On Tuesday, October 4, 2022 at 2:21:01 AM UTC-4, DD'eDeN aka note/nickname/alas_my_loves wrote:
https://www.sciencedaily.com/releases/2022/09/220928113007.htm
Per r norman at SAP:
Invertebrates and early chordates, like the hagfish (myxine), have
body fluids very similar to sea water, which has not changed that much
in the half billion years. There are differences in individual ion concentrations, but the osmotic pressure is very close. The later
vertebrates are a completely different story, having salt
concentrations far lower. One major hypothesis (frankly, I do not
know whether it is universally accepted) is that they evolved in fresh
water. Modern marine vertebrates including sharks, bony fish,
reptiles, birds, and amphibians, reinvaded the ocean afterwards.
So the body fluids of humans, mammals, and tetrapods in general is
much lower than sea water not because sea water was more dilute back
then but because they inherited that feature from freshwater
ancestors.
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)