Humans are the virtuosos of cultural diversity, with a wide variety of belief systems, cultural practices and a total of about 7,000 different languages. But in terms of genetics, humans show much less variation. Indeed, all of humanity varies less genetically than does a typical wild population of chimpanzees.
In this article, Mark Pagel and Ruth Mace report that the origin and longevity of this extreme cultural diversity might be better understood by thinking about human cultures as if they were collections of distinct biological species.
Just as species carry genetic adaptations to their environments, cultural adaptations can be viewed as evolving in response to social life, they say. Such adaptations work to maintain cultural identity and coherence, and help ensure that cultures are surprisingly robust against outside influences.
Reference: Nature 428, 275 (2004)