The units of selection - Can natural selection favor altruistic actions?
The 'problem' of altruism
If we take a strictly organismic view of natural selection, it would seem to be impossible that natural selection could ever favor altruistic actions that decrease the reproduction of the actor. And yet, in a growing list of natural observations, animals behave in an apparently altruistic manner.
Biologists call a behavior pattern altruistic if it increases the number of offspring produced by the recipient and decreases that of the altruist. The altruism of the sterile 'workers', in such insects as ants and bees (pictured opposite), is one undoubted example; here the altruism is extreme, as the workers do not reproduce in some species. Does this kind of behavior make sense?