The funny thing is that it isn't really arbitrary at all. It's location based. Humans only recently gained the ability to travel vast distances, and in the pas

The funny thing is that it isn't really arbitrary at all. It's location based. Humans only recently gained the ability to travel vast distances, and in the past lived (and bred) within a small, localized region. The "arbitrary" location based ethnicities actually do reflect that genetic ancestry Of course, really wide ones like black/white/asian lose some of their meanings.