To get back to Jakes question though. If there were no God, then we couldn't be made in the image of God, and therefore, our behaviour would be just a more intelligent type of animal instinct. I don't think that as mere animals, we would have much time for art, philosophy, science and other formas of abstract thinking, but would only be engaged in satisfying our lusts for food, sex, warmth, and nurturing our young until they were old enough to fend for themselves.
Marriage would not exist, and maybe even monogamy would disappear, although some mammals and birds are, I believe monogamous. So a question mark there.
I fail to see how there could be a universal moral code of behaviour, that could exist outside of ones own immediate community. That would lead to increased tribalsim and wars, in my opinion.