"I believe in evolution. I don't believe in morality. It's survival of the fittest... if I see something I want, I take it until something bigger than me comes along."
Nice try, sir. Bravo! Very Hobbesian... "the life of a man in the state of nature is nasty, brutish, and short."
Except that evolution doesn't work like that. More importantly, natural selection doesn't work like that. For one thing, natural selection simply isn't interested in the survival of the individual, except insofar as the survival of the individual helps promote the continuation of the species. This has a couple of important consequences (yes, we'll get to morality in a bit).
Sexual reproduction has long shown to be a strong strategy for the continuation of species. Sexual reproduction induces variation, which allows a species to better fill more niches in the environment, adapt to changes in the environment, or to reinforce and preserve advantageous variations that have already been expressed. Reproduction is a good thing, evolutionarily speaking, and so is sex.
But sex (at least for mammals, reptiles, and avians) requires more than one member of a species to get together. A lone male by himself cannot reproduce, neither can a lone female. They have to find a way to find each other and co-exist for a bit for sex to happen. "So why can't one of them, the male perhaps, just take what he wants?" Good question, seems reasonable. A little of the ol' rape makes the world go 'round. The truth is, though, that outside of some communities of Republicans, most females are capable of fighting back. They can claw, they can bite, they can run, they can hide. And while making the male overcome a few obstacles can be good for the species, there's a limit. If the female becomes too hurt, too tired, or otherwise unable to give birth to offspring (fertilized eggs for reptiles and avians, live offspring for mammals), then there's no continuation of that genetic line.
So it helps if the female wants it, at least a little. Maybe not all the time, maybe not with any particular male, but for most species of reptiles, birds, and mammals have to be able to co-exist with another member of their species long enough to make a love connection. They have to be able to do the nasty without it getting too nasty. So sex isn't all taking; there's some giving going on there as well.
But of course, that's not where morality really comes in. Because natural selection throws our amoral believer in "evolution" for another loop. That new twist is co-operation. Animals of the same species working together for their mutual benefit and the survival of their species.
Crows form murders, wolves form packs, cats form prides. Even herbivores get into the action, with herds and flocks. Apes, bless their anthropomorphic hearts, band together in troops. Humans build clans and tribes. In each case, evolution has provided each group of animals with some rules for getting along. Share food. Don't arbitrarily get in fights with other members of your pack, pride, or troop. Participate in group food gathering or hunting. Share child rearing duties. Establish a co-ordinated strategy for group defense. Maybe establish some vague system for who gets to reproduce with whom.
And it works. Individuals who follow the group's rules get to enjoy the benefits of group membership. Individuals get their needs met, and the group and the species goes on when individuals die. We know these systems work, because we see them work. Our theories of evolution tell us that if co-operation weren't a viable strategy, then any species that tried it would die out. And yet they haven't. Co-operative groups are all over the animal world. Each group has rules that their members follow.
The natural origins of morality.
Googlebombing for a cause: www.minnesotangos.org