“Meh, my question is — why is rape wrong? Let’s hope that the fittest male spreads his seed to the most desirable woman!”
Why is anything wrong? Because our parents said so.
Seriosuly though, short answer, inviolable natural rights. Or because civilization operates best the less horrible violence there is. Morality is all about either how an individual treats himself, or about the interaction between people and what’s best for both of them. In either case, evolution has little to say, for evolution is all about the gene. Genes don’t care about what organism they’re in, or how the organisms get along, so long as they get to the next generation (actually, genes don’t care about anything, but for metaphor’s sake).
We, on the other hand, being complex organisms, care about ourselves.
Sure, we care about ourselves. We care about reproducing and having sex, and stealing and all of that fun stuff :)
From a cursory study of my children, I’m not exactly sure how we ever created a civilization to begin with. Yikes!
Forget about the chicken and egg — which came first, civilization or children?! :)
On a more serious note: I’m not exactly sure where inviolable natural rights came from. It seems to me a strongman can violate these inviolable natural laws.