Morality is a learned survival technique. Without law life would be nasty, brutish and short. I realize laws need not be moral, but most are rooted in a desire to protect life or property. More power to you for wanting to examine these questions.
Most people never bother.
Hobbes, Locke, and Rousseu are good reads in the nature of man. There are also some socio-biologists, and functionalists like Comte who can give you an idea where you sit. Altruism is a fascinating area to me.