Vincent Torley (vjtorley), a philosopher from Australia, has struggled with the idea for several weeks and now he thinks he has some challenging questions for evolutionary biologists. Those creationists are really fast learners. It took me several years of study before I really grasped the basic concepts and the theory behind population genetics. Torley's questions are at: Will the real Neutral Theory please stand up?. The obligatory piling on by "News" is at: Is there a real neutral theory of evolution?.
Torley begins with ...
So I’d like to ask Professor Moran a few questions:Some evolution at the morphological level can be attributed to natural selection and some is due to random genetic drift. The latter category includes neutral morphological changes and a small percentage of detrimental morphological changes.
1. Do you agree or disagree with the view expressed by Motoo Kimura that natural selection is necessary to explain evolution occurring at the morphological level?
In the strict form of neo-Darwinism, very little room is given to neutral variation, and virtually all morphological and physiological characters are thought to be products of natural selection (Mayr, 1963; Ford, 1964). Certainly, most morphological and physiological characters are well-adapted to the environment in which the organism lives, and there is no question about the importance of natural selection in the formation of intricate morphological characters. However, are all individual differences in morphological and physiological characters adaptive as claimed by extreme neo-Darwinians? More than 4 billion people live on this planet, and all of them except identical twins are different with respect to various morphological and physiological characters. Are all these differences adaptive? Is random genetic drift unimportant for generating morphological and physiological diversity among organisms? I doubt it. It seems to me that in some morphological characters a substantial part of genetic variation in nonadaptive.So, the answer to your question is "yes;" natural selection and random genetic drift are both necessary to explain evolution at the morphological level.
2. How do you respond to Dr. Gert Korthof'sI respond by saying that Gert Korthof
Kothof’sclaim that the neutral theory "is not a theory of evolution," because it "is not sufficient to explain complex life and adaptations"?1 If not, why not?
3. Can you point to any complex structures, functions or behaviors which you believe could not have arisen in the absence of natural selection? (You’ve already nominated the change occurring in the human brain over the past few million years as an event in which natural selection played an indispensable role; what else would you put on your list?)The vast majority of complex structures seem to be adaptations of one sort of another. I suspect there are many "functions" and "behaviors" that are neutral, or even detrimental, but it's difficult to rule out any adaptive component.
4. In which of the following events do you see natural selection as having played a decisive role: the origin of eukaryotes, the origin of multicellularity, the 20-million-year Cambrian explosion, the origin of land animals, the origin of the amniote egg, the origin of angiosperms, and the radiation of mammals immediately after the extinction of the dinosaurs?I think that natural selection played an important role in all of those events.
5. Or is it simply your contention that natural selection, while not playing an important role in the origin of complex structures and novel morphological features, exerts a refining and purifying effect subsequent to their appearance, weeding out non-viable life-forms?No. I have always contended that natural selection plays an important role in the origin of most complex structures and novel adaptive morphological features. There are likely to many "novel morphological features" that are non-adaptive.
It's also true that negative natural selection acts as a break on evolution by preventing detrimental changes and "weeding out non-vaible life forms."
1. Gert Korthof himself supplies the complete quotation in the comments below. He says, "Corneel, thanks for defending me! Small correction: the blog is mainly in Dutch, but the website you linked to is in English. Obviously: the misquote IS in English. And now the full quote: 'Please note that 'the neutral theory of evolution' is not sufficient to explain complex life and adaptations. In that sense it is not a theory of evolution. However it is accepted that the neutral theory explains a lot of differences in DNA. Kimura: 'Of course, Darwinian change is necessary to explain change at the phenotypic level -fish becoming man- but in terms of molecules, the vast majority of them are not like that. (7)'" Looks like Vincent Torley might have quote mined a scientist. Isn't that amazing?