[throwaway4889]

>How does this explain different phenotypes in grouped populations?

Random fixation and/or founder effect, among a myriad of effects that don't involve natural selection.

>Let's say for instance that a species of ant is known to be more aggressive, why it was that way is probably generic drift. Why it stays that way is because of its environment, and it is selected for.

Or the different alleles for aggressiveness (whatever that means, and assuming they exist) got fixed due to drift? Who knows. The burden of proof is on the adaptationist to show that something other than contingency happened.

[Waterfall]

Why is the founder effect not a part of natural selection? If one population lives and becomes specialized in a way of life is it not natural selection? All mammals come from a common ancestor and genetic drift occured or the founder effect over a long period of time. There are cave fish that are blind but bred with non blind types gives their offspring eyes back. What is the difference between founder effect, and natural selection? Are they not part of the same force?