Haeckel in Biology Textbooks

Was there any particular criterion for the choices of stages there?All the chick ones are within about a day of each other while the mouse stages cover almost a week. The chick numbers aren't days, a day 15+ chick embryo is practically hatched. Hamburger Hamilton stage 15, Hamburger Hamilton (HH) is the standard staging system for chicken development, is about 2-3 days worth of post fertilisation development.If you took later human (Carnegie stage 14 maybe) and chick (say HH21) embryos they would also be very similar to the E10.5 mouse embryos.For anyone really interested in comparative development the full text of the seminal Hamburger and Hamilton paper on chick development is available online as a PDF as is Karl Theiler's work on the development of the mouse available here. The only online version of the original Carnegie staging paper, here, has very poor figure reproduction. You would probably be better with a more modern atlas of human development like the Multidimensional Human Embryo although for earlier stages the UNSW pages are better.TTFN,WKEdited by Wounded King, : No reason given.

I'll give it a shot when I get home from work, it has to be noted though there isn't really a 'same stage' here. You can choose specific criteria, such as somite number, but there are significant differences in the timing of a number of features making any 'same stage' call an educated guess at best. Its not that the embryos don't look similar but that specific features look most similar at different times in the development of each embryo.For a detailed analysis of this problem, specifically mentioning its context in terms of Haeckel's work, see Bininda-Edmonds et al.(2002). This paper is also interesting as the last author is Michael Richardson who is at the same time responsible for perhaps the most detailed scientific critique of Haeckel's work, in specific reference to fraudulent/misleading diagrams, and the best defense of the importance of Haeckel's work in general in the wider context of evo-devo.TTFN,WK

That was one of the paper's but the paper I originally referenced and several others by Richardson also make similar points.The PDF for that paper, and many others relevant to this subject including those previously referenced upthread, are still available through the wayback machine's cache of the old version of Richardson's site.A particularly relevant illustration which I don't think has been linked to yet is Richardson's alternative embryo series illustration set out like Haeckels but with micrographs instead of drawings. Sadly that one doesn't have the mouse on it. TTFN,WKP.S. Haven't got around to that diagram yet, sorry folks.Edited by Wounded King, : No reason given.Edited by Admin, : Reduce image width.

Yes, they are yolk sacs. Hmm, I disagree, but I've probably looked at more embryos, human or otherwise. Do you still find this the case with the hi-res version? They are certainly extremely contrasty, the large pools of black look like shadows in most cases but I'm not sure where they are all coming from. One problem is that the human embryos are probably smaller than most of the other ones so the resolution in the original image was probably poorer. Were you confused by the extraembryonic tissues still present in the top row? They are the stuff that looks like a triangular spray of tissue coming from the middle of the embryo.TTFN,WK