Why are Haeckel's drawings being taught in school?

I don't think that many evolutionary biologists use this term either. I work in the field of embryology and we always talk about the pharyngeal arches or branchial arches in animals that do show gills, such as in developing tadpoles.What is entirely true is that both fish and human embryos have pharyngeal pouches which go on in fish to form the gills and in humans to form a number of craniofacial tissues, elements of the ear, the parathyroid and thymus. Presumably then you would want all instances of Bohr's atom to be removed from physics and chemistry textbooks. If you intend to remove all simplifications and generalisations in educational textbooks then you are going to have a hell of a job.It might also help if you could substantiate your claim that Baer's observations of general features developing in common at a particular stage and then diverging as development progresses is false. It is certainly true that early stages are also highly divergent but this doesn't show that there is no stage where there are such common feature, although there is evidence to show that there is no single chracteristic 'phylotypic' stage. Maybe you should take a look at some of the comprehensive embryological studies that have been done recently and with considerably more sophisticated techniques than were available 100 years ago. Arguably the whole field of evolutionary developmental biology (evo-devo) is an ongoing elaboration of exactly the sort of study you are describing.I would recommend you to read some of the research by Richardson which has gone in some detail into the discrepancies between actual development and Haeckel's drawings as well as showing a number of problems with an assumption of the existences of a true typical phylotypic stage. Some of Richardson's papers are freely available online. TTFN,WK

I think one problem here is in the idea of Haeckel's drawings being 'source material' for illustrations in textbooks. A figure which is 'after' or based upon a previous figure by someone else can be substantially different from the original.So a figure 'after' Haeckel's might be a replicate in layout but with anatomical data derived from fresh observations, similarly it might simply be a picture with some additional colouration, such as you suggested was the case in another instance.Perhaps one reason that the fakery of Haeckel's drawing is so frequently 'rediscovered' is that there are so many different things wrong with Haeckel's figure. The exact flaws noted by Haeckel's contemporaries may differ from the specific issues Richardson addresses, such as the period of development of the pharyngeal pouches in the chick.Indeed Richardson himself has some good things to say about Haeckel in a letter to Science. TTFN,WKThis message has been edited by Wounded King, 06-23-2005 07:16 AM

ARN provides a list of the textbooks that Jonathan Wells has evaluated on his own idosyncratic criteria. 8 of those either use Haeckel's drawings or a re-drawn illustration along similar lines. Of course this doesn't tell us what the context is so I can't say whether any of these texts present the pictures as 'fact' and certainly not as a 'fact' supporting Haeckel's theories.TTFN,WK

Here is the problem, the critics you quote have as poor a concept of the principles involved as you do.The point of a structure being homologous is not that it evolved from whichever structure it is homologous to but that they both evolved from a common ancestral structure. Therefore the human arm and bird wing are considered homologous both being thought to derive from the ancestral tetrapod limb.Do you have absoloutely any credible source that agrees with your quotes claim that a gill is essentially just a 'tap' rather than a 'pump that constantly monitors the chemical composition of the water'. On the opposing hand we have a number of references. Which shows that the gills can both extract calicum and export it. Which details a number of ion pumping activites in the gills.You could always read the original research article upon which the Pharyngula piece was based (Okabe and Graham,2004).Why on Earth do you credit the 'factual' claims of the people at Darwin-Watch?TTFN,WKThis message has been edited by Wounded King, 07-04-2005 09:04 AM

Have you looked? You could have got all this, and the relevant references, just from actually reading the original paper. If you had actually read the Okabe and Graham (2004) paper, and I can't think why you haven't since it is freely available, you would have found out that they not only look at Gcm2 but also at the expression of two zebrafish homologues of parathyroid hormone and a gene which encode a calcium level responsive receptor (CasR.While CasR isn't exclusive to the parathyroid gland it certainly shows a commonality of function between the parathyroid gland and the gills, especially when coupled with the production of parathyroid hormone.TTFN,WK

Perhaps because that is a ludicrously vague request. This could easily encompass every single evo-devo paper published in the last 20 years. Do you understand anything about either biology or science in general?Do you have any evidence at all that Gcm2 is required for salt regulation? What the paper shows is that Gcm2 is required for the development of the gills in the same way that it is required for the dvelopment of the parathyroid. It does not suggest any functional role in salt regulation for Gcm2.Have you actually read this paper yet?Despite your pretensions to want a proper scientific discussion you seem totally unfamiliar with any research beyond the pre-digested rubbish you are scraping from creationist web sites, i.e. Darwin-watch. The only paper you seemed to use to back up your argument about Haeckel is the Richardson reference, and you continuously overstate what that shows, and the only paper relevant to convergent evolution in DNA you ever came up with was the one that I gave to you. Apparently you do not know how to do a literature search. The work is ongoing, your complete unfamiliarity with it reflects badly on you, not the amount of research.TTFN,WK

The NCSE has handily sollated all of the figures Wells references. They are Figure 10 in the 'Haeckel's Embryos' page in their discussion of Wells' 'Icons of Evolution'. Only 3 of those diagrams could tenably be said to be substantially based on Haeckel's and in at least 2 of those cases, Futuyma and Guttman, the diagrams are used in a clearly historical context.Sadly I doubt that Randman has looked at what any of these books actually say.TTFN,WKThis message has been edited by Wounded King, 07-07-2005 06:20 PMThis message has been edited by AdminJar, 07-07-2005 06:33 PM

You know, I'm starting to come around to Randman's way of thinking, but I have found a much more egregious and long standing problem.Forget 'Gill slits', what we really need to get rid of is the 'Adam's Apple'. This scurrilous creationist propaganda has been common usage for far too long and is pervasiv in any number of medical and anatomical textbooks.Not only is this not an actual 'Apple', as creationists persistently claim by their very use of the term, but they then further compound their crimes by trying to tie their misrepresentations of anatomy into their contrived account of man's origins.TTFN,WKP.S. Did you ever consider that some aspects of terminology have a historical basis which doesn't neccessarily match the current state of knowledge about their function?

Now that is just a downright stupid argument. My brain and yours both contain DNA of 2 different organisms, therefore you don't have a brain. Does that sound like a sensible argument? Presumably Fish don't have brains either due to not having the same DNA as me.They may not have exactly the same DNA but they share an astonishingly large amount which also happens to share an astonishing degree of functional similarity to those seen in the development of other organisms.Why don't you stop just stating ridiculous arguments and start providing some evidence. Instead of calling on us to provide more and more common markers why not come up with some unique markers which are found in the branchial arches of fish but not in the mammalian pharyngeal arches. At the moment you seem to have a complete inability to do actual research and a total failure to be able to even read the references which are handed to you on a plate.At the moment you have nothing other than the somewhat bizarre claim that just because they are a 'biomechanical fold' which occurs in a similar position in a number of different developing embryos the structures are not therefore homologous. Using a similarity to suggest that these structures are disimilar just seems ass-backwards.TTFN,WKThis message has been edited by Wounded King, 07-08-2005 02:39 AM

These ridges do develop into those structures, and they develop into the craniofacial structures, elements of the endocrine system and jaw bones in fish as well, what do you know, another similarity.Do you just want us to change the name? Oh wait, biologists already mostly use branchial and pharyngeal so I guess we already did. You mean apart from the way that the structures in fish and amphibians which express many of the same specific molecular markers and give rise to the same tissues go on to give rise to gills, temporarily in the case of most amphibians. There is actually a lot of research out there about this, why not show us you can actually do some and provide some references for it yourself.TTFN,WK

So you want us to call them craniofacial-endocrineal-branchial arches instead in fish? Catchy name. Do you have any idea what you are talking about, because you don't seem to. And even when we tell you where you are mistaken you keep making the same mistakes. I already pointed out previously that they are correctly called pharyngeal throughout the vertebrates, at least for any organism with a pharynx, and branchial in organisms, such as fish and amphibia, in which there are gills either transiently or permanently.TTFN,WK

This just seems to be degenerating into an argument from semantic pedantry. If what you want is to expunge all historical terminology, over generalisations and simplifications from education then you have quite a task ahead. Are you going to get around to tackling Bohr's atom at all? In fact surely the very word atom should be removed since what we call 'atoms' can be divided and the word atom is rooted in the concept of indivisibility. Oh dear, the way the whole of nuclear physics is taught is false.TTFN,WK