"Charles Darwin presented his theory of evolution in his book On the Origin of Species, published in 1859. In so doing, he transformed biology from a scientific backwater to a fully professional science. Prior to Darwin, biology was little more than the art of catching a critter, killing it, cutting it open, and then writing detailed descriptions of what you saw. Alternatively, some biologists concerned themselves with classifying organisms according to whatever arbitrary characteristics had their attention that week. Valuable work, no doubt, but hardly a science. Real science involved abstract theorizing, mathematical modeling, and predictive power to several places past the decimal point. Or so went the stereotype, at any rate. That all changed with Darwin.

By marshaling evidence from classification, biogeography, embryology, and comparative anatomy, he established, to the satisfaction of most scientists, that organisms shared a far greater degree of relatedness than had previously been appreciated. He also provided a possible mechanism to explain how populations of organisms gradually became better adapted to their environments-the process of natural selection. He anticipated, and provided cogent replies to, numerous theoretical objections to his ideas. Biology now had a bona fide theory from which to work, one that could be tested against data and which suggested fruitful directions for further research"--.