Comment on MIGHTY MIGHTY HETEROMORPHIN TIME

lol3droflxp@kbin.social ⁨11⁩ ⁨months⁩ ago

• GBU_28@lemm.ee ⁨11⁩ ⁨months⁩ ago

  This was the “fuck around” era of evolution and being wacky was cool

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• LouisGarbuor@sh.itjust.works ⁨11⁩ ⁨months⁩ ago

  In my history of life class I was tought it was to do with controlling buoyancy, although all the variation seems odd for that.

  Maybe a combination of controlling buoyancy with species identification?

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  • lol3droflxp@kbin.social ⁨11⁩ ⁨months⁩ ago

    Might be plausible. I’ll have to look it up at one point, maybe there’s some research on this. I think it may be hard to guess why because we don’t have many swimming animals with shells. I don’t know if snails may offer some answers but they are maybe to different in lifestyle.

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    • LouisGarbuor@sh.itjust.works ⁨11⁩ ⁨months⁩ ago

      Probably too different, as snails are benthic, while ammonites where probably nektonic.

      Iirc the shells being longer is something about allowing gases in the shell to compress or expand as needed to control bouyancy. I would imagine there is a sac of gas, and the ammonites would siphon water in or out as needed to compress or decompress the gas.

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      • lol3droflxp@kbin.social ⁨11⁩ ⁨months⁩ ago

        It is certainly a challenge to keep a large animal with such a thick shell afloat. However that would just explain the immense size of the shells. Their shape is just extremely weird and sometimes I’d even expect it to be detrimental to their ability to navigate the open water. If they were planktonic it would not be as problematic I guess but I still don’t see the functional advantage. Maybe mimicry? But of what?

        They look a lot like the calcareous shells of some polychaetes but they have a sedentary lifestyle attached to rock or other substrates which is not what we’d expect for Ammonites.

        Maybe it’s a puzzle that will remain unsolved.

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