DrBarr asks:
"How could altruism have evolved?"
Altruism, at its root is self serving. Those species that engage in altruistic behaviour are more successful.
Keep in mind that our history is tribal. All of the members of the tribe were very closely related genetically and thus helping a member of the tribe helped the survival of the tribe's DNA. Consider this in light of the willingness to commit genocide when dealing with members of another tribe. A male lion protects its own offspring and willingly murders the offspring of another male not part of the pride.
Our species success relates directly to how individuals define the breathe and scope of the tribe. Some think the tribe is literally their tribe. Others think it is their nation and yet others their religion and yet others those of their culture or skin color.
Some of us consider our tribe to be every person on the planet and are horrified by their behaviour toward other members of "the tribe."
