Sam Kean, on the naturalistic fallacy, from his very charming 2012 book about genetics, The Violinist's Thumb:
Remember that most of our genetic predilections for behavior were shaped by the African savanna many thousands if not millions of years ago. So while ‘natural’ in some sense, these predilections don’t necessarily serve us well today, since we live in a radically different environment. What happens in nature is a poor guide for making decisions anyway. One of the biggest boners in ethical philosophy is the naturalistic fallacy, which equates nature with ‘what’s right’ and uses ‘what’s natural’ to justify or excuse prejudice. We human beings are humane in part because we can look beyond our biology.