I heard one paleontologist say that, since there are over 7000 species of birds, & only over 5000 species of mammals, in a way, this still is a dinosaur planet. We've gained a lot of biodiversity outside dinosauria, but there are still more species of living dinosaurs than living mammals.
Absolutely, if number of different species is the only deciding factor in a animal groups dominance then yes, birds do outnumber mammals. However arthropods outnumber every other animal group combined so if that alone is the reasoning then the world isn't really a dinosaur or a mammal planet.
Mammals did achieve flight themselves in the form of bats, but generally, bats have never really been able to compete with birds and it's likely why nearly all bats are nocturnal.
@theatheistbear3117 I say this is NOT true. I say birds evolved in direct competition with pterosaurs - it drove their early evolution into flight for the bird- like dinosaurs and smaller pterosaurs were falling out of the fossil record well before KPA. With the exception of the larger species of pterosaurs, they were being out competed by bird-like dinosaurs.
Still disappointing though, for a different reason. Predatory ground birds are just so rare (only 1 or 2 groups ever evolved), it would be lovely if we knew of more. Being a flightless predatory bird is in itself unique given the rarity.
I'd add: dinosaurs didn't take over because the dinosaurs left were birds which are highly specialized for flight, not specialized to grow large. I'll explain: Birds during the late triassic-early jurrassic lost their heavy bony tail in order to be light for flight. The issue with this is that as theropoda this made them front heavy. Their solution was to adapt a crouching stance with the femur being held in an angle in order for them to stand upright. The issue with this is that all large animals need a column stance. Dominant megafauna is always the bigger/stronger herbivores or bigger/stronger carnivore until climate change causes their extinction due to their high caloric needs, then the meek inherit the earth and get large again-repeat. Birds, with their squatting stance can't get very large as fauna. Terror birds were at most a few hundred pounds. Birds are as old as mammals about 150 million years old, yet the largest bird EVER was a herbivore that weighed about as much as a bovine [similar weight to a cow], it's femur was very robust to support its weight. Birds are simply inefficient as large megafauna. I wouldn't say birds are at a disadvantage in cold weather. Turkeys, owls many other birds live far north. Only birds can survive in the coldest place in the world in the south pole, no mammal can live in its surface. Nonavian dinosaurs actually thrived in the poles where half the year it was a snowy hellhole. But large theropoda like trex, large ornithischians like the ornithopods, and of course all sauropoda had a column stance with their legs positioned directly below their center of gravity to support their massive and powerful bodies. Dinosaurs are very different from ectothermic snakes, crocodilians and monitor lizards.
Dang, I was going on same logical chain, "what do dinos have that birds don't" "the tail" "how does that affect the situation" "their posture is different, and their leg muscles lack the tail connection". That's how far I got before reading your post. My contribution would be that bipedal dinos were probably faster and more agile on land than similar sized flightless bird because of the tail provided better lever point to leg muscles, provided a countermass around pivoting point for quick turns and posture makes them more stable. IOW they were much better moving on land than birds that came after and for birds to take same position back would require too many adaptations.
@@michaelanderson7715 Maybe, but also truth. That was the point of this video. What remained was avian dinosaurs and those could not take over for reasons mentioned.
I have Evangelical Christian parents, meaning young Earth creationists. This video's explanation of the world makes a lot more sense than the one I was told growing up. Even though I'm an adult now, my mother is still like, "Evolution is very convincing, but you can't let yourself believe it. It's a temptation to deceive you into doubting your faith." It's a total rejection of natural history. Lots of people don't realize _how many_ kids grow up like I did. (The USA is 40% young Earth creationists.) I think you should know if it weren't for videos like this on RU-vid, I'd still be so unaware of so much about the world! Anyway, GREAT VIDEO! Thank you for making this educational material free to public access; it's priceless for being so easy to understand even for viewers without a science background. Here's a comment for the algorithm and a sub because I look forward to watching more!!
I too was raised that way and am learning science as an adult. I think it's more difficult than learning it as a kid because I have to unlearn all the young earth creationist stuff that I was taught growing up. but I am trying.
@@rachelcornelius1449 My mom is like, "if I knew then what I know now, blah, blah, woulda home schooled you..." As hard as my basic biology homework was without any help, I feel like I dodged a major bullet there. At least I graduated with a basic understanding of why humans are considered mammals, something rejected by their church even though we're warmblooded, hairy, and have milk ducts. Was your homework called "evil" too? I'm always curious to ask my fellow ex-Christian youth about their elementary schooling experiences.
It is completely possible that teachers are using certain videos as asset material and that's why certain series over others have more views? I love all of your stuff, I grew up wanting to be a paleontologist so I never lost interest in this stuff and I love hearing how you put your stuff together! Great job!
At the current moment the reason why some of my vids have substantially more views than others is because some of my videos got picked up by the algorithim and are currently being promoted in RU-vid search. At the beggining of this month this channel had 1900 subscribers and now we are nearing 8k! ....It's also entirly possible that I'm about to wake up and none of this is real!... XD
@@PaleoAnalysis I like the way you think, sir, let us hope "the Matrix" let's you keep your rightful success! Honestly though, great videos. It's fun enough for young adults to watch and enjoy and not stupid, so as a grown man I can watch it and learn stuff. You've found a good balance, that's why people like your stuff, it's actually fun to watch and learn.
I suspect it's because birds are optimized for flight, so re-evolving into a ground living life form would be a bigger leap than the smaller, land based mammals getting bigger. It's like they'd have two stages to go through, versus one.
we literally have ground dwelling birdslike the ostrich, the emu, the elephant bird etc. and those are just the big boiz, many smaller flightless birds too.
@@daftwulli6145 Right. Not saying it can't be done, but it was a disadvantage. Plus, some of those examples are extinct because they could only move into those large bodied niches on isolated islands. Not saying there are no ground birds, but there clearly aren't as many.
@@DarthBobCat Elephant birds went extinct a few hundred years ago due to human activity,and the rest is very much still screaming and kicking, and to be fair a lot of species had trouble with humans since we change so fast it is neigh impossible for evolution to keep up
@@daftwulli6145 there is (was) not one bird with four bearing load legs, that was the pair of legs I was refering to, most flightless birds have vestigial arms
I have always found New Zealand to be very special in regards to the most dominant. Birds filled nearly every single large to medium sized ecological niche. From Moas as large foragers to the Haast's eagle as a large apex flighted predator. Of course, this was ruined once humans set foot and introduced pests.
Funny enough, Hawaii is the same way. All bird fossils until humans get there. Many of them flightless, 'cause wings only get you lost at sea when your home is an island in the middle of nowhere I guess
I like the fact theres no large predators like lions tigers or bears in New Zealand or large snakes or mosquitos which are replaced by sand flys- i wonder what u use to keep sand flys from biting u- does Off work?
@@iduswelton9567 there are mosquitos here. I encounter them more frequently than sand flies and there are parts of the south island which I'm told are absolutely crawling with the bastards.
You mean once human arrived and ate them or turned them into feather cloaks? Before another group of humans arrived and introduced the concept of conservation?
One thing I wish you'd mentioned is that exothermia gives an advantage in terms of how much food an animal needs to survive. I mean, compare eating a single rat once every couple weeks (ball python) with eating basically your whole body weight in food every day (meerkat). This is why basically any environment or niche that doesn't give endotherms an advantage ends up being dominated by exotherms, because endothermy is expensive.
Ectothermy is only efficient at small body sizes though. A large animal will take a lot longer time to heat up in the sun, so at larger body sizes it will always be at a disadvantage against endothermy. Small animals, on the other hand, lose body heat at a much higher and faster rate and they need disproportionately more food to keep their constant, internal body heat while small ectothermic animals only require a small amount of energy and a little basking in the sun. Also, dinosaurs were either fully endothermic or at the very least mesothermic and their dominance was due to their superior and very efficient respiratory system that worked the best among the other clades in the very low-oxygen Mesozoic era.
I also think it's considerably harder to evolve out of a specialized lifestyle, like flight, then it is to just expand into your already terrestrial one. Unlike whales and marine reptiles, who have a full tail, all 4 limbs, lungs and the transition of being semi-aquatic, birds usually don't do as well on land as they have less to adapt from.
Depends on your lineage, birds have a body plan this is still quite suited to walking around and have been noted to quite rapidly evolve flightlessness if required.
@@CAMSLAYER13 They usually evolve flightlessness in environments where they lack predation (like Islands) and they are very limited in their ground dwelling adaptations (relative to other terrestrial tetrapods).
@@arnigeir1597 while lack of predation seems to be a strong incentive to give up flight there are plenty of flightless birds that have existed with predators. I think the problem they had was flight is too good and is even better if theres sporadic amounts of food. Like you said about turtles etc doing well without any changes, birds are already well suited to travelling as much as they need to eat while mammels would have been scrambling for resources and had to start filling more niches
@@CAMSLAYER13 Animals fill niches whenever they are available, but the type of animal that fills it, can have allot of impact of their competitiveness, like how we don't see allot of fish crawling back on land, even during mass extinctions.
Dinosaurs also re-evolved in a convergent way. In some sense, mammals are the synapsid's version of the diapsid's dinosaurs. Both complex warm blooded lineages that had massive extinctions during climatic shifts but still managed to rebound and refill the niches left empty. I mean both lineages still exist today in abundance but reshuffled in their role a bit. Dinosaurs are still quite abundant when you consider birds, which inhabit every continent even Antarctica. On a different note, Birds took advantage and filled the roles left by the extinction of Pterosaurs, I wonder if bats might do the same if flying birds suffered an extinction event.
There are some speculative biology shows about the last theme you mentionated. "Wild Future" has bats taking the skyes in the part 2, but there is still evolved birds all along the show. Guess the point of not having one continent aplies again: not a single especies can rule all the world
@@zy9662 and the marine reptiles that I don't think get talked about nearly as much as they should. Mosasours imo are probably the coolest animals to have existed to date.
There appears to be a common perception that dinosaurs evolved into birds. Not true. Birds are a branch of dinosaur that existed before the extinction. It's just the branch that survived and later evolved into a very successful niche.
@@Demane69 Of course not all dinosaurs evolved into birds. And birds look very different now than the ones that existed when there were other dinosaurs. That was my point, that the evolution of dinosaurs didn't completely die off. Many branches went extinct just as mammalian branches have gone extinct. That doesn't change the fact that birds are still a continuation of dinosaurs, just as living mammals are a continuation of extinct ones. Also, birds fill many niches, predominantly flighted ones but swimming and terrestrial birds are also quite abundant. You seem to imply by your last statement, that they are only very successful in a sole niche. Even if bats took over as the predominant flighted animals, birds would have many other niches they could and do still fill.
Nice video man! But if I could, I'd like to say that the phorusrhacids weren't actually the only group of predatory flightless birds that dominated or codominated the landscape for some time. There were also the bathornids who thrived in direct competition with placental mammals. Not to mention the fact that terror birds were already on their way out before the great american biotic interchange. A common theory is that both of these groups went extinct due to shifts in the environment rather than being outcompeted. So I think it could actually be possible for birds to fill a hyper carnivorous predatory niche even in the presence of mammalian carnivores.
Yeah, I almost go into the Bathornids but I figured they are actually pretty closely related to phorusrhacids and seriemas, so I decided to save it since making an aditional stop on along the way in the Miocene would have made this video likely come out late. (This is about as long of a video that I can realistically get out in 7 days until I get faster at it)
While birds can evolve to directly compete with the large carnivorous mammals, they kind of struggle against the extremely competent small ones. Thus, transitional forms to large carnivorous birds are hard. They pretty much have to evolve from a large version of a bird like the seriema and secretary bird, which use their flight and legs that are naturally good against snakes to fill a niche small mammals are not well suited for. Of course, the natural easy lunches from the boom and bust cycles and constantly aggressively expanding nature of rodents are great for all small predators. Of course, in the air, it is a different story.
@@UniDocs_Mahapushpa_Cyavana bouncing of that... i remember reading squirrels are the largest predator of bird eggs in North America esp. when acorns are unavailable. Eggs are bird's greatest weakness.
As alluded in the video, the dinosaurs are still doing quite well in Australia and parts of Indonesia. I believe there was a war between emus and humans in 1932 and the dinosaurs won that one. Some crocodilians could grow to 28ft until mid-last century. The leatherback sea turtle is actually substantially larger than that carbonomese turtle mentioned in the video. There is no shortage of human sized flightless birds walking on sidewalks of Brisbane and Sydney.
Would love to know the details of that epic battle I keep hearing about......I believe it too. I believe with the right environment, pressures, and predators (or lack thereof) that nature can go any way with enough time.
My thought is, any dinosaur who survived the impact would've starved even if they pushed another 100,000 years. Other animals took advantage of their extinction and outcompeted them more then likely.
What are the odds of some few of those surviving dinosaurs (which are small and have many birdlike features) start to evolve into stem birds to fill the niche of pterosaurus because they were outnumbered and outcompeted by the surviving mammals ?
Not necessarily. Depends on size and diet. Small dinosaurs that were omnivores and that would eat anything could have survived (in theory) since birds, reptiles, amphibians, fish, mammals, insects, etc. all made it though and these small dinosaurs could have fed on all of the above. Clearly, other factors were involved, we just don't know everything that happened IMHO.
I wonder if part of the reason why mammals managed to take over had to do with the fact that at least fresh water reptilians such as amphibious crocodiles and turtles mostly breezed through the extinction. Since they suffered few extinctions, were well adapted to enviornmental fluctuacions and their enviornment restored relativelly quickly, they had little evolutionary pressure and their evolutionary rate barely increases while mammals (and probably birds and lizards) were forced to survive in a highly damaged enviornment and exploded in diversity as the enviornment recovered. Also on the last world of the Dinosaurs, probably the closest thing we saw to a fully Dinosaur ruled ecosystem in recent times was in New Zealand. And then we happened.
Marshlands, habitats similar to Floridas Everglades, didn't have many extinctions during the kt extinction. Maybe this is why giant crocodiles, giant subaquatic snakes [titanoboa] and giant turtles evolved so quickly after the extinction. Vegetation certainly died off but these wetlands normally have slow flowing or still water full of decaying vegetation so the end of photosynthesis killing vegetation wouldn't have really ''polluted'' and changed the chemical composition of the water in the wetlands. Wetland water is normally deprived of oxygen, so the fish and amphibians in them are adapted to this. In other habitats, when plankton and vegetation died off due to a lack of photosynthesis, the declining oxygen levels would have spelled death for many animals at the base of said ecosystems. On top of that, struggling land animals would still visit these wetlands in order to drink, perfect for crocodilians. Todays seaturtles are not the seaturtles from the cretaceous. Cretaceous seaturtles went extinct, todays seaturtles were marshland turtles that filled the vacant niche ages later, there's an episode in Eons going over how the leatherback sea turtle has re-evolved multiple times independently.
@Monte Cristo If it was such a big advantage we would see a trend towards viviparity dominance in groups that sport viviparity and oviparity. This might be the case in mammals and sharks/rays, but is quite likely not the case in teleosts and squamates, which are still mostly oviparous in spite of viviparity evolving many times in both clades. Then there's the elephant in the room: Non avian Dinosaurs soundly dominating land ecosystems and kept live-bearing mammals in marginal niches for around a 100 million years. Really struggling to see the superiority there ;)
@@miquelescribanoivars5049 Indeed without the dinosaurs dying out.....there would be no place for powerful mammals at the top of the food chain and for us to exist, we would have been savagely hunted to extinction.
given the sheer geographic spread and biodiversity seen in birds, it’s hard not to say that this is at least in part a bird (dinosaur) planet. We have seals and whales (and some humans, I guess) in the South Pole but the dominant/only native land animal on Antarctica is a bird. The most mobile/terrain-spanning non-human animals are birds. The highest in altitude are birds. Until humans arrived birds were the dominant clade in New Zealand. Birds have spread to occupy niches as diverse as insect-like flower pollinator to terrestrial omnivore to flighted apex predator.
That is a video idea that has sat in my little black book of ideas for a long time... And every week I open that book, look at that, then turn the page because I have absolutely no earthly idea how to make that video and do that story justice.
@@PaleoAnalysis it does suck because Antarctica’s ice also buried its entire fossil record. There’s next to no evidence to show the animals and ecosystems of ancient Antarctica. It’s such a tragedy because it was likely just as unique and diverse as South America and Australia with weird combinations of polar marsupials and giant penguins
Yeah and the video doesn't touch on the predators of Africa before getting in contact with Eurasia, from what I have read there has been found fossils from only one potential carnivorous Afrotheria, would be interesting to know if some birds were at the top of the food chain before the placental Carnivora arrived
@@prestigev6131 What makes it even worse is that you can't legally set foot on antarctica without the permission of your government so even if you wanted to set up a spot over an ancient mountain range, melt through the ice, and dig up some fossils you legally can't. At least not without cutting through a mountain of red tape first.
Smaller animals always have the greatest chances of surviving a mass extinction. At the time of the KT extinction, the smaller non-avian dinosaurs species probably just weren’t diverse enough to hold on.
Something that has to be noted is that mammals actually got very large very quickly after the start of the Cenozoic. We had mammalian megafauna as early as the Early Paleocene, both big herbivores like pantodonts and apex predators like some of the mesonychians (Ankalagon being the earliest mammalian apex predator I can think of, from the Early Paleocene). What this means is that there never actually was an interval where birds and non-bird reptiles got to large sizes before mammalian got big and outcompeted them-mammals got big at least at around the same time as, if not earlier than, the large flightless birds did, flipping the narrative on its head. It was really the birds that managed to get big in an already mammal-dominated world. Also, terror birds were not outcompeted by mammals. They were already in chronic decline by the time GABI took place (only one species of terror bird was even functioning as an apex predator by this point, and there were only 2-3 species left), so the influx of North American carnivores wasn’t why the group as a whole died out.
In terms of biomass, we arguably live in either the age of bugs or the age of livestock and humans. Unless you count plants, since they outweigh everything else combined.
you are comparing apples to oranges here, plants are a whole kingdom just like animals, so you have to compare kingdown against kingdom not kingdom against a much smaller group
It's pretty fair to say that at least this tiny blink in time is the age of livestock and humans. Not only are we the only current Antarctic mammal (pretty impressive for a tropical species) but I daresay no other animal has made it to the moon. "Look at those cave men go." That said, we still have a lot of work to do if we want to catch Tyrannosaurus on the all-time Leaderboard of Badassery.
Most interesting and informative video. This channel is a great find! One small request: Can you please add metric to your numeric data. That will really help the rest of the folks living outside the USA. Many thanks! 😊
Great video! And I completely get Your point on mixing the complete history of Earth series with other videos like the museum adventures or the paleo catalog. Its more interesting to watch (and to create i presume).
I honestly believe that some small generalized dinosaurs survived the asteroid, such as Troodontids, oviraptorids, alvarezsaurids and dromaeosaurs. If you ask me why, it is because the majority of them were omnivorous, small (most species were below 10kg) and highly adaptable.
@@alcyon7536 They likely died out because they were Outcompeted by Mammals and Reptiles. During the age directly after the extinction. When everything was put on an even playing field these small Dinos were unable to Outcompete the other Species in this competition. Things such as egg numbers and egg incubation time could have played a large role in Dinos being out competed in a harsh recovering environment.
@@mouse3872 I really dont think that is why, I don't understand the egg idea because birds did just 'fine' and so did turtles, reptiles and crocodiles. Dinosaurs were more efficient (at the same size) compared to mammals and reptiles, you name it! I think something else that we haven't discovered may speficially targeted dinosaurs. But that's just my theory
@@alcyon7536 it's not JUST that they laid eggs it was a combination of different things the way they Nested, the incubation period, and the way they raised their young. Plus the body plan of Dinos weren't really suited to quickly borrowing like small reptiles and Mammals
One thing I've noted is that big dinosaurs had different ecological niches as they grew. Which is different to today, where animals have to parent their young up to their final niche when they can't survive in that niche as youngsters.. This meant there were fewer small dinosaurs to survive the mass extinction, since the small dinosaurs grew big before the environment recovered, even if they were living on available insects, say, during the nuclear winter.
Actually, that's not entirely true. It wasn't about the lack of small dinosaurs but the baffling total lack of medium-sized dinosaurs. Dinosaurs were either very small or giant behemoths, and there were no in-betweens, which, as it turns out, resulted from the juveniles' of large species occupying the medium-sized niches as they grew.
Your channel and content really take me back to my Historical Geology class, which is the one that helped me decide to study geology. For the record that class was taught by an invertebrate paleontologist. Sadly, I am a fairly indifferent paleontologist, fossils either like you, or they don’t! I did better with igneous rocks and structural geology. That aside, that was probably the most fun class I ever took.🙂
Your videos are sooo imaginative and so informative-and so funny! As a regular person who has a penchant for attempting to envision an arc of events, your videos give me a large picture with just enough detail that I can see, or at least imagine, the trees as well as the forest. Thank you!
Thank you for the content. The eon videos are brilliant and I’m happy you’re taking the time to make them excellent content rather than rushing it. It’ll make you happy when they’re released as well rather than it becoming a chore to make them.
I think you misframed the beginning of the Paleogene, which in turn kept you from fully explaining why dinosaurs didn't return to be the major dominant clade of terrestrial vertebrates; Starting in the Paleogene, the ramaining taxa _didn't_ start on equal footing. The remaining dinosaurs were adapted for flight, whereas most remaining mammalian clades were comprised of mostly small, mostly nocturnal and largely burrowing, quadrupeds. Neornithes were driven to the skies by strictly terrestrial dinosaurs, and did not much compete with terrestrial mammals. And were reduced to bipedal locomotion. Whereas mammals had already been in competition with small, or even inftant, terrestrial dinosaurs and other terrestrial animals in the Mesozoic. They had far more options and a much better predispostition when it comes to radiating into terrestrial niches. Early Paleogene mammals had a huge leg-up in terms of terrestrial species variety. The reason birds did not compete as much terrestrially was simply because it wasn't free real estate, which the skies were. It would've made no sense to invest so many resources to dominate the land, when you have to invest far fewer to dominate the skies. None even, mostly.
And don't forget the other birds. I heard there were some ancient penguins that could grow large like seals, not to mention birds like Argentavis with its huge wingspan.
some dinosaur eggs survived the initial asteroid impact and hatched months later but the hatchlings barely had any food to thhrive on so they died out from disease and starvation weeks or months later
@@bipolarminddroppings Maybe. I've yet to find a single video that covers it on RU-vid. There aren't even college lecture courses here from what I can find. MothLight has an evolution of butterflies video, but it unfortunately doesn't touch the evolution of their metamorphosis.
I'd love to hear more about this, too! Butterflies, flies and beetles all share the feature of metamorphosis, likely due to a shared common ancestor, but I don't know how it actually started. It's neat because it allows the same species to specialize for completely different niches or purposes in different lifestages.
Great video! I do have a question. I live in Florida, so naturally there is little or no rock here, but we do have fossils and some of the lakes and rivers here are full of them. So how is the fossilization process differ from a place like the badlands from a place like Florida? The tusks I found were definitely a mineralized fossil, but are the minerals coming from the water or something else?
Very good, thank you. Time to check out the rest of your channel now I've happily found it. Another thought: Specialism. It's hard to radiate in to new niches when you're a specialist. Also 'unevolving' specialisms that might hinder and particularly 'reevolving' lost traits that might help is much harder than starting with a generalist body plan. eg: You can get a bat from a shrew-like creature. But no teeth or hands for birds.
I think something that isn't talked about enough is the simple fact that mammals were less derived and more basal made it easier for them to adapt and evolve to fill new niches, while birds which had many derived features such as beaks, wings and lacking long tails were at a disadvantage at exploiting new niches. It is easier to make a new work of art from a ball of clay than an already sculpted statue. Also while it is common to blame the North American Interchange for what happened to Terror Birds, if I recall correctly Terror Birds were already in decline when it happened most likely due to climate change. While it is true that they could have bounced back if the Interchange didn't happen, it probably wasn't the primary cause of their decline.
Ive also heard that they were less well adapted to land than mammals, like with short tails, a beak and bones more hollow than non avian dinosaurs so that could have also made it harder for the birds to succeed
Its a fairly straightforward answer I think. The KT extinction vastly changed Earth's climate, reduced the oxygen levels and the environment was no longer capable of supporting megafauna
@@nickgreen2905 yeah there is. I'm not even gonna argue this one. It's a fact that oxygen levels were higher, it's essential for supporting such large organisms
This video is amazing, I would love it if you continued walking through how the animals became what they are today. I know that might be a little more modern than your normal stuff but I think it's so fascinating to see the bridge of the old world and what we have now.
Question: What was the ecosystem like at what is now the Caribbean Sea during the last ice age 20,000 years ago? The Caribbean islands are mountain peaks that rise from a relatively flat plateau which is itself 165 feet down at the lowest. During the last ice age, however, ocean levels were 426 feet lower than they are today. That means the sea floor was above water. There's a chasm between St Thomas and St Croix that descend 15,000 feet as well which would have brought sea water deep inland which would have meant that the climate wouldn't have been dry. Temperatures in the tropics are reported to have been 8.6 to 10.8 degrees cooler during the ice age, and so with temperatures being a consistent 78 to 83 degrees today the climate would have still been a comfortable upper 60's to low 70's. Is there any data on what kind of life lived there? Or if any humans could have lived there? And what will happen to that region if another ice age comes about in the future?
I actually wondered super hard why the terror birds died out........now it makes sense if they could have spread out among all the continents, they likely would have dominated all the lands and still been alive up until today. They just couldn't adapt like mammals in isolated regions. Thanks for the elaborate details and crisp explanations!
Not likely as they were already losing control of south America even before the introduction of north American predators, but it was the final nail in the coffin
The scariest possibility is that the meteor had only a minor effect on the climate in and of itself. But that the ecosystem was so finely tuned and evolved to what it had been before that there was a mass extinction of animals and plants.
R u series I just joined on the second I knew you really did your homework, on every subject you mention in your videos, everything you have said is 99.9% close and more than enough to what most others are talking or try keep talking about, your material is simple and well written, and perfect length/time, and I’m most always say that I’m always looking for more like this type of information, yours is right on point thanks.
The percentage of oxygen in the Atmosphere was reduced permanently by the KT event which shifted the balance for which species could grow large based on respiratory systems design.
You are making an argument for birds here not against them. The earliest dinosaurs managed with only 15% in the air. Dinosaurs/sauropods took over at an estimated 19%. Lower than it is today, during the Cretaceous and after the kpg extinction. The low oxygen Level would put birds at an advantage over mammals as their respiratory system is more efficient. Birds are all about breathing and air.
Another great video! This indeed was a great topic. I'd love to see some videos on the history of ancient avians or even just a highlight of the ones you think are interesting. Thanks again for all your hard work!
Excellent video exploring a really interesting topic. I also happen to have one burning question I would like someone who knows about the subject explore: "Has anybody ever tried to explain why there were no obligate dinosaurian carnivorous quadrupeds and no bipedal mammalian or proto-mammalian hunters (prior to humans, that is)? What differential pressures or biological constraints existed that made one body shape viable for one group but not for the other?" I surmise that 'body plan inflexibility' may be a huge chunk of the short answer, however there is a ton of nuance in that phrase that I think the vast majority of laymen ignore (myself included) and I would love to know some of the details. Also, if there were specific differential environmental pressures that pushed each group into different body plans for carnivory I would also love to learn about them.
So glad I chanced upon this video! PA guy, you're good! Perfect mix of solid science, engaging graphics, common sense, and silly relief. Such a joy for a retired educator to be taught by a master educator!
A really good, interesting and fun book about this was just released: "The Last Days of the Dinosaurs" by Riley Black It's about the extinction event and the days, years and millennia afterwards
It’s also good to mention that, dinosaurs were incredibly diverse animals, whereas birds are literally just one small portion of that. The only way they could dominate is by growing large and taking the “bipedal theropod” niche. You were never going to get sauropods or triceratops like animals out of birds, so that really limited what their “domination” could even look like, which was, pretty much, just what the phorusrachids achieved
Don't forget that most mammals, including all of the most successful kinds, were wiped out by the KT event. The most successful mammals in the mesozoic were the multituberculates. They included the largest and most common mammals. After the KT event, only a few of those survived, and then they vanished. Only burrowing and aquatic mammals survived. The same is true for avian dinosaurs. The enantiornithes who dominated bird life during the mesozoic died out completely. Only a few ground and water-dwelling bird types survived.
If the speculative evolution Silmarillion that is Serina: Planet of Birds showed me anything, it's that birds most definitely have the potential to return to dinosaur-level dominance if not more. The problem being that it could take half a billion years or more and any competition from other animals could completely throw them off the path. In any event, I actually think it best if birds just stayed birds. As much as I love dinosaurs, it's clear they've had their time and that they're better off living life as the fluffy high-flying aces they are today, as they really are too specialized for flight to evolve into much else without divine intervention. Besides, Archosaurs are a much broader group of reptiles whose last few members still live today in the form of crocodiles, alligators, gharials, and caimans. Thus, the potential for new dynasties of giant reptiles is never far away. Dinosaurs themselves owe much of their success to archosaurs, and considering many crocodylomorphs before the Mesozoic had evolved into various dino-esque forms it's really not impossible for them to do it again, this time with perhaps even more success. If you can't reignite an old flame, why not light a new one?
I've always been wondering this, why Cynodonts, Dicynodonts, and a few Gorgonopsids survive the Permian extinction, but Anapsids, Reptiliemorphs, and whatever family Moschops is in (IDK what it is called) didn't?
Most likely competition from mammals. A point the video didn't touch is that while reptiles and birds sometimes occupied megafauna niches in isolated pockets, they got replaced by mammals the instant there was a landbridge with the northern hemisphere. The only exception that comes of the top of my head is the terror birds which established themselves successfully in north america but were outcompeted by smilodon in the south.
Terror birds coexisted with North American predators for 1 million years so many scientists now believe that while competition was a factor, something else was the nail in the coffin for their species
This content helps me a lot to put together these huge eras! I’m an ex-YEC (brought up that way), trying to get a BS in conservation tech writing now, and panicking because OMG I KNOW NOTHING and there’s so much that’s happened in science since the 1980s (
I still find it hilarious how turtles, really slow, with basically no defensive weaponry, and snakes who have no legs, managed to survive, yet almost every single dinosaurs got wiped out.
@@PaleoAnalysis True, but they also have no way to punish an attacker, so a very determined animal will normally eventually manage to either break the shell, or bite the legs and tail enough to kill it.
Sometimes avoiding conflict is the best way to survive conflict. Turtles use a breeding strategy of flooding an environment with offspring so some will inevitably survive. This assures that at least some of them will make it to adulthood to be able to reproduce again. Also on a side note, growing up in Florida I know of a couple turtles with big "don't fuck with me" energy... Ever heard of an Alligator Snapping Turtle?
Very good point, even the most competent animals in the combat category will lose some fights, while you can't lose a fight if you never enter one. And yes you're also right, certain turtles do have very strong bites. And they evidently did have a good strategy as they ended up outlasting a lot of species. Oh yeah and also thanks for the great video
Our view of turtles defensive capabilities are heavily skewed due to our capabilities to use tools. Some of the first animals to dissappear in recently settled regions by humans were tortoises, there's even evidence that pre-sapiens species caused local extinctions on even small land tortoises.
I find your videos extremely entertaining! The addition of the animation it's the perfect distraction to keep it from being just you reading a script about the history of the world. This was a brilliant idea! It also keeps young people interested, and the young at heart. Keep up the good work. I'm waiting for the day for you to hit 100,000 subscribers!
I have the opposite opinion, those animations ruin the videos and makes people not take him seriously. I have to fast forward every time I see one. Otherwise, enjoyable videos and voice.
Here, in Louisiana, we have several things which survived from the ancient period. They all have one thing in common, they live in swampy environments, and can acquire air from the surface. (Cypress tree, alligator, gar fish, bowfin)
Each dinosaur clad was highly specialized. They lived in certain habitats, ate certain things... Mammals were diverse - ultimate opportunists, filling in all the cracks in the Cretaceous world. Most were also small and a windfall in resources could feed more or last longer. When the world's habitats were destroyed, whether you blame Chixilub, volcanoes, or disease... Or a combination thereof, all large specialized animals - reptiles, dinosaur mammals, fish - you name it, died when their special niches failed. Modern birds whose ancestors survived the collapse of habitats, survived by becoming the new world's ultimate travelers, migrating from areas lacking food to areas that had food. Feathered locusts. Mammals simply did their own thing and adapted depending on the opportunities presented. Some learned to hunt birds, some, insects, some went after worms or fish or, whatever. When the climate began to stabilize again, some specialized at eating plants. But notice most mammals still possess the dentition of an animal capable of eating anything, if necessary. Chisel teeth in front for slicing, canines for fighting, molars for grinding. Rodent is possess chisel teeth and I suspect deviated from mammals much earlier than others. While both mammals and birds developed giants later on, there were two limiting factors: food and oxygen. Current levels of oxygen are about a third less than experienced by pre-paleocene periods. Food... When there are large fluctuations in environmental conditions a creature survives in place by being efficient with its food supplies - or it migrates. Both have risks but tend to keep animals on the smaller side. Large animals of any type are more susceptible to adverse conditions than small animals.
Nice and detailed, but I'm missing the simplest part of it: To continue after the extinction event the dinosaurs needed to reproduce, and that might have presented an absolute roadblock in any of several ways: Due to absence of skeletal remains above the iridium layer we assume no dinosaurs survived past the impact, but dinosaurs reproduced through eggs, and with eggs protected in nests, eggs might have survived the impact, at least for some species; likely some even did. However, some dinosaurs cared for their young like birds, so without surviving adults it meant the end of the line in those cases. Dinosaurs also didn't brood like birds, but left their eggs to the environment; maybe sometimes helped by vegetation providing insulation or heat through rotting. That strategy would have collapsed with the extreme atmospheric conditions following the impact and extremely few young would have come out. Moreover, it's quite possible that the sex ratio depended on the incubation temperature - whereby any offspring surviving the previously listed issue might have been of one sex only, which won't take you far as a species... Today we see turtles struggling with that last problem, due to global warming, and that's nothing compared to the climate upheaval back then. So, I guess the problem was that all the adults died, leaving any hatching young without support; and that the few young that did hatch were hopelessly few and largely incapable of reproducing. Even if a few had managed to clear those hurdles where were the ecosystems previously supporting the recent overlords of the previous world? The previous underlings were likely better adapted to live on scraps. The other groups of animals, those that did survive might have fared better on all of those parameters, with more initial survivors and reproduction and feeding strategies that were better under the extreme circumstances.
In modern times, one of the most successful and widespread terrestrial apex predators (not counting us) is actually a bird, the Peregrine Falcon. Even other raptors avoid confronting it when airborne as the infamous falcon punch (more like a kick) has enough kinetic energy to knock out birds much larger than the Peregrine itself. Additionally, it's distribution is wider than that of any eagles or Tyrannosaurids. Its close relatives, the other large-bodied species in the Falco genus, like the Gyrfalcon, are a bit more geographically restricted, but they still contribute the dominance of large Falco species as a whole. They might not rule the land, but dinosaurs have taken over the skies.
What I find really interesting is that it wasn't even just one group of bird that survived. FOUR groups survived and exist today. The ancestor of ratites, waterfowl, landfowl, and then... well... the ancestor of every other bird. Ratites are things like ostriches and emus. Waterfowl are things like ducks and geese. Landfowl are things like chickens and turkeys. Every other bird is.. falcons, parrots, songbirds, hawks, vultures, etc etc. Anything that isn't in one of those other groups.
I can see why many suggest that the chicken(bird) is related to T-REX. I worked on a farm and in the hen house, should a mouse come inside there and get spotted by the birds, they attack it with a vengeance. Not ignore it, attack it and eat it. These were egg laying hens. Should a snake get into the chicken coop, it too was "gone for lunch." While getting eggs sometimes some get cracked so I smash them on the ground in the chicken coop and the chickens go for the yolk and the shell. When the birds are let out in the daytime as they could run around the yard in the orchard, there was not a bit of green grass to be seen as they eat the greens...as well as any other seeds I gave it like wheat, oats, etc. There were 40 orange trees in the orchard with bare dirt everywhere. At the house which was 100 feet away that had a 4 foot high fence which seemed to blind the chickens and they could not see the green lawn and vegetable garden behind it. So they kept within 75 feet of the chicken coop. There was 400 chickens. Best lawn mower you could ever have as it got rid of the green and the root and weeds at the same time. Also snakes, mice, bugs. The chicken was not afraid of any of it. I figure they would take on a wasp nest too(or never let it form) . Question: We originally thought that dinosaurs were reptilian, but are now thinking they may be warm blooded and feathered? Or do we have 3 distinct lines of dinosaurs? Avian & reptilian and fish like? As the water was a buffer zone, why did it not protect the fish dinosaurs as it seems they died out in that mass extinction time period?
Really liked the video, you did a great job of putting things in perspective what I think is the best and most interesting way to learn. Keep on keeping on!
You should do a video on plesiosaurus and how it eventually died out with other sea life. I've just stumbled onto your channel and I'm loving your videos it's so easy to follow along
Short answer, birds don't have tails that allow them to grow to such massive sizes that dinosaurs could achieve and it would take reptiles to long to recreate the evolutionary steps to become like dinosaurs again.
Another thing that contributed to the reptiles large size during that time. Is the fact that reptiles tend to not stop growing throughout their life as long as They have food they have the ability to grow.
I totally agree. Also, people misunderstand evolution. It is not dictated by the environment "causing" mutations in the DNA, but by random mutations either adapting to the environment or not. Meaning the environment doesn't "force lifeforms to evolve", but instead forces them to either evolve or die. In other words, dinosaurs could have taken over the world again, and didn't for pure chance. If random mutations had ocurred on birds, or other equally random mutations hadn't ocurred on small mammals, birds would be ruling the world and not us.
This is a refreshing and entertaining channel. It's nice to find some one who can inform and educate without inducing sleep. Humor too, a very good combination. Sign me up...
There is a theory that, had they not been wiped out by the asteroid, some species of dinosaurs, such as raptors, would have eventually evolved to the point of achieving civilization. They had many of the necessary ingredients: Increasing brain size, dexterous hands, appropriate size, and potential ability to work in groups. The big flightless birds that evolved after the asteroid, however, do not seem to have had this ability, primarily because they had wings instead of dexterous hands. By the way, some types of marine mammals, such as dolphins, orcas, some types of whales such as sperm whales, have the brain capacity to develop civilization. But they don’t have some of the necessary ingredients, such as dexterous hands.
Loving ❤ your content b/c you make everything easy to understand w/o rumbling on. My Question: New Zealand and alot of island nations have a pretty diverse wildlife unique to those island. What was the biodiversity in prehistoric time & the sort of dinosaur we would encounter
Some time ago, researchers found out why Gastornis grew so big and why it had such a big and strong beak. The reason for this giant fowl's massive size and all that muscle power is that Gastornis evolved to eat walnuts. So it needed its large size and muscles to crack the shell of the walnuts and eat them.
Size seems to be a factor to surviving, so it's possible what remaining fauna was not enough to support anything but the smallest appetites until plant life recovered over a period of years. The recover of fauna years after the Mt Saint Helens eruption turned the forested landscape into a moonscape is a good example of timelines.
