Genetic differences between the races can’t exist because there hasn’t been enough time for them to evolve in the 50,000 to 200,000 years since modern humans first emerged from Africa.Read the whole thing there.
The popularity of this argument is bizarre, since genetic differences between the races are written on the faces of the people you see every day. If there wasn’t enough time for these racially characteristic traits to evolve, how exactly did they come into existence? Magic? It’s particularly amusing to hear paleontologist Stephen Jay Gould assert this since his one major contribution to science has been to document that evolution sometimes occurs at the speed of revolution.
In the History and Geography of Human Genes, Cavalli-Sforza calculates the surprisingly short time in which a version of a gene that leads to more offspring can spread from 1% to 99% of the population. If a rare variant of a gene produces just 1% more surviving offspring, it will become nearly universal in a human group in 11,500 years. But, if it provides 10% more “reproductive fitness,” it will come to dominate in just 1,150 years. A classic example is the gene for lactose-tolerance. It was almost nonexistent until humans started milking cattle about 10,000 years ago. Today, its prevalence ranges from negligible among East Asians to 97% among Danes.