These last few days I finished reading the second half of Richard Dawkins' The Greatest Show On Earth and was rewarded with the best collection of evidence for evolution I have ever seen amassed in a single place. Even for someone such as myself, fully convinced of its factual reality, I am even more in awe of its effects all around us. When I was in high school, I recall creationism being mentioned as an alternative idea to evolution. But whereas the evidence for evolution was tangible and all around us, it was evident to me (and probably many of my other classmates) that creationism had no such evidence. Nonetheless, the two theories didn't seem inherently incompatible on that basis alone. Like many people today, and the early Darwin, I adopted a combination of the two. When I went to college, the supporters of creationism needed no help from anyone else in discrediting their position. The untenability of creationism became all the more plain when I came to the conclusion that religion itself was not only insupportable but positively undesirable. As a younger man, and like most religious folk today, I was guilty of the logical falacy of argumentum ad consequentiam (402). After reading Dawkins book, I have a greater sympathy for the frustration he feels when he encounters evolution deniers.
Dawkins described many important evolutionary scientists and their work, among those I found most interesting were Richard Lenski's experiments with E. coli (117), John Endler's work with guppies (133), and Sydney Brenner's work with C. elegans (243). In addition, the description of recent fossil discoveries, such as Puijila darwini were very interesting, and animals visibly evolving within our lifetime, like P. sicula (113).
I also learned something about human diversity. It is estimated that Homo sapiens walked out of Africa 100,000 years ago (186) and diversified into all the races that we see around the world today. I have sometimes wondered if, in our modern world we would begin to lose genetic diversity as there are no longer physical barriers to prevent races from interbreeding. However, Dawkins uses the metaphor of shuffling and reshuffling cards in a pack to demonstrate the combination of parental genes in offspring, and that therefore “there is no such intrinsic tendency for variation to decrease in a population” (29) when different gene sources combine. “Genes don't blend, they shuffle.” Subtle point, but important and easily overlooked. So even if all the people in the world are equally as likely to interbreed with any other person, no genetic diversity will be lost as a result of it [see also this].
After reading this book, I realized more than before that “All animals are much closer cousins to each other than we used to think.” (359) Even insects, surprisingly, bear marked similarities to you and I. If you don't believe that, then read the book.
4 hours ago