Editing Recapitulation theory (section)

=== Contemporary criticism ===
[[File:Wilhelm His chick brain compared to folded rubber tube.jpg|thumb|upright=1.3|Drawing by [[Wilhelm His Sr.|Wilhelm His]] of chick brain compared to folded rubber tube, 1874. Ag (Anlage) = [[Midbrain#Corpora quadrigemina|Optic lobes]], matching bulges in rubber tube.]]

Haeckel's theory and drawings were criticised by his contemporary, the anatomist [[Wilhelm His Sr.]] (1831–1904), who had developed a rival "causal-mechanical theory" of human embryonic development.<ref>{{cite web | title= Making visible embryos: Forgery charges | url= http://www.hps.cam.ac.uk/visibleembryos/s4_2.html | publisher= University of Cambridge | access-date= 27 October 2016| quote= Rütimeyer's ex-colleague, Wilhelm His, who had developed a rival, physiological embryology, which looked, not to the evolutionary past, but to bending and folding forces in the present. He now repeated and amplified the charges, and lay enemies used them to discredit the most prominent Darwinist. But Haeckel argued that his figures were schematics, not intended to be exact. They stayed in his books and were widely copied, but still attract controversy today.}}</ref><ref>{{Cite web | title= Wilhelm His, Sr | publisher= Embryo Project Encyclopedia | year= 2007 | access-date= 27 October 2016 | url= http://embryo.asu.edu/pages/wilhelm-his-sr-1831-1904 | quote= In 1874 His published his ''Über die Bildung des Lachsembryos'', an interpretation of vertebrate embryonic development. After this publication His arrived at another interpretation of the development of embryos: the concrescence theory, which claimed that at the beginning of development only the simple form of the head lies in the embryonic disk and that the axial portions of the body emerge only later.}}</ref> <!--Wilhelm -->His<!--anatomist-->'s work specifically criticised Haeckel's methodology, arguing that the shapes of embryos were caused most immediately by mechanical pressures resulting from local differences in growth. These differences were, in turn, caused by "heredity". <!--Wilhelm -->He<!-- anatomist--> compared the shapes of embryonic structures to those of rubber tubes that could be slit and bent, illustrating these comparisons with accurate drawings. [[Stephen Jay Gould]] noted in his 1977 book ''Ontogeny and Phylogeny'' that His's attack on Haeckel's recapitulation theory was far more fundamental than that of any empirical critic, as it effectively stated that Haeckel's "biogenetic law" was irrelevant.{{sfn|Gould|1977|pp=[https://archive.org/details/ontogenyphylogen00goul/page/189 189–193] |ps=: "Haeckel sensed correctly that His was a far more serious competitor than his empirical critics... His would have substituted a drastically different approach and relegated the biogenetic law to irrelevancy—a fate far worse and far more irrevocable than any odor of inaccuracy."}}<ref>{{cite journal |author= Ray, R. S. |author2=Dymecki, S. M. |title= Rautenlippe Redux -- toward a unified view of the precerebellar rhombic lip |journal= Current Opinion in Cell Biology |volume= 21 |issue= 6 |pages= 741–7 |date= December 2009 |pmid = 19883998 |pmc= 3729404 |doi= 10.1016/j.ceb.2009.10.003}}</ref>

[[File:Haeckel vs von Baer.svg|thumb|upright=2.0|Embryology theories of [[Ernst Haeckel]] and [[Karl Ernst von Baer]] compared]]

Darwin proposed that embryos resembled each other since they shared a common ancestor, which presumably had a similar embryo, but that development did not necessarily recapitulate phylogeny: he saw no reason to suppose that an embryo at any stage resembled an adult of any ancestor. Darwin supposed further that embryos were subject to less intense selection pressure than adults, and had therefore changed less.<ref>{{cite web |last1= Barnes |first1= M. Elizabeth |title= The Origin of Species: "Chapter Thirteen: Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs" (1859), by Charles R. Darwin |website= The Embryo Project Encyclopedia |url= https://embryo.asu.edu/pages/origin-species-chapter-thirteen-mutual-affinities-organic-beings-morphology-embryology |access-date= 18 April 2016}}</ref>