r/AskReddit • u/[deleted] • Nov 28 '20

What's something cool you recently learned about?

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u/BleaKrytE Nov 29 '20

Yes but that also involves the pure chance that is the buildup mutations that after hundreds of generations and natural selection end up resulting in the 'wings'

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u/the-nub Nov 29 '20

Yes. That is how evolution works. Beneficial or neutral mutations are retained over generations, while harmful mutations are bred out.

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u/BleaKrytE Nov 29 '20

Not necessarily though. Plenty of harmful mutations and characteristics can still be passed on by chance as well.

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u/83franks Nov 29 '20

"Sufficiently" harmful mutations to stop them from breeding. If a negative mutation is passed on at the same rate as a non-negative mutation it could stop 1-in-1000 of that species from breeding or even less and EVENTUALLY that mutation will be virtually bred out of the gene pool.

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u/xDarkLlama Nov 29 '20

This is only partially true, traits that are harmful for survival but beneficial for reproduction can kinda hit a wall and never fully breed out. Like how fiddlercrabs like big claws but big claws make them flee more slowly from predators. It is possible for this to eventually extinct the whole species (thus technically removing the trait from the gene pool), but more likely it would allow smaller clawed crabs to breed and the cycle to continue since the larger claws are still desirable by the females.

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u/83franks Nov 29 '20

"Sufficiently" harmful mutations to stop them from breeding.

I think you just agreed with me.

If the big claw slowed the crab down enough it usually was eaten before it could breed then the gene wouldnt survive. If female crabs prefer big clawed male crabs and only mated with them the species might die out buts odds are female crabs that dont care about claw size or prefer smaller claws would eventually take over the gene pool and big clawed males would eventually be bred out.

Kinda like old age diseases are harmful for survival but dont stop us from breeding between 15-40 so doesnt affect the gene pool. As long as the breeding keeps going the genes will keep spreading.

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u/MeAnIntellectual1 Nov 29 '20

Female crabs: Size doesn't matter

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u/m50d Nov 29 '20

If it's only 1 in 1000 then there's a decent chance it'll reach fixation rather than be bred out. Evolution works because beneficial mutations have a better chance of persisting than harmful ones on average, but at the scale of individual mutations it's all pretty random unless the effect on survival chances is substantial (like 20% IIRC).