Oddbean

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 @0c1a9324 @f740824b Living and active Grandmothers have a protective effect for grandchildren's survival and thriving in both whales and humans. So it's possible that evolution does select for a healthier old age, just not for men.

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 @e0c06ded @f740824b Yes, but men and women are just minor permutations of a common, shared genome—we're the same species, after all! So selection for longevity in one sex will spill over to the other.

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 @0c1a9324 @e0c06ded Yes. And what is the big picture, what is nature's agenda? Can it have one? It seems to.

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 @0c1a9324 @e0c06ded And longevity is never immortality.

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 @e0c06ded @0c1a9324 yes-- but it almost all organisms it still maintains the "planned obsolescence". Longer life for some, yes. But still quite finite. Still set up to to break down. Aging is not an accident of nature, it's a tool of nature. It has variances sure.

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 @f740824b @e0c06ded Vertebrate animals have ageing. It's less obvious that invertebrates, eukaryotes, and non-animals (eg. plants and fungi and archaea) have baked-in senescence: indeed, many don't. (I speculate wildly that senescence is a side-effect of cellular differentiation into specialized tissues including the immune system, and didn't get selected out because it didn't impair reproductive fitness. Cf. naked mole rats—mammals with extreme longevity and cancer-resistance.)

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 @0c1a9324 @e0c06ded It may be a side effect but it seems very pragmatic and that argues for evolutionary selection. It has value for a species. But I think DNA has some secret we haven't uncovered yet.