[jewpinthethird]

Theory: the reason why we look so different is a result of two things:

1) A lot smaller population 10,000 years ago.
2) Isolation.

But with new advancments in technology, humans no longer have to adapt to their environment to survive. Thus, inter-racial breeding will eventually led to less races. But that will be a long time away from now, if we dont blow each other up first.