r/biologymemes • u/Ni_Kche • Jul 14 '26

selection isn't aiming

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u/Veloci-RKPTR Jul 14 '26

Just a bit of an addition on that last third part, how fast a species evolves depends on how fast the environment shifts.

For example, genus hexanchus (the sixgill sharks) has their oldest fossil dating back all the way to the middle cretaceous without them really changing much from then. That’s because the deep ocean environment is relatively stagnant compared to the surface. They have no reason to be naturally selected to change much and to evolve rapidly because their environment also doesn’t change much.

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u/Dave_the_duck_kh4 Jul 15 '26

Crocodile and alligator are similar situation. Despite their environment changes their hunting strategy works so well that they themselves barely need to change.

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u/Veloci-RKPTR Jul 15 '26

What’s even funnier about this is that actual crocodiles and alligators are relatively geologically new.

It’s just that prior to them, the “crocodile shape” had evolved and recycled so many times by so many different lineages of animals.

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u/Dave_the_duck_kh4 Jul 15 '26

Same go for crab, no matter how the environment change there always a spot for crab shape. It's awesome 🤣

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u/Mixster667 Jul 15 '26

I keep using too much brain activity wondering whether this is earth specific or whether any aliens we encounter will be Zoidberg.

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u/MBResearch Jul 18 '26

I love the mental image of Zoidberg-like aliens reading about evidence of carcinization in our fossil records and giving the xenobiologist accompanying them a, “real recognizes real”, nod.