I have just finished Jerry Coyne’s book on the fact of evolution entitled Why Evolution Is True. I say fact, of course, since there is no longer any discussion of whether evolution happened in biology. Not because evolution is dogmatically unquestionable, as evolution deniers will say, but because such a discussion is utterly pointless.
He begins the book by describing what evolution is (itself often misunderstood) and a bit about systematics. It’s a good basic description of how phylogenetic trees are built from a comparative morphology point of view. He moves on to some interesting examples of visible evolution in the fossil record, discussing the near-continuous changes in radiolarians and foraminiferans, some of the recent fossil evidences for various transitions such as the aquatic-terrestrial tetrapod transition, dinosaur to bird, and (with good reason, as Jerry demonstrates, the darling of modern paleontology) land-sea mammalian transition.
Jerry continues with some of the earliest evidences of evolution that was discussed in The Origin, such as vestigial organs and atavisms, as well as something somewhat more modern – evidence from pseudogenes. Embryology is also strong in this chapter and he clearly describes what “phylogeny begets ontogeny” means, with examples. This easily leads into, of course, how bad design occurs. I’ve always enjoyed examples of clearly inept design, and here Jerry gives some of the more famous ones like the tortuous path of the aortic arches in humans and how such a ridiculous ‘design’ arose from contingency dictated by our evolutionary past.
Biodeversity figures prominently in the next chapter. One of the most important evidences of evolution is the radiation of evolution from islands seeded by organism from afar. This was, of course, Darwin’s inspiration. This was probably the most informative chapter for me, clarifying some concepts that I hadn’t considered before. He also heads creationists off at the pass showing why special creation simply can not account for biodeversity and spins a good story of the convergent evolution of marsupials in the context of the separation of the supercontinent Gondwana into the continents we know today. It is interesting how the fossil record, and by extension evolution, gives strong confirmation of tectonic plate theory.
Coyne finally gets to the meat of evolution: natural selection. His description of natural selection in action leaves no room for evolution deniers and Jerry relentlessly pushes their arguments out of the way like a bulldozer. He starts with what Darwin did – artificial selection in plant and animal breeding, and how significant morphological changes can be accomplished (teosinte, anyone?). Examples of natural selection from the laboratory and from nature (the biggest lab there is) are also given. Jerry gives some mention to the concept of genetic drift is given, which is unusual. To the good, of course. It is all too often ignored in popular science publications.
The next chapter is devoted to sexual selection, with examples of course. A good discussion of sexual dimorphism is given, and why the males of a species are often far more brilliantly colored than the females. He also gives counter examples where the reverse is the case, and how this is predictable. Speciation is the subject of the next chapter and how it arises. We finally get to hominin evolution and what the evidence is for it having occurred. Jerry presents the amusing fact that creationists call some of these fossil ancestors apes and others humans, yet they can’t agree amongst themselves which is which. If ever there was evidence that humans evolved from an ancestor common to chimps and ourselves, that is it.
His last chapter is devoted to the question of why many people have a problem with something that has so much evidence in favor and really nothing against it. We do not find rabbits in the Precambrian, for instance. Jerry makes an excellent point – it isn’t about the evidence at all. It isn’t even (and this is my own observation) about whether evolution is true. It’s about fear. Coyne gives a telling quote from IDiot philosopher Nancy Pearcy (what do philosophers really have to offer science? Science is about empiricism, not fluff.):
Why does the public care so passionately about a theory of biology? Because people sense intuitively that there’s much more at stake than a scientific theory. They know that when naturalistic evolution is taught in the science classroom, then a naturalistic view of ethics will be taught down the hallway in the history classroom, the sociology classroom, the family life classroom, and in all areas of the curriculum.
Coyne euphemistically calls this attitude “unnecessarily alarmist”. I call it hogwash. As Jerry points out, you can not derive meaning, purpose or ethics from evolution. (I would also add atheism to that list.) This does not mean that we can not find meaning, purpose and ethics elsewhere, though I think that there is a significant body of evidence that suggests that the latter has a natural origin. Just because some of our behavior is genetic, that does not mean it is unchangeable, and Coyne presses this point home.
Here’s another case in point (via Pharyngula), this time from Australian asshat Anglican Bishop Tom Frame –
The problem I face is weariness with science-based dialogue partners like Richard Dawkins. It surprises me he is not chided for his innate scientific conservatism and metaphysical complacency. He won’t take his depiction of Darwinism to logical conclusions. A dedicated Darwinian would welcome imperialism, genocide, mass deportation, ethnic cleansing, eugenics, euthanasia, forced sterilisations and infanticide. Publicly, he advocates none of them.
The fear displayed by Frame is palpable, and nowhere does he consider whether evolution is valid. PZ Myers had an excellent retort:
You would think that, since Darwin himself did not consider any of those actions to be either commendable or a consequence of his theory, maybe someone would realize that perhaps those aren’t logical conclusions of “Darwinism”. You would think that somebody would consider that, while Newton described the acceleration of falling bodies accurately, it does not imply in any way that he he advocated pushing people off of tall buildings. [Emphasis mine.]
I absolutely love the part I boldfaced because it puts this irrational fear in its proper place as a form of silliness.
I don’t have too much sympathy for those who can’t face evolution as fact and reject it, as Pearcy does, simply out of fear of the implications. The term describing such people is “intellectual cowards”. People living in countries whose acceptance of evolution is nearly universal are not rapists and murderers, any more than they are (and actually, they are less so) than in intellectual backwaters such as Turkey and the US (sorry, Americans – this is simply the case where evolution is concerned. As a transplanted American myself, no insult is intended.).
One thing Jerry obviously set out to do through the whole of the book (and accomplishes) is to dispel the defaming myth that evolutionary theory is untestable. There are many examples he gives that demonstrate the predictive value of evolutionary theory. The most famous ones include Darwin’s own prediction that the earliest hominids would be found in Africa and the prediction not only of where the recent fish-land tetrapod Tiktaalik would be found in the geological column, but also what it would look like.
Overall, technically competent readers will be a little ho-hum about the subject matter, but that does not mean I did not get anything out of the book. No surprise, given that it wasn’t written with the technically competent reader in mind. It was aimed at the all-too-often-seen commenter of evolution who displays his/her ignorance at every statement made on the subject, and to this type of reader he does a great service if even a few minds realize that in the search for the truth how futile it is to deny the evidence and that the fear-mongering which produces this head-in-the-sand attitude is just so much hot air.