Selfishness is in some ways one of the key assumptions of evolution. We are taught that evolution is the survival of the fittest at all costs and that the strong survive at the cost of the weak. I think it might be a universal truth that the phrase ‘nature, red in tooth and claw’ must appear once in any evolution discussion. But, like most assumptions, it’s not necessarily true and there are many exceptions to the rule. In particular, altruism is particularly troubling to ‘traditional’ evolutionary thought.
Self sacrifice shouldn’t exist. If an organism should prioritize its own success over any other, how can we explain the existence of firefighters, emergency workers, or even the parent who risks death for a child? Similarly, shouldn’t a worker ant abandon a fight, rather than die for its queen? In theory, any gene or mutation that causes these behaviors should naturally weed itself from the population, not rise until it becomes a fixed trait of the species. Altruism should die before its even really born. Yet it exists, how?
The answer lies in understanding that, for all he did, Darwin was not completely correct and biologists do not read The Origin of Species like a bible. One thing that Darwin didn’t understand is that evolution can act not just on an individual organism, but also on genes, families, or even groups or ecosystems. A couple of different types of theories exist to explain these extra-Darwinian pressures. Kin selection is particularly interesting. Basically, you will go out of your way to help family because they share the same genes.
On the other hand, it’s also possible (as the eternal E. O. Wilson states in his new book The Social Conquest of Earth) that rather than altruism being an artifact of culture, that altruistic genes survive because the allow social structures to exist in the first place.
The debate is ongoing and it’s likely that no one theory completely explains our social behavior. Darwin knew that his theory couldn’t stand up to the complications of human culture but he never expected his theory to go uncontested or unchanged. And as new research and ideas spring forth and evolve, it’s likely that the study of sociobiology will only become more interesting.