People who claim to want "proof" of evolution would benefit from reading Darwin's On the Origin of Species. It gives a very good picture of how science works and what kinds of evidence scientists consider compelling. What Darwin did there was show why his theory blew creationism out of the water.
I should have written this post in honor of Darwin's birthday last Sunday, but I'm traveling this week, and I'm under the weather. But better late than never. Darwin was born in 1809, the same year Edgar Allen Poe was born. Of the many Facebook and blog posts acknowledging Darwin's birthday, one of the most interesting was on the site Why Evolution is True. There, biologist Jerry Coyne discussed Darwin's writing and why he used to assign On the Origin of Species to his students. I've read about half of it, though I do plan to finish. I felt obligated to read a number of other books in the last few months, including book by authors who were interviewed for this column.
But Origin is a great book and is written for real people. What I've read so far has given me a new appreciation for Darwin's achievements as a scientist as well as the magnitude of the seismic shift he unleashed on the world. Other people, including Darwin's own grandfather, had proposed that plants and animals could evolve, and even that one species could evolve into another. But Charles Darwin was the first to grasp how. He was the one to recognize natural selection as the mechanim by which living things became exquisitely adapted to their environments.
To make a case for evolution by natural selection, Darwin included hundreds of observations - not just from his voyage around South America on the Beagle, but also from woodlands and gardens in England. He meticulously explained how natural selection better accounted for these observations than did the separate creation of each species. He was nothing if not thorough, which may be why I haven't finished his book yet. I think he'd forgive me, since he took more than 20 years to write it, though his original intent was a much longer series of scientific volumes. He condensed them quickly into one book when he realized that Alfred Russell Wallace had independently reached the same theory.