From the Inbox: Did Stephen Jay Gould fabricate evidence of Louis Agassiz’s racism?

This one is from an e-mail sent to me via my neglected website over at commondescent.net regarding a page I have there that is mostly a bunch of quote from Charles Darwin on the subject of race and slavery. The point of the page (that I originally created over a decade ago) was to counterbalance creationists’ never-ending demonization of Darwin as some sort of rabid racist—who was somehow responsible for racism and genocide—by the use of selective quotation of his writings (for example, Bergman 1997).

Anyway, someone going by “ML” writes:

ML: Why do Atheists get so upset when a Theist speaks about Darwin being Racist?

Atheism or theism does not enter into this, at least not inherently. I would think that anyone, theist or atheist, who interested in science and history would be upset by how professional creationists use invalid reasoning and false or misleading historical narratives to attack both evolutionary theory and historical figures involved in its development.

In the case of the claims that Darwin was somehow particularly racist, creationists are attempting to poison the well against evolution by claiming that the founder of evolutionary biology had some objectionable and/or erroneous views. They are arguing, in essence, that since Darwin was a racist evolutionary theory is suspect.  This is form of an ad hominem fallacy*.

Whether or not Darwin was a racist is completely irrelevant to the question of evolutionary theory’s validity. It stands or falls on its own merits regardless of what Darwin thought—for example, Isaac Newton believed in alchemy but this in and of itself does nothing to cast doubt on his laws of motion.

Logical fallacies aside the creationists’ treatment of Darwin on the subject it is also simplistic and disingenuous in both the way they exaggerate Darwin’s supposed racism relative to his peers—well-to-do white men of the early to mid-nineteenth century—and in how they conveniently ignore clear cases of racism in their own camp (more on this shortly).  

[*Side note: creationists typically go further and attempt to argue that evolutionary theory itself is inherently racist or must logically lead to racism. That however that topic is for another time.]

ML: Racism is simply thinking you are superior to another race. One does not have to wish another race harm to be a Racist.

Why don’t you stop confusing the issue and trying to downplay the reality that Darwin was in fact racist.  He thought that whites were superior in many ways to blacks. That is RACISM.

I am not attempting to downplay the reality of anything. I am trying to be both factually and historically accurate. My personal opinion is that from a modern perspective Darwin probably was somewhat racist; however this is judgment that has to be inferred from a number of conflicting things he wrote on the subject. Some things he wrote—especially if they are taken out context of both history and his larger writings—seem to be racist in nature. However, he also wrote many things about race that was very egalitarian particularly in comparison with views of many of his contemporaries.

Given this, I think it is unfair and dishonest to single Darwin out for special criticism in this regard, especially if those doing so leave out evidence of more clear-cut racism on the part of their own intellectual predecessors.

ML: One also does not have to believe slavery is right or wrong to be a Racist.

That is true, one would have to look at the reasons an individual gives for why they condemned slavery. Some opposed slavery on the basis that the institution of slavery had negative effects on slave owners and white society in general. Others did so out of a concern for those enslaved (and of course many opposed slavery for both reasons).

I think it is fair to say that while someone who opposed slavery largely out of concern for those enslaved might still be a racist, they are probably not as racist as someone who either opposed it primarily out of concern for slaver owners or who did not oppose it at all (even arguing its favor).

ML: Your article is so biased its pathetic.

Insults, that’s nice. You are going to have to do better than that ML. However, I will admit that the page could probably do with some expansion and updating.

ML: Quoting Louis Agassiz in a letter to his mother (1846), quoted in Gould, Stephen The Mismeasure of Man (1981) p. 44-45,

Stephen Gould IS AN EVOLUTIONARY BIOLOGIST AND AN ATHEIST!! What a source you got there!

A Letter that no one knows it really existed because it just so happens the only person who ever heard of it happens to be an ATHEIST.

Here we have yet another ad hominem fallacy, i.e., the source is an evolutionary biologist and an atheist, therefore it cannot be trusted.

Sorry but the fact that someone has delusional beliefs regarding the relative honesty of either evolutionary biologists (a category that includes a number of Christians btw) or atheists, does not constitute Prima facie evidence that there is any reason to doubt the veracity of the quote as given by Gould.

What’s more, while many—including myself—have taken issue with Gould on any number of subjects, I am unaware of any serious critic ever having suggested that Gould fabricated evidence whole cloth to support his views.  So even on an individual level, there is no reason to take seriously the suggestion that Gould was in the habit of perpetrating fraud.

Of course, anyone who knows me knows that I cannot leave it at that (let’s see, where did I leave my BFG 9000).

These accusations of fraud ML is making regard a quote from the 19th century paleontologist Louis Agassiz that I gave as an example of unambiguous racism on the part of one of Darwin’s creationist contemporaries. Here is the quote in question, which comes from a letter Agassiz wrote to his mother:

It was in Philadelphia that I first found myself in prolonged contact with Negroes; all the domestics in my hotel were men of color. I can scarcely express to you the painful impression that I received, especially since the feeling that they inspired in me is contrary to all our ideas about the confraternity of the human type (genre) and the unique origin of our species. But truth before all. Nevertheless, I experienced pity at the sight of this degraded and degenerate race, and their lot inspired compassion in me in thinking that they were really men. Nonetheless, it is impossible for me to repress the feeling that they are not of the same blood as us. In seeing their black faces with their thick lips and grimacing teeth, the wool on their head, their bent knees, their elongated hands, I could not take my eyes off their face in order to tell them to stay far away. And when they advanced that hideous hand towards my plate in order to serve me, I wished I were able to depart in order to eat a piece of bread elsewhere, rather than dine with such service. What unhappiness for the white race ―to have tied their existence so closely with that of Negroes in certain countries! God preserve us from such a contact.” (Agassiz, 1846, Emphasis mine)

ML states that no one knows if the letter Gould claims to be quoting from even exists, implying that Gould may have made this quote up. Is there anyway for us to discern whether or not this might be the case, or are we forever lost in perpetual doubt?

Well we could start by seeing what Gould says about the source of this quote:

Agassiz had never seen a black person in Europe. When he first met blacks as servants at his Philadelphia hotel in 1846, he experienced a pronounced visceral revulsion. This jarring experience, coupled with his sexual fears about miscegenation, apparently established his conviction that blacks are a separate species. In a remarkably candid passage, he wrote to his mother from America: [...quote given above - TB...] The standard Life and Letters, compiled by Agassiz wife, omits these lines in presenting an expurgated version of this famous letter. Other historians have paraphrased them or passed them by. I recovered this passage from the original manuscript in Harvard’s Houghton Library and have translated it, verbatim, for the first time so far as I know. (Gould 1981, p. 44-45)

Uh oh, “other historians”, “original manuscripts” at Harvard; it is starting to look bad for ML’s fraud hypothesis.

OK, let’s take a look at what historian Edward Lurie’s biography of Agassiz might contain:

After observing Negroes for the first time during a visit to Philadelphia late in 1846, Agassiz confided to his mother:

I hardly dare to tell you the painful impression I received, so much are the feelings they [Negroes] gave me contrary to all our ideas of the brotherhood of man and unique origin of our species. But truth before all. The more pity I felt at the sight of this degraded and degenerate race, the more . . . impossible it becomes for me to repress the feeling that they are not of the same blood as we are. (Lurie 1960, pp. 256-257)

While not identical, it seems clear that this quote, by Lurie given in 1960, is from the same source as Gould’s twenty-one years later.

Lurie give as a source as: “Agassiz to Rose Agassiz, December 2, 1846, Agassiz Papers, Houghton Library”, which means that both he and Gould claim their source is an 1846 letter from Agassiz to his mother.

Now at this point I figured I would have to stop and argue that this was sufficient evidence to refute ML’s insinuation since I do not live in the vicinity of Harvard and so could not go there and check their collection for the letter.

However, this is the age of the internet and after some poking around I discovered that Harvard’s Houghton Library not only lists the material in their Agassiz collection they also have scans of the original documents including…

 Wait for it…

 The letter from Agassiz to his mother dated December 2 1846.

Now the scans aren’t great and the letter is in French (differing interpretations of which accounts for the minor differences between Lurie and Gould’s quotations) but they are there for anyone, ML included, to read for themselves.

I did, and despite the fact that my French is extremely limited I was able to find the passage in question starting bottom third or so of page 13 and ending on page 14 (you gotta love the interwebs).

Given this, I am sure we can expect a retraction from ML regarding this libel against Gould.

References

Agassiz, Louis (1846) A letter to Rose M. Agassiz, quoted in Gould, Stephen (1981) The Mismeasure of Man, W.W. Norton & Company, NY,  p. 44-45

Bergman, Jerry (1997) “Evolution and the Origins of the Biological Race Theory“, Journal of Creation, 7(2):155–168

Gould, Stephen Jay (1981) The Mismeasure of Man, W.W. Norton & Company, NY

Lurie, Edward (1960) Louis Agassiz: A life in science, Johns Hopkins University Press (1988)

Goodbye Neil…

One of my earliest memories is from the day after my fourth birthday in July of 1969. It is just flashes of my parents being very excited about something and images of a large rocket on a TV, it was, of course, the launch of Apollo 11 which carried the first humans to land on the Moon.

Yesterday we have lost the Commander of Apollo 11, Neil Armstrong (1930–2012), however as long as long as our species endures something of him should endure with us, the memory of the first person to set foot on another world.

Goodbye Commander and thank you for risking it all to take that giant leap for mankind.

[A bittersweet coincidence of sorts. I didn't hear of Armstrong's death until early Sunday morning because my wife and I were watching a marathon of old Star Trek shows (Enterprise/Voyager/DS9).]

Answering feedback on Haeckel’s embryo drawings

A commenter named Brad, who is apparently a creationist, left a comment to one of my recent posts.  In that post, “Creationist foists “fraudulent” embryo picture on his readers“, I talked about how creationist Brian Thomas ironically used a biologically inaccurate picture of a human embryo to illustrate his article in which he denies the evidence for evolution from developmental biology and implies that all such evidence is based on the supposedly fraudulent embryo drawings 19th century biologist Ernst Haeckel.

Not wanting it to be neglected in the comments section, I have moved my response to Brad up to a full post.

Brad: Wow, evolution is like magic. It turns gills into ears, tonsils, and glands (and part of the larynx).

There is no magic involved in evolution, you’re thinking of creationism, the very heart of which is the claim that living things are the miraculous creations of a supernatural being.

Brad: Calculate the odds…

Since by all available evidence it did in fact happen, the odds are 100%

Brad: Granted, it was a bad choice with the stock photo; however, that’s possibly an oversight vs. the intentional use of known fraudulent drawings for decades in school textbooks.

I would suggest that it was an “oversight” brought on by ignorance of the subject and a lack of curiosity to even check. As for the recycling of Haeckel’s embryo illustrations in textbooks (as illustrations of evidence rather than as a historical reference) this due to the regrettable and all too common laziness on the part of textbook publishers who often recycle not just images but even language as well. See: Stephen Jay Gould’s essay “The Case of the Creeping Fox Terrier Clone” (Gould 1991).

I agree that some* of Haeckel’s drawings exaggerated overall similarity of the embryos they depict and that more accurate illustrations should be used. However, I am unaware of any fundamental anatomical inventions in the illustrations that if corrected would affect the evidence from comparative embryology for evolution.

So, please explain in your own words exactly what anatomical details were altered in Haeckel’s drawings that created evidence for evolution where none exists in actual vertebrate embryos.

Remember, specific anatomical details and in your own words. I don’t want quotes of vague generalities from other people. You’ll note that in my post on pharyngeal clefts at no point did simply I quote some scientists opinion that the pharyngeal apparatus of amniote embryos are homologous to the pharyngeal apparatus of “fish”. Instead I pointed to the anatomical and genetic evidence for this.

If you are going to argue against this, then you are going to have to do likewise.  And if you want to present an alternative scientific explanation you are going to have to present something that is logical, coherent, makes reference to the empirical evidence at hand and does not rely on untestable miracles or divine fiat.

Brad: O’Rahilly and Müller stated that ‘the pharyngeal clefts of vertebrate embryos … are neither gills nor slits’.1

I don’t have this reference handy and I don’t know when I’ll get a chance to get to my local university’s science library (whose website says they have it) I was able to find a later edition on Amazon with a free preview which allowed me to get what seems like the relevant section.  If the older edition has any important differences please let me know (assuming you have the book and didn’t just cut and past the quote from a creationist and/or anti-abortion website).

Here is the the section which seem to contain Brad’s quote with the part Brad quoted in red:

Recapitulation, the So-Called Biogenetic Law.

The theory that successive stages of individual development (ontogeny) correspond with (“recapitulate”) successive adult ancestors in the line of evolutionary descent (phylogeny) became popular in the nineteenth century as the so-called biogenetic law. This theory of recapitulation, however, has had a “regrettable influence on the progress of embryology” (G. de Beer). The work of Carl Ernst von Baer in 1828 was much closer to the mark. According to the “laws” of von Baer, general characters (e.g., brain, notochord) appear in development earlier than special characters (e.g., limbs, hair). Furthermore, during its development an animal departs more and more from the form of other animals. Indeed, the early stages in the development of an animal are not like the adult stages of other forms but resemble only the early stages of those animals. The pharyngeal clefts of vertebrate embryos, for example, are neither gills nor slits. Although a fish elaborates this region into gill slits, in reptiles, birds, and mammals it is converted into such structures as the tonsils and the thymus. According to the hourglass model of evolutionary development, a conserved pattern of developmental gene expression is linked with considerable resemblance among embryos of different species at a constricted phase, whereas divergence is found earlier and later. Morphological evidence for such a phase, however, is unconvincing (Richardson et al., 1997). (O’Rahilly & Müller 2001, p. 16)

Although there are issues I could take with their description of recapitulation as necessarily being about a strict correspondence between embryos and the adult forms of ancestors or with the short shrift they give the concept of the phylotypic stage (at least in this paragraph), however those are really nuanced points that are not necessary to get into here.

One point I will quibble with regards the presence of slits in certain amniote embryos.

Everything I have seen on the subject indicates that the pharyngeal clefts of some “reptiles” and birds do normally perforate during development and are therefore technically “slits” for a short time before they re-close. This also sometimes occurs in mammals, including humans, though it is not a normal condition. (see my earlier article for links). Also they’ve left out any reference to the larvae of amphibians some of which do develop functional gill slits.

Beyond that, they are absolutely correct, the pharyngeal apparatus of amniotes never function as gills and as I said in one of my earlier posts, I don’t know of any biologist who has ever claimed that they do, save one, the creationist Louis Agassiz.

The Great Satan, Ernst Haeckel, stated in no uncertain terms in his writings that these structures never function as respiratory organs in amniote embryos.

It is not required that the pharyngeal apparatus of amniote embryo function as gills for them to be evidence—not absolute, stand alone proof, but evidence—of their ancestors aquatic nature any more than it is necessary for the hind limb buds of whale embryos to function as working legs for them to be evidence that their ancestors once walked on land.

Brad: Blechschmidt is more forceful, concluding that ‘the so-called basic law of biogenetics is wrong.

The late Erich Blechschmidt (1904-1992) was a scientific outlier (as are some of his followers, i.e. Brian Freeman). That is his views were not representative of developmental biologists as a whole. Creationists love to quote Blechschmidt and other outliers such as Alan Feduccia (who denies that birds are descended from dinosaurs) and Charles Oxnard (who denies that australopithecines are human ancestors) in an attempt to make it seem as if they are tapping into some real controversy amongst scientists. In reality they are just quoting people who are only slightly less on the fringe of science than themselves.

You can find someone with an advanced degree that will say just about anything. For example there is PhD astronomer (and creationist) Gerardus Bouw who argues that the Earth is the center of the solar system.

In this case Blechschmidt (and Freeman) seem to be the source for creationists absurd argument that pharyngeal clefts are merely “flexion folds” caused by the bending of the embryonic neck (Freeman 2001).

As for the biogenetic law, no one is arguing for that. If you read the article you were commenting under you would have seen that I quoted Michael Richardson (a critic of Haeckel) as saying that there are studies which support the recapitulation of individual character transformations, just not whole ancestral stages (Richardson & Keuck 2002, p. 522)

Brad: ” ‘No buts or ifs can mitigate this fact.’ He adds that the gill stage myth is ‘not even a tiny bit correct or correct in a different form…It is totally wrong’. 2 This view is shared by many mainstream embryologists.

No, it is not.

Although among the strongest opponents to Haeckel in recent years, and favourably differing from him by a paramount respect for detail, Blechschmidt resembled Haeckel in several respects: they both were intrepid and very persuasive defenders of their views, they were both artists at heart – witness Haeckel’s illustrations and Blechschmidt’s giantsized models of human embryos – and, most importantly in the present context, they both stuck to some outdated ideas not shared by the majority of contemporaneous biologists: Haeckel remained Lamarckist, defending the inheritance of acquired characters throughout his life, and Blechschmidt strove to maintain the special status of Man by condemning any embryological interpretation or terminology suggesting his descent from other vertebrates. (Sander 2002, p. 531, emphasis mine)

So Blechschmidt apparently had issues with accepting the evolutionary development of humans from other animals. As I said an outlier with an extreme minority view.

Brad: in the end, this is probably an argument evolutionists should give up on.

You’ll understand, I hope, that this evolutionist will not be taking advice on what is or is not valid evidence from a creationist.

Brad: But keep right on with it if you insist, it just makes dogmatic evolutionists sound nuts.

Only to those too ignorant to know better and/or too intellectually lazy to look up the evidence for themselves.

*Note: I am thinking primarily of the first stage shown in the comparative embryo illustration in the 3rd edition of his Anthropogenie (1874)

References

Freeman, Brian (2001) “The Myth of the “Biogenetic Law””, The American Biology Teacher 63(2):84

Gould, Stephen Jay (1991) “The Case of the Creeping Fox Terrier Clone”, in: Bully for Brontosaurus: Reflections in Natural History,  W.W. Norton & Co., pp. 155-167

O’Rahilly, Ronan & Müller, Fabiola (2001) Human Embryology & Teratology, 3rd Edition, Wiley-Liss

Richardson, Michael & Keuck, Gerhard (2002) “Haeckel’s ABC of evolution and development“, Biological Reviews, 77: 495-528

Sander, Klaus (2002) “Ernst Haeckel’s ontogenetic recapitulation: irritation and incentive from 1866 to our time”, Annals of Anatomy 184:523-533

Creationist foists “fraudulent” embryo picture on his readers

I decided I am not going to bury the lead on this one. Brian Thomas of the Institute for Creation Research (ICR) just posted another in a long line of creationist screeds attacking the evidence for evolution from comparative embryology, which as usual claims that the evidence is based on fraud and pins much of the blame for it on 19th century biologist Ernst Haeckel.

I began writing a rebuttal straight away but then I happened to take a second look at the bright pink image of an embryo atop the article and it brought me to a sudden halt. So, having backed up, let me start again.

Thomas: German zoologist Ernst Haeckel is perhaps most famous for defending evolution with the argument that creatures replay their evolutionary past when developing in the womb. …In his zeal to promote evolution, Haeckel foisted faulty embryo sketches onto his readers, and the zeal of his followers has perpetuated those falsehoods for over a century. (Thomas 2012, emphasis mine)

Yeah, about that…

That’s right, yet another irony meter has been reduced to subatomic particles by a creationist.

Read on»

“Reason and creationism”

My friend and colleague (frienlleague?) Dr. Eugenie Scott gave, yet another, excellent talk titled “Reason and creationism” at the Global Atheist Convention, Melbourne, Australia (4/15/2012). Have a watch:

NCSE Home Page

“What Can YOU Do to Support Intelligent Design?”

A visual approximation.

Over at the Discovery(less) Institute’s Complaint Dept., resident attack chihuahua, Casey Luskin answered some fan mail that supposedly asked how people, sans financial resources, could support intelligent design (creationism). He suggests a variety of things that boil down to: submerge yourself into the intelligent design creationism bubble and pester your kid’s teachers and school administrators into foisting creationist misinformation onto their students:

There are lots of ways you can support Discovery Institute and ID in ways that don’t involve money. One of them – liking Discovery Institute’s Center for Science & Culture on Facebook of course — you already did. You could also become a follower of our Twitter account, follow our podcast on Twitter, or listen to ID the Future online. Reading Evolution News & Views will help keep you up-to-date on the debate. You can also subscribe to our Nota Bene newsletter, which is free.

Those are all ways for you to stay informed. But there are also ways that you can reach out to others. These include:

  • Start your own ID blog, or participate in other ID blogs like Uncommon Descent. It’s always good to have pro-ID voices on the Internet, although I’ll warn you that lots of Internet ID-critics just want to shout you down and call you nasty names, so it’s not uncommonly the case that you’d be wasting your time by engaging them.
  • Become a voice for academic freedom in your local community. One easy thing you can do is sign the Academic Freedom Petition. You can write letters to the editor to local newspapers, calling on them to stand up for good science education and provide corrections to misinformation or biased reporting on this issue.
  • Another constant need is to ensure that your local public libraries, secondary school libraries, and university libraries have up-to-date copies of intelligent design books. Even if you don’t have the money to donate the books, recommend books to the library and ask if they would consider adding them to their collections.
  • You might consider starting a local organization to increase awareness about intelligent design. A great way to do this is to start an Intelligent Design and Evolution Awareness (IDEA) Club. These extracurricular clubs are affiliated with the IDEA Center (which is a distinct organization from Discovery Institute), but they can organize events on local college campuses or in communities to show videos or bring speakers to educate the public about the issue. IDEA Clubs are a great way to raise awareness and understanding of the scientific case for intelligent design in your local community — you could start one yourself, or help a student do so. See www.ideacenter.org for details.
  • Besides IDEA Clubs, if you know university students who are interested in ID, you can encourage them to get involved with Discovery Institute’s Summer Seminars on Intelligent Design. And if you know pre-college students who are college-shopping, encourage them to consider how the school they’re going to attend deals with topics like the origins of life and of human beings. (Note: I went to a science-focused public university that was largely anti-ID and had a great experience, so I’m not saying students must go to a pro-ID college. But they might want to consider this issue, one way or another, when they apply.)

Finally, another way you can make a difference is to advocate for positive changes in education in your local school or community. If you have kids, find out how their schools cover evolution. For public schools, we recommend that they teach the scientific evidence for and against Darwinian evolution without getting into alternative theories like intelligent design. A lot of this is explained in our Briefing Packet for Educators – but if you want to get involved more directly, contact us here at Discovery Institute and we can help you. For private schools, we have another list of recommended resources, which I recently discussed here.

What is significant by its absence from this list is any suggestion that his readers should directly familiarize themselves with what the overwhelming majority scientists are actually saying or with the actual evidence, unfiltered by the ID creationist spin zones that he lists.

Now I understand that Mr. Luskin probably believes that all of mainstream science is engaged in a global satanic conspiracy to hide the Truth ™ from the masses, but for the sake of intellectual rigor he should want people to be familiar with the thing that they are fighting so fiercely against; and not just the version presented in the IDC echo chamber.

If someone asked me how they could prepare themselves to deal with creationists I would tell them that they need:

  • A good grasp of modern evolutionary theory and the broad evidence behind it both paleontological and neontological (preferably including some reading of the primary scientific literature), as well as a smattering of other sciences that touch on historical issues (cosmology etc.).
  • At least a basic knowledge of the history and philosophy of science (especially the histories of biology and geology).
  • And, most especially, a thorough knowledge of creationist arguments through direct reading of creationist literature (and other media) and the history of the creationist movement (I highly recommend Ronald Numbers book The Creationists (2006) for that last part).

Of course, no one can be an expert in all the relevant fields of science. Even most scientists, while they might be experts in their particular area of study, may have only a basic grasp of the several other fields outside of their own that is required in order to effectively counter creations claims. You can start off talking with a creationist about cosmology—because many of them do not understand that the Big Bang theory is not part of evolution—and in quick succession be grilled about various aspects of geology, biology and physics.

Worse yet, most scientists have only superficial level of knowledge regarding creationist arguments and tactics, which makes sense given that they trained in doing science and not counter apologetics. Moreover, many feel, with some justification, that to get such training is a waste of their valuable time. Unfortunately, this can lead to public relations setbacks for science education if they then allow themselves to be snookered into formal debates with professional creationists.

Again, from my experience you need not only a basic knowledge of a variety of scientific subjects—especially geology, paleontology and biology—but a good knowledge of creationist arguments in order to keep from getting steamrolled by the creationist shotgun approach to debate (a.k.a. the “Gish Gallop“).*

For that reason, unlike Mr. Luskin, I strongly encourage people, both scientists and interested laypersons, to study the work of the opposition, not just what people like me say about it.

[*I would generally advise against live public debates in the first place. Instead, stick to written ones that do not allow creationists effective use of the Gallop in the first place.]

“The Curmudgeon’s Guide to Creation Science”

The Sensuous Curmudgeon has given us an eloquent exposition on why “creation scientists” are immune to empirical evidence and why there is no science in “creation science”. I highly recommend you give it a read.

[Hat tip to Richard Hoppe over at Panda's Thumb.]

An ex-pigeon

However it is not merely a pigeon that has shuffled off its mortal coil, tis a late pigeon that was once studied by Charles Darwin (Natural History Museum at Tring, Hertfordshire, England), making its image being shared here a matter of course. Photograph by Annie Leibovitz.

[Hat tip to Michael Barton at The Dispersal of Darwin.]

“Gill slits” by any other name…

Charles Darwin once said that he thought the evidence from the comparative anatomy of embryos “by far the strongest single class of facts” in favor of common descent (Darwin, 1860) and while it has since been eclipsed by genetics, it remains one of most compelling subsets of evidence for evolution. And perhaps the single most striking detail of the comparative embryology in vertebrates, are the structures colloquially known as “gill slits”.  

Embryonic “gill slits” or “branchial clefts” (branchia is Greek for gill) or more properly pharyngeal clefts (grooves, folds, etc.) are part of what is called the “pharyngeal apparatus” found in front (ventral) and sides (lateral) of the head/neck region of all vertebrates in the “pharyngula stage” of development. In “fish”, and the larva of amphibians, these develop into respiratory organs used to extract oxygen from water while in amniotes (“reptiles”, birds and mammals) they are modified into other structures.

Before I go on, a brief digression about “fish”. Throughout this article I will often use “fish” in the generic sense; but it should be noted that the term as it is commonly used—to refer to any vertebrate that swims in the water, has fins and gills—is not a valid scientific classification. This is because the three main types of animals commonly called “fish” —the Chondrichthyes (sharks, rays, skates and chimaeras), the Actinopterygii (ray fined fish, which constitutes the majority of living fishes), and the Sarcopterygii (lobe fined fish, the group from which four legged land animals, i.e. tetrapods, evolved)—are not a monophyletic group. That is they are not very closely related to each other despite some of their outward similarities (like gills). For example the living Sarcopterygii, lung fish and coelacanths share a more recent common ancestor with us (and all tetrapods) than with the other “fishes”.

OK, so the “pharyngeal apparatus” consists of a series of paired pharyngeal arches and fissures which develop on the exterior with a corresponding set of pharyngeal pouches on the inside of the throat, separated from the external fissures by a thin membrane (more on the details in a moment). And in fact the possession of these structures at some point in development, along with a hollow dorsal nerve cord, a notochord and a post anal tail, are the defining characteristics of the phylum chordata to which we and all other vertebrates belong.

Copyright © 1999 McGraw-Hill Companies, Inc.

Please note that the above illustration is diagrammatic and not intended to be photographically accurate (I have to say that lest I be accused of by creationists of conveying a fraud). Below are actual photographs of both a skate embryo and a human embryo for comparison. Also note: the gill structures in the embryos of Elasmobranch fishes—the subdivision of Chondrichthyes which contains sharks, rays and skates—are much less derived that in other “fishes” and therefore generally more similar to those of amniote embryos than the corresponding structures in the bony “fishes” (which are significantly modified).

(Gillis et al 2009, p.5721)

The first of the arches, the mandibular arch, forms the jaw in all jawed vertebrates (Gnathostomes). Most vertebrates develop a total of six arches but the full complement is usually only retained into adulthood by hexanchiform sharks. Hexanchiformes are very plesiomorphic which means that they are more like earlier types of sharks.  Some species of hexanchiformes even develop a seventh arch. Likewise the extant jaw-less vertebrate, the lamprey, also have seven gill openings.

Read on»

Open mouth, insert hoof

Ken Ham, president/CEO of Answers in Genesis (USA), which is headquartered in Kentucky has attacked an exhibit at the Kentucky Horse Park on horse evolution in a recent post to his blog “Around the World with Ken Ham” and it is yet another glittering example of creationist scholarship.

Reading it immediately brought to mind the words supposedly* whispered by Thomas Huxley as he rose to respond to Samuel Wilberforce in their exchange at the 1860 Oxford evolution debate:

“The Lord hath delivered him into mine hands”.

The reason this came to mind was that it is clear from his comments that he has not bothered to educate himself on the subject and is just mindlessly repeating tired, long refuted creationist clichés on the subject of horse evolution.  In other words, he’s lobbing softballs at defenders of science like me.

Alright, without further ado let’s saddle up and ride forth into the mind of Ham:

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