What Mr. Scopes was teaching was not just evolution, but eugenics in the 1900s sense of selective breeding. His biology textbook was "Civic Biology." Bryan was not just disturbed by the teaching of evolution but more broadly by the whole social Darwinist agenda, including genetic superiority. "Civic Biology" was a vicious social Darwinist tract. Here are some excerpts from the book, courtesy of Eugenics Watch:
Hunter's Civic Biology, p. 195-196
The Races of Man. — At the present time there exist upon the earth five races or varieties of man, each very different from the other in instincts, social customs, and, to an extent, in structure. These are the Ethiopian or negro type, originating in Africa; the Malay or brown race, from the islands of the Pacific; The American Indian; the Mongolian or yellow race, including the natives of China, Japan, and the Eskimos; and finally, the highest type of all, the caucasians, represented by the civilized white inhabitants of Europe and America.
In fact, the textbook Scopes was using would be roundly condemned by Liberals today as a virulenty racist tract. Read more by clicking HERE.