Only in the final word of The Origin of Species, “evolved,” does Darwin make reference to evolution. In previous chapters, he uses the terms “divergence” and “descent with modification” to explain his theory of natural selection. Perhaps Darwin avoids using the word evolution in presenting his theory because of the resistance to and controversy surrounding previously proposed theories of evolution, such as those of Jean-Baptiste Lamarck and Robert Chambers. In the final sentence, however, Darwin drives home the idea that species “have been, and are being, evolved,” characterizing his own theory as one of evolution.