I think I missed an opportunity in this video to discuss the difference between the osmotic pressure and ion gradients, but I'll be honest...I do not know a good, simple way to explain it!
By the way Hank, your video about the hardest problem evolution ever solved inspired me so much that I created a whole Dungeons and Dragons species whose tale embodies these struggles and overcoming them and it's one of my favorite things that I've ever made
13:45 team, take a breath. The part of that air you really need—the O2 molecule—that was put there BY WORK. For billions of years, Cyanobacteria in the ocean have pumped that O2 out molecule-by-molecule as a byproduct of all their effort. That O2 is what made the ozone layer—which works with the earth’s magnetic field to make the surface of our planet livable and not a radiated hellscape. We get to be here because of incalculable amounts of effort that came before. Life made the world for us. The truth is—I promise—that the world really wants you to be here.
I think we forget how much of evolutionary time was spent on basic cellular mechanisms (why we share so much DNA with plants). My guess is that all of these things are probably possible but that the amount of time necessary to find basic cellular changes (especially if you don't want to break the higher organism stuff) is just stupendous compared to the time it takes to evolve some organs or other ways to deal.
So after a few minutes, it's obvious that the correct question isn't "why don't ocean fish taste like salt" because it's "why don't sharks taste like pee."
Fish electrophysiologist here, this fish ion channel stuff is my jam! My PhD lab and several old colleagues studied this stuff for their living. Thanks Hank, this is the type of stuff we'd talk about over beers.
Hank covered osmolarity and sodium, but I wonder if calcium may be an even bigger deal? Calcium is high in sea salt but its concentration is intensely controlled in the cells and blood. Almost every time your body converts electricity into action - like a muscle contraction, neurotransmitter releasing, apoptosis, insulin release, even stopping a second sperm from entering an egg cell! - calcium is the converter. It's crazy how central this is: calcium is almost always the bridge between electricity and other physiological responses. If it's not controlled, the heart stops, the brain cells can't communicate, and most organs fail.
A common theme: change in a cell's ion concentrations (voltage) -> calcium channels open in response (voltage dependent calcium channels) -> calcium concentration increases, sometimes in just a tiny part of a cell -> calcium bind to proteins and trigger a change in their shape.
you say I've done nothing all day but you wouldn't believe the ion gradients I'm maintaining
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Hank: The Ocean is trying to turn fish into ocean.
D=
Hank covered osmolarity and sodium, but I wonder if calcium may be an even bigger deal? Calcium is high in sea salt but its concentration is intensely controlled in the cells and blood. Almost every time your body converts electricity into action - like a muscle contraction, neurotransmitter releasing, apoptosis, insulin release, even stopping a second sperm from entering an egg cell! - calcium is the converter. It's crazy how central this is: calcium is almost always the bridge between electricity and other physiological responses. If it's not controlled, the heart stops, the brain cells can't communicate, and most organs fail.
A common theme: change in a cell's ion concentrations (voltage) -> calcium channels open in response (voltage dependent calcium channels) -> calcium concentration increases, sometimes in just a tiny part of a cell -> calcium bind to proteins and trigger a change in their shape.
hank: fish
Also Hank: Fish keep the ocean outside of their body.
Give that person a raise! 😂