Modern Homo Sapiens originated between 110 ,000 and 50,000 years ago. But until 50,000 years ago, it existed only in Africa. Then, in just a few thousand years, they suddenly expanded into the whole of Europe and Asia, and eradicated all the previous humanoids like Homo Neanderthalus and Homo Erectus. Genetic research shows that certain genes related to the brain size have changed, indicating that humans are still evolving (indeed some areas of genetic modifying aka designer babies, may even evolve into a new species altogether in a few hundred thousand years or so).
One can note that a Darwinian type of evolution today exists not only for Homo Sapiens itself, but for various cultural organisations of humans within the species. The difference between cultures or human �families� is as a result of an evolutionary �genetic drift� along the lines of survival of the species to suit the environment, as heathfield has so adequately identified above.