I think by "Who owes the world morality?", Copacetivist was asking something like "Who is bound by moral rules?"/"Who is morally responsible?"/"Who has a duty to follow the principles of morality?"
Frazer, I think part of what you were saying is that what we call "morality" is simply a set of rules that humans have invented and which have evolved over time, and Copacetivist said the same sort of thing. I'm of the opinion that in many areas, not just morality, Evolution and Reason are in some sort of battle. Reason is our only escape route from Evolution - the only way we can break free from acting as Evolution demands is to follow Reason. Similarly, certain habits/tendencies/patterns of thought have become hard-wired into our brains because they have been naturally selected, but just because they are useful for survival this does not mean they are reasonable. With morality, I think we have more of a memetic (as opposed to genetic) example: Reason tells us that utilitarianism is right (IMO), but over the generations other ideas about what we should do have become more popular, have been better at "surviving" and so many people adopt those instead. And if utilitarianism is correct, it's easy to see how people can quickly come to believe that the rules of thumb derived from utilitarianism which are suitable to particular circumstances, are in fact the ultimate, immutable principles of morality. So I think that evolution has
affected our sense of the right morality, which we access through Reason, not that morality is reducible to evolving rules of conduct created by humans.
Another example of evolution interfering with reason on the moral front is our tendency to opt for the nearer good, even if we know that it would be better for ourselves overall to choose the good that's further into the future (procrastination being a prime example). This may be the result of an evolved rule in our brains that was useful to us many many years ago when humans had far less certainty about their futures, less security, less ability to plan ahead etc., which says, "Go for the nearer good, cos there's a high chance that when the time comes for you to have the later good you won't actually be able to get it." Like Harry, in When Harry Met Sally, when he says that he always reads the last page of a book first so that way if he dies, he knows how the book ends
even though if he
doesn't die, it would have been better for him overall to wait til he's read the rest of the book to read the ending. This one is kind of a weak theory but I hope it helps you get the gist of what I was saying about evolution interfering with our true sense of morality in general.