Re: Ch. 3: Why are there so many different kinds of animals?
I'm just throwing out a summary of this chapter in hopes of generating a discussion. it may be that this book is not the kind of book that generates much of a discussion and that's okay too.
In this chapter, Dawkins goes into the nitty-gritty of evolution, explaining the concept of drift and gene pools and the role played by natural selection. He again starts with a question—why are there so many different kinds of animals? He summarizes some of the world's myths, but says very few of them actually try to explain the diversity of life. He mentions the story of the Tower of Babel in the Bible—a myth that explains the diversity of language—and uses this as a launching point into the world of evolution.
Evolution is a fairly complex subject, and Dawkins does a good job covering a lot of material. You never get the idea that he's skimming through. He discusses how language has a tendency to drift, showing a passage from Chaucer, for example, which is dramatically different from modern English. Indeed, languages are discussed in terms of groupings and family trees just as animal species are often shown "branching" out from a common ancestor.
One of the more interesting sections of this chapter has to do with islands and isolation. The DNA of a species, like the words of language, drifts apart when separated. Islands have been a major factor in the diversification of species. Not just the kind of islands that we think of, a body of land surrounded on all sides by water. To a fish, a lake is an island. To a frog, an oasis is an island where it can
live, surrounded by a desert where it cannot.
As such, the Galapagos Islands are a fantastic representation of this concept of diversification because they are fairly isolated from the continents. All species that live there were transported there relatively recently. And because the islands are somewhat isolated from each other, they have spawned evolutionary branching of a number of different species (as documented by Charles Darwin when he visited the Galapagos in 1835 aboard the HMS Beagle). For example, there are three distinct species of land iguanas. One of the iguana ancestors even evolved into the only known species of a marine iguana.
Dawkins ends the chapter with the concept that I found so interesting in THE SELFISH GENE. That organisms can be seen as "survival machines" for their genes.
This, of course, is a starkly different perspective than those usually put forth by mainstream religions. This particular passage was singled out on one blog as "pure nonsense" and evidence of Dawkins' indoctrination of children. I would ask if the idea that we are "survival machines" for our genes is at all inaccurate or offensive to some? Do you think Dawkins goes too far here?