Haeckel had fudged his drawings to make the early stages of embryos appear more alike than they actually are! As it turns out, Haeckel's contemporaries had spotted the fraud during his lifetime, and got him to admit it.
Science overlooked and neglected them for 129 years, but now with a single sentence from you, all is made clear. Ontogeny once again recapitulates phylogeny
Aren't these too statements contradictory? Either scientists did spot the mistake during Haeckel's own lifetime and got him to admit it, or they neglected it for 129 years... I mean, one could imagine that Haeckel lived for more than 129 years after publishing the drawings, but that seems like the only way to reconcile the two...
By the way,
here is a summary of the actual paper (you can found it
here, as usual, creationists are over selling it.
aeckel (1874) had claimed that members of all vertebrate classes pass through an identical evolutionarily conserved "phylotypic" stage. Until this new paper appeared, it was assumed that Haeckel was correct and that there was a particular stage of development that was identical in all vertebrates. Only later in development would specific differences appear. Interestingly, there was some discussion as to what exactly this stage was (Richardson 1995). This conserved stage was sometimes considered the neurula stage (Wolpert 1991), the "pharyngula" stage (characterized by the branchial arches; Ballard 1981), the tailbud stage (Slack et al. 1993), or the stages between those of headfold and tailbud (Duboule 1994).
And
But Haeckel's drawings are wrong. Photographing actual embryos at these stages, Richardson and colleagues show that Haeckel's drawings are oversimplified to the point of obscuring important differences between classes of vertebrates. The Richardson et al. paper does not dispute that there is a highly conserved embryonic stage among the vertebrate classes. Indeed, at the late tailbud stage, vertebrate embryos of most all classes possess "somites, neural tube, optic anlagen, notochord, and pharyngeal pouches." However, these authors do criticise the notion that this stage is nearly identical in all species and that differences between the classes can be resolved only after subsequent development.
So, to summarize, while the general theory had long been rejected, one of Haeckel's observations, that the embryo's early stages are almost identical, was still seen as valid (it actually supported a older, less ambitious, law called 'Von Baer's laws that are still considered valid).
Now, the question is when do the developmental pathways diverge? While not uncontested Haeckel's suggestion, that the divergence occurred after the tailbud stage, was generally accepted.
Now, it seems like these suggestion was based on over-simplified drawing that blurred out some difference and it is suggested that the difference actually occur earlier than that...
Fair enough, I say, but hardly as fundamental a shakedown that implied...
By the way, the article also explained the surprising resilience of Haeckel's drawings:
First, Haeckel's illustration was reproduced in Romane's (1901) Darwin and After Darwin. From here, the illustration entered Anglophone biology, "sanitized" from Haeckel. Second, the picture can be used (as it has been in several developmental biology books) to illustrate von Baer's principles rather than Haeckel's biogenetic law. K. E. von Baer had noted that the general features of a large group of animals appear earlier in the embryo than do the specialized features.
By the way, somewhat ironically, von Baer was opposed to 'transformationism'.
By the way, I also found this quote from Darwin (
here):
It is not true that one passes through the form of a lower group, though no doubt fish are more nearly related to foetal state
.
While this assay pre-date the formulation of Haeckel's theory, we can see that Darwin had already examined and rejected its core idea...
