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You're basically arguing for a species-level (or at least a deme-level) view of selection. That's something that we've tried to find for many decades, and there

You're basically arguing for a species-level (or at least a deme-level) view of selection. That's something that we've tried to find for many decades, and there just isn't a lot of evidence for it. Selection happens at the level of the individual animal, not any higher grouping.

jawarner 9y ago
Why doesn't Hamilton's rule or evolutionary game theory in general justify a social-network aware view of evolution? What evidence or theoretical argument would constitute a species level view of selection?
statevol 9y ago
I've taught evolutionary biology to non-biology majors and the way I would explain natural selection is as follows. First, to clarify the last sentence above, selection does not happen at the level of an individual. Selection is a statistical process that requires a population of individuals. For evolution by selection to occur, there has to be 1) variation in traits (i.e. "Phenotypes"), 2) the variation in these traits has to be in part heritible (i.e. Have a genetic basis), and 3) there have to be average differences in success of leaving offspring that themseves go on to reproduce, etc, etc, based on the trait differences amongst individuas.
- int_19h 9y ago
  But diversity is not a phenotype in any meaningful way, is it?
  - akvadrako 9y ago
    Well you can either have a reproduction mechanism that encourages diversity or doesn't. That seems like a trait to me.
ouid 9y ago
I'm not sure what you think selection is. Organisms which do not have diverse offspring are very unlikely to maintain a lineage through big changes to the environment. Big changes to the environment are frequent. Therefore diversity of offspring, as a trait, is selected for.
- jballanc 9y ago
  Unless big changes to the environment happen at least once every generation, then there is no way that diversity of offspring will be selected for. Say you have a population of 100,000 organisms and 1 randomly mutates to produce more diverse offspring. That gives the gene a 0.001% occurrence in the population. Hardy-Weinberg principle says that gene will remain at about that percent of the population unless it is selected for. So if a generation passes without selection for that trait, there is a very high probability that gene's occurrence drops back to 0%. In other words, without a constant source of selection, there is no way for a trait to become fixed in a population.

jawarner 9y ago

Why doesn't Hamilton's rule or evolutionary game theory in general justify a social-network aware view of evolution? What evidence or theoretical argument would constitute a species level view of selection?

statevol 9y ago

I've taught evolutionary biology to non-biology majors and the way I would explain natural selection is as follows. First, to clarify the last sentence above, selection does not happen at the level of an individual. Selection is a statistical process that requires a population of individuals. For evolution by selection to occur, there has to be 1) variation in traits (i.e. "Phenotypes"), 2) the variation in these traits has to be in part heritible (i.e. Have a genetic basis), and 3) there have to be average differences in success of leaving offspring that themseves go on to reproduce, etc, etc, based on the trait differences amongst individuas.

int_19h 9y ago
But diversity is not a phenotype in any meaningful way, is it?
- akvadrako 9y ago
  Well you can either have a reproduction mechanism that encourages diversity or doesn't. That seems like a trait to me.

ouid 9y ago

I'm not sure what you think selection is. Organisms which do not have diverse offspring are very unlikely to maintain a lineage through big changes to the environment. Big changes to the environment are frequent. Therefore diversity of offspring, as a trait, is selected for.

jballanc 9y ago
Unless big changes to the environment happen at least once every generation, then there is no way that diversity of offspring will be selected for. Say you have a population of 100,000 organisms and 1 randomly mutates to produce more diverse offspring. That gives the gene a 0.001% occurrence in the population. Hardy-Weinberg principle says that gene will remain at about that percent of the population unless it is selected for. So if a generation passes without selection for that trait, there is a very high probability that gene's occurrence drops back to 0%. In other words, without a constant source of selection, there is no way for a trait to become fixed in a population.