Good points Crash.
While I reflexively disagree with any purported directionality to physical evolution, I may alter my view here. It seems to me that our cultural evolution(social structure leading to warfare in these examples) have led to the strengthing of some groups over others, both culturally and physically through gene transfer and selection by physical stress and disease resistence.
Now I am not a eugenesist nor am I claiming this to be a good thing morally; it just is the way things happened.
I am thinking specifically about the book 'Guns, Germs, and Steel' by Jared Diamond. For those who haven't read it, it seeks to explain why some groups took over others due to the groups of plants and animals that they domesticated rather than any intrinsic superiority of the group. It is kind of a 'right place, right time' hypothesis of historical development.
But as Crash says, it's a lot to tease out from the multiple threads of history.
ABB