Ernst Haeckel

61

Ernst Haeckel : biography

16 February 1834 – 9 August 1919

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. "Ernst Haeckel and the Struggles over Evolution and Religion" Robert J. Richards Annals of the History and Philosophy of Biology, Vol. 10 (2005): 89–115 Recent analyses (Richardson 1998, Richardson and Keuck 2002) have found that some of the criticisms of Haeckel’s embryo drawings were legitimate, but others were unfounded.Michael K. Richardson. 1998. "Haeckel’s embryos continued." Science 281:1289, quoted in NaturalScience.com webpage : A Letter from Richard Bassetti; Editor’s note."While some criticisms of the drawings are legitimate, others are more tenditious", Richardson and Keuck "Haeckel’s ABC of evolution and development", Biol. Rev. (2002), 77, pp. 495–528. Quoted from p. 495. 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.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 & 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. Robert J. Richards, in a paper published in 2008, defends the case for Haeckel, shedding doubt against the fraud accusations with base on the material used for comparison and what Haeckel could access at the time."Haeckel’s embryos: fraud not proven",Robert J. Richards, Biol Philos (2009) 24:147–154 DOI 10.1007/s10539-008-9140-z The controversy involves several different issues (see more details at: recapitulation theory).

Notes

Research

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 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 microorganisms that have never been found.

He was one of the first to consider psychology as a branch of physiology. He also proposed many now ubiquitous terms including "anthropogeny", "phylum", "phylogeny", "ecology" ("oekologie"), and proposed the kingdom Protista 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 a Lamarckian inheritance of acquired characteristics (Lamarckism).Ruse, M. 1979. The Darwinian Revolution. Chicago: University of Chicago Press.

Haeckel advanced a version of the earlier "recapitulation theory", previously set out by Étienne Serres in the 1820s and supported by followers of Geoffroy including Robert Edmond Grant, which 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 first advanced by Karl Ernst von Baer. "Strong" recapitulation hypothesis views ontogeny as repeating forms of the ancestors, while "weak" recapitulation means that what is repeated (and built upon) is the ancestral embryonic development process.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)" He 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. Haeckel introduced the concept of "heterochrony", which is the change in timing of embryonic development over the course of evolution.