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> Evolution doesn't have a way to see into the future in that way. Model A: Let's say there is an environmental change every 100 years, and if a population is

> Evolution doesn't have a way to see into the future in that way. Model A: Let's say there is an environmental change every 100 years, and if a population is not diverse enough, then it dies. After 1000 years, we would expect the only populations to be around would be those that are diverse. Yes, it is true that if there there is a short-term advantage to nondiversity in a population, then it will evolve to be nondiverse, and it will die - in this sense you're right that evolution does not see into the future. However, given the existence of diverse populations assuming the Model A, we can conclude that these populations have found a local minimum of fitness in which diversity is advantageous. Further, there might be "genetic guards" to nondiversity, such that fixation of a gene promoting nondiversity is rare (because this would resilt in extinction!), either through social sexual selection or by such a mutation being a rare event.

hackinthebochs 9y ago
>However, given the existence of diverse populations assuming the Model A, we can conclude that these populations have found a local minimum of fitness in which diversity is advantageous. But any mechanism in which "diversity" is advantageous will be advantageous for more specific reasons. Diversity is just too unspecific. Perhaps you're speaking in terms of group selection, so in a sense evolution evolves diversity in populations. But I don't think this works either. Aside from group selection itself being highly questionable, every environmental event in your Model A would reduce the diversity of the remaining populations. Remaining populations were more diverse in the past (owing to their ability to survive abrupt environmental shifts), so any trend in diversity is in fact downward on large timescales. On short timescales, diversity only grows when there are no selective pressures at work on a given gene. There just is no pro-diversity selection going on.
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hackinthebochs 9y ago

>However, given the existence of diverse populations assuming the Model A, we can conclude that these populations have found a local minimum of fitness in which diversity is advantageous. But any mechanism in which "diversity" is advantageous will be advantageous for more specific reasons. Diversity is just too unspecific. Perhaps you're speaking in terms of group selection, so in a sense evolution evolves diversity in populations. But I don't think this works either. Aside from group selection itself being highly questionable, every environmental event in your Model A would reduce the diversity of the remaining populations. Remaining populations were more diverse in the past (owing to their ability to survive abrupt environmental shifts), so any trend in diversity is in fact downward on large timescales. On short timescales, diversity only grows when there are no selective pressures at work on a given gene. There just is no pro-diversity selection going on.

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