'which came first, teeth on skin or teeth in mouth' is a question I never could've imagined would need to be asked and it's really weird and strange to think about but this is exactly why I love this channel so much! So many topics I had no idea even existed but I always come away feeling like I definitely needed to learn about it. I'm a little disappointed the video didn't go into more depth on 'teeth on skin' though, what were the advantages to that, why did it develop, etc.
I think it would be interesting a video about ears, the outer part of them, when they first show up in the fossil record and why (I think) only terrestial mammals have them.
It is extremely interesting that Mammals are the only lineage of tetrapod to develop ear pinna (the outer ear). I would love for a video on this as well!
@@andrearivera1622 Well it does have purposes as Ear Pinna can serve to filter sounds better into our ear canals for better hearing and in most other mammals apart from many primates including us and some other mammals; communication purposes and a warning system. The position of say a dog or cat's pinna can very clearly tell you how they are feeling or what they are listening to without them having to vocalize it. Additionally having the ability to swivel your ear to listen in on sounds of interest without having to move your head, body or neck is a huge advantage when listening out for predators or other animals that may want to harm or eat you. Now that I think about it perhaps Ear Pinna evolved in tandem to the evolution of the more complex mammalian ear 🤔
Outer ears wouldn't really show up in the fossil record often. They are not made of bone. It's made of cartilage (I believe) and wouldn't fossilize or be preserved well.
I think I read somewhere once that having beaks instead of teeth also helped drive down the amount of time between when a bird lays an egg and when that egg hatches. That seems to me like that would be beneficial for creatures living in the aftermath of the K-T extinction.
@@icollectstories5702 typically, yes. The newborn bill is more like cartilage than bone in terms of "squishiness". Having an egg tooth helps zip open a hardshelled egg. Its also not a real tooth, but more of an extra hard nub at the tip of the bill- or nose, if youre a reptile. Snakes have one too! I'm not sure about other reptiles but I'm sure if snakes and birds have them, the others also must
Something occurred to me watching this, we get lots of content about the fist land vertebrates but do we know much about when arthropods moved onto land? Was there a single major movement by arthropods or had their subphyla already split off and had separate events leading them to become partially or fully land dwelling.
Its tricky because fossils for land arthropods are the same as aquatic ones. (Legs and lungs already were a thing). "foot"print evidence is the earliest known evidence of arthropods on land.
I was actually looking at this question a few weeks ago. There are three main groups of terrestrial arthropods are myriapodia (centipedes and millipedes), arachnids (spiders, scorpions, ticks, mites, and others), and hexapoda (insects and "wingless insects"). A few other arthropods are terrestrial, but those are the three main groups and by far the oldest.
From my limited understanding of arthropod taxonomy, I think with insects the idea is that wingless insects like springtails were likely the first to arise, as they live in incredibly damp environments even when terrestrial, and then they diversified from there. I really dont know much about bug evo though, lol
I don't know but ... crabs look like giant spiders to me and crayfish look like baby lobsters. The movement to land was either coastal like crabs to spiders (just hanging out on the beach for longer and farther inland) or moving upstream (salt water to freshwater first) like lobster to crayfish and then colonizing interior. Darn cool question.
The existing land lineages are so far apart that it is unlikely that they had a terrestrial common ancenstor. Their LCA was probably before land plants and terrestrial life was possible. So most likely independent movements to land.
I enjoy every episode, but it is evident that the speaker matters as much as the content. If not more. This lady´s genuine enthusiasm is infectious. Her colleague´s humour is refreshing. I hope to see more of this duo.
@@Stevie-J something about this doesn't add up. Tounge is very much under powered. There needs to be a 5th element. The interesting thing is though, that tounge vs tounge isn't just a draw it's very sexual.
One of my biology teachers explained part of the reason birds lost teeth was because enamel is the densest material in our bodies, and it helped conserve weight for the same reason that female birds have only one functioning ovary. I wasn't sure how founded that would be, but it was something that stuck out to me.
I think it's a great illustration of the way evolution works that several lineages of birds, including waterfowl and the Pelagornathids, have evolved beak structures that function like teeth. Natural selection can only work with the biology an animal already has.
In the early stages of chicken embryo development, the embryo does indeed grow teeth in it's proto-beak (for lack of a better term). However, they are then reabsorbed a short time thereafter. It does show however, that at one point, the chicken's ancestors, did indeed have teeth (T. Rex certainly fits that description).
Hey! I was wondering if you could do a video about how insects evolved out of the oceans. We all know how fish first walked onto land, but how did bugs get onto land?
Tungsenia: allow me to introduce you a new innovation, teeth! *millions of years later* Most animal groups: these teeth get in the way, let’s ditch them for something less biologically expensive
@@naamadossantossilva4736 Meanwhile, 400 million years later... Humans: *eating the pizza diet* Meh, are teeth REALLY necessary? We just need softer pizzas...
I'm hoping for more flora taxonomy! How did alder, maple and beech become dissimilar from spruce, juniper, cypress? I'm sure there are equally interesting stories about their diversion, convergent evolution and likely some unique aspects that aren't found in animalia
Same thing happened to eyes. Animals needing great eyesight evolved them. Animals not needing great eyesight lost them. Even when they evolved from predecessors previously having acute vision. (You should do an episode on the evolution of eyes)
Another evolutionary "cost" of teeth could also be that they can get infected - you don't have that risk with a beak. They are also more easily damaged in general.
Pretty sure beaks can get infected too. And being that they only have one, it's a huuuuge problem if that does happen, or if a bird loses any part of their beak
@@stanpines9011 I never said it was or wasn't. I said they can definitely get infected. Next time you rush to correct someone, maybe make sure you're actually correcting the right thing.
@@StonedtotheBones13 Yeah but by chance is way more easy to infect teeth, in the great game beaks are more stable, more difficult to be damaged and thus it can be more reliable
@@fingersmcoy at any point did i state it was factual? actually no, i did not. i was complimenting eons and this will be my only response to you. check yourself homie
Outside-in makes more sense to me considering the general paths evolution took. Dentine started as armor that eventually gained a secondary use as teeth.
The question is why mammals didn't also try for beaks, like our Aussie duckbill friend? Like all your fantastic episodes EON they bite deeply into the subject matter. 😁 It was quite a satisfying dish! 🦊✨✨
I remember reading something a while back that said that the reason us mammals don't have beaks is due to the fact that we have to drink milk as infants, and if you had a beak, you can't make the sucking motion that's required to drink milk. So basically the reason us mammals never evolved beaks is because we suck. Platypus get away with a beak because the mothers sweat milk
I think to answer this you have to go back to our therapsid ancestors one of the defining characteristics of cynodonts is anatomical changes to the structure of jaws which granted them the ability to chew. Chewing is a unique adaptation to Cynodonts and all their living descendants offering one of the most effective ways of predigesting food. No other vertebrate group is capable of chewing their food they instead rely on tripping tearing and or slicing food into smaller pieces, with the closest analog seeming to be gizzards of birds at least among extant animals. In this sense chewing adapted jaws are a powerful evolutionary advantage which largely necessitates the preservation of teeth and the ability to produce enamel. From the fossil record we can see that our ancestors and their cousins in fact convergently further specialized their jaws and teeth for better filling this ecological role such as by reducing the jaw bones over time through repeated secondary losses or repurposing as those bones were adapted to build the mammalian ear and analogous ears of close synapsid cousins. In effect the jaws and teeth of mammals are our evolutionary lineages most defining characteristic dating back to our Permian therapsid ancestors. Beaks while versatile are unable to be used to perform similar roles as beaks but can conversely perform most of the same functions which make beaks successful so from an evolutionary perspective switching from mammalian chewing jaws to beaks would require adapting to an increasingly different mode of lifestyle which would only be an option if there was an open ecological niche that provided an opportunity to do so. In this sense the competition from archosaurs and to a lesser extent dicynodonts was probably one of the main limitations that locked cynodont descendants into the chewing mode lifestyle as it allowed them to exploit food sources archosaurs couldn't allowing them to persist despite having a vastly inferior respiratory system compared to archosaurs. Basically mammalian jaws and teeth adapted for chewing were probably the defining traits that allowed cynodonts and their descendants to avoid getting out competed by archosaurs. Then when the archosaurs either went extinct or became so specialized they were no longer in direct competition and the few mammals that survived were finally able to diversify and so we see mammals start to experiment more giving us stuff which fills now vacant niches such as baleen whales. Beaked mammals however would still have to compete with chewing mammals and beaked birds which would put them at an evolutionary disadvantage without some similarly impressive adaptations.
Beaks and tongues may have beaten teeth but we're still the ones eating chicken and frog legs, not the other way around. Certain traits do not pair well with others. As noted, lactation and beaks don't work well. It's possible that teeth end up having some hidden advantage for certain lifestyles and diets. It's hard to be an apex predator without teeth, for example.
That's probably straight up wrong. Why would animals ever wander out of the sea if they have nothing to eat onshore? Escaping predators might be a thing, but that's hardly enough to develop a whole new breathing system. Animals should have been very busy on land to develop such adaptation.
I would like to see a future video about mammalian ears vs bird ears. I think it is interesting, because while mammalian ears are supposedly more complex because mammals have 3 bones in inner ear and also have an outer ear, but most musically sensitive animals are birds, they sing songs, dance etc.
Beautiful video. 1. Though amphibians use tongues for feeding, the tongues cannot completely replace the teeth. Frogs actually push their eyes down to bring the food into their tract. 2. Also seeing grass in Permian era illustrations irks me a bit.
@@Cillana from what I've seen, the eyeballs of frogs sorta push the food down their throat. The projectile tongue occupies most of the skull and only while eating the frog closes its eyes to push the food down.
@@adityamohan1773 okay 👍 thanks for answering Edit: I have seen video where frogs use their hands to shove food in their mouth. Then they use their eyes to swallow.
Dude- your guys videos are so AMAZING! they are accurate, well put together, and the illustrations are awsome!! I have a request for a video i would LOVE to see- i doubt you will see this comment but, i heard somewhere that the reason we only really find the adult and baby dinosaurs, and we don't have to many fossils of like 7 year old dinosaurs, is because some medium sized dinos (like Nanotryranous) were actually just a Tryanosaurus Rex but in their teens? Idk if its true but I WOULD LOVE to see a vid on it if you see this comment!🥰 Edit: yall i said that idk if its true
This missing ones are the ones that got eaten. It's a race to get big enough so you are too big to be predated. If you don't make it, you get torn to pieces and wind up in somebody's stomach.
This was a great video, but my favorite part is the end where you acknowledge the lands that were originally belonging to Native Americans. It's not just their history we stole, it was their entire history of life on earth in that place, a place belonging to native peoples, who should've gotten a say in the matter.
I agree. Check out the Dollo's law of irreversibility. In birds that circumstances when they need something to grasp using their mouth, they never evolved teeth, instead to evolved keratin parts that act like teeth in their beaks.
I have never considered whether frogs have teeth or not. I regret to know that they do. Mind you, I would not have been any happier to learn that they do not. I just never would have really wanted to think about frogs as creatures that either do or do not have teeth.
I don’t think building nests is a trait that gets evolved, it seems more like an adapted behavior than a genetic trait, don’t u think? Or did u just mean how they started building nests and not necessarily how they “evolved?”
Evolution has no direction. So perhaps there will eventually be descendants with no teeth, shorter tongues, or both -- or no descendants at all. I'd be interested to know how they avoid biting their tongues, or if they heal quickly. Perhaps they learn tongue coordination well as younglings.
@@icollectstories5702 If you watch chameleons videos, they do everything slowly, even chewing their prey once caught, I guess they never really bite their tongue because they're very cautious ^^
You missed an opportunity here to talk about Geese! They have beaks but they also have teeth (or at least something resembling teeth) on their tongues! Nightmare material!
I had some toads as a kid and I almost never saw them use their tongue to catch prey. They would just chomp down on it. Don't get me started on those weird frogs at 6:51. They're literally just a mouth with two hands to push in food, they'll eat *anything* that gets in front of them.
Umm... I am not sure if they are classified as teeth, but Canadian geese have serrated beaks that look and feel a lot like teeth. They may not be teeth from a taxonomic perspective, but I would argue the the function is similar. I took a bit while feeding them at the park; it hurt more than my boa constrictor from uni.
They're not teeths stricto-sensu, because they're not made of dentine, but of keratine, as the rest of the beak. But yeah, they have teeth-like structures, and they even have other teeth-like structures on their tongues (a close-up look on a geese mouth is terrifying XD). Although it may hurt, they're not meant to bite, but to filtrate water, just like the baleens of a whale. Baleens are not teeths either (although primitive whales and some seals do use teeths to filtrate water), they're made in keratine and support hairs).
From my experience as a human with human offspring, I've observed that teeth are fairly expensive to maintain. Their surface area is large compared to beaks, providing lots opportunity for infection. And their relative complexity and fragility means imperfections arise in almost every individual's case. Perhaps because they happened to emerge so early in evolutionary history they provided a revolutionary advantage at the root of the tetrapod family tree, but once a simpler alternative structure arises in a derived lineage they quickly disappear? It's interesting that species that loose teeth retain genes for them in an off-state. Is there any evidence that teeth have ever re-emerged after they disappeared?
One draw back of teeth and teeth like structures that are not necessarily in beaks. Teeth can become infected as they wear down over time. Becks are constantly replenished like nails, since they are both made of keratin.
This makes me feel better about the fact that I (and most of the people in my mum's side) am missing several teeth! They just.... never existed. I don't have any gaps, though, because I also have a small mouth. There's even one tooth that I have that's actually a baby tooth - the adult tooth never showed up, and it isn't hiding in my gums either, according to x-rays. That one particular baby tooth, the same exact molar, without an adult tooth runs in the family. My great grandmother lived to nearly 104 with a baby tooth in her mouth since she was a teeny tot!
It always amazes me when creationists try to say "where are all the transitional fossils and animal" and think it is actually some kind of gotcha in their favor. Like seriously? We literally have 1000's of them. Their willful ignorance and blindness is truly amazing.
They are tetrapods, so yes. They shared a commmon ancestor with dinosaurs. For most of their evolution, pterosaurs had beaks. It wasn't until the latter part of the Cretaceous that toothlesness became the norm.
It was very interesting and something that I've been wanting to see is a video about the evolutionary history of mosquitos. I do really hate them, but I wonder how and why they came to be
Hey hey! Shoutout to our little Nova Scotia here on the East Coast of Canada 🇨🇦❤ That's such a neat fact, I had no idea we had a reptile here like that 🦎
'which came first, teeth on skin or teeth in mouth' is a question I never could've imagined would need to be asked and it's really weird and strange to think about but this is exactly why I love this channel so much! So many topics I had no idea even existed but I always come away feeling like I definitely needed to learn about it. I'm a little disappointed the video didn't go into more depth on 'teeth on skin' though, what were the advantages to that, why did it develop, etc.
I would love to learn more about the teeth on skin option too!
sharks have dentin scales! unfortunately i don't know much more than that basic fact, but it might be a cool thing to research :)
Dentin scales are very hard and have ridges on them (going from head to tail), allowing for increased defense and aerodynamics in sharks
i’m gonna wow at parties when i say this instead of “the chicken or the egg”
I'd imagine, if it was skin teeth to mouth teeth we'd have animals around today that have skin teeth. Instead I think this fish is an outlier
Really enjoy kallie’s story telling. Her passion for the subject is evident. Thank you
As is her passion for bad jokes. 😂
What are her squirtistics
her voice too
So much better than the painted lady
@@stevenkanzler2319 - Love them both!
I think it would be interesting a video about ears, the outer part of them, when they first show up in the fossil record and why (I think) only terrestial mammals have them.
It is extremely interesting that Mammals are the only lineage of tetrapod to develop ear pinna (the outer ear).
I would love for a video on this as well!
@@horse14t yeah and if it has any evolutionary advantage for us
@@andrearivera1622 Well it does have purposes as Ear Pinna can serve to filter sounds better into our ear canals for better hearing and in most other mammals apart from many primates including us and some other mammals; communication purposes and a warning system. The position of say a dog or cat's pinna can very clearly tell you how they are feeling or what they are listening to without them having to vocalize it. Additionally having the ability to swivel your ear to listen in on sounds of interest without having to move your head, body or neck is a huge advantage when listening out for predators or other animals that may want to harm or eat you.
Now that I think about it perhaps Ear Pinna evolved in tandem to the evolution of the more complex mammalian ear 🤔
IIRC, owls have feather structures that help guide sound into their ears, though not the type of outer ear that mammals have.
Outer ears wouldn't really show up in the fossil record often. They are not made of bone. It's made of cartilage (I believe) and wouldn't fossilize or be preserved well.
The Ballistic Tongues is definitely a solid band name if ever there was one.
@@Stevie-J @Ryan Colligan Also the Toothless Toads
I think I read somewhere once that having beaks instead of teeth also helped drive down the amount of time between when a bird lays an egg and when that egg hatches. That seems to me like that would be beneficial for creatures living in the aftermath of the K-T extinction.
Except for egg teeth?😜
Are the beaks of baby birds too soft to make it out of the shell?🤷
I heard that the loss of teeth in birds was a weight-saving device. Beaks are a lot lighter than jaws.
@@icollectstories5702 typically, yes. The newborn bill is more like cartilage than bone in terms of "squishiness". Having an egg tooth helps zip open a hardshelled egg. Its also not a real tooth, but more of an extra hard nub at the tip of the bill- or nose, if youre a reptile. Snakes have one too! I'm not sure about other reptiles but I'm sure if snakes and birds have them, the others also must
@@kitgodsey monotremes have em too
Something occurred to me watching this, we get lots of content about the fist land vertebrates but do we know much about when arthropods moved onto land? Was there a single major movement by arthropods or had their subphyla already split off and had separate events leading them to become partially or fully land dwelling.
Its tricky because fossils for land arthropods are the same as aquatic ones. (Legs and lungs already were a thing). "foot"print evidence is the earliest known evidence of arthropods on land.
I was actually looking at this question a few weeks ago. There are three main groups of terrestrial arthropods are myriapodia (centipedes and millipedes), arachnids (spiders, scorpions, ticks, mites, and others), and hexapoda (insects and "wingless insects"). A few other arthropods are terrestrial, but those are the three main groups and by far the oldest.
From my limited understanding of arthropod taxonomy, I think with insects the idea is that wingless insects like springtails were likely the first to arise, as they live in incredibly damp environments even when terrestrial, and then they diversified from there. I really dont know much about bug evo though, lol
I don't know but ... crabs look like giant spiders to me and crayfish look like baby lobsters. The movement to land was either coastal like crabs to spiders (just hanging out on the beach for longer and farther inland) or moving upstream (salt water to freshwater first) like lobster to crayfish and then colonizing interior. Darn cool question.
The existing land lineages are so far apart that it is unlikely that they had a terrestrial common ancenstor. Their LCA was probably before land plants and terrestrial life was possible. So most likely independent movements to land.
I enjoy every episode, but it is evident that the speaker matters as much as the content. If not more. This lady´s genuine enthusiasm is infectious. Her colleague´s humour is refreshing. I hope to see more of this duo.
I just want to say that the concept of a "ballistic tongue" is one of the cooler ones in biology.
I mean it hurts enough biting your tongue while chewing - can't imagine impaling it while sling shotting it.
No wonder they evolved to be toothless.
I want an adapted game of rock paper scissors. But I think rock still beats ballistic tongue.
@@Cat_Woods tounge wets paper, that's all I got.
@@benhalpin7306 LOL
@@Stevie-J something about this doesn't add up. Tounge is very much under powered. There needs to be a 5th element.
The interesting thing is though, that tounge vs tounge isn't just a draw it's very sexual.
One of my biology teachers explained part of the reason birds lost teeth was because enamel is the densest material in our bodies, and it helped conserve weight for the same reason that female birds have only one functioning ovary. I wasn't sure how founded that would be, but it was something that stuck out to me.
You should watch the video named When Birds Had Teeth too.
Hmm yeah it has been found that theory is not true.
"Why would you prefer a beak to teeth?"
"Ummm... I guess you've never had a toothache."
I'd also assume that calcium may sometimes play a role.
But if your beak got broken, would it heal before you starved? I'd imagine a jaw would be easier to heal.
@@icollectstories5702 I just imagined beaks made of dentine... Curse you, lmao
@@icollectstories5702 a tooth never heals
@@parthbonde2106 But, depending on the animal, it gets replaced
I love how full of information PBS Eons videos are while being quick and easy to watch. Perfect for work breaks
I think it's a great illustration of the way evolution works that several lineages of birds, including waterfowl and the Pelagornathids, have evolved beak structures that function like teeth. Natural selection can only work with the biology an animal already has.
In the early stages of chicken embryo development, the embryo does indeed grow teeth in it's proto-beak (for lack of a better term). However, they are then reabsorbed a short time thereafter. It does show however, that at one point, the chicken's ancestors, did indeed have teeth (T. Rex certainly fits that description).
Hey! I was wondering if you could do a video about how insects evolved out of the oceans. We all know how fish first walked onto land, but how did bugs get onto land?
I second this!
Insects? Arthropods appear on land 419 MYA, before insects evolved.
Inside the walking fish
@@AndrewTBP Pedantry doesn’t make you look smart nor cool, you knew what OP meant
So excited for this episode! I remember asking for the evolution of teeth. Didn't think it was important enough to get its own episode
Tungsenia: allow me to introduce you a new innovation, teeth!
*millions of years later*
Most animal groups: these teeth get in the way, let’s ditch them for something less biologically expensive
Mammals : You gotta spend money to get money.
Someone tell the squirrels to not put so much into tooth regeneration!
It's like VCR
@@naamadossantossilva4736 Meanwhile, 400 million years later...
Humans: *eating the pizza diet* Meh, are teeth REALLY necessary? We just need softer pizzas...
@@Zaxares and bigger beards to hide the weak jaws
I'm hoping for more flora taxonomy!
How did alder, maple and beech become dissimilar from spruce, juniper, cypress?
I'm sure there are equally interesting stories about their diversion, convergent evolution and likely some unique aspects that aren't found in animalia
Ukoppoiu
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J6opllppploôi9
@@vangmua3260 What
Angiosperms vs gymnosperms.
Same thing happened to eyes. Animals needing great eyesight evolved them. Animals not needing great eyesight lost them. Even when they evolved from predecessors previously having acute vision. (You should do an episode on the evolution of eyes)
And how all mammals have atleast basic night vision
@@onyxgrnr666 And lost some color vision with that, but primates re-evolved a third cone, losing some night-vision in the process for most of them ^^
Another evolutionary "cost" of teeth could also be that they can get infected - you don't have that risk with a beak. They are also more easily damaged in general.
Pretty sure beaks can get infected too. And being that they only have one, it's a huuuuge problem if that does happen, or if a bird loses any part of their beak
@@StonedtotheBones13 yeah but a beak is overall more sturdy
@@stanpines9011 I never said it was or wasn't. I said they can definitely get infected. Next time you rush to correct someone, maybe make sure you're actually correcting the right thing.
@@StonedtotheBones13 Yeah but by chance is way more easy to infect teeth, in the great game beaks are more stable, more difficult to be damaged and thus it can be more reliable
Every two weeks or so tune into this channel to be educated about some new thing, and without fail it is amazingly informative. Keep up the good work.
All your narrators are top tier. TOP TIER.
I would love a whole video about how tetrapods invented herbivory.
I love explaining this to people, it is rarely known in my community that we decent from the placoderms. i love your content for keeping me up to date
you do know all of this is just guesswork, right? we dont know any of this as fact
@@fingersmcoy at any point did i state it was factual? actually no, i did not. i was complimenting eons and this will be my only response to you. check yourself homie
Outside-in makes more sense to me considering the general paths evolution took.
Dentine started as armor that eventually gained a secondary use as teeth.
I really love this channel, i can learn other things that werent taught to me and also this channel improves my english vocabs!
The question is why mammals didn't also try for beaks, like our Aussie duckbill friend? Like all your fantastic episodes EON they bite deeply into the subject matter. 😁 It was quite a satisfying dish! 🦊✨✨
I remember reading something a while back that said that the reason us mammals don't have beaks is due to the fact that we have to drink milk as infants, and if you had a beak, you can't make the sucking motion that's required to drink milk. So basically the reason us mammals never evolved beaks is because we suck. Platypus get away with a beak because the mothers sweat milk
I think 1 of the reasons why mammals in general have not lost its teeth are that the mammalian teeth is more moldable than the sauropsid teeth.
I think to answer this you have to go back to our therapsid ancestors one of the defining characteristics of cynodonts is anatomical changes to the structure of jaws which granted them the ability to chew. Chewing is a unique adaptation to Cynodonts and all their living descendants offering one of the most effective ways of predigesting food. No other vertebrate group is capable of chewing their food they instead rely on tripping tearing and or slicing food into smaller pieces, with the closest analog seeming to be gizzards of birds at least among extant animals.
In this sense chewing adapted jaws are a powerful evolutionary advantage which largely necessitates the preservation of teeth and the ability to produce enamel. From the fossil record we can see that our ancestors and their cousins in fact convergently further specialized their jaws and teeth for better filling this ecological role such as by reducing the jaw bones over time through repeated secondary losses or repurposing as those bones were adapted to build the mammalian ear and analogous ears of close synapsid cousins. In effect the jaws and teeth of mammals are our evolutionary lineages most defining characteristic dating back to our Permian therapsid ancestors.
Beaks while versatile are unable to be used to perform similar roles as beaks but can conversely perform most of the same functions which make beaks successful so from an evolutionary perspective switching from mammalian chewing jaws to beaks would require adapting to an increasingly different mode of lifestyle which would only be an option if there was an open ecological niche that provided an opportunity to do so.
In this sense the competition from archosaurs and to a lesser extent dicynodonts was probably one of the main limitations that locked cynodont descendants into the chewing mode lifestyle as it allowed them to exploit food sources archosaurs couldn't allowing them to persist despite having a vastly inferior respiratory system compared to archosaurs.
Basically mammalian jaws and teeth adapted for chewing were probably the defining traits that allowed cynodonts and their descendants to avoid getting out competed by archosaurs.
Then when the archosaurs either went extinct or became so specialized they were no longer in direct competition and the few mammals that survived were finally able to diversify and so we see mammals start to experiment more giving us stuff which fills now vacant niches such as baleen whales.
Beaked mammals however would still have to compete with chewing mammals and beaked birds which would put them at an evolutionary disadvantage without some similarly impressive adaptations.
The platypus _is_ a mammal, a monotreme. It doesn’t have a beak like birds do, the bill is fleshy and flexible.
Beaks and tongues may have beaten teeth but we're still the ones eating chicken and frog legs, not the other way around.
Certain traits do not pair well with others. As noted, lactation and beaks don't work well. It's possible that teeth end up having some hidden advantage for certain lifestyles and diets. It's hard to be an apex predator without teeth, for example.
The idea that no land vertebrates were eating plants until about 300 MYA is absolutely wild, how have I never heard about this before?
That's probably straight up wrong. Why would animals ever wander out of the sea if they have nothing to eat onshore? Escaping predators might be a thing, but that's hardly enough to develop a whole new breathing system. Animals should have been very busy on land to develop such adaptation.
@@hellstorm300 insects
Watching this video while eating made me very aware of my teeth! Thanks for another great video, Eons!
My grandma also evolved and lost her teeth
😂
Did she grow a beak, too?
It’s amazing how video after video you guys still manage to create interesting content!! It’s like paleontology was a infinite well of surprises
Grats on 2million subs! I'm binge watching the episodes iv missed. Been subbed since day one! Love you Eons!
I would like to see a future video about mammalian ears vs bird ears. I think it is interesting, because while mammalian ears are supposedly more complex because mammals have 3 bones in inner ear and also have an outer ear, but most musically sensitive animals are birds, they sing songs, dance etc.
Beautiful video.
1. Though amphibians use tongues for feeding, the tongues cannot completely replace the teeth. Frogs actually push their eyes down to bring the food into their tract.
2. Also seeing grass in Permian era illustrations irks me a bit.
How would teeth help them swallow?
@@Cillana from what I've seen, the eyeballs of frogs sorta push the food down their throat. The projectile tongue occupies most of the skull and only while eating the frog closes its eyes to push the food down.
@@adityamohan1773 Yes, I know. I'm asking what do teeth have to do with swallowing.
@@Cillana in reptiles for an example teeth/fangs help in pushing the food back into the mouth.
@@adityamohan1773 okay 👍 thanks for answering
Edit: I have seen video where frogs use their hands to shove food in their mouth. Then they use their eyes to swallow.
Dude- your guys videos are so AMAZING! they are accurate, well put together, and the illustrations are awsome!!
I have a request for a video i would LOVE to see- i doubt you will see this comment but, i heard somewhere that the reason we only really find the adult and baby dinosaurs, and we don't have to many fossils of like 7 year old dinosaurs, is because some medium sized dinos (like Nanotryranous) were actually just a Tryanosaurus Rex but in their teens? Idk if its true but I WOULD LOVE to see a vid on it if you see this comment!🥰
Edit: yall i said that idk if its true
Oh! They already did this one! Look up PBS Eons: Where are all the Mid Sized Dinosaurs?
th-cam.com/video/YXe9IHVX17U/w-d-xo.html think you mean this video? It's about mid sized dinosaurs.
This missing ones are the ones that got eaten. It's a race to get big enough so you are too big to be predated. If you don't make it, you get torn to pieces and wind up in somebody's stomach.
@@dingfeldersmurfalot4560 but even when they get eaten we can still find fossils- also idk if its true i just want them to do a vid on it lol
@@dingfeldersmurfalot4560 you would still find the bones tho...
A perfect start of a day. Thanks Eons :)
I have always loved this hosts style. Your great!
We should absolutely find a way to turn that frog tooth gene back on. No way that could go wrong.
Yeah. What could go wrong with having a relatively big ballistic tongue shooting back into a mouth of sharp teeth?
I read they managed to do it to a chicken embryo a few years ago, the chicken starting to produce alligator-like teeth.
"Life... uh.. finds a way. "
- Some guy in a movie from the 90's.
Check out the Stephen King short story "Rainy Season" ;)
Southeast asia has fang frogs.
3:38 - Hahaha ngl that looks like something out of Star Wars
Loved the video, keep up the great work guys. You're one of my favourite channels!
Banger after banger, absolutely love this channel
I have always hated teeth because of having sensitive teeth with a lot of past issues. I will now respect them for possibly being my mouth armor
NOT THE BEAK-AUSE PUN NOOOOOO
amazing video, I'm always thrilled when there's something new from this channel
i just love this channel so much it's ridiculous, always makes my day 50000000000x better
This was a really interesting topic. Thanks for all the great content!
This was a great video, but my favorite part is the end where you acknowledge the lands that were originally belonging to Native Americans. It's not just their history we stole, it was their entire history of life on earth in that place, a place belonging to native peoples, who should've gotten a say in the matter.
From a biology standpoint, it's easy for a toothed mouth to evolve into a beak; it's very difficult to go back the other way, i.e. beak to teeth.
I agree. Check out the Dollo's law of irreversibility. In birds that circumstances when they need something to grasp using their mouth, they never evolved teeth, instead to evolved keratin parts that act like teeth in their beaks.
Love these. Stuff I can listen to while doing work. Stuff i wish was available to me as a child.
Would have liked to see more about the evolution of baleen. Maybe a future video?
This channel is gold.
As someone who lost enough teeth, I fully advocate for beaks
Yeah. I want my beak genes back.
This is such a great topic - I always enjoy the subjects that your channel explores. Could you cover the evolution of the eye at some point?
Eyes have evolved multiple times in different lineages, might be too broad for just one video.
@@mboatrightED300 Though that fact makes it even more worth to talk about
Would love to see an episode on the Hawaiian toothed duck like birds that went extinct only recently
I have never considered whether frogs have teeth or not. I regret to know that they do. Mind you, I would not have been any happier to learn that they do not. I just never would have really wanted to think about frogs as creatures that either do or do not have teeth.
I love how she says "giant sea scorpions" like that's just normal 😂
For the time IG…
Normal for PBS Eons. They have a video on the sea scorpions. The largest arthropods ever.
loving the longer videos!
Here’s a possible topic suggestion:
How did birds evolve the ability to build nests in trees?
I don’t think building nests is a trait that gets evolved, it seems more like an adapted behavior than a genetic trait, don’t u think? Or did u just mean how they started building nests and not necessarily how they “evolved?”
I think its hard to get fossil record of nests
What about Chameleons who have both sling shot tongues and teeth? are they transitioning to toothlessness?
Evolution has no direction. So perhaps there will eventually be descendants with no teeth, shorter tongues, or both -- or no descendants at all.
I'd be interested to know how they avoid biting their tongues, or if they heal quickly. Perhaps they learn tongue coordination well as younglings.
@@icollectstories5702 If you watch chameleons videos, they do everything slowly, even chewing their prey once caught, I guess they never really bite their tongue because they're very cautious ^^
You missed an opportunity here to talk about Geese! They have beaks but they also have teeth (or at least something resembling teeth) on their tongues! Nightmare material!
I was just about to say that! Geese are terrifying!
I think that what they have is called tomial teeth.
I had some toads as a kid and I almost never saw them use their tongue to catch prey. They would just chomp down on it. Don't get me started on those weird frogs at 6:51. They're literally just a mouth with two hands to push in food, they'll eat *anything* that gets in front of them.
My one eyed Toad struggles to eat certain things such as Worms because they use their eyes to create suction to swallow.
Umm... I am not sure if they are classified as teeth, but Canadian geese have serrated beaks that look and feel a lot like teeth. They may not be teeth from a taxonomic perspective, but I would argue the the function is similar. I took a bit while feeding them at the park; it hurt more than my boa constrictor from uni.
They're not teeths stricto-sensu, because they're not made of dentine, but of keratine, as the rest of the beak.
But yeah, they have teeth-like structures, and they even have other teeth-like structures on their tongues (a close-up look on a geese mouth is terrifying XD). Although it may hurt, they're not meant to bite, but to filtrate water, just like the baleens of a whale. Baleens are not teeths either (although primitive whales and some seals do use teeths to filtrate water), they're made in keratine and support hairs).
From my experience as a human with human offspring, I've observed that teeth are fairly expensive to maintain. Their surface area is large compared to beaks, providing lots opportunity for infection. And their relative complexity and fragility means imperfections arise in almost every individual's case. Perhaps because they happened to emerge so early in evolutionary history they provided a revolutionary advantage at the root of the tetrapod family tree, but once a simpler alternative structure arises in a derived lineage they quickly disappear? It's interesting that species that loose teeth retain genes for them in an off-state. Is there any evidence that teeth have ever re-emerged after they disappeared?
Thank you for showing the dakotaraptor, I was freaking out about birds with teeth! 😅
Whoever composed this went hard. Hats off homie
I'll watch this later but ya get a thumbs up already just cuz you're PBS Eons and awesome.
Thaaanks, great episode.
One draw back of teeth and teeth like structures that are not necessarily in beaks. Teeth can become infected as they wear down over time. Becks are constantly replenished like nails, since they are both made of keratin.
I wasn't picturing skin covered in human teeth until you said something, thanks.
Each visit to the dentist makes me wonder - isn't there any other feeding structure I can choose :(
There should be a video on why sharks have been so successful for almost 400 million years. I just thinks it’s awesome!
Ballistic tongues is now my new favorite band name
This makes me feel better about the fact that I (and most of the people in my mum's side) am missing several teeth! They just.... never existed. I don't have any gaps, though, because I also have a small mouth.
There's even one tooth that I have that's actually a baby tooth - the adult tooth never showed up, and it isn't hiding in my gums either, according to x-rays. That one particular baby tooth, the same exact molar, without an adult tooth runs in the family. My great grandmother lived to nearly 104 with a baby tooth in her mouth since she was a teeny tot!
What a nice soundtrack...
Grand video once again keep it up.
Enjoyed your video and I gave it a Thumbs Up as a support
Something really strange is that chitinous beaks also evolved in mollusks (cephalopods) as well as a toothed, tongue-like organ: the radula.
"toadally" toothless? top tier pun there eons
Great stuff thanks for posting
Awesome as always.
I just read a paper on teeth Evo/Devo and am doing my senior research on it. So strange how this video came out just in time!
You just summarised my upcoming review paper and just-begun PhD project... I don't know if I am amazed, pleased or concerned.
I feel like Callie gets all of the weirdest or grossest episodes. And she makes it fun!
I wish this episode was longer :(
It always amazes me when creationists try to say "where are all the transitional fossils and animal" and think it is actually some kind of gotcha in their favor. Like seriously? We literally have 1000's of them. Their willful ignorance and blindness is truly amazing.
This channel has the best presenters :)
Omg, that background music. Some serious dark souls vibes. I love it.
Really interesting. Thanks for teaching me something new.
Didn't pterosaurs also adapt from teeth to beaks?
They are tetrapods, so yes. They shared a commmon ancestor with dinosaurs. For most of their evolution, pterosaurs had beaks. It wasn't until the latter part of the Cretaceous that toothlesness became the norm.
It was very interesting and something that I've been wanting to see is a video about the evolutionary history of mosquitos. I do really hate them, but I wonder how and why they came to be
I want a video on the evolution of emotions. Hormones, instincts, behavior.
Thanks a lot for making videos
"Ballistic Tongue" sounds like an awesome band name lol
You’ve talked about teeth and eyes, and how some other things may have evolved. But necks. When and how did necks evolve?
I’d love to see a video on the paleontology of the Indian subcontinent over the Eons 😀
This is great info, thank you!
Amazing as usual. I found the music a little distracting this time tho
i love your videos so cool i think you need more people to see this
Awesome Episode 😃
Ballistic tongues is not the term we expected, nor the one we needed, but one we got none the less 😆
As someone who's doing some spec evo right now, this is really handy
all the paleoart chosen for this episode is SUPER adorable!
Hey hey! Shoutout to our little Nova Scotia here on the East Coast of Canada 🇨🇦❤ That's such a neat fact, I had no idea we had a reptile here like that 🦎