Because it takes longer than that. It's more along the line of black people evolved to have more melanin so they could survive in the bush. White people didn't need that, so they're white - they evolved in northern climates, and have more hair. >Why haven't we adapted to our environment to not need shelter or clothes? Because we build shelters and make clothes. Those that would survive better without them have no evolutionary advantage at this point; those they would die have just as much chance of spawning offspring as those that would survive. >Why are people still born with really bad issues that ultimately lead to their death? Similar to the shelter people, those that would croak from sickness have their lives prolonged due to medical advances, and get to pass their substandard genes on to the next generation