natural selection still applies, because the people with defects affecting life-span and physical appearance are still unlikely to live to the age where they reproduce or attract someone to have children with, but it is less relevant, what I like the idea of is that a few thousand years down the line,we, Homo sapiens sapiens, will have evolved, in Africa they may evolve to deal with heat and disease common to their area, in Europe I believe it will be less drastic/more slow, but it is an eventuality nonetheless.