Ernst Haeckel's embryological diagrams and biology textbooks

[randman]

So you claim Richardson did not say evos accepted the concept of the phylotypic stage based on Haeckel's data?

How many times do I need to quote you his 1997 paper before you will accept that's what he wrote?

Some authors have suggested that members of most or all vertebrate clades pass through a virtually identical, conserved stage. This idea was promoted by Haeckel, and has recently been re- vived in the context of claims regarding the universality of developmental mechanisms. Thus embryonic resem- blance at the tailbud stage has been linked with a con- served pattern of developmental gene expression – the zootype. Haeckel’s drawings of the external morphology of various vertebrates remain the most comprehensive comparative data purporting to show a conserved stage.

Contrary to recent claims that all vertebrate embryos pass through a stage when they are the same size, we find a greater than 10-fold variation in greatest length at the tailbud stage. Our sur- vey seriously undermines the credibility of Haeckel’s drawings, which depict not a conserved stage for verte- brates, but a stylised amniote embryo. In fact, the taxo- nomic level of greatest resemblance among vertebrate embryos is below the subphylum. The wide variation in morphology among vertebrate embryos is difficult to reconcile with the idea of a phyogenetically-conserved tailbud stage, and suggests that at least some develop- mental mechanisms are not highly constrained by the zootype.

One puzzling feature of the debate in this field is that while many authors have written of a conserved embry- onic stage, no one has cited any comparative data in sup- port of the idea. It is almost as though the phylotypic stage is regarded as a biological concept for which no proof is needed.

Our aim in this paper is to examine the idea that em- bryos from all or most vertebrate clades pass through a highly conserved stage; and that at this stage their exter- nal form is virtually identical. Haeckel’s drawings of em- bryos at tailbud stages are widely used in support of this hypothesis.

Another point to emerge from this study is the considerable inaccuracy of Haeckel’s famous figures. These drawings are still widely reproduced in textbooks and review articles, and continue to exert a significant influence on the development of ideas in this field

http://www.oeb.harvard.edu/faculty/...uments/Richardson et al 1997 Anat Embryol.pdf

 

[RandFan]

Yes, it's totally wrong.

TOTALY! Just look at the drawings side by side with the photos. Do you see any similarities? Oh, you do? Okay, look closer. Do you see any differences? Okay, a few. Yeah, that's what I mean by TOTALY!

 

[RandFan]

So you claim Richardson did not say evos accepted the concept of the phylotypic stage based on Haeckel's data?

Why does Richardson represent the end all of everything Haeckel? After all of this research, analysis and critique, did Richardson become a creationist?

 

[A'isha]

So you claim Richardson did not say evos accepted the concept of the phylotypic stage based on Haeckel's data?

How many times do I need to quote you his 1997 paper before you will accept that's what he wrote?http://www.oeb.harvard.edu/faculty/...uments/Richardson et al 1997 Anat Embryol.pdf

Because you're ignoring not just what else he wrote in his 1997 paper, but what the scientists in the papers he references wrote. Haeckel was just one source among many used by scientists. Huettner's 1943 "Fundamentals of comparative embryology of the vertebrates", and Rugh's 1964 "Vertebrate embryology: the Dynamics of Development", as well as the individual direct studies made by scientists like Raff all of which used either photographs of embryos, highly detailed drawings that were done long after Haeckel died, or molecular genetics.

Richardson's criticism was that these other sources of data focused on comparing too few animals (for instance, Huettner focused on only frog, chick, and human embryos, albeit in exhaustive detail, while Raff compared closely related species of sea urchins). He thinks that this focus has left the question of whether there are similarities across a much, much wider array o species is an open one, since while Huettner's work clearly shows a similarity between the three species he studied, and Raff's work shows a similarity across the species he studied, at the time of Richardson's paper the only data set that laid out many, many different species out side-by-side was Haeckel's.

So, it's not that the basic idea of the phylotpyic stage or vertebrate similarity in general relied on Haeckel, it's that the known and proven similarities between a smaller array of species was extrapolated out to the wider array based solely on that smaller data. Richardson's whole point was to say "Hey, if you other scientists want to prove that extrapolation has merit, you're gonna have to show some work other than Haeckel's drawings, since his doesn't cut the mustard by virtue of being both inaccurate and incomplete."

And, science being science, evolutionists gladly turned to other data that had nothing to do with Haeckel, such as the two studies in the 2000's that I linked you to.

 

[shadron]

No its partly wrong. Incorrect though some of his ideas were his basic premise that embryos go through a process that reflects the evolutionary process is correct.

Haeckel believed that you could see all the steps that evolution had taken by watching the growing zygote. That is why he had this "thing" about seeing tetrapods all start out as if they were fish embryos. The modern idea says that it doesn't follow that evolution is being replayed in development; rather, that the effects of a mutation occurs in that stage of development which happens to be appropriate for the change, where it must necessarily occur because the development is ripe. Sometimes it is that they happen in somewhat the same sequence as evolution occurred, as the tissues that change reach an optimal stage for transference to their new task; at other times they happen when one would not expect it, but where the random mutation dictated it must.

An example would be the human hairlessness. Had the mutation actually been a total loss of hair, that could appropriately be expressed by simply never developing any hair or hair follicles at all. For humans, it isn't total hair loss, but rather a mutation that makes hair grow much shorter than usual over most of the body. This could only occur after follicles are developed; as it happens, fetuses put on a coat of hair that is later lost, thereby "recapitulating phylogeny" (or better, morphology) but only accidentally. Had the mutation been one that deleted follicles, no such appearance would be possible.

 

[Cainkane1]

Haeckel believed that you could see all the steps that evolution had taken by watching the growing zygote. That is why he had this "thing" about seeing tetrapods all start out as if they were fish embryos. The modern idea says that it doesn't follow that evolution is being replayed in development; rather, that the effects of a mutation occurs in that stage of development which happens to be appropriate for the change, where it must necessarily occur because the development is ripe. Sometimes it is that they happen in somewhat the same sequence as evolution occurred, as the tissues that change reach an optimal stage for transference to their new task; at other times they happen when one would not expect it, but where the random mutation dictated it must.

An example would be the human hairlessness. Had the mutation actually been a total loss of hair, that could appropriately be expressed by simply never developing any hair or hair follicles at all. For humans, it isn't total hair loss, but rather a mutation that makes hair grow much shorter than usual over most of the body. This could only occur after follicles are developed; as it happens, fetuses put on a coat of hair that is later lost, thereby "recapitulating phylogeny" (or better, morphology) but only accidentally. Had the mutation been one that deleted follicles, no such appearance would be possible.

So apparently Haeckel is partly right. His theory is only partly discredited because I've read that developing embryos do go through what appear to be evolutionary stages. On the whole I'd rather read what Haeckel has to say than read why some Ider has to say errors and all. I'm sure hes more accurate than Kent Hovind.

 

[randman]

His theory is only partly discredited because I've read that developing embryos do go through what appear to be evolutionary stages.

Except what you read is wrong. They do not go through the proposed past evolutionary stages.

 

[RandFan]

Except what you read is wrong. They do not go through the proposed past evolutionary stages.

Except when they do.

 

[A'isha]

So apparently Haeckel is partly right. His theory is only partly discredited because I've read that developing embryos do go through what appear to be evolutionary stages. On the whole I'd rather read what Haeckel has to say than read why some Ider has to say errors and all. I'm sure hes more accurate than Kent Hovind.

I recommend Stephen Jay Gould's 1977 book on the topic, Ontogeny and Phylogeny. It's slightly dated, since it predates the modern resurgence in comparative embryology, but it does cover the whole topic, and even discusses Haeckel in historical perspective regarding the topic.

The Stephen Jay Gould archive even has it online.

 

[pakeha]

Oh, randman, what a muddle you're in!
You don't seem to understand your quotes mean the opposite of what you say they do.
You shift goal posts and here's the latest example.
I'll use that tacky yellow hiliting because it'll make things things very clear.
First, you launch into your usual ill-mannered attacks to daunt the readers here.
And a question- what do you think people reading here for the first time react to your vugarity and bad manners?

Wrong. Do you actually know what Haeckel was actually trying to show or are you just taking evos word for it?

Here's a hint for you. Do any of Haeckel's depictions of embryos actually look like adult forms fully formed? Was he not basically showing embryos reflect their evolutionary history and faked the data to push that idea?

Haeckel specifically tried to show all embryos pass through a phylotypic stage, something evos are still claiming in many instances, often using Haeckel's faked data.

In this followin post we see the shifted goalposts, with the usual bad mannered outburst

So you claim Richardson did not say evos accepted the concept of the phylotypic stage based on Haeckel's data?
How many times do I need to quote you his 1997 paper before you will accept that's what he wrote? ...

It's really a pointer to the lack of any basis to your arguments you do that sort of thing.
And frankly lamentable you somehow imagine you can argue here that

... evos accepted the concept of the phylotypic stage based on Haeckel's data...

 

[RandFan]

Those lying theiving conspiracy evolutionists:

Wells and Haeckel's Embryos

In the case of Haeckel, though, I have to begin by admitting that Wells has got the core of the story right. Haeckel was wrong. His theory was invalid, some of his drawings were faked, and he willfully over-interpreted the data to prop up a false thesis. Furthermore, he was influential, both in the sciences and the popular press; his theory still gets echoed in the latter today. Wells is also correct in criticizing textbook authors for perpetuating Haeckel's infamous diagram without commenting on its inaccuracies or the way it was misused to support a falsified theory.

Wait, that doesn't make any sense, randman says evolutionists don't do that. ???

 

[randman]

Those lying theiving conspiracy evolutionists:

Wait, that doesn't make any sense, randman says evolutionists don't do that. ???

Wells is a creationist and IDer, randfan.

 

[RandFan]

Wells is a creationist and IDer, randfan.

Here's a hint, PZ Meyers ISN'T! Meyers is an evolutionary, developmental biologist with much more brain power and ever so much better credentials than you will ever dream of. Do you even have a degree in biology?

Did you even bother to follow the link?

Pharyngula PZ Meyers

 

[Lowpro]

Wells is a creationist and IDer, randfan.

Wells also misrepresented data for his claim. He was a liar and a fraud as much as Haeckel was. We can play this game the other way if you care to...

 

[randman]

Wells also misrepresented data for his claim. He was a liar and a fraud as much as Haeckel was. We can play this game the other way if you care to...

No, he didn't. You guys just made up a bunch of misinformation and deception like you did with Haeckel to try to smear him.

 

[randman]

Here's a hint, PZ Meyers ISN'T! Meyers is an evolutionary, developmental biologist with much more brain power and ever so much better credentials than you will ever dream of. Do you even have a degree in biology?

Did you even bother to follow the link?

Pharyngula PZ Meyers

I've read it before. Haeckel was way smarter than PZ and yet Haeckel promoted a bunch of bs as well.

 

[Lowpro]

No, he didn't. You guys just made up a bunch of misinformation and deception like you did with Haeckel to try to smear him.

No*:

Wells is particularly incensed at the authors of introductory textbooks who, he claims, are misleading their students. I agree that he can reasonably argue that textbooks should not use the obsolete and inaccurate drawings done after Haeckel's work, but, in what I consider the most amusing line in this entire chapter, Wells expresses indignation that "Some textbooks, instead of reproducing or redrawing Haeckel's embryos, use actual photos." How dare those nefarious textbook authors use photographic data to support their ideas!

In his first appendix, Wells rates a number of college textbooks, giving them letter grades for how well their ideas fit with his. All the books get either a D or an F for their handling of vertebrate embryos. However, it is obvious that he is stacking the deck against them.

To get an F, a textbook needs only to use a version of Haeckel's drawings, claim that early similarities in vertebrate embryos are evidence for common ancestry, and refer to gill slits. I agree that books should not use Haeckel's illustrations, unless it is to make a historical point. However, similarities in structure are evidence for common ancestry; it's a little unfair to penalize a book for making a valid point. Similarly, vertebrate embryos do have "gill slits", even if the associations of that term confuse Dr. Wells.

To improve their grade to a D, a book uses "misleading photographs" of real embryos instead of the Haeckelian drawings. Again, however, what is the objection here? These aren't fudged or inaccurate drawings. They are photographs of vertebrate embryos that accurately illustrate what they look like, that anyone with a microscope and access to embryos can see (Figure 3). Is it next on his agenda to condemn classes that allow students to examine live or preserved embryos in the laboratory?

What does a textbook have to do to get an A? First, it may not use misleading drawings or photos. Wells has not shown that the photos used in any of these books are misleading at all. Second, it should not use the term "gill slit". This is a capricious requirement; there is nothing categorically wrong with that particular term.

Feel free to read that over, but if Wells is going to pass of this crap he's a devious liar who misrepresents textbooks and evolution theory in general. Don't need us to smear him when he gave himself enough rope to hang himself with, just like you are randman


*to be fair this is part of a MUCH larger article http://www.talkorigins.org/faqs/wells/haeckel.html which you should read in its entirety so as to grasp overall context of the article.

 

[Lowpro]

I've read it before. Haeckel was way smarter than PZ and yet Haeckel promoted a bunch of bs as well.

So are you saying PZ was less intelligent but still correct? You haven't refuted the claims that RandFan quoted against your argument...

 

[randman]

Haeckel believed that you could see all the steps that evolution had taken by watching the growing zygote. That is why he had this "thing" about seeing tetrapods all start out as if they were fish embryos. The modern idea says that it doesn't follow that evolution is being replayed in development; rather, that the effects of a mutation occurs in that stage of development which happens to be appropriate for the change, where it must necessarily occur because the development is ripe. Sometimes it is that they happen in somewhat the same sequence as evolution occurred, as the tissues that change reach an optimal stage for transference to their new task; at other times they happen when one would not expect it, but where the random mutation dictated it must.

An example would be the human hairlessness. Had the mutation actually been a total loss of hair, that could appropriately be expressed by simply never developing any hair or hair follicles at all. For humans, it isn't total hair loss, but rather a mutation that makes hair grow much shorter than usual over most of the body. This could only occur after follicles are developed; as it happens, fetuses put on a coat of hair that is later lost, thereby "recapitulating phylogeny" (or better, morphology) but only accidentally. Had the mutation been one that deleted follicles, no such appearance would be possible.

Don't humans have hair pretty much all over their bodies except the palms of their hands and soles of their feet? The fact embryos develop follicles and hair, even a coat of hair, just means they develop a coat of hair which they shed as part of the process of development.

There are all sorts of details about people and animals. Cherry-picking the similarities while minimizing the differences in order to overstate that the data does and does not say is par for the course with evos.

 

[Lowpro]

Don't humans have hair pretty much all over their bodies except the palms of their hands and soles of their feet? The fact embryos develop follicles and hair, even a coat of hair, just means they develop a coat of hair which they shed as part of the process of development.

There are all sorts of details about people and animals. Cherry-picking the similarities while minimizing the differences in order to overstate that the data does and does not say is par for the course with evos.

OH I get it now, the reason you don't like evolution is that you don't understand the fundamentals of evolution and development. I thought as much...

No one's minimizing the difference, they're explaining why they exist in the first place (Something ID fails out the door to attempt...) minimize my ass you're just misrepresenting the discipline. There is no cherrypicking for evolution randman.