Where do atheists get their morality from?

[Cyberman]

Evolution may, in fact almost certainly must, play a part in developing systems of morality

But not evolution by natural selection. The human concept of the group goes back to Homo Erectus where we have found skeletons which show signs of individuals recovering from broken leg bones. While they may have been crippled because the bone was not properly set these individuals were still given food and water by other members of the group.

Human culture interferes with evolution by natural selection.

A fascinating example, I didn't know that. Plus you managed to say in a few sentences what I've been trying to get across in several posts.

Once a species gains some measure of control of their environment, be it tool use (which isn't just restricted to anthropoid species), hunting, farming (I understand some ant species actually farm certain varieties of moss in their nests, for the purposes of having a guaranteed food supply) or whatever else, then natural selection takes rather a back seat. Throw language into the mix and all bets are pretty much off, evolutionarily speaking.

This was actually an advert for BT (British Telecom, for the uninitiated) and later a Pink Floyd single, but it's a quote from a certain "wheel-cheered scientist" on the subject of human social development:

For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen. Speech has allowed the communication of ideas, enabling human beings to work together to build the impossible. Mankind's greatest achievements have come about by talking, and its greatest failures by not talking. It doesn't have to be like this. Our greatest hopes could become reality in the future. With the technology at our disposal, the possibilities are unbounded. All we need to do is make sure we keep talking.

Now give that species a written language and retire immediately, because the blue touchpaper of a dominant society has been lit.