It's fascinating to see how much more we know about this stuff than 40 years ago when I first studied it. The most strikingly new information comes from advances in genetics, the analysis of chromosomes and DNA. The notion that Darwinian evolution is mere speculation is knocked into a cocked hat. (What is a cocked hat, anyway?*)
Of greater contemporary interest is the significant evidence that human evolution continues, even over relatively short periods, and that racial differences--accumulated statistically significant genetic diferences in separately breeding populations--are not imaginary, as some politically correct academics would have us believe.
Do these differences negate the common humanity of all people? No.
Are they significant? Yes.
- The emergence of lactose tolerance, that allows adults to digest cow's milk, in the centers of cattle domestication.
- The emergence of mutations for light skin, at least twice, among northern populations where exposure to sunlight reduces vitamin deficiencies.
- The emergence of mutations that protect against malaria when one gene is present but cause disease when two are present, again at least twice.
- The accumulation and persistence of mutations, among Ashkenazic Jews, who were confined to professions that required high intelligence, that are lethal when two genes are present, but in the one-gene form may contribute to high intelligence. This one's still a hypothesis, although the higher IQ of Ashkenazic populations is demonstrated.
The history of the last century or so gives us reason to be chary of simplistic translations into politics of scientific findings and speculations about race, or invocations of science or psuedo-science to justify political views some people already have. And to be doubly chary of any claimed policy implications of this line of inquiry.
There is, however, no doubt that evolution within the human family is still occurring and important inherited statistical differences between populations are real. It may be politically correct to deny it, but it's true. You'd certainly want your doctor to know.
*"Evolved from the bicorne, the black-coloured cocked hat is triangular in shape, with the brim at the left and right sides turned up and pinned together; the front and back ends are pointed; there is usually a cockade in the national colours at the right side. It is often trimmed in gold or silver."
Definition from Wikipedia. Also a picture.