slartibartfastibast:

shieldfoss:

slartibartfastibast:

shieldfoss:

cromulentenough:

firerozebud:

catchymemes:

Conditional Immortality of Lobsters

wait, how does this work with all those giant prehistoric bugs (scorpions and dragonflies and stuff) that were giant in the time of the dinosaurs or whatever. Is it just that they were species that never needed to molt or is there some other reason why this wasn’t an issue for them?

I don’t think insects molt. I don’t know if Scorpions do.

Limitations of oxygen metabolism are different when amount of oxygen is different.

That makes sense

To answer the original question more fully:

On earth, water tends to have a wider range of possible oxygen concentrations than air (mostly because gas is more immediately turbulent, whereas liquids are waaay less immediately turbulent (but technically both are still fundamentally turbulent, unless of the super variety (but I mean come on))). If that’s indeed a major thing constraining lobster size, there would be places small lobsters can go that old lobsters can’t, so maybe someone could look for evidence of that. The maximum size would then be determined by the accessible environmental maximum of oxygen concentration, which could be crazy high in some places, idano. On land, the species size maximum is generally set by much harder limits related to oxygenation and circulation physics stuff. When submerged, the wateriest subsets of land-biology anatomy lose many of the gravitation/bouyancy-related pressures they’ve had to contend with since first leaving the water (in the evolutionary sense). This is also why human legs swell up shrink [edit: herpderp] for a while when we first inhabit microgravity.

The size distribution of water-animals-that-didn’t-leave-for-a-while-and-then-return-with-fucking-upwards-facing-nostrils-on-their-backs will have a more apparent per-species variance than we’re used to seeing on land. Robert Wadlow was only about me-and-a-half along the longest dimension, and his heart gave out pretty early. So, like, fish and crustaceans and cephalopods and reptiles and stuff, but not mammals. Whales can be big, but they still have a hard in-vivo developmental upper bound on size from the doggo days.