The video I linked at the end about birds vs dinos (avian vs non-avian dinos) is currently a member-only video (meaning you have to be a channel member to watch it), but don't worry, it will be out for everyone in a couple weeks! ;)
Delightfully presented! Hard to believe only 23 mammal species survived the KPg extinction. I never realized how close mammals came to going extinct along with the dinos.
mammal burrowing might have been a big factor ... picture regions where many mammals were in hibernation during the worst of the impact winter. Also, high valleys ... similar to Lake Tahoe today ... might have acted as refuges with the air clearing much sooner than lower elevation regions so that a high wetland that was frozen over and in hibernation during the impact awoke months later after the high elevation air was relatively clear as the heavier particles had settled out. Also, one can imagine a lot of flies and cockroaches for awhile after the mass death and these insects would have favored small mammals and birds as a food source.
Howdy Rachel, extinction events are so interesting. What we can piece together always makes an interesting story. I especially like the paleo-reconstruction of tectonic maps, something useful in my previous career studying paleo-environments. They seem to get more detailed since I retired. Thanks, your topics are always interesting.
A great video. Personally I find find the “mammals vs dinosaurs” angle helpful, because some dinosaurs survived, presumably for the same reasons that some mammals survived, and presumably many mammals went extinct as well. Also, there are more dinosaur species alive today than mammal species.
Thanks! First congrats Dr.Geo Girl for completing and successfully defending your thesis. Let me vote for more videos like this. What could be more interesting than learning the story of us. Our distant but essential ancestors who made it thru bottleneck allowing us to be here now. With regard to your unnamed species. I think they will make thru the current trouble. As a species because of their adaptability, yes, but probably not technology based industrial capitalist civilization. Thats going down. See Collapse by Jared Diamond.
9:27 I never thought about it that way before, Dinosaurs prevented mammals from becoming large, but mammals prevented dinosaurs from becoming tiny. For the same reason; mammals already dominated the tiny animal niche.
It's not quite that simple. There WERE small dinosaurs, specifically the juveniles of the big ones. That is the most plausible answer to the question "Where are the mid-level predators?" The top predators WERE the mid-level predators while they were growing up. So the lower limit on dinosaur size would actually depend on dinosaur parental care. The surface-area-to-volume ratio limits egg size to about football size or a bit bigger, so even an Argentinosaurus would have begun its life dog-sized. As soon as its mother stops feeding it-if she even started-it goes out into the ecosystem and starts munching.
The birds made a bid for dominance before mammals could get started. There are, after all, a lot more bird species than mammalian ones. However, because birds were specialized for flight, they had built in limitations that held them back long enough for the mammals to get the upper hand.
Hi Rachel, I enjoy your videos although my own interest has been mostly physics and mathematics although I also grew to love biology while at university. Like you I did a PhD and did two postdocs before becoming a lecturer. Academic work can be very rewarding but also doesn't pay the best. Lots of nice videos to watch on all things geological, it'll be fun. Many thanks, Frank.
Rachel: I think a more in depth discussion of the relationship between birds and dinosaurs would be fascinating. Are birds the successor of the dinosaur line (especially the theropods)?
@@wrekced The two main branches of dinosaurs are the sauropods ("lizard-footed") and theropods ("beast-footed"). Birds are evolved theropods. The sauropods are also ornithischians ("bird-hipped"), whereas the theropods, including their fluttering, chirping descendants, are also saurischians ("lizard-hipped"). Go figure.
I gotta subscribe to support someone with a local connection to my hometown university, even though I graduated up the street at NMSU. Anyway, it was a very informative video. Thanks Dr. GEO Girl.
We have to consider that most birds also died out after the KT event. The sole survivors were bird with no teeth, but sharp beaks. This points to the diet of those birds: seeds and detritus eating insects, worms and other arthropoda. After the KT event, Earth was experiencing a strong winter, and most plants were either dying or at least not thriving. Every animal that relied on green plants for survival, or on predating on animals which eat green plants, was having a hard time. But seeds can survive a winter, and thus also feed animals during a winter - and with some luck, a few of them also during a very long winter. In the same way, animals feeding on dead plants were having a good time, as enough plants were dying. Thus insects and worms and millipedes were surviving, and with them the birds preying on them.
Well presented review of the subject. In my totally naive way, what I got from this is, "Want to survive life-changing events? BE FLEXIBLE and able to adapt to the new order of things." :)
I've said this before, but I would love to see a mini-series like Prehistoric Planet follow the events from the day of the asteroid impact to basically the end of the asteroid's/comet's influence on the environment when photosynthesis was back in full swing again. It would be pretty bleak until the end, but it's a pretty damn important epoch (in the colloquial sense of the word) in our evolutionary history.
Good idea, but first we must figure out what happened when and why. The super-volcanism that formed the Deccan Traps happened at about the same time. Some researchers have gone so far as to say that the Deccan volcanism was larger than conventionally estimated and caused the mass extinction, "faking" a meterorite impact (iridium layer and all) in the process. Others acknowledge the impact but argue that the shock waves from it jiggled the Deccan area enough to crack it open and get the volcanism started. Still others argue that the Deccan volcanoes were tossing up lava and carbon dioxide at intervals for a long time both before and after the impact and therefore were only secondary in the mass extinction in particular.
Dinosaurs were losing their diversity leading up to the K-Pg extinction event and some mammals were filling niches and increasing in diversity but the species of dinosaurs extant in the latest Cretaceous were more wide spread, had more numerous individuals than those before and were in dominant positions in the trophic cycle that no mammals back than could even be close to so it would be false to assume that the dinos were in decline and the asteroid just speeded up their inevitable doom as some have argued. However it is true that having less diversity means being more exposed to major extinction events. The asteroid impact was a real game changer for life on Earth and undoubtedly animal life would have been significantly different back then had that not occurred. Rachel I am more interested in natural history than geology and geochemistry but in order to better understand the previous you definitely need to know some of the latter so I think your channel is an intelligent composite!🙂
So, it's more like "small animals survived, large ones did not" - and the small ones were (some) mammals and avian dinosaurs, but not larger mammals and dinosaurs. Afterwards, these surviving groups diversified again and evolved large size, but it was predominantly mammals that became large this time (though there are / have been a few large birds as well)
@@elvis4868size wasn't the issue how well a species can adapt to survive rapidly changed climate not all experts agree that they needed to be very small to survive an asteroid impact
@@sebgur4401 Probably few to none of them were smaller chickens - whereas, average birds of the present day are. Even there, size might have been a large factor. Then there's mobility - and the ability to spot things from the air, or catch things in the air.
@JosephLMcCord this! It's a numbers game. Mammals sacrificed the numbers dinos laid as eggs for internal toughness and it paid off with a mutation allowing all mammals with exceptions to give live birth.
I didn't realize that so few mammal species (~7%) survived the extinction event, which makes it a close call for us as well. I wonder if many insect species survived? They could have been a good high protein food source for those surviving mammals.
I just found this channel because of my interest in the evolution of Eukariotic cell reproduction. Wow! I'm super impressed with all the content. The graphics, the erudite explanations, the un-dumbed-down simplicity for us armchair scientists. Well done! I hope and expect that you'll be as successful at this as you want to be.
Hi Rachel nice to meet you btw. What do you think about tapetum lucidum being one of the most advantageous features in a post apocalyptic scenario? It seem a common trait amongst who survived the meteor strike imho! Thanks for the enthusiasm you put in all your job!
Fascinating video, thanks. Further questions came to my mind, especially one you are already working on answering -- why did the avian dinosaurs survive? Another big one -- if major groups of non-Avian dinosaurs were already in decline, how might that have played out if the big asteroid impact had not happened (or happened much later)? And finally, is adaptability just the flipside of having a really excellent niche you have adapted to fill, or are there roles and body plans that are inherently adaptible -- smallish intelligent omnivorous fast-breeding burrowing-capable animals like rats, highly mobile, intelligent, non-obligate carnivores like coyotes, and smallish, fast, super-agile hypercarnivores like feral cats?
The really odd thing is that multiple lineages of birds (I.e. avian dinosaurs) survived but NO non-avian dinosaurs did. There were some small dinosaurs like avimimids so it’s not just size. I guess flight was the main determinant. Another question is if avimimids survived would we call them flightless birds?
I think it took Rachel only a few months to achieve better lighting (i.e., not over-lighting / over-exposing). It took Grace Helbig and Mamrie Hart the better part of a decade to learn how to do that!
Thanks Doc.. good stuff. I don't really know, but suspect that Vulcanization could have been changing ( decreasing ) the Oxygen levels ( maybe hurting really large dinosaurs.) but the Astroid catastrophe would have been the killing blow . I think these fires would have been like nothing before or since. Oxygen levels would have dropped so much that large animals just couldn't survive if any stayed alive after impact. I don't think it would have taken long for the entire earth to be affected . But as you point out... small animals would have had a windfall. The Earth can take a lot of punishment... people... maybe not so much. Two subjects I hope you address are .. The Shifting Magnetic Poles ( I try not to think of this too much. ) and a closer look at Saber Toothed Cats.... What was goting on with those critters ? Thanks again.. I love this stuff.
At about that time, volcanic super-activity was piling up the huge lava beds named the Deccan Traps. That didn't decrease oxygen directly, but the ash and carbon dioxide emissions would have had major effects. The eruption of Mount Tambora, a comparatively modest squirt, in 1815 cancelled summer the next year. en.wikipedia.org/wiki/Year_Without_a_Summer
I concur that the available evidence suggests a gradual decline in species diversity of dinosaurs prior to the KT extinction....but I am hesitant to be sure that was really happening and I am skeptical that any gradual decline that was happening _necessarily_ played a role in why all the non-Avian dinosaurs went extinct. (I should have also mentioned that your videos are exceedingly excellent, and I regularly recommend them to disparate people.)
7:00 "only ... about 23 species (of mammals) survived, and only one of them was a eutherian". Thank you. I had wondered about that for a long time. So if that proves out long term, there were more species of dinosaurs that survived than eutharians, and not that many more species of mammals overall. 9:20 "in a way, mammals prevented dinosaurs from becoming small, because they were so dominant (in small body niches)". Thank you! You are the first person I've ever heard vocalize that! You are living proof of the correlation between great intelligence and great beauty. I try convincing my children of that correlation using my own example, but sonehow they remain unconvinced. Now I have even more proof! I suspect that being quadrupedal is a big advantage over being bipedal when scurrying about under bushes and running into small holes, and dinosaurs were bipedal unless they got big. I also suspect that the dinosaur superpowers of hollow bones and an awesome unidirectional respiratory system weren't much of an advantage for small animals that didn't fly, whereas mammalian superpowers of chewing and mother's milk are just as useful for small animals as they are for big animals. So birds did great at small sizes, and other dinosaurs were outclassed by mammals at small sizes. 12:45 Not sure that a reduction in diversity in a clade is necessarily a decline of the clade. That can just mean that a smaller number of generalists fill more roles. Or it can be a mix; hadrosaurs evolve to more effectively compete with large sauropods, sauropods decline, and things that eat sauropods decline.
There is a general trend thoughout evolutionary history - more complex and intelligent species outcompeting less so species. Dinosaurs were in long steady decline mainly caused by mammals taking their resources. An Asteroid impact made little difference to this in my opinion.
There was a lot of cooked and frozen dinosaur to eat for years after the asteroid impact. Worms, bugs and seeds for reptiles, birds and rodents to eat like today!
I have question of sorts. Early in the video you showed estimated maps of post-pangea. There was pictured some inland seas making up large parts of america and other continents, which I recall to be estimated based on fossil remains, mostly shellfish. I forget, however, why this can't simply be the product of intense wetlands and fresh-water lakes??
Well, we can tell the extent of inland seas based on sediments deposited as well, then the fossils just help in a way of confirming what may have lived in these seas, and we can also esimate the level of connectedness that such seas had to the ocean and thus, understand their potential salinity. We also tend to sea marine fossils in very large connected transgressive seas, which we would not see if it was a freshwater lake. So, it depends on the exact sea that we are reconstructing, but in general there are many different ways we estimate the extent, salinity, and life content of these ancient seas :)
Another highly informative video. It's hard to completely explain the pattern of extinction at the K-Pg boundary. I was glad that the point was made that many dinosaur groups were in decline in the latter part of the Cretaceous. This was a point made by several prominent paleontologists such as Niles Eldredge and Robert Bakker back in the 1980s when they cautioned against rushing onto the bandwagon of the extraterrestrial impact hypothesis. Even if one accepts the impact hypothesis, there were certainly changes going on in Earth's ecosystems apart from that event. Now why did crocodiles survive? So much left to explain.
Oh I didn't know he had a book! I used his 2022 article on the topic as one of my major references for this video and found it incredibly interesting and well written! I'll have to go check out his book now, thanks for mentioning it ;D
what many people dont take into consideration is the point that reptiles lay eggs that require a steady state of temps during the incubation period. Adverse temp changes stop the incubation and the eggs fail, thus reducing the numbers immediately. Let this occur for several years, you end up with a huge gap of reproduction missing
I would have thought that somewhere, some small species of non-avian dinosaur would have survived. Perhaps they did for many thousands of years but in an isolated region eventually becoming extinct. Their fossils may yet be found.
I've often wondered how long a dust cloud blocked off the sun to plants on the Earth, from the strike. I'm thinking 10 years, but have there been any studies on the subject? How long can seeds sit under ground before they are unable to sprout? Will seeds sprout in a darkened room, if the room is kept warm??
I wonder what would've happened, Rachel, if at the KT extinction event there were small bipedal non-avian dinosaurs no bigger than a house-cat that were able to burrow like mammals?
Some species of mammals and birds have something else in common: they hoard food, namely seeds. They harvest seeds in the summer or autumn and store them in the ground, to survive the following winter. Some ant species, or termites, also do something like. They pull branches and leaves down into their tunnels and cultivate fungi, which they then eat. Big, meat-eating creatures cannot maintain a store of food, because the meat rots when it is warm. Maybe that also had to do with survival.
08:30 f _This kind of reminds me of a very specialised and dominant species today ..._ We are _not_ very specialised. In fact, we are pretty much generalists who can survive very different and in part difficult conditions.
8:30: "one modern very specialized and dominant species today that might not do so well with change". I honestly not sure of which species are you talking about? Because if you ment humans, then we're NOT specialized at all in terms of food variety, climates and other environmental conditions. We're actually one of the most generalized and successful species in evolution. It's true that we became depended on technology and civilization, but this is cultural dependency, not biological. In a case of a mass extinctions, it is very likely that at least some humans will survive.
I mean mainly our dependence on civilization and while we are general in terms of the diet we can eat, I feel like we are very specific about the diet we do eat (especially within developed regions), so for example, when I picture people that are accustomed to civilization, technology, and all the things that come along with that, and then I imagine they were put in a position in which they needed to survive without those things... I mean we have tv shows that show us that we have come so far in our advanced civilizations that we can no longer survive in nature the way early humans did. And in our case, with things the way they currently are, that is great, we are more dominant and successful due to our technology and civilization, but at some point if we need to become a bit more resourceful again, I feel like many people would not be able to (including myself lol). But I do agree, I think that some humans would survive, but I think it would be relatively small percentage, and it would probably be the ones that are a bit less reliant on tech and civilization. But who knows, I could be wrong, that's just the way I see it :)
@@GEOGIRL Yes, I agree. A fall of the civilization will be traumatic. And without the supply chain many many will die. But I think that those who will survive, including in developed countries, will manage (including yourself ;) ) because we all have at least a basic understanding of agriculture, lighting up a fire, find shelters in ruins or even build something very very simple, and most importantly, work in groups. So it won't be an extinction :)
Truly fascinating! So many facets (and I'm a hard-rock geologist at heart 😄). I'd love to know when bats evolved to rival (in some aspects) the avian dinosaurs.
Even among the few surviving species, I would assume very few *indivuduals* survived. Could some of these have been just a handful of lucky ones in a single location? I guess this will be just speculation. 🤔
I think you have found your ecological niche. And here you will thrive. And I am a scavenger of knowledge. My niche is on the ground munching on the seeds of wisdom that you toss into this environment. Thank you for the nourishment.
If the theory is correct, there's something that isn't mentioned: the food supply suddenly increased. If the mammals had an omnivorous diet, they had plenty of food and if that was the case, they had more offspring.
Not sure if she mentioned it, sort of a blur after a while. But was thinking, if the planets was dark for a few years. Mammals have better senses, hearing, smell, whiskers and such. Not so reliant on eye sight, like maybe dinosaurs.
My thoughts on it is mammals and birds can with stand cold better than reptiles. Dinosaurs didn’t all die on the same day it took years after. Crocs and others in the taxa can hibernate during such times. The oceans must have cooled cause the reptiles died off with food still available. Fish survived also
The mammals were in the asteroid piloting it like a space Noah's ark. Then they ate all the dinosaurs. Then they conquered the fish people that rode in on a previous asteroid. Before that the Amoeba were h ere.
How did insects do during the Cretaceous extinction? I would think they did well with so many corpses to feed on, thus causing small mammals to become insect eaters.
IDk the temp changes need to be looked at more.I think what really happeened is some species were able to get to colder temps when it was too hot and vise versa.Then the OTHER factor would be when moving to a better climate was there enough food to keep alive long term?Nature needs to be balanced or some species will die. Large dinosaurs needed huge amounts of food so it would seem obvious they would be the first to go. The waters at the time would be a different game as travel might be easier to get to cold/hold temps no difference than flyers that move about during the seasons. As for pre humanlike species thy would be decently able to move about climate regions as needed.
Mammals are so underrated 😮 how badass do you have to be to live through all dinosaurs and the dinosaur killer? I say they were more powerful than people think....
Mammals vs. dinosaurs continues to play out to this day at innumberable birdfeeders, hence the proliferation of squirrel-resistant models. Mark Rober was so impressed by the local squirrels's birdfood larceny that he created an obstacle course for them: ruclips.net/video/hFZFjoX2cGg/видео.html
Very interesting, although I do not have enough biological background to understand the details. You seemed to suggest that homo sapiens may not survive the next extinction event which will surely come, although maybe not for a long time. I suppose our size is against us, although our species is supremely adaptable - so maybe a chance of survival?
Isn't it true that what we know about the KT extinction and immediately afterward is based on a handful of tiny sites, mostly in North America? How can we draw such grand and confident conclusions about what was happening in the world based on so little data?
Where does this exact number of 23 species come from? Are these the only three species in the fossil record? Is this number the result from looking at modern mammal DNA? Is ist a guess or is it the absolute number of different species we know of and could there be more? I am always exited if science suddenly comes up with such accurate statements
And to think, without Mama Eomaia we wouldn't have the privilege of watching Dr. Geogirl. Its amazing that billions of different events had to play out just for me to be eating potato chips and watching this video on You Tube, its pretty mind blowing Yo think that there are entire solar systems that are gone forever and noone will ever know they existed in the first place.
I wouldn't consider Humans a specialized species; we are the general species. The growing problem with modern humans is they are high level from subsistance living. They make a living away from actually hunting/gathering(much less agriculture). So, if the agricultural sector fails, then they don't know how to survive or where to go(there's a lot people that have gone "prepper(including Sam Altman of openA.I. and the facebook guy)) James Burke has a great episode about this in his first Connections series - umm, episode one actually of his first Connections series. You can see that here on youtube!
They did not survive the event any more than Dinosaurs did. There was far greater diversity of Dinosaurs before the impact, while mammals were a very small population overall. After the impact both groups where small with only a handful of survivors. Mammals bounced back faster becoming the most diverse. While the surviving Dinosaurs became birds and surviving reptiles barely changed at all. That is still all three groups surviving the impact or being wiped out by however you want to phrase it. No one was excluded.
![Digital Circus Episode 4 [TRAILER]](http://i.ytimg.com/vi/abZtsmMUbJo/mqdefault.jpg)
The video I linked at the end about birds vs dinos (avian vs non-avian dinos) is currently a member-only video (meaning you have to be a channel member to watch it), but don't worry, it will be out for everyone in a couple weeks! ;)
Hey, GeoGirl… Do You have comments limited, or something?
Maybe a filter on?
Delightfully presented! Hard to believe only 23 mammal species survived the KPg extinction. I never realized how close mammals came to going extinct along with the dinos.
Where did you get 23 from?
mammal burrowing might have been a big factor ... picture regions where many mammals were in hibernation during the worst of the impact winter. Also, high valleys ... similar to Lake Tahoe today ... might have acted as refuges with the air clearing much sooner than lower elevation regions so that a high wetland that was frozen over and in hibernation during the impact awoke months later after the high elevation air was relatively clear as the heavier particles had settled out. Also, one can imagine a lot of flies and cockroaches for awhile after the mass death and these insects would have favored small mammals and birds as a food source.
This might not be such an evolutionary leap, as many Mammals likely fed on bugs they found on Dino dung before the K/T event
Excellent DR GEO GIRL. Thanks
Let us ascend GEO GIRL to 100k subs.
I always enjoy listening to you ramble in the background while I'm cooking dinner for myself
She's easy on the ears.
I've tried that but her slides are too pretty or informative to miss.
Howdy Rachel, extinction events are so interesting. What we can piece together always makes an interesting story. I especially like the paleo-reconstruction of tectonic maps, something useful in my previous career studying paleo-environments. They seem to get more detailed since I retired.
Thanks, your topics are always interesting.
A great video. Personally I find find the “mammals vs dinosaurs” angle helpful, because some dinosaurs survived, presumably for the same reasons that some mammals survived, and presumably many mammals went extinct as well. Also, there are more dinosaur species alive today than mammal species.
Rachel 🪃,
Very well put together. Thank 🙏 you.
👏👏👏👏
Thanks! First congrats Dr.Geo Girl for completing and successfully defending your thesis. Let me vote for more videos like this. What could be more interesting than learning the story of us. Our distant but essential ancestors who made it thru bottleneck allowing us to be here now. With regard to your unnamed species. I think they will make thru the current trouble. As a species because of their adaptability, yes, but probably not technology based industrial capitalist civilization. Thats going down. See Collapse by Jared Diamond.
Thank you so much! ;D
Adaptability is pretty doggone important. Life throws curveballs.
9:27 I never thought about it that way before, Dinosaurs prevented mammals from becoming large, but mammals prevented dinosaurs from becoming tiny. For the same reason; mammals already dominated the tiny animal niche.
Yeah, Repenomamus would eat them up
No, there have been tiny saurs.
@waltertanner7982 not that many. It's number of them, not any existing that matter
It's not quite that simple. There WERE small dinosaurs, specifically the juveniles of the big ones. That is the most plausible answer to the question "Where are the mid-level predators?" The top predators WERE the mid-level predators while they were growing up. So the lower limit on dinosaur size would actually depend on dinosaur parental care. The surface-area-to-volume ratio limits egg size to about football size or a bit bigger, so even an Argentinosaurus would have begun its life dog-sized. As soon as its mother stops feeding it-if she even started-it goes out into the ecosystem and starts munching.
The birds made a bid for dominance before mammals could get started. There are, after all, a lot more bird species than mammalian ones. However, because birds were specialized for flight, they had built in limitations that held them back long enough for the mammals to get the upper hand.
Hi Rachel, I enjoy your videos although my own interest has been mostly physics and mathematics although I also grew to love biology while at university. Like you I did a PhD and did two postdocs before becoming a lecturer. Academic work can be very rewarding but also doesn't pay the best. Lots of nice videos to watch on all things geological, it'll be fun. Many thanks, Frank.
Rachel: I think a more in depth discussion of the relationship between birds and dinosaurs would be fascinating. Are birds the successor of the dinosaur line (especially the theropods)?
I agree! That is something I have contemplated recently. There were two main branches of dinosaurs, if I remember right. But only the birds survived.
@@wrekced The two main branches of dinosaurs are the sauropods ("lizard-footed") and theropods ("beast-footed"). Birds are evolved theropods. The sauropods are also ornithischians ("bird-hipped"), whereas the theropods, including their fluttering, chirping descendants, are also saurischians ("lizard-hipped"). Go figure.
Excellent as usual!
Thank you so much!
I gotta subscribe to support someone with a local connection to my hometown university, even though I graduated up the street at NMSU. Anyway, it was a very informative video. Thanks Dr. GEO Girl.
Love NMSU too!
We have to consider that most birds also died out after the KT event. The sole survivors were bird with no teeth, but sharp beaks. This points to the diet of those birds: seeds and detritus eating insects, worms and other arthropoda. After the KT event, Earth was experiencing a strong winter, and most plants were either dying or at least not thriving. Every animal that relied on green plants for survival, or on predating on animals which eat green plants, was having a hard time. But seeds can survive a winter, and thus also feed animals during a winter - and with some luck, a few of them also during a very long winter. In the same way, animals feeding on dead plants were having a good time, as enough plants were dying. Thus insects and worms and millipedes were surviving, and with them the birds preying on them.
Well presented review of the subject. In my totally naive way, what I got from this is, "Want to survive life-changing events? BE FLEXIBLE and able to adapt to the new order of things." :)
Exactly, and this is the problem currently with too many people, regarding adaptation zo the upcoming Climate Event catastrophe.
I've said this before, but I would love to see a mini-series like Prehistoric Planet follow the events from the day of the asteroid impact to basically the end of the asteroid's/comet's influence on the environment when photosynthesis was back in full swing again. It would be pretty bleak until the end, but it's a pretty damn important epoch (in the colloquial sense of the word) in our evolutionary history.
Good idea, but first we must figure out what happened when and why. The super-volcanism that formed the Deccan Traps happened at about the same time. Some researchers have gone so far as to say that the Deccan volcanism was larger than conventionally estimated and caused the mass extinction, "faking" a meterorite impact (iridium layer and all) in the process. Others acknowledge the impact but argue that the shock waves from it jiggled the Deccan area enough to crack it open and get the volcanism started. Still others argue that the Deccan volcanoes were tossing up lava and carbon dioxide at intervals for a long time both before and after the impact and therefore were only secondary in the mass extinction in particular.
"I'm very specialized for this ecological role, but unfortunately there is no ecosystem. I guess I'll just die."
-The Dinosaurs
When chimps enter water
Dinosaurs were losing their diversity leading up to the K-Pg extinction event and some mammals were filling niches and increasing in diversity but the species of dinosaurs extant in the latest Cretaceous were more wide spread, had more numerous individuals than those before and were in dominant positions in the trophic cycle that no mammals back than could even be close to so it would be false to assume that the dinos were in decline and the asteroid just speeded up their inevitable doom as some have argued. However it is true that having less diversity means being more exposed to major extinction events. The asteroid impact was a real game changer for life on Earth and undoubtedly animal life would have been significantly different back then had that not occurred. Rachel I am more interested in natural history than geology and geochemistry but in order to better understand the previous you definitely need to know some of the latter so I think your channel is an intelligent composite!🙂
Thank you. Great explanation!
Wonderful video, Dr. GG! 🦖🦕☄🔥👏
Amazing topic. Looks like dinos were on the way out but the impact sealed their fate.
Exactly by 50 mya non avian dinosaurs would have disappeared without the asteroid
So, it's more like "small animals survived, large ones did not" - and the small ones were (some) mammals and avian dinosaurs, but not larger mammals and dinosaurs. Afterwards, these surviving groups diversified again and evolved large size, but it was predominantly mammals that became large this time (though there are / have been a few large birds as well)
But there were also small non-avian dinosaurs. Why didn't those survive?
@@sebgur4401 luck? like was said in the video mammals dominated the small vertebrate niche so there werent that many non avian dinos
@@elvis4868size wasn't the issue how well a species can adapt to survive rapidly changed climate not all experts agree that they needed to be very small to survive an asteroid impact
@@sebgur4401 Probably few to none of them were smaller chickens - whereas, average birds of the present day are. Even there, size might have been a large factor.
Then there's mobility - and the ability to spot things from the air, or catch things in the air.
@JosephLMcCord this! It's a numbers game. Mammals sacrificed the numbers dinos laid as eggs for internal toughness and it paid off with a mutation allowing all mammals with exceptions to give live birth.
I didn't realize that so few mammal species (~7%) survived the extinction event, which makes it a close call for us as well. I wonder if many insect species survived? They could have been a good high protein food source for those surviving mammals.
I just found this channel because of my interest in the evolution of Eukariotic cell reproduction. Wow! I'm super impressed with all the content. The graphics, the erudite explanations, the un-dumbed-down simplicity for us armchair scientists. Well done! I hope and expect that you'll be as successful at this as you want to be.
Hi Rachel nice to meet you btw. What do you think about tapetum lucidum being one of the most advantageous features in a post apocalyptic scenario? It seem a common trait amongst who survived the meteor strike imho! Thanks for the enthusiasm you put in all your job!
Fascinating video, thanks. Further questions came to my mind, especially one you are already working on answering -- why did the avian dinosaurs survive? Another big one -- if major groups of non-Avian dinosaurs were already in decline, how might that have played out if the big asteroid impact had not happened (or happened much later)? And finally, is adaptability just the flipside of having a really excellent niche you have adapted to fill, or are there roles and body plans that are inherently adaptible -- smallish intelligent omnivorous fast-breeding burrowing-capable animals like rats, highly mobile, intelligent, non-obligate carnivores like coyotes, and smallish, fast, super-agile hypercarnivores like feral cats?
This is really interesting🎉 thank you!
It would be great to see a similar rundown on the current mass extinction.
It is coming soon! :)
I love Geo Girl! She makes the best videos! ❤🎉😊
The really odd thing is that multiple lineages of birds (I.e. avian dinosaurs) survived but NO non-avian dinosaurs did. There were some small dinosaurs like avimimids so it’s not just size. I guess flight was the main determinant. Another question is if avimimids survived would we call them flightless birds?
Great video on that cool subject! Im still looking forwars to that GANYMEDE Video!!!!!❤ 😅🙃
00:10 That close up! 😍Stunner!
I think it took Rachel only a few months to achieve better lighting (i.e., not over-lighting / over-exposing). It took Grace Helbig and Mamrie Hart the better part of a decade to learn how to do that!
@@eaterdrinker000 I dont know anything about lighting, I just think Geo Girl is hooooooooot!
Thanks Doc.. good stuff. I don't really know, but suspect that Vulcanization could have been changing ( decreasing ) the Oxygen levels ( maybe hurting really large dinosaurs.) but the Astroid catastrophe would have been the killing blow . I think these fires would have been like nothing before or since. Oxygen levels would have dropped so much that large animals just couldn't survive if any stayed alive after impact. I don't think it would have taken long for the entire earth to be affected . But as you point out... small animals would have had a windfall. The Earth can take a lot of punishment... people... maybe not so much. Two subjects I hope you address are .. The Shifting Magnetic Poles ( I try not to think of this too much. ) and a closer look at Saber Toothed Cats.... What was goting on with those critters ? Thanks again.. I love this stuff.
At about that time, volcanic super-activity was piling up the huge lava beds named the Deccan Traps. That didn't decrease oxygen directly, but the ash and carbon dioxide emissions would have had major effects. The eruption of Mount Tambora, a comparatively modest squirt, in 1815 cancelled summer the next year. en.wikipedia.org/wiki/Year_Without_a_Summer
I concur that the available evidence suggests a gradual decline in species diversity of dinosaurs prior to the KT extinction....but I am hesitant to be sure that was really happening and I am skeptical that any gradual decline that was happening _necessarily_ played a role in why all the non-Avian dinosaurs went extinct. (I should have also mentioned that your videos are exceedingly excellent, and I regularly recommend them to disparate people.)
Thank you i enjoyed your video and look forward to seeing your video on non avian dinosaurs
7:00 "only ... about 23 species (of mammals) survived, and only one of them was a eutherian". Thank you. I had wondered about that for a long time. So if that proves out long term, there were more species of dinosaurs that survived than eutharians, and not that many more species of mammals overall.
9:20 "in a way, mammals prevented dinosaurs from becoming small, because they were so dominant (in small body niches)". Thank you! You are the first person I've ever heard vocalize that! You are living proof of the correlation between great intelligence and great beauty. I try convincing my children of that correlation using my own example, but sonehow they remain unconvinced. Now I have even more proof!
I suspect that being quadrupedal is a big advantage over being bipedal when scurrying about under bushes and running into small holes, and dinosaurs were bipedal unless they got big. I also suspect that the dinosaur superpowers of hollow bones and an awesome unidirectional respiratory system weren't much of an advantage for small animals that didn't fly, whereas mammalian superpowers of chewing and mother's milk are just as useful for small animals as they are for big animals. So birds did great at small sizes, and other dinosaurs were outclassed by mammals at small sizes.
12:45 Not sure that a reduction in diversity in a clade is necessarily a decline of the clade. That can just mean that a smaller number of generalists fill more roles. Or it can be a mix; hadrosaurs evolve to more effectively compete with large sauropods, sauropods decline, and things that eat sauropods decline.
There is a general trend thoughout evolutionary history - more complex and intelligent species outcompeting less so species. Dinosaurs were in long steady decline mainly caused by mammals taking their resources. An Asteroid impact made little difference to this in my opinion.
Excellent video, thank you, :)
There was a lot of cooked and frozen dinosaur to eat for years after the asteroid impact. Worms, bugs and seeds for reptiles, birds and rodents to eat like today!
I have question of sorts. Early in the video you showed estimated maps of post-pangea. There was pictured some inland seas making up large parts of america and other continents, which I recall to be estimated based on fossil remains, mostly shellfish. I forget, however, why this can't simply be the product of intense wetlands and fresh-water lakes??
Well, we can tell the extent of inland seas based on sediments deposited as well, then the fossils just help in a way of confirming what may have lived in these seas, and we can also esimate the level of connectedness that such seas had to the ocean and thus, understand their potential salinity. We also tend to sea marine fossils in very large connected transgressive seas, which we would not see if it was a freshwater lake. So, it depends on the exact sea that we are reconstructing, but in general there are many different ways we estimate the extent, salinity, and life content of these ancient seas :)
Good job.
Another highly informative video. It's hard to completely explain the pattern of extinction at the K-Pg boundary. I was glad that the point was made that many dinosaur groups were in decline in the latter part of the Cretaceous. This was a point made by several prominent paleontologists such as Niles Eldredge and Robert Bakker back in the 1980s when they cautioned against rushing onto the bandwagon of the extraterrestrial impact hypothesis. Even if one accepts the impact hypothesis, there were certainly changes going on in Earth's ecosystems apart from that event.
Now why did crocodiles survive? So much left to explain.
We love you geo girl! Yewww.
Thanks so much!
@@GEOGIRL *NO* Thank *you* so much
Interesting topic
Have you read Steve Brusatte’s book on this topic “rise and reign of the mammals?” Its one of my favorites
Oh I didn't know he had a book! I used his 2022 article on the topic as one of my major references for this video and found it incredibly interesting and well written! I'll have to go check out his book now, thanks for mentioning it ;D
@@GEOGIRL yeah you’re welcome!
what many people dont take into consideration is the point that reptiles lay eggs that require a steady state of temps during the incubation period. Adverse temp changes stop the incubation and the eggs fail, thus reducing the numbers immediately. Let this occur for several years, you end up with a huge gap of reproduction missing
I love your video ❤
Can you someday make a video about how lactation evolved?
I would have thought that somewhere, some small species of non-avian dinosaur would have survived. Perhaps they did for many thousands of years but in an isolated region eventually becoming extinct. Their fossils may yet be found.
very cool thanks :)
I've often wondered how long a dust cloud blocked off the sun to plants on the Earth, from the strike.
I'm thinking 10 years, but have there been any studies on the subject? How long can seeds sit under ground before they are unable to sprout? Will seeds sprout in a darkened room, if the room is kept warm??
I'm getting into Paleoecology, an I don't know why.
I wonder what would've happened, Rachel, if at the KT extinction event there were small bipedal non-avian dinosaurs no bigger than a house-cat that were able to burrow like mammals?
Thank you for the video, i have just a question, what are the evidences that support what you are presenting in the video?
Thank you in advance.
Some species of mammals and birds have something else in common: they hoard food, namely seeds. They harvest seeds in the summer or autumn and store them in the ground, to survive the following winter.
Some ant species, or termites, also do something like. They pull branches and leaves down into their tunnels and cultivate fungi, which they then eat.
Big, meat-eating creatures cannot maintain a store of food, because the meat rots when it is warm.
Maybe that also had to do with survival.
It is also possible that the surviving mammal groups had already developed the ability to hibernate or starve-sleeping like the shrews.
Interesting Topic
Hey geo girl, nice videos. Quick question tho...??
You look like you do butt stuff 😅
While both dinosaurs and mammals tried to duck the stone from the space, only the mammals avoided being hit by it. Because they were small.
I’d love more details about the multiterbiculates and where did the monotremes come from? I realize this is biology and not geology, but I’m curious.
08:30 f
_This kind of reminds me of a very specialised and dominant species today ..._
We are _not_ very specialised. In fact, we are pretty much generalists who can survive very different and in part difficult conditions.
Some small dinosaurs evolved in Mesozoic era (even in the presence of small mammals) and survived KPg extinction event. There were... birds.
8:30: "one modern very specialized and dominant species today that might not do so well with change".
I honestly not sure of which species are you talking about? Because if you ment humans, then we're NOT specialized at all in terms of food variety, climates and other environmental conditions. We're actually one of the most generalized and successful species in evolution. It's true that we became depended on technology and civilization, but this is cultural dependency, not biological. In a case of a mass extinctions, it is very likely that at least some humans will survive.
I mean mainly our dependence on civilization and while we are general in terms of the diet we can eat, I feel like we are very specific about the diet we do eat (especially within developed regions), so for example, when I picture people that are accustomed to civilization, technology, and all the things that come along with that, and then I imagine they were put in a position in which they needed to survive without those things... I mean we have tv shows that show us that we have come so far in our advanced civilizations that we can no longer survive in nature the way early humans did. And in our case, with things the way they currently are, that is great, we are more dominant and successful due to our technology and civilization, but at some point if we need to become a bit more resourceful again, I feel like many people would not be able to (including myself lol). But I do agree, I think that some humans would survive, but I think it would be relatively small percentage, and it would probably be the ones that are a bit less reliant on tech and civilization. But who knows, I could be wrong, that's just the way I see it :)
@@GEOGIRL Yes, I agree. A fall of the civilization will be traumatic. And without the supply chain many many will die. But I think that those who will survive, including in developed countries, will manage (including yourself ;) ) because we all have at least a basic understanding of agriculture, lighting up a fire, find shelters in ruins or even build something very very simple, and most importantly, work in groups. So it won't be an extinction :)
Please talk about what insects survived the Meteor impact as there is not alot out there about it.
Humans are the ultimate generalists.
Whatever happens some of us will survive.
Truly fascinating! So many facets (and I'm a hard-rock geologist at heart 😄). I'd love to know when bats evolved to rival (in some aspects) the avian dinosaurs.
Even among the few surviving species, I would assume very few *indivuduals* survived. Could some of these have been just a handful of lucky ones in a single location? I guess this will be just speculation. 🤔
I think you have found your ecological niche. And here you will thrive. And I am a scavenger of knowledge. My niche is on the ground munching on the seeds of wisdom that you toss into this environment. Thank you for the nourishment.
If the theory is correct, there's something that isn't mentioned: the food supply suddenly increased. If the mammals had an omnivorous diet, they had plenty of food and if that was the case, they had more offspring.
Eutherians look super cuddly 👍
Not sure if she mentioned it, sort of a blur after a while. But was thinking, if the planets was dark for a few years. Mammals have better senses, hearing, smell, whiskers and such. Not so reliant on eye sight, like maybe dinosaurs.
My thoughts on it is mammals and birds can with stand cold better than reptiles. Dinosaurs didn’t all die on the same day it took years after. Crocs and others in the taxa can hibernate during such times. The oceans must have cooled cause the reptiles died off with food still available. Fish survived also
The mammals were in the asteroid piloting it like a space Noah's ark. Then they ate all the dinosaurs. Then they conquered the fish people that rode in on a previous asteroid. Before that the Amoeba were h ere.
How did insects do during the Cretaceous extinction? I would think they did well with so many corpses to feed on, thus causing small mammals to become insect eaters.
Walk without rhythm and you won't attract the Asteroid
IDk the temp changes need to be looked at more.I think what really happeened is some species were able to get to colder temps when it was too hot and vise versa.Then the OTHER factor would be when moving to a better climate was there enough food to keep alive long term?Nature needs to be balanced or some species will die.
Large dinosaurs needed huge amounts of food so it would seem obvious they would be the first to go.
The waters at the time would be a different game as travel might be easier to get to cold/hold temps no difference than flyers that move about during the seasons.
As for pre humanlike species thy would be decently able to move about climate regions as needed.
Mammals are so underrated 😮 how badass do you have to be to live through all dinosaurs and the dinosaur killer? I say they were more powerful than people think....
Dinosaurs are still living… the avialan clade descended from the theropod dinosaurs are very much with us! Birds are flying dinosaurs! 😊
But I want a pet brontosaurus, not a parakeet.
The world needs more smoking-hot nerds in it. Looking good, angel... _Doctor_ angel.
- why don't you have internet on your phone? Sigh... You're such a dinosaur!
- Great! I mean, Peregrine Falcons are fascinating. Thank you
Mammals vs. dinosaurs continues to play out to this day at innumberable birdfeeders, hence the proliferation of squirrel-resistant models. Mark Rober was so impressed by the local squirrels's birdfood larceny that he created an obstacle course for them: ruclips.net/video/hFZFjoX2cGg/видео.html
Nice vid... but gonna keep bugging you to share those rocks on the shelves... that you decided not to have in the BG in this one.
Am I the only one with a huge crush on her? God she's cute
Very interesting, although I do not have enough biological background to understand the details. You seemed to suggest that homo sapiens may not survive the next extinction event which will surely come, although maybe not for a long time. I suppose our size is against us, although our species is supremely adaptable - so maybe a chance of survival?
Isn't it true that what we know about the KT extinction and immediately afterward is based on a handful of tiny sites, mostly in North America? How can we draw such grand and confident conclusions about what was happening in the world based on so little data?
no, not true
I hadn't been on your channel for a month or two, but today your face is glowing! Something is different. Are you pregnant or hight on love?
Where does this exact number of 23 species come from? Are these the only three species in the fossil record? Is this number the result from looking at modern mammal DNA? Is ist a guess or is it the absolute number of different species we know of and could there be more?
I am always exited if science suddenly comes up with such accurate statements
there are almost twice as many species of dinosaurs (11,000) alive today as there are species of mammals (6,400) alive today.
And to think, without Mama Eomaia we wouldn't have the privilege of watching Dr. Geogirl.
Its amazing that billions of different events had to play out just for me to be eating potato chips and watching this video on You Tube, its pretty mind blowing
Yo think that there are entire solar systems that are gone forever and noone will ever know they existed in the first place.
7% is not to bad. I don't think I ever put a number on it; but, I'm thinking I expected less than that.
I wouldn't consider Humans a specialized species; we are the general species. The growing problem with modern humans is they are high level from subsistance living. They make a living away from actually hunting/gathering(much less agriculture). So, if the agricultural sector fails, then they don't know how to survive or where to go(there's a lot people that have gone "prepper(including Sam Altman of openA.I. and the facebook guy))
James Burke has a great episode about this in his first Connections series - umm, episode one actually of his first Connections series. You can see that here on youtube!
I saw some Science News article a year or so ago, that the Dinosaurs were not "already going out" before the Cretacious impact.
What's your favorite age of the Earth
They did not survive the event any more than Dinosaurs did. There was far greater diversity of Dinosaurs before the impact, while mammals were a very small population overall. After the impact both groups where small with only a handful of survivors. Mammals bounced back faster becoming the most diverse. While the surviving Dinosaurs became birds and surviving reptiles barely changed at all.
That is still all three groups surviving the impact or being wiped out by however you want to phrase it. No one was excluded.
8:33 pandas?
We are Mammals !!!!
I don’t understand how aquatic dinosaurs didn’t survive
🌹🌹
I think the key was mammals could survive off of insects large dinosaurs could not
Cheetah is too specialized to survive changes. Koala, kolibrie, bees.