3 ms·

> A species that goes years without losing any blood, is effectively operating its body in an evolutionary out-of-spec configuration. It might work, for a while

> A species that goes years without losing any blood, is effectively operating its body in an evolutionary out-of-spec configuration. It might work, for a while; but it wasn't heavily optimized for. I think your/the hypothesis fails...take certain species of jellyfish that are biologically immortal, they don’t have blood at all. Coincidentally they are considered top of the food chain, so another knock to the hypothesis.

peterwoerner 6y ago
I think she/he/it was referring more specifically to mammals and other animals with blood.
- throwaway_jobs 6y ago
  Why would you think they were referring specifically to mammals? Mammals isn’t mentioned once whereas species/animals is used very broadly In the context of very broad ideas of evolution. In either case, the hypothesis suggests animals should live longer in the wild than in captivity. So let’s take the only mammal that isn’t more likely to die from age/don’t die from old age, the naked mole rat. We don’t understand why they die and any given day there is a 1 in 10,000 chance they die at any age. In captivity they should have the same lifespan as lab rats (6 years); however, in the wild the have an average lifespan of 17 years and in captivity that expands to 30 years (again in contrast to the hypothesis where wild animals of the same species should live longer than those in captivity).
derefr 6y ago
> they don't have blood at all Then that would be an evolutionary in-spec configuration, since Cnidaria-phylum species have evolved under selection pressure for hundreds of millions of years in that "never losing blood, because it doesn't have any" configuration. For a similar reason, you wouldn't expect most plants to be troubled/benefited by the loss of solutes (= sap); a maple tree should probably live about the same lifetime whether it's tapped or not, because maple trees evolved mostly without predation. But for plants that have evolved over eons entirely under conditions of predation (e.g. where they're a primary ecological water source, like cacti in the desert—observable by the fact that they possess defenses to predation), you would expect a difference in longevity between those that lose transported solutes to predation, vs. those who don't.

peterwoerner 6y ago

I think she/he/it was referring more specifically to mammals and other animals with blood.

throwaway_jobs 6y ago
Why would you think they were referring specifically to mammals? Mammals isn’t mentioned once whereas species/animals is used very broadly In the context of very broad ideas of evolution. In either case, the hypothesis suggests animals should live longer in the wild than in captivity. So let’s take the only mammal that isn’t more likely to die from age/don’t die from old age, the naked mole rat. We don’t understand why they die and any given day there is a 1 in 10,000 chance they die at any age. In captivity they should have the same lifespan as lab rats (6 years); however, in the wild the have an average lifespan of 17 years and in captivity that expands to 30 years (again in contrast to the hypothesis where wild animals of the same species should live longer than those in captivity).

derefr 6y ago

> they don't have blood at all Then that would be an evolutionary in-spec configuration, since Cnidaria-phylum species have evolved under selection pressure for hundreds of millions of years in that "never losing blood, because it doesn't have any" configuration. For a similar reason, you wouldn't expect most plants to be troubled/benefited by the loss of solutes (= sap); a maple tree should probably live about the same lifetime whether it's tapped or not, because maple trees evolved mostly without predation. But for plants that have evolved over eons entirely under conditions of predation (e.g. where they're a primary ecological water source, like cacti in the desert—observable by the fact that they possess defenses to predation), you would expect a difference in longevity between those that lose transported solutes to predation, vs. those who don't.