Thursday, 1 March 2012

Cultural species selection

In a video interview between John Maynard Smith and Richard Dawkins, Maynard Smith suggests that the distribution of parthenogenesis on the twigs of the tree of life shows that sexual recombination is a trait which is often maintained by species-level selection. The video is called: Explaining the maintenance of sex.

Maynard Smith goes on to explains why there's no parthenogenesis in conifers and mammals in another video, called: Are mammals stuck with sex?

Are there other traits which appear to be maintained by species-level selection? John Maynard Smith suggests viviparity as another possibility - in a video called: Viviparity may be a big evolutionary mistake!

Small size is another obvious candidate. Meteorite strikes regularly kill all species with individuals larger than a mouse. So there is systematic species-level selection for being small. Living in the deep ocean is probably favoured by species-level selection on similar grounds. Of course, these are cases where species-level selection gets rapidly swamped by other forces.

The other candidates that spring to mind involve traits that result in speciation. Easily evolving incompatible songs, habitats, or genitalia are other possible candidates. A tendency to swim off to islands might produce new species.

Self-incompatibility is one trait though to be subject to species selection - and a study titled: Species Selection Maintains Self-Incompatibility.

Culture has species too - or at least it has groups of cultural entites that cross easily among themselves but harder with outsiders. Outcrossing is never entirely prohibited in the realm of culture, but things like Cobol programs or origami designs are pretty closely analogous to cultural species - in that they recombine with each other a lot more than with the rest of culture. Is there cultural species selection? So far, we don't seem to have a lot of data on the topic. However, because species boundaries are weaker, cultural species selection may be a less significant force than species selection is in the organic realm.

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