"What Darwinian evolution did, I would say, is provide what people thought was a scientific justification for separation of races," Ham said in an interview.

In the new book, Ham says that Darwin's theory that natural selection caused gradual biological changes over time, puts some races "higher on the evolutionary scale" and others "closer to the apes."

"Although racism did not begin with Darwinism, Darwin did more than any person to popularize it," Ham writes.