Discussing the controversy over teaching evolution in public schools, correcting popular misinterpretations of Darwin's theories, and defining Social Darwinism with author and geneticist Richard Lewontin.

John T. Scopes was a young teacher who taught biology. He was arrested because in Tennessee, no theory of the origin of man could be taught in schools. Clarence Darrow, an attorney from Chicago, defended Scopes in the "Scopes Monkey Trial" of 1925. Scopes was found guilty and was fined $100.

Evolution and the future of the human race are among topics in Carl Sagan's and Ann Druyan's book, "Shadows of Forgotten Ancestors: A Search for Who We Are." Included is an excerpt of the astronomer Harlow Shapley speaking at the beginning. Carl Sagan also reads an excerpt from the book at the end.