I take exception to evolutionary explanations of moral or moralistic (proto-moral) behaviour. Not because I don't think they work -- they do. But because they're explaining the behaviour, but not the moral. Let me unpack this: behaviour is, minimally, one's doing something rather than having something happen to one. Further, behaviour seems to be something of a process -- it's not the moving of my arm, the pressing on the light switch, and the electrical current surging along the wires to the lightbulb; my behaviour is, instead, turning on the light, a process which is constituted by these physical events.
So far, so good. Clearly, we can explain the contitutive parts of behaviour in an evolutionary-type fashion (either selectionist or developmental -- I'll gloss both as "evolutionary"). I move my arm when turning on the light because it's a very efficient way to turn on the light and, through my life, I have come to associate moving my arm with the most efficient way of turning on the light. I'll even buy that we can explaining the whole process in an evolutionary fashion -- that is, all these constituents came together because, collectively, they are the most efficient way, etc, etc.
What we can't so explain, though, is why the behaviour is moral: that is, why it receives praise or blame. (And, indeed, I note from the post I linked to that the praising/blaming is being presumed and not explained.) There have been heroic attempts, but I don't buy any that I've read. (More on that in the dissertation!) The only way I know to account for the fact that value -- particularly, morality -- is not amenable to evolutionary explanation is that value is not natural. That is, it is a supernatural property.