Nature/Nurture
This a bit of a bugbear of mine - the suggestion that nature 'makes you fast/slow, bright/dumb, altruistic/selfish' - or nurture does the trick instead.
But all that nature (genetics, basically) can do is offer a set of capacities to the organism. It can't guarantee that those capacities will be fulfilled. Someone might have the genes to give Bolt a run for his money, but if he grows up in a sedentary, car-driving, sport-averse society, that capacity will be 'nurtured' out of him. On the other hand, someone who shares a habitat with hungry cheetahs, is likely to fulfil every ounce of capacity (if he survives).
Altruism is a social interaction - so it's likely to follow social rules, dependent on the society in question.