72: [[Bryophyte|Muscinae]]]]
[[File:Haeckel Chaetopoda.jpg|thumb|upright|''Kunstformen'' – plate 96: [[Chaetopoda]]]]
[[File:Aeginura grimaldii by Haeckel.png|thumb|right|[[Medusa (biology)|Medusa]] of Aeginura grimaldii (bottom view)]]

Darwin's 1859 book ''[[On the Origin of Species]]'' had immense popular influence, but although its sales exceeded its publisher's hopes it was a technical book rather than a work of popular science: long, difficult and with few illustrations. One of Haeckel's books did a great deal to explain his version of "[[Darwinism]]" to the world. It was a bestselling, provocatively illustrated book in German, titled ''Natürliche Schöpfungsgeschichte'', published in Berlin in 1868, and translated into English as ''The History of Creation'' in 1876. Until 1909, eleven editions had appeared, as well as 25 translations into other languages. The ''Natürliche Schöpfungsgeschichte'' cemented Haeckel's reputation as one of Germany's most forceful popularizers of science. His ''Welträthsel'' were reprinted ten times after the book's first publication in 1899; ultimately, over 400,000 copies were sold.<ref>{{harvnb|Daum|1998|pp=305–6}}</ref>

Haeckel argued that human evolution consisted of precisely 22 phases, the 21st – the "[[Transitional fossil|missing link]]" – being a halfway step between apes and humans. He even formally named this missing link ''Pithecanthropus alalus'', translated as "ape man without speech".<ref>{{cite journal |last1=Schmutz |first1=Hans-Konrad |title=Hypothetische Bindeglieder zwischen Affe und Mensch: Zur fossilarmen Frühgeschichte der Paläoanthropologie |journal=Sudhoffs Archiv  |date=1984 |volume=68 |issue=1 |pages=77–83 |jstor=20776898 |url=http://www.jstor.org/stable/20776898 |access-date=11 March 2021}}</ref>

Haeckel's literary output was extensive, including many books, scientific papers, and illustrations.<ref name="WorldCat">{{cite web|title=Ernst Haeckel|url=https://www.worldcat.org/search?qt=worldcat_org_bks&q=Ernst+Haeckel&fq=dt%3Abks#x0%253Abook-%2C%2528x0%253Abook%2Bx4%253Aprintbook%2529format|publisher=WorldCat|access-date=4 June 2017}}</ref>

===Monographs===

* ''Radiolaria'' (1862)
* ''Siphonophora'' (1869)
* ''Monera'' (1870)
* ''Calcareous Sponges'' (1872)

===''Challenger'' reports===

* ''Deep-Sea Medusae'' (1881)
* ''Siphonophora'' (1888)
* ''Deep-Sea Keratosa'' (1889)
* ''Radiolaria'' (1887)

===Books on biology and its philosophy===
[[File:Haeckel arbol bn.png|thumb|upright|"{{lang|de|italics=no|Monophyletischer Stammbaum der Organismen}}" from {{lang|de|Generelle Morphologie der Organismen}} (1866) with the three branches Plantae, Protista, Animalia]]

* ''Generelle Morphologie der Organismen: allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie.'' (1866) Berlin (''General morphology of organisms: general foundations of form-science, mechanically grounded by the descendance theory reformed by Charles Darwin'')
* [http://de.wikiversity.org/wiki/Haeckel,_Ernst_(1868) ''Natürliche Schöpfungsgeschichte''] (1868); in English [https://web.archive.org/web/20121022155413/http://www.geology.19thcenturyscience.org/books/1876-Haeckel-HistCrea/Vol-I/htm/doc.html  ''The History of Creation''] (1876; 6th ed.: New York, D. Appleton and Co., 1914, 2 volumes)
* ''Freie Wissenschaft und freie Lehre'' (1877), in English, ''Free Science and Free Teaching''
* ''Die systematische Phylogenie'' (1894) – ''Systematic Phylogeny''
* {{Cite book|title=Anthropogenie, oder, Entwickelungsgeschichte des Menschen|publisher=UTET|location=Torino|year=1895|language=it|url=https://gutenberg.beic.it/webclient/DeliveryManager?pid=589685}}
* ''Die Welträthsel'' (1895–1899), also spelled ''Die Welträtsel'' – in English ''[[Riddle of the Universe|The Riddle of the Universe: At the Close of the Nineteenth Century]]'', Translated by Joseph McCabe, New York and London: Harper & Brothers Publishers, 1900.
* ''Über unsere gegenwärtige Kenntnis vom Ursprung des Menschen'' (1898) (''On our current understanding of the origin of man'') – in English [[s:The Last Link|''The Last Link'']], 1898
* ''Der Kampf um den Entwickelungsgedanken'' (1905) (''The struggle over thought on evolution'') – in English ''Last Words on Evolution: A Popular Retrospect and Summary'', Translated from the Second Edition by Joseph McCabe, New York: Peter Eckler, Publisher; London: A. Owen & Co., 1906.
* ''Die Lebenswunder'' (1904) – in English ''[https://openlibrary.org/works/OL16420977W/Wonders_of_life_A_Popular_Study_of_Biological_Philosophy The Wonders of Life]''
* ''[http://nbn-resolving.de/urn:nbn:de:hbz:061:2-22176 Kristallseelen : Studien über das anorganische Leben]'' (1917) (''Crystal souls: studies on inorganic life'')

===Travel books===
* ''Indische Reisebriefe'' (1882) – ''Travel notes of India''
* ''Aus Insulinde: Malayische Reisebriefe'' (1901) – ''Travel notes of Malaysia''
* ''[[Kunstformen der Natur]]'' (1904) – ''Art forms of Nature'', [http://nbn-resolving.de/urn:nbn:de:hbz:061:2-170858 Digital Edition (1924)] 
* ''Wanderbilder'' (1905) – "Travel Images"
* ''[https://archive.org/details/visittoceylon00haecuoft A visit to Ceylon]''

For a fuller list of works of and about Haeckel, see his entry in the [[s:de:Ernst Haeckel|German Wikisource]].

{{botanist|Haeckel}}

== See also ==
* [[Dysteleology]]
* [[Embryology]]
* [[Haeckelites]]
* ''[[Haeckel's Tale]]''
* [[Heinrich Schmidt (philosopher)]]
* [[Karl Blossfeldt]]
* [[List of wildlife artists]]
* ''[[Magosphaera planula]]''
* [[Proteus (2004 film)|''Proteus'' (2004 film)]]

== Footnotes ==
{{Reflist|refs=

<ref name=hopwood2006>{{cite journal|last=Hopwood |first=N |title=Pictures of evolution and charges of fraud: Ernst Haeckel's embryological illustrations. |journal=Isis; an International Review Devoted to the History of Science and Its Cultural Influences |date=June 2006 |volume=97 |issue=2 |pages=260–301 |pmid=16892945 |url=http://www.hps.cam.ac.uk/people/hopwood/haeckel.pdf |doi=10.1086/504734 |s2cid=37091078 |url-status=dead |archive-url=https://web.archive.org/web/20131029191323/http://www.hps.cam.ac.uk/people/hopwood/haeckel.pdf |archive-date=29 October 2013 }}</ref>

}}

== Sources ==
* {{cite book | last=Darwin |first=Charles | author-link=Charles Darwin | year=1859 | title=On the Origin of Species |title-link=On the Origin of Species | publisher=John Murray |  location=London }}
* {{cite book | last1=Darwin |first1=Charles |last2=Costa |first2=James T. | author-link=Charles Darwin | year=2011 | title=The Annotated Origin  | publisher=Harvard University Press |  location=Harvard}}
* {{cite book | last=Darwin |first=Charles | author-link=Charles Darwin | year=1871 | title=The Descent of Man | title-link=The Descent of Man, and Selection in Relation to Sex |  publisher=John Murray |  location=London}}
* {{cite book |last=Desmond |first=Adrian J. |author-link=Adrian Desmond |title=The Politics of Evolution: Morphology, Medicine, and Reform in Radical London |url=https://archive.org/details/politicsofevolut00adri |url-access=registration |publisher=University of Chicago Press |location=Chicago |year=1989 |isbn=0-226-14374-0 }}}

== External links ==
{{sister project links|b=no|n=no|q=no|v=no|wikt=no|author=yes|d=Q48246}}
* [http://de.wikiversity.org/wiki/Haeckel,_Ernst_(1868) E. Haeckel: Natürliche Schöpfungsgeschichte 1868 (front page of 1st edition, German)]
* [http://de.wikiversity.org/wiki/Haeckel,_Ernst_(1899) E. Haeckel: Die Welträthsel 1899 (front page of 1st edition, German)]
* [http://www.ucmp.berkeley.edu/history/haeckel.html University of California, Berkeley] – biography
* [http://www.slate.com/id/2124625/ Ernst Haeckel – Evolution's controversial artist.] A slide-show essay
* [http://www.zum.de/stueber/haeckel/kunstformen/natur.html ''Kunstformen der Natur''] (from [http://www.biolib.de/ biolib.de])
*''[https://phaidra.cab.unipd.it/o:420516 Kunstformen der Natur]'' (Digitization from Phaidra)
* [http://draves.org/pix/kdn/ PNG alpha-transparencies of Haeckel's "Kustformen der natur"]
* [http://www.nightfirefilms.org/proteus_home.html Proteus] – Animated documentary film on Haeckel's life and work
* [https://web.archive.org/web/20120315074743/http://www2.uni-jena.de/biologie/ehh/haeckel.htm Ernst Haeckel Haus] and Museum in [[Jena]]
* {{cite book|author=Schmidt, H. |year=1934|url=https://publikationen.ub.uni-frankfurt.de/opus4/frontdoor/deliver/index/docId/9235/file/schmidt_heinrich--haeckel_high.pdf |title=Ernst Haeckel: Denkmal eines grossen Lebens.|publisher=Walter Biedermann|place= Jena| language=de}}
* View works by [https://www.biodiversitylibrary.org/creator/1421 Haeckel] at the Biodiversity Heritage Library
* [http://www.mrkism.com/diatomea/ aDiatomea: artificial life experiment with 3d generated diatoms, influenced by Haeckel]
* [http://www.cppdigitallibrary.org/items/browse?advanced%5B0%5D%5Belement_id%5D=48&advanced%5B0%5D%5Btype%5D=contains&advanced%5B0%5D%5Bterms%5D=Haeckel%2C+Ernst%2C+1834-1919.+Anthropogenie%2C+oder%2C+Entwickelungsgeschichte+des+menschen Images from ''Anthropogenie, oder, Entwickelungsgeschichte des menschen'']
* {{Gutenberg author |id=2037| name=Ernst Haeckel}}
* {{Internet Archive author |sname=Ernst Heinrich Philipp August Haeckel}}
* {{Librivox author |id=3578}}
* {{PM20|FID=pe/006881}}
* [http://www.openscience.fr/Ernst-Haeckel-s-Radiolarians-and-Medusa-The-influence-of-his-visits-to?lang=en Ernst Haeckel's Radiolarians and Medusa] – article on Haeckel in Villefranche-sur-Mer
{{natural history}}
{{philosophy of religion}}

{{Authority control}}

{{DEFAULTSORT:Haeckel, Ernst}}
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