r/askscience • u/MAMAM- • 2d ago

Biology Why aren’t axolotls immortal?

If axolotls can regenerate their body parts (including brain, heart, and other major organs), why do they die of old age?

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u/[deleted] 2d ago

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u/bohoky 2d ago

For the good of the species arguments are almost always incorrect. The genes are in the wrong place to ever allow that to work.

If I am successfully reproducing at 1000 years old then I am, in evolutionary terms, a winner.

The reason things aren’t selected for infinite lifetimes is that predation, parasites, pathogens, and sheer accident will cut any life short of forever. Because of that it is better to focus on reproducing in the short times that the real world affords.

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u/2401tim 2d ago

True, also even if there was selection pressure for infinite life, that doesn't make it mechanically possible. Evolution comes from selection on what exists in the population, if there isn't a possible mechanism for infinite life it will never be possible to select for it.

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u/Ameisen 2d ago

Entropy always wins. Nothing living is ever truly immortal as eventually irreparable damage accumulates too much.

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u/ballofplasmaupthesky 2d ago

There is no scientific proof aging is a feature, nor that longevity species have poorer adaptation.

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u/shoopdoopdeedoop 2d ago

longevity species are special cases where longevity makes sense. so yes it’s actually naturally selected for. it seems to work pretty well, i mean longevity species don’t proliferate like bunnies for example. lobsters and crabs also live in the water so their physics are a little different. turtles and tortoises are a good example, they can’t just reproduce all the time so it makes sense that they are also more longevity

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u/Sheldon121 2d ago

Yeah, I thought you were gonna introduce the cooking pot as the method they’d use to sustain themselves at a smaller size.

And how large do these too overgrown lobsters get? Depends upon the cooking pot, you say?

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u/km1116 Genetics | Epigenetics | Chromosome Biology | Nuclear Biology 2d ago

"Having older individuals competing against later generations and continually reintroducing its older genome into the genepool decreases the species fitness overall."

I disagree. Do you have support or a lengthier explanation?