SciShow Tangents - Sight

Starting point is 00:00:00 Hello and welcome to SciShow Tangents, the lightly suggestive, the lightly competitive science knowledge showcase i'm your host hank green and joining this week as always is science expert sari reilly hello and our resident everyman sam schultz hi i want to ask you two a question and i want you to give me the closest honest answer you can give me how many tabs do you have open right now? Oh, I just actually did a tab call. I have. Nice. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24. I have 25 tabs open.

Starting point is 00:00:59 And you only have one thing open? I only have one window. That was the call. I collapsed them all into one window i have 16 tabs across four windows but they're not distributed equally one of them one of my windows has one that's that sweet freelancer lifestyle look how many tabs you have open yeah i have as of now i think 64 tabs and the vast majority are in one window and there's one with 10 and there's one with three is there any kind of method to the 10 and 3 like are they not at all here's the method i'm selling a lot of i'm trying to sell socks right now so it's just all like

Starting point is 00:01:37 panic no time to do anything and it takes extra time to do the remove to turn the tabs off and so it's just like during during panic times you can tell how stressed out i am how much work i have to do by how much the tabs accumulate is this a lot for you or like a that's a lot this is a lot for you i think i'd say that this is this is uh above average it's certainly not your record you know it'd be really cool if chrome kept track and was like, it showed you the amount of tabs that you had over the course of a year. Yes. A year in review of Chrome?

Starting point is 00:02:10 I would love that. It's like Spotify splacked, whatever it's called. Wrapped. Wrapped! Versus splacked. It wasn't splacked after all. Yeah. It's a real word and not a fake word that you just made up.

Starting point is 00:02:23 Well, here it is. For the Chrome engineer listening in the audience, go to your boss with this feature ID. It's called Chrome Splacked. And it shows you all it shows. That'd be amazing, actually. Like, how many tabs did you have open? What websites were, like, the top ones?

Starting point is 00:02:40 Like, Wikipedia, YouTube, Twitter. That seems sad. And then at the end of the year, I get to find out what a monster I am. Yeah. And like fun stats would be, which tabs do I open and then close the fastest? Because that's definitely Twitter.

Starting point is 00:02:54 Sometimes I just subconsciously start typing it and I'm like, no, I don't want to be here. I don't care about this. I'm going to close that tab again. I was just here 45 seconds ago. I, for one, cannot wait for Chrome Splacked. Me neither. I think I love it. Maybe there's a way to sort of

Starting point is 00:03:10 tease it out. It's not like Google doesn't know. Google is very aware of all the websites I went to this year. Well, every week here on SciShow Tangents, we get together to try to one-up amaze and delight each other with science facts while also trying to stay on topic and occasionally connect with absolutely stellar features for the Chrome engineering team.

Starting point is 00:03:28 Our panelists are playing for Glory. We're also playing for Hank Bucks, which I will be awarding as we play. And at the end of the episode, one of you will be crowned the winner. Now, as always, we're going to introduce this week's topic with additional science poem. This week, thank God it's not for me because I didn't do it. From Sari. This week, thank God it's not from me because I didn't do it. From Sari.

Starting point is 00:03:50 Let's play I Spy with my little eye and process all the photons that fly right by. That red bird, that yellow green tree, that fluffy black cat who's staring at me. Our sight doesn't work like touch, taste, or smell. We got proteins called opsins in our rod and cone cells. The light becomes electric for your optic nerve and your brain eats it up like a yummy hors d'oeuvre. A lot goes on in that squishy gray goop to generate these images of tow trucks or poop. You got shape, color, depth, and movement or distance, facial recognition, or non-existence. Yep, that's right. While some visions are true, we got hallucinations or mirages here too.

Starting point is 00:04:26 Cosmic rays causing stars or illusions great and small, not to mention those wavelengths we can't see at all. So if seeing is believing and our sight is what we got, then bees and shrimp and tarsiers live in worlds that we do not. We work with these limitations and do the best we can and strive to make something beautiful for more than just humans oh my gosh like like 25 of the way into your poem i became aware of my existence in the sort of story of chemicals moving away from being dead like that was like why to be like i just it's like i just sense the world and it like and experience consciousness because because i have because i can i can i can interact with space and detect photons. Like, also, 75% of the way through this poem, I thought to myself,

Starting point is 00:05:30 we should have a kids show where Sari writes kids songs about science. Yeah. That's my dream. Can we reboot Schoolhouse Rock? Oh my God, yes, we can. I would love to meet a guy who does Schoolhouse Rock. I mean, Sari, there is literally no one else who would be more capable of rebooting Schoolhouse Rock than us.

Starting point is 00:05:49 I'm also the producer of a children's show. Yeah, yeah, yeah. So we're there. I've got a bunch of nerds who like to watch my content who keep popping out babies. Oh Lord. So the topic for the week is Sight. Wow is a really off topic, but I'm excited about our new project. And sight is, is any way of detecting photons? I think so. I think it is.

Starting point is 00:06:16 Or is it like, what about like heat detection, like pit organs? Is that kind of sight sight because it's infrared photons i think it's in the realm i think if you drew a big umbrella of everything that could count as sight then eyes had to evolve from something so yeah i mean it's not like you like seeing like seeing badly definitely counts as seeing i'm not saying that eye spots are eyes but but I do think that they are sight. After I said it, I felt apprehensive, but I still feel like I'm right. If you can tell the differences between light patterns. And we mean any part of the electromagnetic spectrum there by light? Or do we mean confined? Because there's no reason to confine it.

Starting point is 00:07:01 I think you have to include all of it. If we just say visible light, that's very human-centric. Yeah, totally. We invented what visible light was because we were like, that's what we can see. Well, honestly, I think that that is surprisingly, there's a fairly clear line that you can draw around that. Like it's detecting photons in the electromagnetic spectrum. Sari, can you tell us anything about where sight comes from etymologically? A little bit.

Starting point is 00:07:28 It seems like it is fairly straightforward in that a lot of the Germanic roots of the word sight relate to words that sound like sea, which makes sense. relate to words that sound like sea which makes sense yeah the mystery i guess is where sea came from because there are probably a lot of we we still have a lot of words for to observe or to see or like vision sight all these different things that mean observing the world around you and so we're not entirely sure where the word see comes from. It could come from a root that has to do with like to follow as in like you word eye, if you trace it back far enough, sounds kind of like the word see if you just add an S on it, like see eye.

Starting point is 00:08:30 And then that's about it. Just another one of those caveman words. Yeah, it goes deep. And that means that it's time to move on to the quiz portion of our show. So the world only looks like what our eyes say it looks like. Everything from the colors that we are able to see to the distances that we can process are based on how our eyes

Starting point is 00:08:50 work and how they relay information to our brains. So if you asked different animals what the world looked like to them, you would get a lot of different answers because there are many different ways to see out of many different types of eyes. So the following are three stories of animal vision, but only one of them is true. You're going to have to tell me which one is true, and I'm going to start now. So mantis shrimp, we all know mantis shrimp got weird eyes. They can see a wide array of colors, but it turns out that they can also see non-colors. Scientists have found proteins in the mantis shrimp's eyes that react with chemicals associated with fish smells, helping them visualize the location of their next meal.

Starting point is 00:09:32 Their eyes can not just sense photons, but also chemicals. But that might not be true. It might be this one. Snakes don't have great vision, but some species are able to improve their sight when threatened by restricting the amount of blood that flows to structures around the eye so that the vision is less obstructed by blood. Creepy. Or it could be story number three. Scallops have up to 200 eyes along the edge of their shells. Did you know that? That's pretty cool. And to change how light hits the pupil, each eye has an eyelid-like structure embedded with a crystalline array. Opening and closing the eyelid changes the focus of light reaching the scallop's eye so that it can get a clearer image. So is it story number one, mantis shrimp can see smells using olfactory receptors connected to their eyes? Story number two, snakes can improve their vision

Starting point is 00:10:25 by controlling the blood flow to their eyes. Or story number three, scallops have a crystal eyelid to focus light onto their iris. Doesn't everything improve their vision by controlling blood flow to their eyes? Is that how like the contracting works? That's muscle. It's not, blood doesn't have any part of that this isn't a

Starting point is 00:10:46 trick of some sort it's doing all its blood work uh so in this case i think the snake story is that there's like the blood vessels in the eye and it doesn't they don't like want as much blood in the retina area i drain it out uh and so it's just like less just hold the blood back for a second while i try and see better. I don't know. That makes sense to me because if you're focused, I don't know. It's like you want to control your heart rate. You're in a tense situation and you're like, okay, calm down.

Starting point is 00:11:15 I want to look for a second. And that feels like something that would be possible. If I was programming a snake in a video game, I'd be like, yeah, we get the bloods pumping. And then there's a moment where we can have sharp vision and pause our blood for just a fraction of a second. What are you talking about? I don't know. Okay. I'm just saying it makes logical sense.

Starting point is 00:11:40 If I made a snake simulator, I would put that in there. That would be like a tech tree that you could put points into. The blood eye. Oh, man. Yes. Going to snake vision. Okay, I get you now. The mantis shrimp one is like in a cartoon when there's a smell coming off a pie.

Starting point is 00:11:59 And it pokes the person on the shoulder. And it's like, doot, doot, doot. And then you float with the, yeah. So I think that's fake. Cartoon cartoony. Yeah. And I don't know if scallops are like articulated enough to have a crystal eyelid. I know that they have eyes, but that's not the fact.

Starting point is 00:12:23 And I think those eyes are like crystal like crystal-y ish like they're hard definitely like guys with rock eyes right like yeah yeah because they gotta be tough if they're gonna be facing out into the the ocean and you can't and i feel like a scallop come get your eyes i'm only about 60 sure of what a scallop is also is it kind of like a clam it's like a clam yeah okay it's the kind of clam it's like the clam shell that like ariel has on her bikini they're what you give the otter in animal crossing when you're swimming exactly yeah yeah okay okay okay that's very clear to me i think it's got to be the snake thing i think sari is exactly right. If it was a snake video game, that's the snake power a snake would have. I think it's a snake thing, too.

Starting point is 00:13:08 I would be shocked if it was either of the other two. Well, you're both right. Yay. Wow. Be a little happier about it. You got me. Well, I kind of felt bad for you, actually. Well, there's lots of cool stuff uh built into the other fact so mantis shrimp do have a set of amino acids in their eyes called mycosporine

Starting point is 00:13:34 like amino acids and they're usually found in the skin of marine organisms as a way to protect cells from uv light but in the mantis shrimp eyes they're used as a filter that help tune out wavelengths of light that reach each different color receptor to help pick out particular colors. So it's one of the, I think, one of the ways that they see all the different colors that they can see. And scallops, you are right. They have weird rock eyes. They have a bunch of tiny eyes on their shell that are super weird and complex. So light passes through a pupil and a lens and a retina before reaching a curved mirror at the back of the eye

Starting point is 00:14:05 which is made out of guanine crystals and the mirror sends the light to the receptor on the retinas which then sends the signal on nerve cells controlled by other parts of the scalps which then sends the uh which and that sends the signals to nerve cells that control other parts of the scalps movement and behavior is it in the shell wait it's on the rim of the shell and it connects to the blob inside yeah yeah whoa i didn't know that so like a clams it just doesn't seem like because they're hard all the way around for some reason it doesn't seem to me like they are animals they are rocks though yeah they just seem like rocks like rocks. But there's like a living thing in there. So scientists were curious about how scallops are able to focus light.

Starting point is 00:14:49 And they realized that while scallops don't have irises like we do, their pupils can open and contract. So that's really a thing. And that changes the shape of the cells in the cornea. So super cool and weird. That's wild. They don't have an eyelid. They don't have a crystal eyelid

Starting point is 00:15:05 unfortunately for me but the coach whip snake is a non-venomous snake found throughout the u.s and mexico and like other snakes it doesn't have an eyelid but they do have a thin scale over the eye called a spectacle and as researchers studied the coach whip spectacle they realized that there were blood vessels within the spectacle that would expand and contract and uh expand and constrict to make sure that the blood cells didn't crowd out the vision of the snake so it's not on the retina it's actually in the in the scale over the eye the cycles of expanding and constricting are are regular but there are a few cases where the snake will intentionally regulate blood flow to accommodate for things like if the snake is shedding, the blood vessels will stay dilated to help support the growth of the new cells.

Starting point is 00:15:49 And when the snake feels threatened, it'll constrict the blood flow for several minutes to lower the amount of blood so that they can see better what's going on. Wow. They're living contact lenses, basically. Yeah. Is that what they, yeah. I love that it's called a spectacle. That's cute. lenses basically yeah is that what they yeah i love that it's called a spectacle that's just definitely that is a good instance of yeah a little a human namian being like oh you got a little you got a little eyeglass on there oh a little spectacle yeah it's wild like when you

Starting point is 00:16:17 have to like dig through the dirt and you don't have eyelids you do have to have something there a protective covering over your eye that that's replaceable which is why but they do that so they just shed them after after they've used them for long enough um where here it is okay that's not it we're gonna get home through your 60 something tabs huh so that means that sam and sari are tied with one next up we're gonna take a short break Something tabs, huh? I got it in another window. So that means that Sam and Sari are tied with one. Next up, we're going to take a short break, and then we'll be back for the Fact Off. Welcome back, everybody.

Starting point is 00:17:13 It's time for the fact off. Our panelists have brought science facts to present to me in an attempt to blow my mind. And after they have presented the facts, I will judge them and I will award Hank Bucks any way I see fit. But to decide who goes first, I have a trivia question that you can try and answer. Some of the largest animal eyes that humans have found come from squids. Living up to its name, the colossal squid has what might be the largest eyes in the history of the animal kingdom.

Starting point is 00:17:38 So not just now, but in all time. How large is the diameter of the colossal squid's eye oh the part of my brain that knows how big like measurements are is not there this is like like not like it's not like it's currently inaccessible but it's never been there just it's never been there how big is a basketball i'd say a basketball is about 10 inches. A foot? Yeah. Basketball. That was too big.

Starting point is 00:18:09 Whatever you were just doing, Sam, was too big. That's what I'm going with. I'm going with 11 inches. 11 inches? Yeah. Okay. I think it's smaller than that. I think I could grab it in a fist. I think I could be like, ooh, an eyeball.

Starting point is 00:18:21 And pluck its eyeball right out of its head. Some people could palm a basketball, Sari. Yeah, not me though. I'm saying me specifically could reach in, grab that little squid eye, pull it out. So I'm going to say... It's the biggest eye ever though, Sari. The biggest eye ever. Five inches.

Starting point is 00:18:39 Think of how big their eyes are. It's big. That's big. I can't imagine another thing with the eye this big. That's pathetic. If it's that big, I'm going to be sad. I can't imagine another thing with the eye this big. That's pathetic. If it's that big, I'm going to be sad. I don't have the answer in front of me right now.

Starting point is 00:18:49 I might have it shortly, but it wasn't in the doc and Tuna's pasting it in. But I just got to tell you, they're definitely bigger than what Sam said. It's so big. They're like deep down where it's very dark. So it's not just that they're big.

Starting point is 00:19:05 It's that they need to collect a tiny amount of light. They need a lot of eye. What is it though? Did Tuna paste it in? 10.629 inches. Oh, so it is about the size of a basketball. Okay. I know.

Starting point is 00:19:18 I would need, I, Sari Riley, would need two hands. But some of the world's best basketball players could absolutely pull out the eye with just their hands. And you know what? People pay a lot of money to see that. That's sport. That's sport. Oh, man. I was shocked to find that a basketball is, in fact, nine and a half inches.

Starting point is 00:19:40 And I was quite close on that. You're great. You know everything about basketball. I know everything about squid eyes. We're quite a pair. I had a friend once who was a giant squid and he often talked about how big his eyes were. And then Shaq dunked his eyeball and that was the end of him.

Starting point is 00:19:54 And now he's dead. So that means that Sam gets to decide who goes first. I want to go first. I just want to get it over with. Plants are great. They grow fruits and vegetables. They make flowers. They make our air cleaner.

Starting point is 00:20:12 They have so many talents, but they simply don't have eyes. A tree can't see its neighbors. A flower can't see the bee taking a drink of its nectar. That's just the way it is. taking a drink of its nectar. That's just the way it is. But a plucky climbing vine called Bochila trifoliolata might change everything we think we know about plants forever or something. Do you already know this?

Starting point is 00:20:35 Uh-huh. I do. But Sam, it is one of the best science facts. And I almost brought it up early in the episode and I was like, it might be one of the fact off facts. Yeah. Because this is the weirdest thing. So i completely agree that it is a fantastic fact and it is a a big question mark in my own mind uh but continue bokela is like i said a type

Starting point is 00:20:58 of vine with the special ability to mimic the leaves of trees it climbs in pictures that i've seen it copies the shape and color of the tree leaves. And one vine can even have several different shapes of leaf on it, depending on like where it's growing, if it's growing on the ground and then up, it'll just have different leaves. Why it does this isn't super clear, but it's probably a way to avoid predators

Starting point is 00:21:18 by either like hedging into beds and having lots of leaves and hoping bugs won't think that all of them look tasty or possibly by attempting to mimic poison leaves. And how it does it is even more unclear. But scientists are on the case. In November 2021, a study showed that bochila mimicking a mottled tree shared similarities in bacterial communities with that tree that it didn't share with bochila that wasn't mimicking anything. And another theory is that the plant has a symbiotic relationship with a microscopic organism that steals genes from plants that the vine is growing on

Starting point is 00:21:53 and brings them back to the host. But none of this really sounds like it has anything to do with sight so far, huh? Well, in September of 2021, a study was published detailing an experiment where researchers let vokila grow on an artificial plant and vokila i hope i'm saying that word right i've said it so many times according to this paper at least seemed to attempt to mimic the artificial plant that it was growing

Starting point is 00:22:16 on so it was a plastic plant it was made out of plastic so it's not genes it's not microbiome it's It was made out of plastic. No genes. So it's not genes. It's not microbiome. It's not smell. So a bochila leaf is a short, overly, it's a short, overly leaf that ends in three points. The fake plant had long leaves that ended in just one point.

Starting point is 00:22:35 And as the bochila grew up the fake plant, its new leaves started to lose their points and got longer and skinnier. Their data also seemed to show that the more bochila leaves there were facing the fake plant, the more detailed the mimicry became. This result was shown across all of their bokeh plants, and the mimicry improved over the course of several months. So the paper concludes with the possibility that these plants can possibly just depend on chemicals or DNA, these plants can possibly just depend on chemicals or DNA and possibly have some sort of ocelli, which is a simple light detecting lens that could be helping the bokela suss out the shape of nearby plants. And I've seen pictures of bokela in nature mimicking real plants, and I gotta say,

Starting point is 00:23:17 they do a way better job of mimicking real plants, which to me suggests that there does seem to be some sort of chemical or bacterial thing happening. But they did at least partially successfully mimic a fake plant. And they knew that there were leaves around even when the leaves are fake. So while scientists haven't really settled on how they pull this mimicry off, I feel comfortable in putting forth my theory that a lot of the information that Boquilla get come from chemicals or DNA. But the vines do indeed seem to have some sort of ability to see. So it looks like we're going to have to add sight

Starting point is 00:23:48 to the plant kingdom's already impressive resume is what I'd say if I was a scientist. I don't actually know, but. I like a little bit of Sam deciding as part of your like, you know, I'm not saying that I know what I'm talking about, but it seems to me. As the resident everyman. It's a lot to do all of those things. You know, I don't, I'm, I'm not saying that I know what I'm talking about, but it seems to me.

Starting point is 00:24:06 As the resident, every man. It's a lot. It's a lot to do all of those things. So if site works, why do all the rest? But hey, I guess they're doing a better job in nature. It is wild. Like the, I mean, what we know for sure, like it's definitely true that plants can detect, you know, light. definitely true that plants can detect you know light so we know that and we we and also like just the process of doing photosynthesis is kind of like that there's clearly like a chemical reaction that occurs because it's hit by a photon and yeah so like i i heard this news and i was

Starting point is 00:24:40 like like 2021 brand new research who knows knows? Like sometimes stuff is weird. And the big question though I had is obviously there's a lot of pressure, evolutionary pressure to do this because there's lots of parasitic plants that mimic their host tree. But in this case, it doesn't need a particular host tree. And then it developed a way to mimic various host trees so do you know why it is working so hard to look like it's not like a tree is going to say oh actually you're my leaf i'm shouldn't attack you because trees can't attack i mean it kind of seemed like they didn't even know why it does it in the first place so so we don't so we don't even

Starting point is 00:25:21 know why it does it it seems like there must must be a pretty strong pressure. Yeah, it doesn't seem like it's stealing nutrients from the trees. But maybe it is. I don't know. But the articles I read were just like, meh, maybe it's because of bugs. I got to level with you, though. Sari gave me that fact. So don't make me sound too smart. Yeah.

Starting point is 00:25:39 Hey, Sari, why do you think the bookie was working so hard to hide inside of a tree? I don't know. Bugs? I mean, I did read a lot of articles about it. She just sent me a sentence that said, hey, this is a pretty cool plant. And I said, oh, yeah. Yeah. I mean, I can't make a TikTok about that because there's already a viral TikTok about it, which I did very much enjoy.

Starting point is 00:26:02 Yeah. Okay. But it would be a very good TikTok as evidenced by the fact that there's a viral TikTok. Because the fact that already was one. Yeah. That's not necessarily

Starting point is 00:26:09 that might be a vote in your favor because it's like guaranteed it is a good fact for a TikTok. Sari, what do you got? Sight is all about interpreting light in your environment. So kind of like we were talking about

Starting point is 00:26:20 with the colossal squid, if you're trying to see when it's dark outside or dark around you and there's no sunlight, you have way less to work with. And nocturnal animals have found all kinds of ways to supplement their vision with other senses, do mental gymnastics to process the information or increase the amount of light that reaches their photoreceptors somehow. Kind of like how cats have some reflective tissue tucked behind their retinas called a tapetum lucidum or colossal squid eyes are just gigantic

Starting point is 00:26:46 but i want to take a closer look at dynopsis spinosa aka the ogre-faced spider because during the day they lay flat and pretend to be a twig which is just wonderful i wish that could be me and then at night they hunt they're part of a family of net casting spiders so instead of spinning a big web and then sitting on it they spin webs between their front legs and actively catch insects with them what which explains why they need such good eyesight they're waving around their leggies two of their eight eyes are huge and face forward which I guess, where that ogre face name came from. And these giant eyes are possibly the largest spider eye on the planet, up to 1.4 millimeters in diameter. Take that, squids. And their lenses can concentrate light really well. But that's not all. Every

Starting point is 00:27:38 single night at sunset, as they're spinning their net web between their two front legs, At sunset, as they're spinning their net web between their two front legs, these huge eyes synthesize almost entirely new light-sensitive membranes. And then every single morning at dawn, as they're settling into their twig camouflage, those membranes are destroyed again. What's a light-sensitive membrane? It's like the equivalent of our retina, but in a spider eye. Okay. So they grow a retina every night? Yes, they grow, but it's like the equivalent of our retina but in a spider eye okay so so they they grow a retina every night yes they grow but it's insect eye it's compound eye and it's a hexagon but yes they grow a retina every night and then they destroy it in the morning because they don't need it anymore

Starting point is 00:28:15 which is a ridiculous amount of effort and the only paper i can find that talks about it which was published in 1978 calls this quote cumbersome and in metabolic terms extravagant metabolic extravagant is like the best definition of all of humanity where we're just like we need to go to the gym we need to run for no reason metabolic extravagance yeah Just eat a bunch of food. Yeah. So I love that turn of phrase. Great paper. And apparently this kind of turnover of a photoreceptive thing occurs in a variety of invertebrates,

Starting point is 00:28:55 which is news to me, but they do have some guesses as to why these ogre-faced spiders don't keep their good vision during the day. Number one is maybe it's just not energy efficient for it to maintain good night vision while it's pretending to be a twig, which they acknowledge isn't a strong guess, but they threw it out anyway because evolution is weird. Two, maybe these light sensitive membranes are just so unstable that the spiders evolved cellular processes to take care of

Starting point is 00:29:20 the wreckage very quickly and regularly and then just rebuild it. Or three, maybe their eyes would get worse enough over time that it would be just hard to survive and hunt and catch things with their little net legs. And evolution just happened to address this problem by regenerating inner structures every single day. So my conclusion is we may never really know why, but I love learning about metabolically extravagant things because senses just have gone wild in so many different directions and whatever works for an animal works for them could it be that they're so i know that i'm just like throwing stuff out here and maybe you kind of said this but that like it has to be really sensitive to to to see in the night time and they can't close their eyes because they're spiders close their

Starting point is 00:30:12 eyes so like a daytime photons just rip them up out and so they like and and so they need to remake them all the time anyway so in order to have really sensitive eyes they've created a structure that can't handle a lot of photons, a lot of energy. Yeah, I feel like that is a better way to phrase how they phrased in the paper, the unstable one. That in order to make something that's really sensitive, it's definitionally unstable, or the way that it has evolved to make something very sensitive. Yes, whatever biological molecules have gone into this are are really good at their job but only if there is very very little light so even though sari fed sam this fact

Starting point is 00:30:53 and even though it's already a viral tiktok i do know that it's a great tiktok fact because of how it was a viral tiktok and it's just i mean it's just the better like plants can it's the first evidence we have that plants can see so sam has to win now we're talking i know it's just, I mean, it's just the better, like plants can, it's the first evidence we have that plants can see. So Sam has to win. Now we're talking. I know, it's not very fair. In your face, Harry. I mean, I knew it was a good one.

Starting point is 00:31:13 I only give you the good stuff, Sam. I don't try to poison you. And that means it's time for Ask the Science Couch, where we've got a listener question for our couch of finely honed scientific minds. Sam, what do you got? The Zinc on Discord asks, why is our site limited to the particular range of EM radiation that it is? Electromagnetic, I assume?

Starting point is 00:31:37 Yeah, I mean, this is interesting. It probably mostly comes down to what is most useful evolutionarily, and that's gonna to be what light there is to detect on earth plus what light is is like was useful for us to have tools to detect which what why is that i don't know but now i'm going to let sari start talking because she because i i was just saying stuff that occurred to me. I was working through it in real time. No, I mean, that's basically what researchers have done, but just with more statistics and math applied to it.

Starting point is 00:32:14 But then you can also look at genetics to see how our eyes evolved, which is less of figuring out what's optimal and just understanding what actually happened and then drawing conclusions from there. So around 90 million years ago, way back, primitive mammalian ancestors were nocturnal and could see UV and infrared sensitive. They had what these researchers called a bichromatic view of the world, so mostly only seeing those ends of the spectrum. And then by around 30 million years ago, our ancestors had evolved four different classes of ops and genes, which let them see visible light except for UV. So there was this shift as mammals went from being nocturnal to being awake more during the daytime that our genetics changed to stop seeing as much UV and infrared and start seeing visible light as it's being reflected off of

Starting point is 00:33:22 objects in the daytime. And of those colors, blue and green sensitivity was the last to evolve. I don't think they've extrapolated why, but it just seems like red sensitive pigments were first in these random mutations. And then at one point, pretty late in the game, one of those red sensitive pigments became green sensitive all of a sudden because that's how evolution works it's random chance maybe there's just so much green we were like yeah we don't really need to see that it's everywhere yeah but we need to see

Starting point is 00:33:54 a berry or something like that i don't know the best thing about evolution that to get in to lock in is that like you don't get it you don't get an ability because it's useful you get an ability because it's useful and there's a way to get it even if you could do it biochemically if there's not like a like there's not an easy jump and that's a lot of times like what you hear people say about like how could it such a complicated structure as an eye itself develop and uh and the the weird thing is that all of this stuff comes from somewhere strange. Like all your little ear bones used to be part of your jaw.

Starting point is 00:34:30 Used to be jaw bones. Took a lot of practice to get to where we're at. And then it was like, actually, that's kind of good at detecting vibrations in the air. And so they'll be better if they're smaller or if they're a certain arrangement or if you surround them with certain membranes and over time you get an ear.

Starting point is 00:34:44 It would be really wild if it weren't that way and whenever i see some fantasy animal with both wings and arms i'm like nah that's not how this works unless the wings are like the thumbs just moved up there yeah thumbs like all the way up the arm onto the back and now they're wings the only way for it to happen yeah you move the sliding scale of like you know you can customize faces like your eyes can be wider or narrower so you got to move the thumb all the way up the arm so you've been playing a lot of video games lately yes i have i have this freelance lifestyle if you want to ask the science catch your question you can follow us on twitter at Yes, I have. I have this freelance lifestyle. If you want to ask the Science Couch your question, you can follow us on Twitter

Starting point is 00:35:29 at SciShow Tangents, where we'll tweet out topics for upcoming episodes every week. Or you can join the SciShow Tangents Patreon. And there we have a Discord where you can ask us questions. Thank you to at MagpieBR at Robin Han Sopran and everybody else who asked us your questions for this episode. If you like this show and you want to help us out, it's really easy to do that.

Starting point is 00:35:47 And you do like this show, don't you? Because you keep listening. And we keep having a great time. Hey, more and more people keep listening all the time. Yeah, it's growing. It's a good, happy tangent. First, you can go to patreon.com slash scishowtangents and become a patron and get access to things like our newsletter and our bonus episodes.

Starting point is 00:36:03 You can also leave us a review wherever you listen. That helps us know what you like about the show, and it helps other people know what you like about the show. And finally, if you want to show your love for SciShow Tangents, just tell people about us. Tell people about us. Thank you for joining us. I've been Hank Green.

Starting point is 00:36:17 I've been Sari Reilly. And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Sam Schultz. Our editor is Seth Glicksman. Our story editor is Alex Billow. Our social media organizer is Julia Buzz Bozzio. Our editorial assistant is Devoki Chakravarti. Our sound design is by Joseph Tunamedish.

Starting point is 00:36:34 Our executive producers are Caitlin Hoffmeister and me, Hank Green. And of course, we couldn't make any of this without our patrons on Patreon. Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. but one more thing in a 2013 paper researchers took african clawed fraud tat clawed frog tadpoles and severed both of the normal optic nerves in their head but do not worry those researchers also transplanted a chunk of uh of a chunk of flesh called eye primordia onto their butts, which naturally grew nerves that connected to their spines and sometimes off target to their stomachs.

Starting point is 00:37:34 Growing a butt eye is fine, I guess, but a statistically significant number of these tadpoles could actually detect changes in LED light and make behavioral decisions based on those lights. And that indicates that they could see with those butt eyes and interpret that visual information, even though they were not connected directly to the brain. Why did they do this? I don't know, Sam! Whose idea was this?

Starting point is 00:38:05 Well, it's interesting, isn't it? They were right. Yeah. Somebody's in the shower and then like, oh, what if we cut their eyes off and put them on their butts? I'm going to go tell my boss that. Fucked up. Oh, my God.

SciShow Tangents - Sight

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