“In the words of Darwin himself, On the Origin of Species is "one long argument" designed to convince readers that evolutionary changes had occurred on a massive scale and that natural selection was a formidable agent of those changes. Most biologists were quickly convinced, especially with respect to the argument that modern species are modified descendants of extinct ancestral species.

Moreover, the tests of evolutionary theory did not end in 1859. Instantly recognized as one of the most important scientific ideas of all time, the theory has been subjected to at least as much scrutiny as any other major idea in science or the humanities. Had anyone been capable of overthrowing the theory of evolution by natural selection, he or she would have become as famous as Darwin. Although Darwin's theory has not been dismantled, a considerable number of persons have refined the theory in important ways, especially by taking advantage of our improved knowledge of heredity and what this means for evolutionary processes, a subject that was essentially a mystery in the mid-nineteenth century.”