Does Ontogeny Recapitulate Phylogeny?

Hi crash.As Chiro pointed out, Haeckel's strong claim, which he stated as the "Biogenetic Law", is that phylogentically new traits are "added" to the ancestral version. IOW, that during development an individual embryo successively passes through all the adult forms of its ancestors - from the origin of a single cell to the modern organism. This was quite patently wrong, and even at the end of the 19th Century it was being called (loudly) into question. The only bit that remains valid is the observation that most vertebrate classes share many common features really early in development. Things start to diverge fairly quickly however. The other major problem with Haeckel was that he appears to have over-emphasized certain traits in his famous drawings that were not valid in order to prove his point. (Well, that and the fact that later he founded Monism, which says a lot about the person, although nothing about the "law" itself). I don't think anyone is derisive of him beyond that - except for creationists - and he stimulated a great deal of new research, which is a good thing for science. I think overall he advanced the field, but was mostly wrong.

If I understand what you're asking, then my answer would be "not really". I'm not up on evo-devo, focusing more on ecology and conservation biology (so much to read, so little time). I know that there are several major problems with the ontogeny recapitulates phylogeny thingy, especially in relation to plants (e.g., selfing), heterochrony and paedomorphs (like some of the Ambystoma spp). IOW, the Biogenetic Law doesn't hold very often - if at all.In any event, IIRC Gould used hox to show that Goldschmitt might have been on to something, not Haeckel.