Writes Charles Burris:

In his book, From Darwin to Hitler: Evolutionary Ethics, Eugenics, and Racism in Germany (2004), Richard Weikart explains the revolutionary impact Darwinism had on ethics and morality. Darwinism played a key role in the rise not only of eugenics (a movement wanting to control human reproduction to improve the human species), but also on euthanasia, infanticide, abortion, and racial extermination. This was especially important in Germany, since Hitler built his view of ethics on Darwinian principles.

Here is Weikart’s talk on the subject.