0:02 There's only three more days left to get
0:04 this shirt designed by Matias Ball
0:06 because I wanted it to exist and now it
0:08 does and we're making exactly as many as
0:09 get ordered during the pre-order period
0:11 and then we cut it off and that cut off
0:13 date is 3 days from now and I wanted you
0:14 to know that so you don't miss your
0:18 chance. I got so many questions so many
0:20 questions on that video and so many of
0:23 them were very good. I again it makes me
0:24 want to write this book. But one of the
0:26 things people brought up and I have not
0:27 yet read it though I have gotten it on
0:30 Audible is your inner fish by Neil
0:32 Schubin which is a book that is kind of
0:34 about this. It's not entirely about
0:36 this. It's not like just about the
0:38 transition to land but it is about a lot
0:39 of the same stuff. So if you want a book
0:42 like this that book exists but I have
0:44 taken 48 screenshots of questions.
0:46 There's no way I'm going to be able to
0:47 make it through all of those. But let's
0:48 just start. Let's just start and see
0:50 what happens. Most importantly is this
0:54 the same thing as exaptation? No. And
0:56 indeed, I used neofunctionalization
0:58 incorrectly several times in that video.
1:00 Now, I'm not that worried about it. I
1:01 didn't like make one little edit in the
1:04 video to fix a particularly egregious
1:06 instance, but exaptation and
1:08 neofunctionalization are two different
1:10 terms for similar phenomenon.
1:12 >> Neofunctionalization is specifically a
1:15 genetic term when a gene duplicates and
1:17 then there's two copies of the gene and
1:19 then the new copy starts to do something
1:21 new. This happened with keratin a bunch.
1:22 keratin. There's a bunch of different
1:24 keratin genes that do like different
1:25 versions of keratin and each one of
1:27 those is a duplicated gene that then
1:29 took on a new function. Exception is
1:31 sort of a broader term for when some
1:33 existing physiological structure gets
1:35 used in a new way. I use that
1:35 interchangeably with
1:38 neofunctionalization which technically
1:40 is not something that you should do. Do
1:41 whales and company have to unchange the
1:44 shape of their cornea when Oh yeah, they
1:48 did. They did this. Yes. Not only that,
1:51 whale eyes, seal eyes, penguin eyes, all
1:53 did this. Not only did they change the
1:54 shape of their cornea when they went
1:56 back into water, they changed the shape
1:58 of the lens back to a sphere. They all
2:01 of them did this. Isn't that amazing?
2:03 Independently, like these are not
2:05 related animals. Citations and seals and
2:07 penguins are not related. Why did our
2:11 ancestors try and die doing this? I've
2:12 always understood evolution to be lazy
2:13 and that it only does what is necessary
2:15 for survival. Why did our ancestors/evolution
2:16 ancestors/evolution
2:18 want to attempt this feat? Was it to
2:20 escape predators? It was a survival
2:22 advantage. I probably shouldn't have
2:24 said it this way that like did they die
2:25 doing this? Yes, of course they died do
2:28 doing this, but they also survived doing
2:30 it. So, there was an ecological niche
2:33 that became available to them when they
2:34 were able to move on to land. There was
2:36 food there that they otherwise would not
2:38 have access to. And the animals that
2:39 could get access to that food were able
2:41 to make more of themselves. It was a
2:44 success. They were more successful if
2:46 they were able to get onto land and eat
2:48 the bugs that had never seen a
2:50 vertebrate before. Eat the plants that
2:53 were not being eaten by anything and had
2:56 no no mechanisms to prevent themselves
2:58 from being absolutely delicious and full
2:59 of calories. There was a bunch of
3:01 survival advantages to coming onto land.
3:03 And and most of these I mean all of
3:05 these early animals didn't just go onto
3:06 land and stay there. There's kind of
3:08 this idea of Tik Tok being like it
3:10 dragged itself out onto land and it's
3:12 like I'm a land animal, but there was a
3:15 huge amount of time during which all of
3:17 these animals spent some time on land
3:19 and some time in water. And then over
3:21 time, you know, that the ability to stay
3:25 on land for longer increased because the
3:26 further you could go onto land, the more
3:28 value there was in staying on land, the
3:30 more of a new niche you could move into.
3:32 And so every step further, there was a
3:35 huge incentive to take that step because
3:37 there was food there. Um, there were
3:38 also no predators. But I think that the
3:41 big thing was the amount of food that
3:42 they otherwise wouldn't have access to
3:45 or that was being competed for when they
3:46 were in the water. Yo, is that shelf in
3:48 the background broken? No, it was it was
3:51 built that way. I wanted it to be weird.
3:53 And it is. I don't I can't actually
3:55 change the angle of this. I can do a
3:57 phone video, though. The kind of idea
3:59 when we were designing this uh was like
4:02 uh my office crashed into an office. So,
4:03 I get that it looks broken, but this
4:05 part over here is all slanty. And then
4:07 this part here is straight. Straight is
4:09 actually much more useful, much more
4:10 functional, as you might expect. There's
4:13 other uh slanty. There's slanty shelves
4:15 over there. There's a shelf in the
4:17 ceiling, which I love. I need to fix
4:19 that soundproofing, but you know, this
4:21 is I found this light fixture, which
4:23 kicks ass. I honestly kind of wish it
4:25 was broken. Like what my dream was to
4:26 find a bunch of shelves and then mash
4:27 them together, but that turns out to be
4:28 much harder than building them from
4:30 scratch. We have experimented with
4:32 putting glasses that flip vision upside
4:34 down on people. And after enough time,
4:36 they adapted and everything now seemed
4:38 to be the right way up for them. Could
4:39 the same happen with underwater vision?
4:41 No. So in that case, the light was still
4:43 focused on the point it was supposed to
4:44 be focused on. In the case of going
4:46 underwater and having vision, the light
4:48 doesn't hit in a point. It doesn't
4:51 focus. It hits broadly. And taking that
4:53 information and forming that into
4:55 something useful is not as far as I know
4:56 something that can be done through like
4:58 post-processing, which is this is like
4:59 the brain doing it rather than the
5:01 actual function of the eyeball. That's
5:02 something that has to be fixed like in
5:03 the camera. Like if your camera's out of
5:06 focus, you can't get it in focus with
5:08 enough brain power. You have to have it
5:10 be in focus. Since we're still saltwater
5:13 sacks, why salt water dehydrate? I
5:15 understand there's like a concentration
5:16 gradient thing involved, but I don't get
5:19 it. So, we never left the water. But
5:21 importantly, we did actually leave the
5:24 ocean. So, I fudged over this. The
5:27 ancestor of all the tetropods was not a
5:30 saltwater ancestor. It was a freshwater
5:32 ancestor. And this makes sense for a
5:33 number of different reasons. First,
5:36 because of breathing. So, these lungs
5:38 started to increase in capacity. They
5:41 started become more useful because there
5:42 was a situation where there wasn't a lot
5:44 of oxygen in the water. And that doesn't
5:45 tend to happen in salt water that much.
5:47 Does sometimes, but not usually. tends
5:49 to happen much more frequently in fresh
5:51 water. Second, another bunch of stuff
5:52 that I did not talk about in this video
5:54 was like temperature swings and how
5:56 important that was for leaving the
5:58 water. So, tetropods when they were
6:00 first like going on land a little bit,
6:01 it would have been really hard to do
6:04 that from the ocean. And like you can do
6:06 it, crabs do this. Crabs have all kinds
6:08 of ways to deal with big swings in
6:10 temperature, but if you're just in the
6:12 ocean, the temperature swings are very
6:13 mild. And if you're on land, the
6:15 temperature swings are massive. But if
6:17 you're in fresh water, the temperature
6:19 swings in fresh water can be pretty
6:21 significant. And so it makes some sense
6:23 that the animals that would leave the
6:24 water would be once they were already
6:26 somewhat used to larger swings in
6:28 temperature, which is more likely to
6:30 happen in stagnant freshwater than in
6:32 the ocean, which is very big and has
6:33 lots of mixing from lots of depths and
6:35 has a more consistent temperature. And
6:36 there were other reasons for why
6:40 freshwater lobe finned fish were I think
6:41 like kidneys. So kidneys were very
6:44 important. Freshwater fish had to evolve
6:46 kidney-like structures so that they
6:48 could sometimes deal with the extra salt
6:50 that they would encounter in brackish
6:53 environments. So kidneys might actually
6:54 there were people in the comments who
6:55 made the case that kidneys are the
6:58 bigger difficulty than skin which I'm
7:00 perfectly open to and maybe that
7:02 question will come up in this list. What
7:04 is the second favorite fish? I can't
7:06 make it out in the picture. Uh my first
7:07 favorite is the angler fish and I should
7:09 make a video about both of these fish.
7:11 My second is the mulamola which I love.
7:13 People hate the molola. They say so many
7:15 mean things about it, but it is it is so
7:17 weird. It's the animal that goes like it
7:19 increases in size the most over the
7:21 course of its life. I love that. I have
7:22 a question. Can we see evolution
7:24 happening even now? Do we see things
7:25 that are documented differently 100
7:27 years ago or does evolution take longer
7:29 than that? We do see evolution happening
7:30 even now. There's like this famous moth
7:33 that has shifted its coloration as the
7:36 colors around it have shifted and then
7:37 actually shifted back. I think this was
7:40 a thing with like uh coal soot getting
7:42 on trees and the coal soot got on the
7:43 tree trees were darker and so they
7:45 became more visible and the ones that
7:47 were darker and more closely matched the
7:49 color of the tree were more likely to
7:50 survive and over the course of time they
7:52 shifted to darker and now there's not
7:53 that cold sod anymore. Am I making this
7:55 up? I should check. Peppered moth
7:57 evolution. Yeah, the evolution of the
7:59 peppered moth as an instant directional
8:01 color change in the moth population. The
8:03 consequence of air pollution during the
8:05 industrial revolution. I didn't make it
8:06 up. This is great. There's also
8:08 antibiotic resistance in bacteria.
8:10 That's obviously evolution happening
8:12 very quickly. There's also examples that
8:14 are are on shorter time scales but still
8:16 very long, like longer than human
8:18 memory. Darwin's finches uh probably
8:20 have been on the Galopagos, like the
8:21 first finch arrived there about a
8:23 million years ago. And then all of its
8:24 ancestors, there's a bunch of different
8:26 species that are all descended from this
8:28 one finch that arrived just a million
8:29 years ago that have very different
8:31 physiology in order to take advantage of
8:33 different niches in the environment and
8:34 different food sources. My favorite
8:36 example is actually an artificial
8:38 selection example. And this has happened
8:41 over thousands of years. So, this is so cool.
8:42 cool.
8:44 Got to make a whole video about this.
8:46 Wheat. We had wheat. We started doing
8:48 wheat agriculture. And we would weed the
8:51 wheat fields so that all of the plants
8:52 that weren't wheat weren't competing
8:54 with the wheat so that we would just get
8:55 wheat because we just wanted wheat so
8:57 that we can make bread and beer out of
8:58 the wheat. But you may have heard of
9:00 buckwheat. Buckwheat is a grain crop
9:04 that is super useful and it looks a lot
9:06 like wheat, but it is not like wheat. In
9:07 fact, it's gluten-free, which is why a
9:09 lot of people use buckwheat when they're
9:10 making pancakes or something for people
9:13 who are allergic to wheat. Buckwheat was
9:17 a weed that grew next to wheat. And when
9:19 we weeded the wheat, the buckwheat that
9:22 looked more like wheat was less likely
9:24 to get weeded by humans. And over
9:27 generations that weed bred in like
9:30 intermixed with different buckwheats
9:31 that looked more like wheat to the point
9:34 where buckwheat and wheat were almost
9:35 indistinguishable from each other. And
9:39 the wild thing that this created was not
9:41 a huge problem. It was an entirely new
9:44 edible crop. We artificially selected it
9:46 by accident so carefully to look like
9:51 wheat that it became a food. We we made
9:53 it a food by accident because it
9:56 couldn't look more like wheat without
9:58 getting the attributes of becoming more
10:00 nutritious and having bigger seeds that
10:02 like all the stuff that we were
10:03 selecting for when we were looking at it
10:05 when we were weeding actually made it
10:08 into a useful crop. So that's amazing.
10:09 That's not an example of natural
10:10 selection. It's artificial selection,
10:12 but it is kind of natural selection
10:15 because it wasn't done on purpose. It
10:18 was done by just a an animal. It's this
10:19 weird in between crease that's not quite
10:21 natural selection, not quite artificial
10:23 selection. Anyway, takes a long time for
10:26 evolution to happen, but like not so
10:27 long that we can't see it happening.
10:29 Could intelligent life evolve
10:32 underwater? It has a bunch octopuses,
10:34 man. But I think that um a more
10:36 interesting question, which is probably
10:37 the question you're asking, is could
10:39 like a civilization develop under a
10:40 water? And I don't know that it could. I
10:41 think that there might be limitations
10:45 there, specifically when it comes to
10:47 building. Yeah, I like I know that
10:48 people have written science fiction
10:52 about this, but chemistry is is hard is
10:54 easier on land. That's a weird thing to
10:56 say. Obviously, chemistry is easier in
11:00 the wet, but it is easier to control
11:02 things. It's easier to control your
11:03 environment when you're in a dry place
11:05 that you can figure out where the
11:07 different wetss are going to be and what
11:08 you're doing with it. I'm I know I
11:10 always come at these questions from from
11:11 a chemistry perspective, but like it
11:14 would be basically impossible to develop
11:15 the technologies we have developed while
11:19 underwater. And I think that that's
11:20 seems real. When talking about evolving
11:22 digits, you made a point to say on both
11:24 front and rear extremities, which makes
11:26 a lot of sense, but I had never even
11:28 thought about them evolving
11:29 independently. So now I can't stop
11:31 thinking about how we have the same
11:33 number of digits on both. Is that like a
11:35 weird coincidence? No. We use the same
11:38 genes to do both the left and the right
11:39 hand. We're not there's not like a
11:40 separate set of genes for them. We also
11:42 use the same genes to do the legs and
11:45 the feet. Like obviously we have like
11:47 different structures. But overall like
11:49 you know you have two bones here and you
11:52 have two bones here and you have like
11:54 one bone here and one bone in the femur
11:56 and then you have like all the different
11:59 metatarsils and digits and have the same
12:00 thing going on down there. Now this
12:02 isn't always the case. you can make
12:04 changes to that and obviously like these
12:06 are basically exactly the same mirror
12:08 images whereas the feet are quite
12:11 different but there are like the the
12:13 base level genes they're called hawk
12:15 genes that determine body plan we use
12:16 them over and over again and in fact we
12:18 don't just use them over again they're
12:19 used over and over again throughout the
12:21 history of life like the hawk genes for
12:24 lobe fin fishes are the same like this
12:27 like fairly well conserved from then to
12:30 now like weirdest uh version of this you
12:35 can take the hawk gene for a rabbit's
12:38 eyeball and put it in a fly genome where
12:40 it would normally express a part of the
12:44 butt and it will grow a fly eyeball on
12:46 the butt. Absolutely
12:48 one of the coolest things I've ever
12:51 heard about. Bro, just accept it was God
12:53 doing all this and stop confusing
12:54 yourselves and everyone. This is one of
13:00 the reasons why I don't like God. He
13:03 explains too much. If we take God and we
13:05 say, "Wow, good job explaining all of
13:09 this." We miss things. God is an answer
13:11 that answers every question. And if we
13:13 have an answer to every question, then
13:14 we stop looking. And I don't know that
13:17 even if like God exists that that's what
13:19 he would want or they would want or it
13:20 would want. I don't know what God is to
13:23 people. It seems that like there's a lot
13:25 of really interesting stuff here and so
13:27 we should indeed keep looking. That's
13:30 how I feel. Another person asked, um,
13:31 where does God fit into all of this? And
13:33 like, for me, obviously, nowhere. But
13:36 for you, anywhere you want God to be.
13:37 Like, I think that there's lots of
13:39 places for God to be. Maybe God isn't in
13:41 this story, but he's in another story
13:43 for you. Maybe he's in why we're
13:45 curious. Maybe he's in why anything
13:50 exists at all. Maybe he's in love. Maybe
13:51 he's in the relationships between you
13:52 and other people. I think God can be all
13:54 kinds of different places. Is it just
13:56 easier for arthropods to stay dry or is
13:58 that its own crazy story? It is its own
14:00 crazy story. And of course, they had to
14:02 independently evolve air breathing as
14:04 well, but staying dry was a really big
14:06 deal. Holding on to water was a really
14:09 big deal. For the bugs, they obviously
14:10 were able to do it before us. But yeah,
14:11 they did have to do specific things
14:14 evolutionarily to make it so that their
14:15 bodies weren't porous. They like figured
14:17 out how to coat their kitan in like a
14:20 waxy substance that held all of the
14:22 water in and also their joints. special
14:23 things have to happen with their joints
14:25 so that they wouldn't lose water. But
14:27 yeah, diff totally different story uh
14:29 and also a crazy one. And this is the
14:30 thing that I think would separate what I
14:31 would like to write or that I hope
14:33 somebody writes for like from the inner
14:35 fish which is more about like our bodies
14:37 and how that journey is represented in
14:38 us. But I would like to tell that story
14:41 of how everything like plants, bugs,
14:44 fungi, lyken, humans, like all how
14:46 everything went from this much more
14:48 hospitable environment to this
14:50 extraordinarily hostile one and and took
14:54 over that. And um and also like honestly
14:55 I going to make this video at some
14:58 point, but uh I think land is is
15:00 potentially a solution for the firm
15:02 paradox. Like land might be very rare
15:04 and also might be necessary for not
15:07 intelligence but civilization for
15:09 chemistry reasons interestingly but
15:12 that's just my thoughts
15:14 and that's not for this video. I'm
15:15 curious how many times an organism's
15:17 lineage has gone back and forth between
15:19 water and land or what is the organism
15:21 that we know has gone back and forth the
15:23 most times. So obviously tetropods came
15:25 onto land and then we went back into the
15:28 water as whales citations. Um and I
15:30 think that this has happened. So, uh,
15:33 roly polies. So, uh, uh, what are those
15:35 called? What are they called?
15:38 Uh, isopods. Isopods were originally
15:41 marine and they are also not marine. Uh,
15:43 they're with they're isopods that live
15:45 on land. But those land isopods have
15:49 gone uh back into freshwater. So, that
15:50 has definitely happened just like
15:52 mammals. But, I think there might be a
15:54 case where a freshwater isopod that came
15:57 from the land has re-evolved to the
15:58 land. I'm not sure about that though. I
16:00 tried to do research on this question
16:03 and that is as close as I got to like
16:05 somebody who has done one more step. So
16:07 obviously the tetropods of the ocean
16:09 have never come back out onto land. But
16:11 in this case it may be that that
16:13 happened with isopods. Wait, how do
16:15 snakes get away without eyelids then?
16:17 Great question. They shed them. They
16:20 shed the protection on top of their eye.
16:21 So eyelids are for protecting the eye uh
16:23 because you get scratches on the eye.
16:25 They build up and they become a problem.
16:26 Snakes just get scratches on the eye and
16:28 then they shed their skin and they have
16:31 a new layer beneath that's fresh and
16:32 doesn't have the scratches anymore.
16:34 Isn't that cool? I spent five minutes
16:36 since watching this video wondering
16:37 about the evolution of kidneys in the
16:40 renal system. I assume our ability to
16:41 process water is related. But what was
16:43 the impetus to develop kidneys? I
16:44 actually already answered this question
16:47 kind of. It was that the first kidneyike
16:49 structures were to handle for for
16:51 freshwater fish to handle saltwater
16:54 environments. I think, correct me if I'm
16:56 wrong, but yes, kidneys were very
16:57 important. Kidneys were very important
16:59 to taking on the land. If everything is
17:00 a fish, this brings up the age-old
17:03 question. Is shrimps bugs? Yeah, shrimps
17:06 is bugs. Shrimps is bugs.
17:08 Shrimps, I mean, they're they're
17:11 arthropods. Bugs is again, bugs is a
17:13 vibes word. Bugs is not actually just a
17:15 vibes word. There actually is something
17:19 called true bugs, but when you say bugs,
17:21 it is implied to not mean true bugs.
17:24 That's why there's a phrase true bugs to
17:26 just include the true bugs and not all
17:28 the other bugs. Is that a baked beans
17:29 furby? I don't believe I can't believe
17:30 you don't know about my baked beans
17:32 Furby. This is Beanie Sanfurbs. He's a
17:34 baked bean Furby made by the artist
17:36 Sophie G. Stark. You can go and look at
17:38 more of Sophie's work and be truly
17:40 terrified. If lobe fins are
17:42 protoappendages like arms and legs, does
17:44 that mean lobe finned fish have butts?
17:47 Because legs is butts. Look, butts are
17:50 legs. Legs are not butts. You can have a
17:52 leg without a butt. You just can't have
17:54 a butt without a leg. There are many
17:56 organisms that don't have butts but do
17:59 have legs. But in the case of butts,
18:01 they are a part of the leg. That's my
18:03 case. And I just to be clear, this is
18:06 not settled science. This is an inside
18:07 joke. I haven't watched in a while.
18:08 How's the cancer? The cancer is good as
18:10 far as I can tell. Been over two years
18:13 since I finished treatment and I have
18:15 remained in remission. But there is, you
18:16 know, they don't call you cured until 5
18:20 years. But we're just we're just going
18:21 day by day assuming that we're going to
18:22 be fine. Do you think somewhere out
18:24 there in the world could be an organism
18:26 that first evolved in a dry environment?
18:30 How alien would that look? Or not in our
18:31 planet. Do you think life can only
18:34 really begin in water? I'm a chemist and
18:37 like life would definitely need to begin
18:41 in a liquid. Air is too far apart. Gases
18:43 are too far apart and and solids
18:45 obviously don't move around. Like life
18:48 has to begin in a liquid. And I my my
18:50 feeling is that water is by far the best
18:52 one. I like I know lots of people who
18:54 are smarter than me who are like it
18:55 could totally like we we are keeping
18:57 open to the reality that it could happen
18:58 other ways. Obviously there are many
19:00 solvents that chemistry can happen in
19:02 and we know in our solar system we have
19:06 a a moon a world that has liquid water
19:08 cycle that isn't water. It's it's
19:10 methane and that's amazing. And so like
19:17 water is really good. Water is really
19:20 good for chemistry. I like I don't I
19:23 don't see it. But I'm just me. I'm just
19:25 a guy. Do humans evolve at a slower rate
19:27 than other animals? I'd imagine since
19:29 evolution takes so long and human lives
19:30 are so short, technology is basically
19:33 our replacement for evolution. But is it
19:35 a mix of both? At this point, humans,
19:38 well, what I'll say is to start, humans
19:41 evolve much much more quickly than any
19:43 animal that has ever existed. Way more
19:45 quickly. Look at this. Let me show you
19:47 some parts of my body that have very
19:50 recently, like within the the last like
19:52 50 years, have very recently evolved.
19:56 This is an earbud. This is a phone. This
19:58 is a a spray bottle that probably is a
20:00 little older than 50 years. This is a
20:03 tripod. This is a a camera lens. This is
20:06 a a yo-yo. Another recent evolution that
20:08 is an extension of of the body. We
20:10 evolve far more quickly than any animal
20:12 that has ever existed that we know of.
20:14 Certainly any organism on earth. But
20:16 yes, in terms of genetic evolution, we
20:20 currently uh like our world is not set
20:24 up to have humans evolve genetically
20:26 because our world is set up to to
20:28 decrease the amount of death as much as
20:31 possible and evolution happens mostly
20:32 when death happens. Now, there are some
20:34 ways that we think that humans are still
20:35 evolving. A big one is one that there's
20:37 been selective pressure toward the whole
20:39 existence of humans, which is the arms
20:42 race between the size of the baby's head
20:46 and the physiology of the birth. Um, and
20:48 uh, it looks like that evolution, you
20:50 know, up until fairly recently has been
20:52 still happening. The advent of
20:54 C-sections, very common C-sections. Uh,
20:55 so places where that happens, that means
20:57 that that evolutionary pressure no
20:58 longer exists. But yeah, uh, in terms of
21:01 evolution, we don't have we don't have
21:02 like genetic evolution happening at
21:03 anywhere near the rate that it used to
21:05 happen. But we evolve in other ways
21:08 extraordinarily quickly. Like cultural,
21:09 technological, all this language that
21:11 we're using right now is all uh, you
21:13 know, if if that were to evolve
21:16 genetically, it would take
21:19 billions, billions of years for this
21:23 level of information transmission to
21:24 evolve genetically. It's also really
21:25 interesting that keratin didn't really
21:27 adapt into a coating for the body, which
21:30 is what happened with arthropods. Uh
21:32 they they have developed a coating. What
21:33 happened instead was that the dermal
21:34 cells adapted into creating
21:36 exceptionally strong keratin skeleton
21:39 for themselves kind of such that when
21:41 they reach the outside and die, their
21:43 corpses leave behind a layer of tough
21:46 skeletons. Our skin is kind of I this is
21:48 why I included this. Our skin is kind of
21:51 like a coral reef. It is. I love that.
21:53 That's beautiful. And I this isn't
21:55 really a question, but that is that is
21:57 basically true. And what happens the nit
22:00 that I will pick here is that they don't
22:02 create an exceptionally strong keratin
22:04 skeleton for themselves. They create it
22:08 specifically to perpetuate the success
22:10 of the colony of cells that is the
22:11 organism. So they're not doing it for
22:14 themselves. They are murdering
22:16 themselves. They kill themselves to
22:18 protect the colony so that the colony is
22:20 more likely to pass on its genetic
22:21 information. Wait, is there really more
22:24 oxygen in air than the water? Yes. Um,
22:27 so this is a balance between two things.
22:30 So, uh, there's way more molecules. The
22:31 density of molecules is much higher in
22:34 water. Not of air, mostly of water,
22:35 mostly of water molecules, but also
22:37 other stuff. The density of molecules in
22:41 air is much lower. But the percentage of
22:44 oxygen in the air is much higher. And
22:46 that means that in absolute terms there
22:49 is more oxygen in a cubic meter of air.
22:51 More oxygen molecules not just density
22:53 or anything more absolute number of
22:56 molecules in air than absolute number of
22:58 oxygen molecules in a cubic meter of
23:00 water. There are according to rough
23:05 calculations I think around 5.6 * 10 21
23:08 oxygen molecules in a liter of air and
23:12 about 1.2 2 * 10 20 oxygen molecules in
23:14 a liter of ocean water. So that's way
23:17 more that's that's an order of magnitude
23:19 more than an order of magnitude more in
23:22 air than in water. And this is I think
23:25 we will end with this one. My favorite
23:28 question in the whole list. So if gas
23:30 exchange can happen in the gut, does
23:31 that mean we have little bits of farts
23:34 in our bloodstream? Yes. I had never
23:36 thought about this but I thought about
23:39 it and it is definitely true. So a
23:41 number of the gases that are produced by
23:44 microbes in our guts and and also just
23:46 the air that we swallow ends up in the
23:48 gut. A number of those molecules are
23:51 very permeable across that membrane of
23:54 the gut. Very water soluble. Hydrogen
23:56 sulfide can get in there. Hydrogen,
23:58 nitrogen, oxygen, all that stuff can
24:02 dissolve in the body and it definitely
24:04 like unless somebody can tell me why
24:06 this wouldn't happen like this is just a
24:09 physical property. Um, like unless there
24:11 happens to be more in the blood already
24:13 and there's just not like there's that
24:14 doesn't make any sense. It would
24:16 definitely cross it would definitely
24:18 cross that barrier and we would have
24:21 those molecules of fart gas in our
24:24 blood. Oh wait, I actually know a reason
24:26 why this is definitely the case. Using
24:30 dissolved gases to diagnose
24:33 disease, digestive disease. Analyzing
24:35 dissolved gases in the digestive tract
24:37 offers a non-invasive way to diagnose
24:40 various gastrointestinal conditions.
24:42 So I I thought I was talking out of my
24:45 butt. Turns out I I knew in my head
24:47 somewhere there was the knowledge that
24:50 we use dissolved gases in the blood to
24:52 actually learn about the digestive system.
24:54 system.
24:56 I love it. I love it. I love it. I love
24:58 it. Thank you so much for uh coming with
25:00 me on this journey and learning. If you
25:02 want to get this shirt, this is
25:04 legitimately your last chance. This has
25:05 been such an interesting topic to
25:08 discuss. I would love to go deeper. I
25:10 can't I know that I can't. I know that
25:12 I'm going to move on. I've got lots of
25:13 You would not believe my list of video
25:17 ideas, but this has been a wonderful
25:19 time over the last couple of weeks on
25:21 Hank's channel to dive into this. And
25:23 it's been nice to get away from some of
25:25 the things that I am more frustrated by
25:27 and just focus on all the stuff that
25:30 we've learned about ourselves and our
25:34 world and and how to how to tease out
25:37 these bizarre and cool things about it
25:40 all. So, thank you for joining me on
25:41 that journey. I hope that you have
25:43 enjoyed it as much as I have. Wow, I did
25:45 a lot of those, but now I have to go.
