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>it's fair to say that cooperation for the goal of increasing diversity is a pretty heavily selected for trait. It seems like you're making the mistake of thin

>it's fair to say that cooperation for the goal of increasing diversity is a pretty heavily selected for trait. It seems like you're making the mistake of thinking that traits we see were necessarily being actively selected for. It's like saying that because we see an increase in complexity in organisms over time, that evolution is selecting for complexity (its not). It's true that more diverse populations can withstand changes to the environment better. But to then say that the trait of diversity is selected for is a huge stretch. If diversity has no current value then it won't be selected for, and will be selected against in competitive environments. Evolution doesn't have a way to see into the future in that way. Diversity might be selected for in cooperative populations, but only when diverse behavior provides an immediate benefit to the population.

jawarner 9y ago
> 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.
  - deleted 9y ago
    [deleted]
ouid 9y ago
It's not a huge stretch. The two statements are logically equivalent. The only organisms which can be said to have been successful are the ones who are either alive today, or were the n-grandparents of the organisms alive today. Zero organisms alive today have n-grandparents whose reproductive strategy did not encourage diverse offspring. Not all diversity is adaptive, but exactly no anti-diversity is adaptive. Therefore diversity is selected for.
- hackinthebochs 9y ago
  >Zero organisms alive today have n-grandparents whose reproductive strategy did not encourage diverse offspring An obvious counter example seems to be species that reproduce through cloning. >Therefore diversity is selected for. "Selected for" has a precise meaning. You guys are using it way too loosely. Selected for simply means the differential survival of one trait over another. There is no time where "diversity" (that isn't really a more specific adaptation) is selected for.
  - ouid 9y ago
    diversity is selected for as a heritable trait when big, unpredictable changes to the environment end lineages which do not have sufficient heritable tendency towards diversification.
    - scythe 9y ago
      At some point you guys have to start putting this into a mathematical model or it devolves into wordplay. (For example, I could easily say that versatility is selected for rather than diversity. But who cares? We're not saying anything scientific if it doesn't have a formal definition.
    - hackinthebochs 9y ago
      >diversity is selected for as a heritable trait I just don't see this as being meaningful. There is no heritable "diversity" trait. You can apply these concepts at the population level, but only very loosely. The other problem I have is that any metric of diversity decreases over time for a population. Normally when we say evolution selects for trait X, your metric for X increases over time. Instead of diversity being selected for, its more like the gas that drives the engine of evolution. Without diversity in a population, natural selection can't happen. But the diversity comes first.

jawarner 9y ago

> 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.
- deleted 9y ago
  [deleted]

ouid 9y ago

It's not a huge stretch. The two statements are logically equivalent. The only organisms which can be said to have been successful are the ones who are either alive today, or were the n-grandparents of the organisms alive today. Zero organisms alive today have n-grandparents whose reproductive strategy did not encourage diverse offspring. Not all diversity is adaptive, but exactly no anti-diversity is adaptive. Therefore diversity is selected for.

hackinthebochs 9y ago
>Zero organisms alive today have n-grandparents whose reproductive strategy did not encourage diverse offspring An obvious counter example seems to be species that reproduce through cloning. >Therefore diversity is selected for. "Selected for" has a precise meaning. You guys are using it way too loosely. Selected for simply means the differential survival of one trait over another. There is no time where "diversity" (that isn't really a more specific adaptation) is selected for.
- ouid 9y ago
  diversity is selected for as a heritable trait when big, unpredictable changes to the environment end lineages which do not have sufficient heritable tendency towards diversification.
  - scythe 9y ago
    At some point you guys have to start putting this into a mathematical model or it devolves into wordplay. (For example, I could easily say that versatility is selected for rather than diversity. But who cares? We're not saying anything scientific if it doesn't have a formal definition.
  - hackinthebochs 9y ago
    >diversity is selected for as a heritable trait I just don't see this as being meaningful. There is no heritable "diversity" trait. You can apply these concepts at the population level, but only very loosely. The other problem I have is that any metric of diversity decreases over time for a population. Normally when we say evolution selects for trait X, your metric for X increases over time. Instead of diversity being selected for, its more like the gas that drives the engine of evolution. Without diversity in a population, natural selection can't happen. But the diversity comes first.