Life Before Mammals in the Late Paleozoic Era (When Animals Moved to Land!) | GEO GIRL 

Hi Geo Girl, I notice that "Earth System History" was written by Steven M. Stanley. When I was an Honors Historical Geology Student in the '80s, we used Stanley's "Earth and Life Through Time" as one of our texts. I still have it in my library of references. Sincerely: George F. Spicka, Curator of Paleontology (Collections Manager), Natural History Society of Maryland

CORRECTION: Dimetrodons (pelycosaurs) were 'reptile shaped' (reptilomorphs) but did NOT evolve from reptiles. Two major groups evolved from the earliest amniotes: sauropsids (which evolved into reptiles & birds) and synapsids (which evolved into mammals). Because pelycosaurs were synapsids, they actually never evolved 'from' reptiles, they just shared a close ancestor with them (the earliest amniotes). These earliest amniotes were called reptilomorpha (reptile-shaped animals). The classification of 'reptiles' underwent some modification a couple decades ago and apparently my textbook had not adopted that change even though it was written relatively recently, so I apologize for any confusion! Please thank my loyal follower, Ted Etienne, for catching this mistake! ;D

Hey I just found your channel and I love it!! I've always been interested in earth's past. I have so many books on prehistory and books on dinosaurs as well as many hours reading the wiki. Glad to see someone teaching others and getting them interested in the beauty of our past.

I think it's super cool to see life stumble on itself when it's first natural response to predation was bulk up, and when it realized that wasn't working it took the better, faster route. Now that's evolution!

The synapsids like pelycosaurs and the later therapsids are no longer referred to as reptiles-- only the sauropsids nowadays. Older literature, though, will refer to them as "mammal-like reptiles," but that's no longer in use. Great video!

Like others I also just discovered your site. I took Geology 101 in 1966 and fell in love with it because it taught me why, how and where I came from. I told my professor that I wanted to change my major and he asked me what were my goals in a career because in the mid 60s geologist were either teaching or driving cabs. So he dissuaded the change. Then in 1973 we had the Arab oil embargo, North Sea and Gulf of Mexico oil discoveries and geologist were in big demand. Please keep up your postings and I will check out the ones I missed. Very well presented. Thanks.

When I was a kid, we used to collect crinoids walking along the shore of Lake Michigan. They were just stem parts, just like stone cheerios. Fun to make necklaces with.

I would like to compliment the host. Everything is very well done. She happened to read good sources. However, she has a fantastic way to deliver the "matter". She has a future in the science divulgation field. I apologize to all who has been following this channel, but I just came across her. Good job girl!

Love the Carboniferous! Spent quite a bit of my Alaska career studying it, both in the subsurface and the field. So many stunning exposures in the Brooks Range. I remember several Mississippian limestone bedding surfaces that that were so fossiliferous and in situ that you felt like a time traveler walking a Missssippian shallow shelf. Another comment that jogged my old memory banks was your mention of the ginkgo tree, Ginko biloba. When I was cramming for paleontology finals at UC Berkeley I frequently would sit on a bench, just outside the department of paleontology’s building, that was shaded by the most magnificent ginko tree I’ve ever scene. It was my special place. I saved a leaf from that tree that I incorporated into a bookmark…I have it to this day. Wonderful video Rachel!

i know there are rules in nature but its amazing how broad the combinations are that are possibel. we talk a lot about the animals evolving, but for me it seems that plants are also even interresting, the looks of the plantlife in the past was so different, alien, i wish i coud see it, but im happy with the next thing, you people that give me the chance to make an image for me of how our planet, life, evolved. so thank you geo girl for taking us along in the past, maybe it will give us a change to understand who we are today.... respect for your work geo girl! greetings from a belgian waffle:D

I'm going to be honest with you, I've never actually wondered what wacky creatures were running around before the dinosaurs but the algorithm has decided it's about damn time I learned

The amniotic egg and thicker skin were one of those breakthroughs in evolution.

Fascinating worlds. The developing terrestial flora seem to have led to a drastic decline in CO2, yet the temperatures did ot change untill the Karoo Ice age.

Hey GEO GIRL, I am a geologist from Tübingen, Germany. This is a great presentation. Really enjoyed it. You ha a little slip of tongue at 11:10 so now I can´t stop picturing carnivorous swamps. Thanks a lot!

🎉🎉 I've come back from the future to watch this again!!!! I love the carboniferous!!!!

I love that you talked about corals! I feel like no one gives enough emphasis to the reef creatures! Super curious about coral evolution they’ve been surviving for what 500 million years? So cool! You’re awesome!

Interesting! Probably my favorite period in the paleozoic

I have a little Ginkgo Biloba in my backyard and always think of its loooong history when I looking at it 😄 Love watching your lectures, Rachel! 🌺

I have a piece of shale that I found in the eastern rocky mountains west of Calgary Alberta [25 years ago]. It is packed with Crynoid stems and lacy Bryzoans. I have always wondered how old it was, now I know...Early Carboniferous [Mississippian]. Thanks very much Geo Girl!

Being warm-blooded would be especially useful for nocturnal animals, because they can be very energetic when their cold-blooded competitors are sluggish because of cool nights.

Fascinating epoch. Enjoyed this a lot!

Omg so many views! I’m so happy you’re starting to get the recognition you deserve! 😊

It's amazing that the earth could create an environment like this

Thank you! What an informative video! The late Paleozoic has always been a weak spot in my historical geology knowledge. I’m really glad to be filling those gaps! Also, Cordaites vs. Chordates vs. Cordates (heart-shaped leaves), and Archaeopteryx vs. Archaeopteris (my favorite Paleozoic plant!). I don’t know who came up with these names, but they really could have made more of an effort to be less confusing!

Love your videoes keep learning and making curious ❤️

Came back again for this presentation. I suppose being an artist I possess an imagination which takes me anywhere Geo Girl presents, in any earth time. following learning and seeing recreated images of flora and fauna millions of years ago, the conjured shapes of scenes almost too beautiful to behold in each epoch slowed down to our speed. Where would I go first? I think 100 million years ago during the ebb and flow of the Western Seaway in North America. Over 600 miles wide and 2000 miles top to bottom. My fascination would be the offshore islands west of Laramidia and the diversity of fauna inhabiting them. Still have to watch out for Spinosaurus.

Ginkos are freaking cool! First they turn this nice yellow, a rather mellow color, Then they drop almost ALL of their leaves in one night. Ginkos and monkey puzzle trees and redwoods are 3 of the most awesome trees...

I listen to this to bed, 4 nights in a row now! You explain it so well with such a soothing voice. Thank you!

This is so great. Love the format, and the content is so interesting! 😎👍

Just found your chanel and I can see myself binge watching the whole thing in the coming weeks. Quality content. Note for history: subbed at 12.8k subscribers. I hope your channel blows up in popularity in the coming year!

Great video! Artistic depictions of a carboniferous environment look so cool. Fun to learn about.

i learn so much from your channel!! its amazing 😁👍

I find Tiktaalik and acanthastegans fascinating. I'm sure they must have found life difficult and challenging having to accustom themselves to having to bear their entire weight on their limbs.

My favorite period! First stop with my time machine.

I read a hypothesis recently that speculated that the Carboniferous may not have been swampy. The reason we find such massive coal deposits from that period may be that pulp eating fungi had not yet appeared. Hence, the accumulation of forest debris that we now find as coal. I thought that was interesting, if it turns out to be correct. Fascinating presentation. Thanks!

This summer I was working in a selective cut white pine forest. There were huge white pines scattered around while all other trees had been cut. It reminded me of the drawings I’d seen of lycopod forests.

YEEEEEEEEES one of my favourite time periods!

Great summary but the terms used on the mammalian / reptilian lineages runs slightly contrast to current conventions which seems to perturb palaeontologists today. As I understand it: The ancestors to both reptiles (diapsid) and mammals and their relatives (synapsids) were the ‘Amniotes’ and it was these anapsid descendants of amphibians that laid these watertight eggs. It was at this point the synapsids and diapsids split, which is why the term ‘mammal-like reptile’ has fallen out of use in the last decade; the stem-mammals evolved from amniotes, as did reptiles rather than mammals coming from reptiles. Dimetrodon was an offshoot of this lineage (Sphenacodontidae) rather than a direct ancestor of ours, and it’s currently believed it’s sail would be fairly useless for thermo-regulation as it’s vascular infrastructure seems unlikely to have delivered the flow needed to do so, and no other ectothermic life forms have converged on the same solution, making sexual selection another possibility, but there’s no evidence yet of sexual dimorphism which would be expected, but science is always finding new things, so we just don’t know at the moment… The evolution of these synapsids is amazing and well worth looking into further if you get a chance, every bit as amazing as the more popular dinosaurs

Excellent presentation. I learned from it.

As always, amazing :)

I have a Ginko biloba near my house. It's an astonishingly beautiful tree. I can imagine what a forest of ginkos would have looked like in a carboniferous autumn.

So one important detail of the coal belt is that they generally didn't form on continents instead the coal deposits were found along what was then numerous mature topical volcanic arcs mush like modern Indonesia which would over the course of the Carboniferous become accreted/smashed between the continents Laurentia Baltica Siberia and Gondwana. This detail is important context because the late Devonian to late Permian was the great late Paleozoic ice age which involved numerous glaciation episodes interspersed with interglacials following the Milankovitch cycles for over a hundred million years. This caused significant changes in sea levels which caused environmental shifts between shallow tropical seas and tropical jungles. These sea level fluxes as well as the formation of deep basins during arc accretion where submerged organic material can accumulate was likely the true reason behind the great carboniferous coal belts with the mountain building metamorphism finishing the details behind the large frequency coal formation during this time. Also regarding the giant millipedes Arthropleura the discovery of giant Arthropleura living during times with much lower oxygen levels throws out the hypothesis that their large size was the cause of their gigantism instead it seems likely that the absence of competition was what likely enabled them to grow to large sizes then. The timeline for early land life whether myriapods chelicerates or insects is last I checked largely unresolved since the first appearance of these groups in the fossil record were already highly advanced and diverse which presumably couldn't have come from nowhere. Insects were likely around far earlier since the oldest fossils from around 400 Ma had already developed wings likewise by the time Myriapods appear into the fossil record in the Silurian the modern groups had already radiated and diversified. The same is true with Chelicerates with them having appeared in the fossil record largely already diversified. In fact the marine examples the Eurypterids and Horseshoe crabs had an odd peculiarity that they had to return to land to reproduce likely as in the modern counterparts of Horseshoe crabs(Xiphosura) their young lacked the ability to breathe in water until after their first major molt. We have reason to believe this applied to them since the vast majority of their fossil record are exoskeleton molts which in modern examples are produced whenever the animals come to shore to spawn. This along with phylogenetic evidence which identifies Horseshoe crabs as unequivocally being the sister group to the unfortunately poorly studied arachnid group called hooded tick spiders Ricinulei nested deep within the arachnid family tree. Notably supporting this is the mystery of why all arachnids as well as the Xiphosura and Eurypterids which have conventionally been thought to be sister groups to arachnids all possess strong UV fluorescence particularly tuned to the higher energy UV B and UVC radiation blocked out by the modern ozone layer. Moreover all these organisms appear to represent a single radiation to larger body sizes within a otherwise paraphyletic grouping of mites thus suggesting our classical picture of terrestrial colonization is likely incorrect. Thus there is growing evidence to suggest that the lack of these creatures in marine fossil record and their sudden appearance of already highly diverse and "advanced" terrestrial forms in the early Paleozoic is likely a result of fossilization bias of marine environments over terrestrial ones. I.e. animals had already come ashore much earlier based on molecular clock estimates and the lack of fossils some of them namely chelicerates and Myriapods had likely come ashore or into near shore/freshwater environments by the Cambrian likely following the colonization of land by the green algae from which plants descend. So not really new to land just new to gigantism though given they were all from the complex subduction fed volcanic archipelagos could this have been island gigantism?

Great summary!

Excellent channel. Thanks for sharing your knowledge. I’m now a subscriber.

Great info and contextual stuff to help understanding.

Excellent. Thank you

Great stuff

Very good - Thank You ! ! ! 🙂😎👍

Nice channel. I subscribed!

Awesome knowledge you have! 👍

So interesting. Thanks for the knowledge

Excellent presentation - great video.

Excellent channel!

I'll just be stupid and say she makes me remember what it is to learn. She's also nice to look at.

yaaay! more smart girls who know cool stuff! .

What a great channel!

Great video - thank you for clearing up some details of the plants during the carboniferous period. I thought that one of the huge factors that stopped the dinosaurs rebounding was the evolution of grasses.

Please keep talking an teaching. I love your content.

Well done!

The oldest winged insect known right now is Delitzschala bitterfeldensis. (It's probably German paleontologists trying to troll other people not being able to pronounce the name.)

You are amazing and so ambitious and intelligent and inspiring. Thank you

this was great thx 👍🏽

I enjoy these videos

Really interesting stuff. Some of my favorite critters come from old times, like Dunkleosteus and Megatherium, I remember seeing them in books when I was younger. Nice to learn more about them in more modern times, thank you.

Thanks for the upeodate our geology knowledge nice presentation

This is great!

GOOD Job GEO GIRL

I remember the carboniferous very well. Lots of bugs, plants, and oxygen. Gave me a headache.

Great 👍

Mmmmm yeah I really like uhh.. Paleozoic life n stuff! Great video thanks for showing us

really excellent content.

Ah, another channel of interest... get ye to my subscription list!!

Excuse me, where have you been in all my years on youtube? Subscribed immediately.

Very useful video 🙏

Hi, I read that the reason the carboniferous produced coal deposits around the world is that the trees began producing lignin to strengthen their trunks - but the decay organisms were unable to break down lignin until millions of years later.

This video is doing very well, I better watch it. I ❤️ GEO GIRL

Invited this it’s really cool how our ancestry began with worm like creatures with a notochord that gave rise primitive fish which gave rise to jawed fish which gave rise to lobe finned fishes which gave rise to amphibians which gave rise to amniotes which gave rise to stem mammals which gave rise to mammals which eventually gave rise to us via the ancestor shared by rodents, Lagomorphs and primates

Just an FYI, latest research suggests arthropods large size might not be as tied to oxygen as thought, many large milliped fossils have been found prior to the rise in oxygen

As somebody who went to the Milwaukee Public Museum endlessly as a kid, seeing the ordovician reef diorama with the orthocones made my eyes light up

I really did enjoy this video - expanded my brain considerably! Two questions (though maybe you have answered them in other videos): (1) do you think that the high oxygen level you mention gave rise to, or encouraged. the development of wings in insects? and (2) teeth - did some amphibians have teeth, or did teeth evolve again in reptiles?

Un petit bonjour et un gro merci ✌

Thanks. Hey, I'm all for Dragonflies with 2' wing spans! But 10' Centipedes? Uh, nope. tavi.

New Subscriber: This was my second video I watched.

Note: not a professional, but I think I recall someone who knows better than me saying cor-day-tees for cordaites. And yes, the plant folks and the critter folks should have gotten together on those.

I went to drumheller in Alberta, Canada this summer. There is a huge museum there about dinosaurs, since there are tons and tons of dinosaurs fossils around from the cretaceous. the musuem has a very diverse collection, and they also go over the history of earth (although the precambrien sections is barely represented). Iin the permian section they represented dimetrodon-like and therapsids as reptile-like mammals or something like that. You're not alone doing this error if that makes you feel better xD . Reptile definition is not very clear but it does not include synapsids :) BTW did you know they just found there a couple week ago a complete haplosaur with it's skin still intact ? That's insane :O

You could totally be one of the PBS Eons hosts.

Thanks

Good video. I like all the plants and animals. Were the Carboniferous trees built more like banana trees, with more of a stem than a woody trunk? Also, what happened to dimetrodon when it got really windy? I would've liked to see one of those big hellbenders (giant river salamander). I wonder if they were poisonous, and how their skin toxins evolved? So much to discover.

Great video! My PhD advisor says we can't quantify living biomass on preservation bias! Sure we see METRIC LOADS of coal, but this is actually due to the lack of decomposers at this time! Cellulose is still impossible to breakdown in your gut it's tough stuff, reserved for only a few niche organisms bold enough to evolve to break it down :D cheers!

thanks for the science, gal gadot

I believe Cordaites is pronounced "Core-dye-tees" from what I found online. Great and very informative video nevertheless! This is definitely one of my favorite time periods.

Hii geo girl... nice video 😇

Great Penn fossils in North Texas.

Carboniferous is cooler! I remember (through some reincarnation mechanism) splashing and bubbling around in warm ponds snapping a giant dragonfly now and then, what a square meal! Life was simpler then, instead of this complicated world of wars, famine and climate change. The only thing you had to take care of was avoiding deep water where evil fishes could attack you.

An excellent work although might not be of all the public interest. Details well cared, the presentation, including narration, is marvelous, visually appealing as well. Terrestrial animals both vertebrates & invertebrates may often be featured for that period, the video introduces events under water, during transition & the landscape which sets up a stage for newcomers. The structure of the footage is well considered, which makes it distinct from others. Personally, terrestrial creatures in mesozoic is of principal interest. Looking forward to it. Incidentally "before mammals" ? Could be misleading. Yes, those stem groups of mammalian lineage made a debut, but the term sounds misnomer (hair-splitting though). Thanks for your dedication!

Great video. My favorite part was thinking about a forest of stem-like "pre trees"

NEEOOWW!

It would be cool if they were still around, but also terrifying.

Omg she is beautiful, I had to subscribe right away! We need more intelligent women here in England.

The Merriam-Webster dictionary says the pronunciation of "cordiates" is Kor-dites.