Luskin, Haeckel, Richardson, Richards

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Like Napoleon on Saint Helena, good ol’ Casey Luskin is re-fighting old lost battles again (one, two)…

Former NCSE staff member Matzke co-writes that complaints about the use of Haeckel’s drawings is a “manufactured scandal.” 277 Not only are textbooks using inaccurate drawings, but they are using them to illustrate points that are highly disputed by leading embryologists. The earliest stages of vertebrate embryos are quite different and the existence of the cherry-picked conserved stage often portrayed in textbooks as evidence for common ancestry is being called into question.

To say the least, students who are taught that the earliest stages of vertebrate embryos are highly similar, without being told of significant embryological evidence that challenges that view and the very existence of the conserved developmental stage portrayed in many textbooks, are not being adequately informed about the evidence regarding evolution.

Hmm. First, Haeckel didn’t ignore the differences in embryos in the earliest period just after fertilization (differences which are visually significant but mostly fairly trivial, due to the different amounts of yolk in different vertebrate eggs) – in fact, Haeckel himself prominently diagrammed them, as I showed here back in 2006. Whoops! And such diagrams are standard in any book which gives a thorough treatment of vertebrate development, although this may not include the most absolutely introductory general biology texts.

Second, Luskin makes it out as if it’s me and NCSE against developmental biology experts like Michael Richardson (whom he quotes), and as if we ignored the textbooks that did have the classic Haeckel’s embryo drawings. But (as I find out when I go back to the 2006 article which Luskin quotes) actually, no, Richardson’s on our side, and we counted the textbooks that had the drawings – taking the numbers directly from Jonathan Wells, no less! Not good enough for Luskin.

For those who actually want to be fair-minded about it, it’s pretty clear that what happened was that in the mid-1990s, as happens every few decades, a scientist (here, Michael Richardson) discovered the real, but moderate, problems with Haeckel’s embryo drawings. This led to some some guns going off half-cocked in the media and in popular works (e.g. by Gould), and this is the stuff which Luskin cites. In the meantime, the originator of the latest wave, Richardson, learned some more about the complex history of the drawings and the even more complex history of claims and counterclaims about “scandal” by creationists – from Haeckel’s day to today – and published an updated version of his assessment. We quote the updated version, and Luskin quotes the more heated early reactions, pretending (despite knowing better) that the later assessments don’t exist. Oh well.

For a deep, and actually fair and contextual, assessment of Haeckel’s drawings, and the history of claims of scandal and debunkings of those claims, I cannot recommend enough Robert Richards’ recent biography of Haeckel, The Tragic Sense of Life.

Here’s what we wrote back in 2006 – it was part of an article assessing the junk that the ID guys had (temporarily) gotten into the Kansas Science standards: Matzke, N., and Gross, P. (2006). “Analyzing Critical Analysis: The Fallback Antievolutionist Strategy.” Chapter 2 of Not in Our Classrooms: Why Intelligent Design is Wrong for Our Schools. Scott, E., and Branch, G., eds., Beacon Press, pp. 28-56.

Haeckel’s embryo drawings

The Kansas Science Standards state,

[Common ancestry is called into doubt by] Studies that show animals follow different rather than identical early stages of embryological development.

This is a key claim from Jonathan Wells’s book Icons of Evolution. The argument is that evolution is said to be evidenced by embryological similarities as shown in Ernst Haeckel’s famous embryo drawings, but that Haeckel “faked” the drawings to make the embryos more similar than they actually are, and that this “fake evidence” for evolution is reproduced in textbooks for school use.

The facts: Haeckel did exaggerate similarities in very early embryos of different species, and his figures, or derivatives of them, have appeared in a few textbooks (3 of the 10 textbooks that Wells examined).18 But photographs of embryos show strong and unquestionable similarities. The embryos of reptiles, birds, and mammals all resemble one another other much more strongly than do the adult forms, exactly as Darwin noted in the Origin of Species. The similarities, moreover, are not just superficial. They involve most of the fundamental pathways and structures of embryogenesis. Darwin and Haeckel asked why such different adult forms should all be modifications of what amounts to the same embryological plan–if organisms were specially created, they could just as well each develop directly into the adult forms with no embryological resemblance and no cumbersome remodelings during late embryonic life. Michael Richardson, the specialist who, in an exhaustive critique of Haeckel’s work, re-examined all the drawings, observes:

On a fundamental level, Haeckel was correct: All vertebrates develop a similar body plan (consisting of notochord, body segments, pharyngeal pouches, and so forth). This shared developmental program reflects shared evolutionary history. It also fits with overwhelming recent evidence that development in different animals is controlled by common genetic mechanisms. 19

The cry of “fake” from Wells and friends is a completely manufactured scandal.

[…]

18 Alan D. Gishlick, “Icons of Evolution?” See especially Figure 8, comparing embryo photos, and Figure 10, comparing textbooks, at: http://www.ncseweb.org/icons/figures.html

19 Michael K. Richardson, James Hanken, Lynne Selwood, Glenda M. Wright, Robert J. Richards, Claude Pieau and Albert Raynaud (1998). “Letter.” Science 280(5366): 983. http://www.sciencemag.org/cgi/conte[…]80/5366/983c

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Of course, it was obvious that the Discovery Institute would get someone to blog about the responses that they’ve had to Casey Luskin’s recent posts about Haeckel’s embryos, but I never knew it would be such a vicious and personal att... Read More

78 Comments

MEEEEeeeeEEEEEeeeeeee .….

Somebody needs to invent a Luskito repellant.

Seems more like he’s tilting at windmills again.

Robin said:

Seems more like he’s tilting at windmills again.

Well, isn’t that creationism in a – OH so appropriate! – nutshell?

Whenever an anti-evolutions runs out of things to do, they decide to revisit the Haeckel thing again and see if anything’s changed. “Hmmm, yep! I still don’t like it! Better write a blog post!” It’s not like this is an ongoing series of developments (heh) or anything. They must spend a fortune on shovels to keep digging up that horse’s corpse like they do.
Maybe it’s a seasonal thing? Someone should go through the Disco ‘Tute’s archives and see if they always flog Haeckel’s embryos in the late Spring or something.

It is important to note that even if Herr Haeckel’s drawings were faked; hand-drawn sketches are not considered acceptable evidence in these days of digital microphotography. (Am I wrong about this? Is it still possible to get papers published in a peer-reviewed journal with sketches in your Materials & Methods section?) One 19th century biologist’s exaggerated drawings and his slight over-generalizations he inferred from them are not what evo-devo is about.

I’ve noticed they often do the same thing with Darwin and his belief in Lamarckian inheritance. They claim because Darwin was ignorant of the actual mechanisms of genetic transmission, this disproves natural selection and his other ideas as well.

This must be where the term heckler comes from. You know, to haeckle someone, to nitpick about the tiny details of their drawing ability for hundreds of years, even though the theory that they helped to develop has been totally vindicated by history.

Darwin was right. Haeckle was right. These guys just can’t stand it. They must concoct a conspiracy in order to explain why every real scientist has accepted the theory of evolution. Apparently they feel that the best way to do this is to completely ignore all of the evidence that actually convinced people and hope that others will do the same. Get in the lab, do some research, publish some results and quit whining. That is what real scientists do when they want to convince someone.

By the way, the term heckler actually derives from the textile industry, but these guys are once again apparently out to redefine the term. Maybe someone should point out to them the egregious errors that have persisted for decades in their own literature. I am certain that all inaccuracies would be immediately corrected. The probability of this happening is approximately equal to that of a protein spontaneously assembling from nothing. Tornado in a junkyard indeed!

It is important to note that even if Herr Haeckel’s drawings were faked; hand-drawn sketches are not considered acceptable evidence in these days of digital microphotography. (Am I wrong about this? Is it still possible to get papers published in a peer-reviewed journal with sketches in your Materials & Methods section?)

I don’t know about developmental biology, probably drawings aren’t used much in the research literature, but they are common in e.g. paleontology where the fossils are often in matrix, smushed, indistinct from the rock, or otherwise very difficult to photograph.

But diagrams are common throughout scientific textbooks of all sorts and rightly so. They are simplifications, and thus “inaccurate”, but the whole point of a textbook is to give the basics so someone can later on get the details. Such simplifications are always judgment calls, sometimes they can be criticized, sometimes they can be badly wrong, sometimes they can be fraud. Haeckel’s fall into the “they can be criticized” camp IMHO. It’s not like they are wild fantasies.

If AIG or CMI is one’s authority you might think that “Ontogeny recapitulates Phylogeny” (and the similarities of developmental forms in general) is a false concept long abandoned and dis-proven, and therefore cannot be included in any biology textbook or classroom today.

But such is not the case. Stephen Jay Gould wrote a 500 page tome, “Ontogeny and Phylogeny”* where he says in his opening sentence on page 1, “I am aware that I treat a subject currently unpopular.”

He continues, “I tell a colleague that I am writing a book about parallels between ontogeny and phylogeny. He takes me aside, makes sure that no one is looking, checks for bugging devices, and admits in markedly lowered voice: ‘You know, just between you, me, and that wall, I think there really is something to it after all.’ “

Because there is indeed something to it. It’s not a false concept. It just needs modification in light of what we know today about biology. And that’s what Gould did.

On page 213 he writes, “The embryonic features that we share with all vertebrates represent no previous adult state, only the unaltered identity of early development. Thought they do not allow us to trace the actual course of our descent in any way, they are full of evolutionary significance nonetheless; for, as Darwin argued, community of embryonic structure reveals community of descent.”

All you have to do is look at those photographs and you know he’s right.

*-Belknap Press of Harvard University Press, 1977

(PS-No one at AIG or CMI has the record of field work of Gould. No one at AIG or CMI has the scholarship to write an “Ontogeny and Phylogeny” like Gould. Yet they expect us to bow to their pronouncements.)

Luskin epitomizes the old saying:

“A lie repeated often enough…”

On page 213 he writes, “The embryonic features that we share with all vertebrates represent no previous adult state

…and this is the difference between our current understanding of how common descent exhibits itself in development vs. what Haeckel thought.

It’s quite a significant difference, and one the likes of Luskin constantly, though informed otherwise just as often, gloss over in their screeds.

In 1796, Dr. Samuel Hahnemann formulated a Law of Similars. This UTTERLY BOGUS “law” states that the cure for any disease will be found by consuming a substance that produces similar symptoms. “Like cures like.”

Hmmm, does that remind you of anything in modern science? Say, a certain program of “preventing” viral infection with an “attenuated” (might as well be “diluted”) virus?

Obviously, immunization is thoroughly phony, a science built on sand, the collective wishful thinking of people who don’t want to acknowledge the true, intellgent source of disease. Yet again and again, medical “scientists” insist on dredging up Hahnemann’s ghost. It’s not the eighteenth century, people!

I reckon the DI would make a great Sitcom. You’d call it “Gotta Love Luskin”. It would be a cross between “The Office” and “Hogan’s Heroes”

Lenoxus said:

Obviously, immunization is thoroughly phony, a science built on sand, the collective wishful thinking of people who don’t want to acknowledge the true, intellgent source of disease. Yet again and again, medical “scientists” insist on dredging up Hahnemann’s ghost. It’s not the eighteenth century, people!

Uh … this is a Loki troll, right?

It shouldn’t seem strange that there would be doubt. PT gets crazier than this on a daily basis.

Wheels said:

Whenever an anti-evolutions runs out of things to do, they decide to revisit the Haeckel thing again and see if anything’s changed. “Hmmm, yep! I still don’t like it! Better write a blog post!”

It’s either that, or the Peppered Moth: “SCIENTIFIC CRISIS! PEPPERED MOTHS DID NOT LAND ON TREE TRUNKS!”

MrG said: Uh … this is a Loki troll, right?

Poe’s Law: It’s not just for Religious Fundamentalism anymore!

Like Napoleon on Saint Helena, good ol’ Casey Luskin is re-fighting old lost battles again

That he is revisiting an issue from 2006 is a positive sign, people. Maybe it means we have seen the last of his blog posts about how Judge Jones was wrong in Dover in 2005.

But, don’t worry Casey forgives you!

Excuse a dumb but obvious question, but are Haeckel’s drawings actually still used in any currently assigned textbook?

but are Haeckel’s drawings actually still used in any currently assigned textbook?

probably, but if so, it will be because of one of two reasons:

-that school is using a horridly outdated text -the text is using it to illustrate an idea that has been discarded by science.

I believe this was also discussed at length on the various threads covering the subject here and on Pharyngula back in 2006-7, and specific texts containing the diagrams were listed there. A search would likely turn those threads up.

Was it here on PT or somewhere else that someone posted an article about the actual uses of the Haeckel drawings? I’m going from memory so please forgive if i”m not too accurate…

but out of 17 intro to biology books, only 4 or 5 actually discussed Haeckel, only 1 or 2 had his drawings and 1 of those mentioned that the drawings are now considered incomplete.

This will be rather mean, but I thought Michael Richardson was an ass the first time he “discovered” Haeckel.

And I would happily reiterate the recommendation of “The Tragic Sense of Life.”

Luskin is shriller and more persistent than a crowd full of vuvuzelas at a World Cup match.

True eventually the World Cup will be over.

All this gets tedious.

After 39 years of following creationism I have yet to find one creationist/ID argument which does not turn out to be false and often dishonest.

This ontogony/phylogony accusation dates back to creationists in the 60s

My working principle is that any creationist argument is wrong and I have yet to be proved wrong.

I cannot grasp the psychology of this, yet more and more Christians fall for this nonsense

I cannot grasp the psychology of this

I would suggest starting by studying the psychology of mental defense mechanisms, for one, and then how childhood learning patterns are reinforced.

It will immediately start to become clear what is going on.

or, you can jump forward to reading summary reviews like that which came out in Science a few years back:

http://www.sciencemag.org/cgi/conte[…]316/5827/996

that’s a gudun, and will contain any back-references you might need to review.

James F said:

Luskin is shriller and more persistent than a crowd full of vuvuzelas at a World Cup match.

And score more own-goals.

John Vanko said:

If AIG or CMI is one’s authority you might think that “Ontogeny recapitulates Phylogeny” (and the similarities of developmental forms in general) is a false concept long abandoned and dis-proven, and therefore cannot be included in any biology textbook or classroom today.

But such is not the case. Stephen Jay Gould wrote a 500 page tome, “Ontogeny and Phylogeny”* where he says in his opening sentence on page 1, “I am aware that I treat a subject currently unpopular.”

He continues, “I tell a colleague that I am writing a book about parallels between ontogeny and phylogeny. He takes me aside, makes sure that no one is looking, checks for bugging devices, and admits in markedly lowered voice: ‘You know, just between you, me, and that wall, I think there really is something to it after all.’ “

Because there is indeed something to it. It’s not a false concept. It just needs modification in light of what we know today about biology. And that’s what Gould did.

On page 213 he writes, “The embryonic features that we share with all vertebrates represent no previous adult state, only the unaltered identity of early development. Thought they do not allow us to trace the actual course of our descent in any way, they are full of evolutionary significance nonetheless; for, as Darwin argued, community of embryonic structure reveals community of descent.”

All you have to do is look at those photographs and you know he’s right.

*-Belknap Press of Harvard University Press, 1977

(PS-No one at AIG or CMI has the record of field work of Gould. No one at AIG or CMI has the scholarship to write an “Ontogeny and Phylogeny” like Gould. Yet they expect us to bow to their pronouncements.)

Isn’t that also the loud and clear message from Shubin’s Your Inner Fish?

What I have always “loved” about the embryo argument is that it makes the “Cambrian Explosion” argument ludicrous. The creos agree that most of the modern phyla arose at the Cambrian, knowing full well most people don’t understand the concept of phyla and think in terms of lions tigers & bears Oh My. people don’t understand that these early form bear little resemblance to the modern form and the only way scientists can make a statement like that is to use those pesky early embryonic characters that the creos claim are not indicative of common ancestry. Johnny Wells can’t have it both ways. either the embryological characters mean something and therefore we can state that the phyla arose at the Cambrian or they mean nothing and we have no idea if Pikaia is an early chordate or not.

Perish the thought:

Michael J said:

I reckon the DI would make a great Sitcom. You’d call it “Gotta Love Luskin”. It would be a cross between “The Office” and “Hogan’s Heroes”

On the other hand, wasn’t the DI featured recently on a “Doctor Who” episode describing the latest malfeasance of the Daleks?

Not exactly in the strict sense, since Shubin’s book could be subtitled “The Vestiges of Evolution”, since it does shout loud and clear as to how we, Homo sapiens, are the sum products of our phylogenetic (evolutionary) history, as reflected within our anatomy:

Rolf Aalberg said:

John Vanko said:

If AIG or CMI is one’s authority you might think that “Ontogeny recapitulates Phylogeny” (and the similarities of developmental forms in general) is a false concept long abandoned and dis-proven, and therefore cannot be included in any biology textbook or classroom today.

But such is not the case. Stephen Jay Gould wrote a 500 page tome, “Ontogeny and Phylogeny”* where he says in his opening sentence on page 1, “I am aware that I treat a subject currently unpopular.”

He continues, “I tell a colleague that I am writing a book about parallels between ontogeny and phylogeny. He takes me aside, makes sure that no one is looking, checks for bugging devices, and admits in markedly lowered voice: ‘You know, just between you, me, and that wall, I think there really is something to it after all.’ “

Because there is indeed something to it. It’s not a false concept. It just needs modification in light of what we know today about biology. And that’s what Gould did.

On page 213 he writes, “The embryonic features that we share with all vertebrates represent no previous adult state, only the unaltered identity of early development. Thought they do not allow us to trace the actual course of our descent in any way, they are full of evolutionary significance nonetheless; for, as Darwin argued, community of embryonic structure reveals community of descent.”

All you have to do is look at those photographs and you know he’s right.

*-Belknap Press of Harvard University Press, 1977

(PS-No one at AIG or CMI has the record of field work of Gould. No one at AIG or CMI has the scholarship to write an “Ontogeny and Phylogeny” like Gould. Yet they expect us to bow to their pronouncements.)

Isn’t that also the loud and clear message from Shubin’s Your Inner Fish?

Can’t wait for him to get himself a real job. Think he’d be perfect as a backup guitarist for the Katy Perry band, especially when they perform her new hit “California Gurls”:

James F said:

Luskin is shriller and more persistent than a crowd full of vuvuzelas at a World Cup match.

Shaka, when the walls fell.

The beast at Tanagra.

No matter where you go,

Sky at night, stars uncountable. Sleep.

raven said:

Whales are found with legs like their distant forebearers.

Legs? That’s overstating it isn’t it? Limbs in whales and limblessness in other vertebrates: mechanisms of evolutionary and developmental transformation and loss (pdf) clarifies the question.

kereng said: Luskin does not say that the original Haeckel diagram is used in textbooks or that they mention the name Haeckel. Please don’t attack a straw man.

On the contrary, Luskin is still claiming that the Haeckel drawings appear in modern textbooks. If you don’t think so, please give me an acceptable alternative interpretation of this sentence, from his June 17, 2010 EN&V post.
“I’ve come in for some fairly harsh attacks for making the simple observation that textbooks in use today, in arguing for evolution, still use Haeckel’s fraudulent embryo drawings to inaccurately portray the embryological evidence.”

Legs? That’s overstating it isn’t it?

I don’t see why it is overstating anything.

“Most of these examples are of whales with femurs, tibia, and fibulae; however, some even include feet with complete digits.”

Whales are occasionally found with legs. Not very good legs but so what? It’s been 30 million years. The wonder is not that they don’t get out of the water and wander around but that they have legs at all.

This isn’t explainable by creationism but easily explainable by evolution from a land dwelling ancestor.

I forgot to mention the chickens found with teeth as another atavism.

talkorigins Douglas Theobald:

Probably the most well known case of atavism is found in the whales. According to the standard phylogenetic tree, whales are known to be the descendants of terrestrial mammals that had hindlimbs. Thus, we expect the possibility that rare mutant whales might occasionally develop atavistic hindlimbs. In fact, there are many cases where whales have been found with rudimentary atavistic hindlimbs in the wild (see Figure 2.2.1; for reviews see Berzin 1972, pp. 65-67 and Hall 1984, pp. 90-93). Hindlimbs have been found in baleen whales (Sleptsov 1939), humpback whales (Andrews 1921) and in many specimens of sperm whales (Abel 1908; Berzin 1972, p. 66; Nemoto 1963; Ogawa and Kamiya 1957; Zembskii and Berzin 1961). Most of these examples are of whales with femurs, tibia, and fibulae; however, some even include feet with complete digits.

I have looked at eight different introductory Biology textbooks. Of the eight, two do not have any representations of comparative embryology, three use drawings and four use photographs (one uses both drawings and photos). Of the texts that use drawings, only one looks as if they might be the Haeckel drawings and that is the one that also includes the photographs. Almost all of these texts also have extensive discussions of comparative developmental genetics. In addition, most of them also use line drawings to depict comparisons of vertebrate limbs as well as whale and horse evolution. I cannot find anything objectionable in any of this material. Overall a very accurate picture of the basics of evolutionary biology is provided.

Perves (6th) none

Lewis (4th) photos and drawings

Starr (9th) drawings

Solomon (4th) drawings

Raven (7th) photos

Sadava (9th) none

Mader (6th) photos

Campbell (7th) photos

If any creationist has any problem with any of this material, I suggest that they do some research, publish their results in a peer reviewed journal, then complain to the editor of the textbook about any inaccuracies. If you are unwilling or unable to do this then kindly piss off.

Albatrossity said:

kereng said: Luskin does not say that the original Haeckel diagram is used in textbooks or that they mention the name Haeckel. Please don’t attack a straw man.

On the contrary, Luskin is still claiming that the Haeckel drawings appear in modern textbooks. If you don’t think so, please give me an acceptable alternative interpretation of this sentence, from his June 17, 2010 EN&V post.
“I’ve come in for some fairly harsh attacks for making the simple observation that textbooks in use today, in arguing for evolution, still use Haeckel’s fraudulent embryo drawings to inaccurately portray the embryological evidence.”

My interpretation of Luskin’s sentence: He does not claim that Haeckel’s original diagrams are reproduced in modern textbooks but that coloured versions of some of his images are used. He gives an example in the other link: Mader, 2010.

PZ Myers acknowledged regarding the figure in Starr & Taggart, 2001: “That is clearly a reworked version of the Haeckel/Romanes diagram.”

Luskin’s mistake is to think that all those drawings are fraudulent.

I started posting in this thread to find out if there are any significant differences between Haeckel’s diagram and the reworked versions in some textbooks. My conclusion: there are no differences necessary.

kereng

You can interpret that however you want, and, indeed, Luskin does give a more nuanced version in some venues.

But when he says “Haeckel’s fraudulent embryo drawings”, I think I only have one interpretation of those four words. And I think that is the interpretation that he would like to foster, that textbooks are using the original figure (as well as the original interpretation).

Albatrossity said:

But when he says “Haeckel’s fraudulent embryo drawings”, I think I only have one interpretation of those four words.

I think the basic message is: “HAECKEL WAS A BIGTIME FRAUD AND THEM EVILUTIONISTS STILL LETTING HIM GET AWAY WITH IT!”

This being a simplistic read of things, to put it mildly, the Luskito has applied some layers of weasel words in an attempt to conceal the crudity of the message.

I will confess I haven’t read the relevant blog postings by the Luskito. I’ve read plenty of his stuff before, I know what he’s going to say. Do I want to read his postings any more? Do I want a poke in the eye? Does that answer the question?

What’s particularly annoying about this is that if you run across Haeckel’s scientific artwork online … it’s extremely impressive. My favorite is his drawing of a eurypterid / sea scorpion. Here’s a page with some of it:

http://www.criterionforum.org/forum[…]7&t=9261

PZM take note: cephalopods!

Raven, a leg is an *external* appendage of a certain type. Note that the well developed front flippers of cetaceans are not called arms. The case for homologous structures is solid, but I don’t want anyone to have an exaggerated view of it. Except in very rare cases the bones or cartilage of whales and dolphins homologous to pelvic and hindlimb elements are internal or largely so.

You (Raven) know this, but the term leg could easily mislead some readers.

Pete Dunkelberg said:

Raven, a leg is an *external* appendage of a certain type. …. but the term leg could easily mislead some readers.

That raises a question, just what is the generic term for the appendages that sprout from the pelvic and shoulder girdles of vertebrates and manifest themselves variably as legs, arms, wings and flippers?

Surely, there must be a name that describes these structures without referencing function, but I can’t think of one other than “appendage”.

Maybe “forelimb” or “hindlimb”. That kind of encompass arms, legs, and arms-that-are-sometimes-legs and legs-that-are-sometimes-arms and such, but it still doesn’t feel right for wings and flippers.

Sometimes, it’s weird the concepts we don’t have names for.

Ideological preoccupation fouls up historical understanding. You can’t really judge the accuracy/inaccuracy of Haeckel’s drawing without putting them in the context of the practice of scientific illustration in the 19th Century. To this day, the drawings in bird guides are more useful in practice than photos, but their usefulness is a consequence of what could be argued to be their lack of “objectivity,” whatever that is. I recommend Gaston and Galison’s book on this subject, whose title, it happens, is Objectivity. It’s not that I think that G&G provide the last word on the subject, but their book does make you recognize that issues of what counts as true representation are far from simple.

Except in very rare cases the bones or cartilage of whales and dolphins homologous to pelvic and hindlimb elements are internal or largely so.

You (Raven) know this, but the term leg could easily mislead some readers.

One of us is confused here. I’m not talking about vestigal structures. The topic was atavistic structures. These words refer to very different phenomena.

By definition these atavistic individuals are abnormal, perhaps even mutants and rare. What we see though are ancient genetic programs being reactivated. Humans with fur, tails, extra nipples. Chickens with teeth. Whales with legs. The whales with legs aren’t all that much more common than humans with tails. The legs vary in completeness but at least some are external. That is how they are identified.

Raven, I agree that the term “atavistic” could be applied to legs on whales, if there were any. A leg is an external appendage with certain characteristics. I will be pleased and interested to see examples.

Pete Dunkelberg said:

Raven, I agree that the term “atavistic” could be applied to legs on whales, if there were any. A leg is an external appendage with certain characteristics. I will be pleased and interested to see examples.

How about referring not to the whale, but to the whale skeleton? The skeleton is equipped with leg bones, no?

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This page contains a single entry by Nick Matzke published on June 18, 2010 1:50 PM.

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