The Traits That Spawned the Age of Mammals

[@CuriousArchive]

Crazy that almost every mammal from whales, to elephants, to humans came from the same few rat-sized species

[@Bhoddisatva]

Even weirder to think those early mammal ancestors had ancestors who were once of a size to compete with early dinos for all the big ecological niches before gradually losing out.

[@EternalEmperorofZakuul]

@@Bhoddisatva even wierder when you realize our relatives once dominated the Permian

[@nakenmil]

@@EternalEmperorofZakuul even weirder when you think about how there are almost twice as many species of birds as there are mammals, meaning that the dinosaurs are still doing incredibly well and are a succesful animal group.

[@Burt1038]

Even even weirder that some humans are still rats.

[@GohanLSSJ2]

Even crazier than said rat-like beings are descended from lizard-like creatures.

[@rl9217]

Dinosaurs: (dies) Mammals: “Feeling cute, might become the dominant species on earth later”

[@TragoudistrosMPH]

Fluffy baby chicks: 😭

[@張於哥]

@@TragoudistrosMPH yes, dinosaurs' chicks(babies) are also cute 😍

[@張於哥]

Penguin is the cutest dinosaurs living today.

[@Minish4rk360]

@@張於哥 ducks would like a word with you

[@張於哥]

@@Minish4rk360 yes, ducks are also cute.

[@ColumbiaB]

Kallie may set a record here for the amount of complex, difficult information condensed into eight minutes in a forum for popular consumption - while maintaining a reasonable degree of clarity.

[@newq]

Come for the cool fossil critters, stay for the excellent primer on cladistics. That sorta thing is this channels specialty.

[@idjles]

Watch anything from Russell Brand

[@Whateverhasbeenmynameforyears]

That is a very specific record. lol

[@nickname_presentable]

try out PBS space time and then we can talk

[@ColumbiaB]

If ST were really that absorbing, why are you •here•?

[@Evan-rj9xy]

". . . because the dividing line between true mammals and the not-quite-mammals is actually kinda -blurry- _Fuzzy_ " Fixed

[@shafqatishan437]

How do you do it?

[@b.f.2461]

Touché.

[@sriharshacv7760]

nice one.

[@pavel9652]

Hairy topic ;)

[@Carcharodon]

Asteroid: **exists** Mammals: *I see this as an absolute win*

[@seamlyshenanigans861]

🤣

[@SinKimishima]

Until another asteroid hits earth… then it will be the age of octopi, all hail the eight legged overlord

[@Gyomax9744]

@@SinKimishima Splatoon

[@GRIGGINS1]

Diverts asteroid to land in that section of the ocean. Octopi had their shot in the ancient past. They failed to seize the planet. Now they shall be forever barred from ruling. So says the Rodent Mafia.

[@pavel9652]

Known otherwise as board wipe ;)

[@aaronareese1997]

Non-avian Dinosaurs: *die off* Mammals: “It’s free real estate!”

[@dsp6373]

Dinosaurs didn’t die off. They flew off. They’re in the air now. Birds.

[@aaronareese1997]

@@dsp6373 You are right. It should be non-avian dinosaurs.

[@Joanneehlers]

Allosaurus had never seen such bullshis No hate btw

[@OverTheVoids]

Modern human mammals: "Time to pay dem property taxes for my real estate. Stupid government takin' all my hard earned money."

[@張於哥]

Dinosaurs are still living today.

[@libraryofpangea7018]

Request: Please cover more Paleomycology (ancient fungi ), it's highly underrepresented & neglected while mycology is going through a renaissance at the moment. Thank you!

[@libraryofpangea7018]

@Thessalin Idk I think Kallie is much more of a fun-gal! 🔬💧

[@meneeRubieko]

Saw podcast of joe rogen with paul stemets and it blew my mind been interrested as f ever since

[@samsmith4242]

They did a piece on the giant fungi

[@libraryofpangea7018]

@@samsmith4242 Prototaxites yes, but its a very small slice of an emergent field. For instance, there is evidence from duckbill corperlites that they would eat fungally decomposing dead wood & the associated organisms. www.nature.com/articles/s41598-017-11538-w ( The papers focus is on crustacean consumption but relevant evidence for what im talking about is described in the paper) white rot fungus can do what few other microbes can- decompose lignan. Delignifed wood was more readily available for disgestion & fungal sugers also helps the active immune system response as it does in many animals today. In fact, until fungi evolved the ability to delignify wood, most dead wood would compress & is responsible for the large coal deposits of the carboniferous period. ( White rot is also why those deposits won't replenish now that wood is more readily decomposed ) www.nsf.gov/news/news_summ.jsp?cntn_id=124570 Since animals like gastropods, myripods, isopods and even some crustaceans are attracted to fungal activity this provided those dinosaurs the operunity to eat these animals & gain the micronutrients they needed to produce eggs & thus reproduce. Unfortunately Paleomycology is highly under represented, it's the field im studying- because fungi are major context providers when trying to gain a wholism in perspective when we try to understand ecosystems. Both ancient & today. Getting more people into studying ancient fungi will help us learn more about dinosaurs. And on a selfish note it would be nice not to be the only one in student & professionals groups proactively talking about fungi in this context.

[@libraryofpangea7018]

@@meneeRubieko Check out the Mushroom Revival Podcast if you liked Stamets. They give a wide sample of different kinds of Mycology. He is a good introduction to mycology but even he had a hard time articulating how large and impactful the field is.

[@Random_Nobody_Official]

watching this felt like one minute, rather than the real eight minutes.

[@sriharshacv7760]

Probably paleo biology is your natural thing!

[@Random_Nobody_Official]

@@sriharshacv7760maybe...

[@sydposting]

Last time I was this early, cyanobacteria had just learned how to photosynthesize.

[@minecraftstation6422]

Lol time to get pinned

[@sythrus]

@@minecraftstation6422 they would deserve it lol

[@commando232r]

Last time I was earth was still forming!

[@sion8]

Learned? That wasn't learned.

[@svchineeljunk-riggedschoon4038]

And killed most life with oxygen poisoning (:

[@Philoreason]

you're saying the bone inside my ear were actually jaw bones a long time ago!?? wow

[@swimdownx6365]

Is that the difference between mammal like reptiles and monotremes

[@sagaramskp]

Yes. And inner ear and middle ear embryological development is totally independent of each other. It's like the parts of a machine assembled together later. I'm an ENT resident. I know. So a congenital abnormalities of inner ear can occur with totally normal middle ear and vice versa

[@aryyancarman705]

@@sagaramskp wow

[@search895]

It's very interesting because i think all vertebrates with an ear or a voice rely on bone resonance to some extent apart from the ear bones. You can actually buy headphones you put in your head and not your ears today which send the music vibrations through your bones to your hearing system. So it probably started from that principle.

[@Zooollieg]

@@swimdownx6365 they are not mammal like reptiles they are non-mammalian synapsids

[@ValVonRhine]

I still expect "...and Steve!" at the end. 😔

[@princesseville6889]

I for real hope Steve is okay, kinda ridiculous, I never even saw him, but I cant help it..

[@sjonnieplayfull5859]

We all do

[@LuisSierra42]

Maybe he just got poor cause of losing his job because Covid

[@prasanth2601]

The fact that we can able to uncover the history of earth and pre historic animals with the help of a bunch of rocks and fossils is mind blowing.

[@bloodandempire]

This is my favorite show of all time 🥰

[@dballs52]

I thoroughly enjoy it as well.

[@funnygrunt_o7]

EONS IS THE GOAT only thing that would make it better is more hank green hosted episodes he’s been my fav for years 👀

[@isaisvargas]

Agreed.

[@gedepradivayogakrisnanda265]

@@funnygrunt_o7 same, I really enjoy Hank's presentation

[@minecraftstation6422]

Everyone hating first amphibian for being the reason of our existence while ignoring this....rip

[@Yes-gu2wn]

69th... nice...

[@byrdman9833]

Could you guys do a video on the evolution of color vision? And also explore why mammal's color vision in particular is so underdeveloped for the most part compared to other amniotes.

[@ef1876]

It’s not the same as a video, but for mammals at least it’s because our common ancestors were nocturnal so our eyes have retained traits from then (like larger corneas) and limited colour vision is one of them

[@ItsASleepySheepy]

If the current group of Eontologists are the crown group, does that mean Steve is an extinct ancestor?

[@napatora]

pouring one out for steve

[@amandawilcox9638]

Maybe just granpaw.

[@Jake-pn7wr]

I find so much peace and solace in this channel. Such a nice break from the headlines crowding today's news.

[@Silae.]

How you doing

[@Cash5YR]

I miss Steve.

[@Drakijy]

Kallie was always so enthusiastic when saying "and STEVE!" Wonder what ol' dude is up to.

[@lewisirwin5363]

@@Drakijy Eontologiform stuff, I guess.

[@LivingParadox87]

Mah boi Steve!

[@eve5909]

What happened?

[@zachg.4251]

Steve. Gone but not forgotten.

[@jakobraahauge7299]

And hosted by everybody's favourite fossil librarian 😄 thanks! Hope all of you at PBS Eons will have a splendid summer! Loads of love from Denmark ❤️🤗

[@tata-i5l]

Librarian?

[@jakobraahauge7299]

@@tata-i5l On insta she's The Fossil Librarian - really cute wall she has there!

[@EebstertheGreat]

Random question about crown groups: if the tuatara goes extinct, will crown lepidosaurs become synonymous with squamates? After all, all extant lepidosaurs will then be lizards and snakes. That is, since crown (and stem) groups are defined by living representatives, do their definitions naturally change over time, as species go extinct? Or once defined, is a crown group fixed?

[@curtiswfranks]

There are alternative definitions which do not require any members to be extant, but they are also somewhat different or vaguer as far as I know. Personally, I think that it is a poor definitional choice to require the defining members to be extant, for the reason which you indicate. It a crown clade should be defined as follows: Let S be a set of individual organisms. Let α be the MRCA of all members of S simultaneously. The crown clade of S is the set of all individual organisms which are or are descendants of α (or, more broadly, the species to which α belonged). In this way, crown clades monotonically nondecrease as sets, wrt time, where dead former members remain members.

[@no_bitches420]

"it also includes all extinct descendants of that common ancestor"

[@thomasrichardholtz9031]

No. Because when we fixed the name we actually had living tuataras. If (as is possible) in the future the tuataras became extinct, we would still refer back to the situation in the 20th and early 21st Century when the crown definition was proposed.

[@mathiaspint6808]

@@no_bitches420 the point was that that common ancestor would change if the most distantly related extant species (in this case tuataras) went extinct (because tuataras are the only extant lepidosaurs that aren't squamates).

[@EebstertheGreat]

@@curtiswfranks Yeah, this seems to be the best way to go. For instance, we could define crown lepidosaurs as the most recent common ancestor of the tuatara and the green iguana and all its descendants (equivalently, the smallest clade containing the tuatara and green iguana). That way, it doesn't matter if the tuatara or green iguana still exists.

[@YourPhysicsSimulator]

And the last stage of mammal evolution is when humans realize that PBS Eons is the greatest channel on KZbin. Almost 2 million people have reached that stage atm.

[@Bmoney902]

I'm obsessed with that thing at 3:01, like it has seriously activated something in my primal brain. It's going to make it's way into my nightmares for sure because I'm watching this in bed.

[@johnythefox100]

It looks like a type of Gorgonopsid

[@Bmoney902]

@@johnythefox100 yes you're right! I googled it and found this image. Thank you! Now I have a name for my new favourite extinct nightmare animal. It looks like a dinosaur and a big cat got it on. Amazing

[@Zimisce85]

They should definitely use it in a movie about a "Triassic Park"

[@1cruzbat1]

Very impressive looking animal! Love to think of that as one of my ancestors!

[@Zimisce85]

@@1cruzbat1 more like the worst nightmare of our ancenstors ;)

[@shrimpisdelicious]

Mammaliaforms: “May I have extra bones in my jaw?” Evolution: “For chewing your food?” Mammaliaforms: “Yeeeeeeesssss…” (Actually repurposes them for better hearing LIKE A BOSS) *MAMMAL TIME!!!*

[@Ben_c-j4u]

Lol

[@rossplendent]

Wow. I had no idea that the middle ear bones evolved by detaching from the jaw! I can see how that developmental shift would have been increasingly helpful with each subsequent mutation.

[@iansilva5101]

This is by far my favorite channel of all time, I have been looking for something like this for a while, a channel that could provide me relatively complex scientific information and facts in a clear, concise and well spoken way and this is EXACTLY everything I was hoping for to find. Thank you for your amazing work and efforts to bring us these awesomely interesting paleontology facts PBS Eons!!

[@HienNguyenHMN]

Other mammalian traits that don't fossilize easily: having a 4-chambered heart, breathing using a diaphragm

[@Dragrath1]

true the ancestor of mammals going back to the Permian likely had 4 chambered hearts though the 4 chambered heart also evolved independently within the stem archosaurs likely for the same reason of partial to complete internal body temperature regulation. Fun fact Crocodilians when developing insider their eggs actually first form a 4 chambered heart before a valve secondarily seals off the 4th chamber. As for breathing it would be interesting to look at how that developed in different lineages as it looks to be a multistep characteristic with no surviving intermediary forms

[@clovebeans713]

Also 4-Chambered heart evolved independently in birds/dinosaurs and crocodiles so technically its not a characteristic/defining feature of mammals like milk/sweat, middle ears, Haversian bone canals, fur.

[@HienNguyenHMN]

@@clovebeans713 Evolving independently means they're not homologous features. They can be used as defining characteristics.

[@adrianortega1431]

Asteroid: (Hits the Earth) Mammals: The age of dinosaurs is over. The time of the mammal has come.

[@GarlicReturns]

Synapsids : time for revenge

[@KimiHayashi]

MY BROTHERS, WE HAVE WON THE WAR

[@HeyHeyHarmonicaLuke]

4:10 "Morganucodon's jaw represents what's sometimes called *a transitional mammalian middle ear."* -- Good one! It would help in the fight against evolution denial if you would give fossil examples like this more often, explicitly using the word transitional. There's still a movement of people who claim none exist.

[@brianmessemer2973]

Between Eons and Space Time, I love getting a bit smarter on Tuesdays 🔥

[@thecrimsoncreep]

It's Wednesday

[@toniatchison3678]

@@thecrimsoncreep 😂

[@crunchylettuce]

@@thecrimsoncreep ✨timezones✨

[@eviebr83]

I love space time... But I usually leave feeling dumb. 😅

[@brianmessemer2973]

@@thecrimsoncreep oh snap yeah it is 🤯

[@skink_wrangler69]

Why did we looks so cute, why can’t we still be that cute

[@commando232r]

Uh well if we did then mammals would die out very quickly due to niches

[@ecurewitz]

Speak for yourself

[@Random_Nobody_Official]

your a dino, your dead.

[@eviebr83]

Do you really want to have fur?😆

[@VinzRex]

I think you still are pretty cute.

[@Xnaut314]

Always love hearing about ancient synapsids and the evolution that eventually gave rise to the world as we know it. A good future video to follow up this subject would be to cover the mammaliaforms that existed alongside the dinosaurs like Castoracauda and Repanomamus that broke the stereotype that mammals only lived defensively in the shadows of dinosaurs, as well as the few extant mammals that survived the K-PG Extinction that might not be crown mammals and died off in the Cenozoic like the St. Bathans Mammal. Obscure mammals need more screentime and you all are the best at doing that!

[@Torbeth]

That is the cutest looking rodent silhouette ever, at the start. You need him on a tee shirt! :-)

[@galvaton10000]

Lol it can be like "Who's that mammaliaform?" Then the silhouette.

[@JMObyx]

Now follow the story of grass!

[@fernandoavila3929]

I believe it was briefly touched in North-American horses or something like that.

[@ceulgai2817]

Yes, please!

[@MammaApa]

Which... kind of grass are we talking here...?

[@JMObyx]

@@MammaApa Don't you watch this channel? The Evolution of ALL grass!

[@Mr_BRRRRT]

I've been watching these videos for the past few days. You helped me in these crazy times by giving me a piece of my childhood in the form of knowledge about paleontology. As an overseas fan, I'd like to ask of you to do a video about the raptor vs protoceratops duel found in the Gobi Desert. It's has always been my favorite fossil ever, tied with the nodosaur found in Canada in 2011.

[@redcoolhax]

I've been interested in mammaliaformes for a while now, and I'm glad you guys did a video on it!

[@carolinacoreas7716]

This is so interesting, it helped me connect a lot of concepts I had learned in my Mammalogy course this past spring.

[@kwakas4ever]

Love Kallie Moore's presentations - she makes learning about some dry subjects fun!

[@daleowens7695]

dry?

[@dynamosaurusimperious2718]

Well this is why I love learning more about Prehistory from this amazing channel,cause it's *FUN*

[@rodchallis8031]

"We are such stuff As monotremes are made on; and our little life Is rounded with a sheep."-- Willy Shakesdarwin.

[@vaimantobe3034]

So this is what it feels like to have a stroke

[@drsetherz]

This might be the best episode of Eons I’ve ever seen. Well done!

[@EdaugEthanbYT]

Natural history is really fascinating

[@swimdownx6365]

What's the difference tween monotremes and mammal like reptiles 0

[@EdaugEthanbYT]

@@swimdownx6365 Monotremes aren’t reptiles. That may not be the answer you’re after but it works

[@totalfreedom45]

Wow! Nothing beats the greatest brainchild of the human brain-the scientific method, whose solid yet pliable backbone is the fusing of constructive criticism, rigorous skepticism, a vivid imagination, and above all the consuming curiosity of a child. 💕 ☮ 🌎 🌌

[@azrielmoha6877]

Oh i thought you're being anti-science at first

[@mharder5262]

Happy to see videos here again. Like listening to this channel at work.

[@Bird_Dog00]

The fox to the chicken: "Remember when your ancestors preyed on my ancestors? How does the shoe feel on the other foot, punk?"

[@Bird_Dog00]

@anis azil what does this have to do with my comment? Do you want to debate the moral superiority of veganism with a predator?

[@christianniebuhr3728]

Hello PBS Eons, ive been bingewatching your videos lately and would really like to know more about the arthropods that walked the earth before anyone else. How did they evolve? Where did they come from? I have so many questions :D Pls make a video on that. Btw love your stuff

[@bruceherrera977]

Glad to see you!! Missed you bunches

[@KRAPYBARA84]

I love this channel so much. I wish I could study in this field as a profession. Even if it's just to read up on the history of these mammals. Also, as a huge rat fan, I love that our earliest mammal cousin buddy dudes looked so RATtical

[@yingle6027]

The World: Changes Turtles: "nah i'm good"

[@mrkommentator5906]

I would be very interested in the evolution of lactation. Like how did this crazy behavior and body features come to be

[@JohnnyArtPavlou]

That’s what I came here for. So let’s say… No problem no breasts are specialized sweat glands. And you got a little baby and it’s looking for some kind of fluid or water or nutrition. OK so you let’s say you get some salt from a sweat gland. And then somehow that goes on for a while until there’s another mutation where more nutrients are put into the sweat glands. By accidental genetic mutation. And the offspring of those creatures thrive and outlive the other ones that were just sucking on sweat. I mean I’m just a normal person and I’m trying to play my limited brain power to the question at hand. There just seems to be certain mechanisms or structures in living beings whose evolution is hard to understand as a step-by-step process. But here we are and I guess I believe in science.

[@charlesgoldberg8825]

Once we figure out the exact date that dinosaurs went extinct we have to start a petition to make it a holiday in every country.

[@gerrardjones28]

Yeah, let's do that for all other mass extinctions too, we actually know the great dying down to the millenia

[@piggy7024]

That is impossible.

[@emm6064]

That leopard-spotted gorgonopsid (?maybe?) really caught my eye! I expect speculative coloration in dinosaurs, but you hardly ever see it in other ancient groups.

[@Cec9e13]

That thing was so goofy I screamed. That was hilarious. Would totally take that home from the animal shelter.

[@jeremyahagan]

Really interesting story. As Eons gets deeper into their subject matter their videos just get better.

[@Temtatork]

"And a few lingering mamaliaforms" it would be interesting to see a video about how those mamaliaforms that survived the kpg extintion survived during the cenozoic but didnt make it to the modern day (sorry for bad english)

[@Dragrath1]

Interestingly there has been some recent work suggesting the extinction of other mammaliaforms probably was important for enabling placental mammals to take over. The role of competition was probably in part driven by the many small to medium sized terrestrial crocodylomorphs based on the overlap of similarly adapted dentition (at least among herbivorous members of these groups)

[@azrielmoha6877]

Multituberculata are one of the mammaliaforms that survived the K-Pg extinction and they actually thrived during the early parts of Cenozoic, mostly as rodent-like generalists. Eventually because of climate change and competition with true rodents, they're driven to extinction.

[@roberthfagundes4013]

This was a increadible well structured video. Extremely didatic. Thank you

[@philochristos]

I sure am glad the mammals made it.

[@louislopez55]

Well, if they didn’t the earth would still be an unpolluted paradise, but who would be here to see it? Nobody I know!

[@higheyrie6176]

I really enjoy how Eons do their intros.

[@jessiec668]

What I took away from the opening of this video is that like so many other things in biology, mammalian-ness is a continuum.

[@MseeBMe]

One of my favourite show in any format.

[@cupcakeknight4349]

Honestly I still miss Steve when you're listing off the patrons, hope he's doing well out there...

[@filippozauc]

Julio arts are amazing! Like every of yours episodes. I love to watch them!

[@zo.yeahhh]

My interest in evolution made me start enjoying anatomy again.

[@jewdd1989]

I always love the content you guys put forth and appreciate that we have these resources now! For ie I remember being told by my history nerd Dad that the chalk pyramids in sw KS were from an ancient interior sea but it’s hard to believe till you see something visually demonstrating what that looked like

[@punditgi]

Captivating info from a mesmerizing presenter. Damn! 🥳

[@brynadoodle]

Thanks for always making wonderful videos that make my day a lot better

[@rosetownstumpcity]

intersting video, as usual. also i really like this presenter, her voice is great :-)

[@avermaak12]

Love this show!!! Kallie is so enthusiastic, its awesome

[@daniell1483]

I was blown away the first time I heard about Gorgonopsids, a group of early proto-mammals that predated dinosaurs. It is interesting to think that the legendary age of dinosaurs may not have occurred at all if some of our early ancestors had done just a little bit better in the evolutionary arms race. Though that far back in time, the very words we use to define animal traits today are not always accurate. Like how dinosaurs were a form of endothermic reptile, despite all modern reptiles being ectothermic. Then of course birds are technically reptiles as they are dinosaurs as well, but so far removed from classic reptiles like lizards that these clearly defined terms just start to fall apart. And that of course says nothing for the animal groups that predated even dinosaurs like archosaurs and temnospondyls.

[@sorrenblitz805]

Well in Gorgonopsids case the Great Dying was a little tougher than most species on earth could handle.

[@daniell1483]

@@sorrenblitz805 Yeah exactly my point. I grew up being taught intelligent design so even now that I know better, I have this tendency of thinking of deep time as a fictional scenario instead of a historical one. So now, looking back, the magnitude of the random chances that got us to this moment seem like such distant odds, you know? That there was a time before humans, before mammals. For most of the time, this was a planet for reptiles.

[@kade-qt1zu]

@@daniell1483 I'm glad you managed to break free.

[@daniell1483]

@@kade-qt1zu Me too, thank you. :)

[@bush.nawaz.t8385]

Here's an idea for a series,PBS eons. Something like, what if. What if dinosaurs never went extinct? Would they be more advanced than us? What if Neanderthals never went extinct? What if the ice age never ended? How would life evolve in that condition? It'd be interesting. I know PBS eons is not a what if channel, but it'd be so cool.

[@amandawilcox9638]

Watch behaviors of larger birds, especially from the parrot and chicken families. (No little & cute birdies for me, either.) Dam dinosaur cousins anyway!

[@patricknelson]

Monotremes (platypus and echidna) are so interesting. Would love to see a video on that topic!

[@Emma-iv2vx]

Amazing channel to learn from. I'm currently working out the geography of my local area because of this channel.

[@cosmicraptor6027]

When you listed the four traits that all mammals have in common you didn’t say that they were all warm blooded. Are not all mammals warm blooded?

[@dannielleeagles7791]

Being warm blooded is not exclusive to mammals which is probably why they didn't mention it

[@Algeriawindows69]

Warm bloodedness is not a mammal exclusive so it doesn't count but fur and milk are a mammal exclusive

[@cosmicraptor6027]

Got it, thanks guys :)

[@horse14t]

Ear pinna is mammal exclusive and yet it's never mentioned as a Mammal trait 🤷‍♀️

[@Ghonosyphlaids]

@@horse14t correct me if I'm wrong, but she was referring to crown mammals, and platypus' don't have ear pinna?

[@JM-rq4nv]

You have the best narrator voice!!!

[@naamadossantossilva4736]

You should do a video about the power of the mammalian jaws.

[@daniellevinson6975]

1:19 - 1:29 Thanks for the vocabulary lesson -- and especially for the underlying concepts therein.

[@Orion225]

I recommend anyone who's interested on this topic to read History of life in 25 fossils.

[@THEEGOBLINNE]

Yes. More PBS eons. This pleases me.

[@thatonedummkopf216]

Can y’all make another video on spinosaurus or the existence of troodon?

[@cf453]

Really fantastic presentation. I had no idea that's how the middle ear evolved.

[@toniatchison3678]

So, some ancient mammalian lifeforms take a poo. 800 million years later, their descendants create a whole branch of scientific research because of it. Yep, human evolution at it's finest, lol.

[@refindoazhar1507]

800 million years ago is not even ediacaran yet

[@toniatchison3678]

@@refindoazhar1507 it was a joke

[@godofmisfortune992]

It’s cool learning about my ancestors, I new my family line had greatness in it. Now I can brag about how my ancestor was the first ever mammal

[@amandawilcox9638]

Yah, but not many points there, since we all can say the same thing!

[@godofmisfortune992]

@@amandawilcox9638 I don’t think you know who your talking to, I’m descended from the first ever mammal, maybe you’ve heard of him. Show me some respect

[@gerrardjones28]

Don't forget about before mammals and before that every single living thing has a connection through the common ancestor

[@crisptomato9495]

Can you guys do a video on the origin of art?

[@carissstewart3211]

"Here we have a swastika from 10,000BC."

[@kertpilman]

Or fart

[@keithfaulkner6319]

@@dr.floridaman4805 i sure hope no one here is dumb enough to pay even 500 pennies.

[@yad7514]

Dinosaurs: go extinct Mammals: *cha cha real smooth*

[@exoboi6974]

If your a mammal and you know it clap your hand's!

[@benhicks9481]

T-Rex: Sad dino noises

[@exoboi6974]

@@benhicks9481 *Laughs in Primate*

[@TragoudistrosMPH]

*Dolphins glare at you*

[@mikefinn]

The Energetic Principle of Natural Selection states: traits that help find, gather, digest, store, utilize and conserve more energy are favored.

[@juggdekaprio5890]

One the oldest mammal relatives is named after Morgan Freeman can’t be coincidental 😅

[@pluspiping]

Despite being a dinosaur and biology nerd since childhood, this is the first I'm really learning about the ear/jaw bone traits that scientists use to classify mammals. It wasn't what I expected, but the video did a good job of explaining!

[@yeetyeey5407]

2:47 so you’re saying that fur is probably the feature that originated… furst…. ok I’ll show myself out

[@amandawilcox9638]

Yeet Yeey, Here's your eyeroll and rim shot! You've patiently waited all week. 🙄🤨🤦‍♀️ Blessings! Go, now.

[@search895]

Fascinating video as always.

[@jellysharkbat]

I hope Steve is doing well!

[@DFloyd84]

I hope Steve's crown group hasn't gone extinct.

[@Rauschgenerator]

Glad you are back again with the last two videos. The weeks without new stuff felt like an eternity. Please don't do this ever again.

[@andrewscoppetta4944]

Kallie, your hair looks fabulous!! Way to flaunt that mammalian DNA 🧬

[@gaemlinsidoharthi]

The background music, along with the sad story or ancestors and their friends whom we lost along the way make this, somehow, a sad tale.

[@ColonelBanana]

Cuteness and science

[@byv4480]

Eons is the absolute BEST!

[@krishnakamble9698]

She forgot to mention the four set of teeth, namely incisors, canine, premolars and molars as an integral feature to all mammals.

[@mikeg2306]

Does anyone else think it’s weird that if monotremes ever became extinct it would change the definition of what a mammal is?

[@Dr.Ian-Plect]

It wouldn't.

[@prn_97_]

if cynodontids never went extinct, we would be calling ourselves therapsids instead of mammals

[@Kholdaimon]

I still miss Steve... :-(

[@davidnitto9008]

New to this channel and love it but not sure who Steve is they keep referring to?

[@ramomirimo3090]

Fascinating information and Kallie you're a star!

[@LuinTathren]

Kallie looks so pretty today. Brains and beauty can be a deadly combination.

[@latronqui]

Wow, that jaw bones ----> ear bones fact just blew my mind.

[@AndrewTBP]

You missed the earlier step. Gill Arches -> Jaws -> Ear Bones