Playing Chess with Pigeons

I’m moving this up from comments because it involves a particular interest of mine, embryology as it relates to evolution and the controversies over various embryo illustrations. Here is the comment by “1wmcaw” in full:

Glazius - I may be a lay person. I am not, however, ill-informed.

Darwin disproved: Take a look at his drawings of in utero creatures. He constantly compared the early embryo and fetus’ of human beings to that of pigs and other animals.

I’m here to tell you that medical science has roundly disproved those drawings/pictures/whatever you want to call them. I’ve seen them with my own eyes, as a lay person. Medical professionals, biologists, anthropologists, abortionists, all of them will concede that the embryo and early human fetus looks absolutely nothing like Darwin’s crude drawing and compares nothing to a fetal pig. We were able to distinguish my son’s genitalia at 13 weeks in utero. He did not possess any “tail” as so classically drawn. Many scientists will admit that human beings do not develop a tail at all in the womb, but that it fits the theory of evolution nicely and so it is still promoted in popular scientific literature.

Oh, and plenty of people understand how God’s creation works. Simply because you do not does not make it untrue.

This is the sort of thing I talked about in my page explaining the title of this blog. An antievolutionist presents an argument, which they apparently half-remembered from some creationist web site, that I am going to have to try to reconstruct for them before I can even address it.

I may be a lay person. I am not, however, ill-informed.

Right of the bat we know we’re probably in trouble. It’s like when someone starts a sentence with “I’m not a racist but…” you know that what is to follow is likely to be racist as hell.

Darwin disproved: Take a look at his drawings of in utero creatures. He constantly compared the early embryo and fetus’ of human beings to that of pigs and other animals.

“1wmcaw” has apparently confused Darwin with another creationist whipping boy from the history of biology, Ernst Haeckel, who did publish numerous comparative illustrations of various vertebrate embryos (including humans and pigs). Here is his most (in)famous illustration from earlier editions of his book (Anthropogenie AKA The Evolution of Man 1874). These illustrations have been attacked for over a hundred years by creationists (as well as some mainstream scientists) and I could write a short book about that but I won’t right now since this is ostensibly about “Darwin’s” embryo drawings.

The bottom row represents a more or less fetal stage and the different organisms are pretty readily distinguishable compared to the same animals on the rows above (that was sort of the point). Most of the criticisms of Haeckel’s drawing have been applied to the top row in the illustration rather than the middle or bottom row, so I don’t see how “1wmcaw” could be talking about them.

Darwin did publish a comparative illustration of two embryos in his book The Descent of Man (1871), but they are of a human and dog embryo. Here they are (below) next to a photographs of a human (top) at approximately the same stage (perhaps slightly earlier), and a cat embryo (bottom). I couldn’t find picture of a dog at this stage but I would imagine they don’t look all that different (most mammals don’t).

I’m here to tell you that medical science has roundly disproved those drawings/pictures/whatever you want to call them. I’ve seen them with my own eyes, as a lay person. Medical professionals, biologists, anthropologists, abortionists, all of them will concede that the embryo and early human fetus looks absolutely nothing like Darwin’s crude drawing and compares nothing to a fetal pig.

No, a fetal pig doesn’t look much like a fetal human but then I don’t know of anyone (including Darwin and Haeckel) who ever claimed otherwise. Nor am I aware of any drawings purporting to be of fetuses that attempt to make them look overly similar.

Human and pig embryos, now that’s another story:

Here we have illustrations of two embryos at about the same point in development, one of a pig and the other of a human. Both are taken from embryology texts (by the same author). Who can tell me which is which?

We were able to distinguish my son’s genitalia at 13 weeks in utero. He did not possess any “tail” as so classically drawn.

That’s because 13 weeks (about 3 months) is much farther into the developmental process than when you’d have to look to see the tail (around the 5th and 6th week). Did your son look something like the picture below?

Many scientists will admit that human beings do not develop a tail at all in the womb, but that it fits the theory of evolution nicely and so it is still promoted in popular scientific literature.

To “admit” such a thing would be to express either dishonesty or ignorance of the subject. Humans and all other members of the phylum Chordata have at some point in their lives a post anal tail. In fact it is one of the defining characteristics of chordates.

A stage 15 human embryo with a clear tail.

While humans normally only have tails as embryos occasionally children are born with tails still intact.

Similar pictures can be found in medical textbooks. Usually the tail is just soft tissue but occasionally children are even born with tails that have extra vertebral bones in them. The re-expression of an ancestral character is known as an atavism. The existence of atavisms is easy to understand under evolutionary theory but difficult to explain under creationism.

So, Darwin not disproved.