Happy Birthday, Charles Darwin, Father of Scientific Racism
Well, he may not be the Father, but he certainly gave scientific racism quite a boost with The Descent of Man:
At some future point, not distant as measured by centuries, the civilised races of man will almost certainly exterminate and replace the savage races throughout the world. At the same time the anthropomorphous apes, as Professor Schaaffhausen has remarked, will no doubt be exterminated. The break will then be rendered wider, for it will intervene between man in a more civilised state, as we may hope, than the Caucasian, and some ape as low as a baboon, instead of as at present between the negro or Australian and the gorilla.
Charles Darwin, The Descent of Man, Chapter 5.
That is just one quote. The Descent of Man is full of racist theorizing. You really have to read it to get the full flavor. If you do not have the time (or stomach) to read the whole thing, try chapter five.
Give him credit for a very influential theory, although he was not the first or only one to theorize on evolutionary concepts. But give him credit for all the influences of his theories-- good and bad. Since it is "Darwin Day," why shouldn't we give as much attention to The Descent of Man as we do to On the Origin of Species? Whoops, I did not give the full title: On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life.
According to Darwin, genocide is the natural result of a natural process. And it is all very scientific.