Transitional Forms as Evidence for Evolution: Tiktaalik and cdesign proponentsists (From The Archives)

I wrote this post back in 2007, after I had  just finished watching the episode of NOVA, “Judgment Day”, about the Dover intelligent design trial. What I liked best about it was the way it highlighted the predictive power of evolutionary theory, something often denied by creationists of various sorts.

When we hear about the discovery of a transitional form or ‘missing link’ like Tiktaalik, it would be possible to presume that this discovery came about by accident. In fact, the paleontologists who found the fossil were looking for just such a transitional fossil, having chosen that particular place to look for fossil evidence of the branching off of amphibians from fishbased on the age of the rocks exposed in that area and Darwinian evolution. In other words, Darwin’s theory makes predictions and they are confirmed (in contrast with intelligent design, which the Dover trial showed clearly knows precisely what experiments to do in order to test its claims, and yet never does them).

This cannot be emphasized strongly enough. This was not simply a find that happened to fit with evolution. This is a case where evolutionary theory made a prediction about where one should look for certain kinds of transitional forms, scientists looked there, and found precisely what evolutionary theory predicted they should. This evidence is as strong as when a witness in a criminal case confesses the stolen loot is hidden in a particular place, the police go search there, and they find it.

Kenneth Miller put it clearly and succinctly in “Judgement Day” when he said ” Any theory that can stand up to 150 years of contentious testing is a pretty darn good theory. And that’s what evolution is.”

A similar example of a prediction made by mainstream evolutionary theory was that the view that humans, having one less chromosome than other primates, had lost one as two chromosomes had fused into one. In one particular human chromosome, one finds not merely a match of genes with two chromosomes found in other primates, but also evidence of the telomeres from the ends of the chromosomes having been incorporated into the midst of the new chromosome formed by the fusion. It is worth noting that the result of this was presumably not mild and gradual. Occasionally such major changes have presumably occurred. We are all mutants, after all.

Another important transitional form mentioned in the documentary was that uncovered in earlier editions of the intelligent design/creationist textbook Of Pandas and People. I had known from reading the book Monkey Girl that they had found manuscripts written just before and just after the judicial decision that outlawed the teaching of creationism in public science classrooms, in which the one before said “creationism” and this was changed in the edition immediately after the decision to “intelligent design”. What I hadn’t known was that there were “transitional forms” providing evidence of this evolutionary process of textbook design. In the version immediately after the judicial decision, there were places where hasty changes had led to forms such as cdesign proponentsists (see, that wasn’t a typo in the title of this post!). The intention had been to highlight the whole word “creationists” and replace it with “design proponents”, but the person making the substitutions had failed to highlight the whole word creationists, and thus ended up making a hodge-podge of the two using this cut and paste method. The evidence for deception on the part of the proponents of intelligent design and creationism in the Dover case is every bit as strong and clear as the evidence for evolution.

A sad irony of the viewpoint of the religious fundamentalists who think they know what is best for science education is that they claim to trust teenagers to weigh the evidence and draw their own conclusions, and yet cannot accept it when the vast majority of those who, having done just that not only as teenagers but in careers in science, overwhelmingly find themselves persuaded by the evidence for evolution.

The transitional forms are consistently found where Darwinian evolution predicts they will be, whether in arctic Canada or creationist literature.