For humanity, I think natural selection operates on communities more than individuals. A tribe/clan/nation with a higher functioning culture will grow in numbers, and will expand and conquer lands around it, either through direct conquest, or by cultural dominance. A lower functioning culture will die out, or be conquered or destroyed by a stronger neighbor.
Strong cultures will have a tendency to select for strong individuals within the group, and give those individuals better opportunities to reproduce. However, a successful culture will also shield its weaker members. Those members may not rise to be elite, but they can probably work in lower class occupations, and may still be able to reproduce with lower class women.
I think that some stronger cultures will tend to raise the genetic quality of their members over generations, but for the most part, I think it's the culture that makes some groups out compete the others.
Strong cultures will have a tendency to select for strong individuals within the group, and give those individuals better opportunities to reproduce. However, a successful culture will also shield its weaker members. Those members may not rise to be elite, but they can probably work in lower class occupations, and may still be able to reproduce with lower class women.
I think that some stronger cultures will tend to raise the genetic quality of their members over generations, but for the most part, I think it's the culture that makes some groups out compete the others.
I'm the tower of power, too sweet to be sour. I'm funky like a monkey. Sky's the limit and space is the place!
-Randy Savage