What Was Earth Like Before Dinosaurs?

when we think back millions of years ago long before recorded history we usually think about dinosaurs right those big boys are cool sure but life on Earth actually existed for billions of years before the first dinosaur chaa onto the scene though it was very different to what you might imagine so come with me on a wild Journey from Earth's very first days all the way through to the dawn of the Dinosaurs [Music] as with most things it's a good idea to start at the start around 4.6 billion years ago dust and gas left over from

the sun's formation bunched together to create colossal space rocks hundreds of miles across I'm massively simplifying but these collided with one another over and over and eventually fused to create create the Earth though certainly not an earth recognizable to you or me no this Earth was a hellish molten world of superheated lava radioactivity and regular asteroid impacts and that was it for a long long time it wouldn't be until almost a billion years later around 3.7 billion years ago that things would get interesting by this time our planet had cooled significantly and was near modern

temperatures that doesn't mean it was hospitable though largely composed of water with the atmosphere mostly devoid of oxygen it was an empty world of tumultuous seas and Rocky Crags the only noise you'd have heard was the ceaseless crash of the tide colliding with the shore that and the occasional volcanic eruption yesh creepy yet deep within the Waters of this spooky Place something nothing amazing and utterly perplexing happened life was born we're not exactly sure how but a miraculous blend of the right processes and ingredients in Earth's oceans led to extremely simple single celled organisms emerging

and some of these organisms produced oxygen for billions of years our single celled friends were free to lay around absorbing nutrients and expelling their own byproduct what a life but ever so slowly they began to change and grow more complex this would finally come to a head at the start of the Cambrian Period some 538 million years ago before the Cambrian the earth's land mass had formed one superc continent called rodinia as the Cambrian began however this would split into several smaller land masses the biggest of which was gond in the Southeast but that's not

the exciting part allow me to introduce you to the Cambrian explosion the most incredible biodiversification event in the history of our blue planet now when I say explosion I don't mean a big fiery bang no this explosion was more metaphorical to describe the sheer number of new creatures that burst onto the scene single cells were so last Millennia now complex life was in Vogue most of the basic body forms we see today first appeared at this time and relatives of crustaceans mollusks starfish and worms developed beneath the waves now don't get me wrong this explosion

still took place over tens of millions of years but considering the lackluster evolution in the billions of years before this was a Monumental event scientists still argue over the cause of the Cambrian explosion remember I said some of those original simple organisms started producing oxygen though well one theory is they rapidly multiplied increasing oxygen levels substantially and allowing for new more intricate life forms to emerge these preed on lesser life forms and kickstarted The evolutionary arms race that would go on to define the development of life on Earth forever more regardless of how it happened

the Earth was now perfect for these new breeds of life the average temperature was much warmer than it had been with Waters likely to have been around 110° F this alongside extra oxygen and carbon dioxide gave life the opportunity to level up and level up it did if you want to level up your knowledge why not drop a like And subscribe come on you don't want to miss out on more awesome videos like this one do you all finished nice one now where were we ah yes the Cambrian Period eyes limbs mouths exoskeletons shells these

adaptations all started around this time though many of the animals that sported the upgrades were still completely alien looking take trilobites these creepy looking shelled arthropods could suddenly be found all over the ocean munching on Plankton Scavenging on scraps and hunting other animals you might recognize them from the abundance of fossils that still remain today indeed trilobites were some of the most successful animals to ever live thriving for hundreds of millions of years but they weren't the only things that appeared during the Cambrian the very first fish would also show up they started out as

slimy jawless eel looking things crucially this marked the moment the first true vertebrates evolved not that they were exactly impressive in the beginning yonan Zan was a weird worm looking guy that possessed a backbone despite looking utterly spineless other animals of the Cambrian were even weirder like the utterly freakish Opa binia a bottom feeder that looks like it was designed by a child or me after a few beers it had used that long beaky thing to pick up tiny prey items and place them directly into its mouth something I wish I had for getting into

Pringles cans but with predator and prey Dynamics becoming firmly established one animal needed to stand or swim above the rest this is a namol loaris meaning abnormal shrimp and it was the top predator of the day a little over a foot long which is huge for that time this nightmare prawn patrolled the oceans devouring soft-bodied animals like worms now with such a Peerless predator on the prowl animals were forced to adapt even more to survive the evolutionary arms race had just been kicked up in notch or at least it should have been see around 485

million years ago just when it looked like everything was coming together and life was steadily advancing disaster struck it's still a mystery as to why but it seems that a dramatic drop in oxygen levels probably caused by volcanic activity led to a mass extinction event damn not everything was wiped out some creatures like our old Pals the trilobites carried on thriving but the event was undoubtedly apocalyptic in scale the Cambrian Period was officially over and the Ovis period was about to begin the Ovis has been largely defined by the great Ovis biodiversification event AKA The

Go you see over the course of some 30 million years continents shifted sea levels fell and oxygen levels in the ocean increased again the shifted continents created new islands which birthed segregated habitats for the freshly oxygenated Waters around them habitats that were ripe for conquering and life was up for the challenge prototype fish continued to evolve into increasingly more fishlike shapes though they still had a long way to go before they'd become anything like Nemo elsewhere more nightmarish beasties were emerging meet the IDS or sea scorpions anybody else get a chill when hearing that these

predatory arthropods weren't actually scorpions but are colloquially referred to as such why because of their long spiked Tails grabby Claws and the fact that they're horrifying seriously the earliest pentecopterus could reach pant weding lengths of over 5 and 1/2 ft add these to the list of things I'm glad are long dead as scary as they were though they weren't top of the food chain that honor goes to Camaros seras a predatory spilop pod related to Modern octopuses and squids Camaros seras could reach a terrifying 23 ft in length shell included and would scour The Depths

for arthropods like sea scorpions to snack on yep Cameros s's sharp beak was more than strong enough to Crunch through hard exoskeletons and shells making it Top Dog in a world filled with armored or derves but fauna wasn't the only thing that was changing Flora was about to take over the world primitive algae had existed in the Seas since the Cambrian but it was nothing to write home about that is until the oriv VIS kicked things up a notch algae evolved and spread onto dry land for the very first time as Moss well sort of

dry land these Earth early migrators lacked roots and other specialized parts needed to retain water without help so they dwell on the edges of water bodies where it was damp despite such humble beginnings though this was the start of Nature's conquest of land not least because plants began absorbing carbon dioxide from the atmosphere and releasing oxygen into it a journey that would one day lead to the creation of Denny's the Ovis period came to an end around 443 million years ago with another mass extinction this time caused by an Ice Age no not that one

there's actually been a fair few of them throughout our planet's history each one has been utterly devastating and this was no exception beginning 460 million years ago and persisting for the next 40 million years glaciers enveloped the southern hemisphere cooling the entire world and crippling marine animal population worldwide though all the main animal groups survived their numbers were drastically reduced and many major species like Camaros sas's didn't make it at all in fact some 85% of all marine animal species were wiped from existence jeez interestingly some scientists blame This calamity on the success of the

new land dwelling plants they claimed the Moss absorbed so much carbon dioxide from the atmosphere that it had a cooling effect on the planet eventually causing the full-blown Ice Age however it happened one thing is for sure the Ovis was over and the saluan had just begun 40 million long years after it formed the ice finally dissipated as CO2 returned to the atmosphere the melting ice caused sea levels to rise and the climate eventually stabilized allowing life to expand again and with the Camero is gone sea scorpions were free to rise to the coveted rank

of apex predator thriving more than ever before they Diversified and got even scarier the carinosa an unusually massive urup terid grew to over 7 ft in length jeez fish too continued to adapt the first piie scene with movable jaw action made its appearance in the saluran period boy now we're getting somewhere oh and the very first coral reefs emerged as well these formed important parts of diverse new ecoystems and played host to the Hardy trilobites and other creatures meanwhile the terrestrial planet life that may or may not have just wiped out most other life on

the planet was going from strength to strength plants on land began to take on far more complex recognizable forms and evolved into mascular stemmed organisms that could absorb and retain water self-sufficiently these plants would form the basis for all modern flora and with them came the next wave of oxygenation for the Earth's atmosphere this time rather than plunging the world into an Ice Age quite the opposite happened the additional oxygen proved enough to support animal life on land arthropods began to crawl out of the oceans with the very first groups probably being mopod mods like

centipedes and millipedes and arachnids like scorpions these creepy crawlies may have initially only left the water to avoid Predators or access new food sources but the prospect of a whole new environment to conquer proved too good to pass up see life was super competitive in the ocean the land however was a new unconquered playground of opportunities not that every species that ventured out immediately lost their gills and learned to there saluan scorpions still had gills even after moving on to land and had to keep them moist to function so they wouldn't have strayed too far

from the water's edge at least not at first the saluan period met its end around 419 million years ago with some relatively minor Extinction events probably caused by the changing climate I say relatively minor because unlike others they didn't bring the entire of life on Earth to its knees and threatened to make the planet totally lifeless again they weren't exactly fun though regardless the devonian period is what followed and it would prove the most influential period of life since the Cambrian for a start the earliest known sharks evolved though they were far from the top

predators we know today in fact they were completely overshadowed by a group of bony fish called placoderms like this absolute Beast Dunley oeus old Dunley was the apex predator of the day at its smallest estimate it was a little shorter than a male great white shark that's three times the size of an adult human but at its biggest it was equal to several great whites put together at an astronomic 26 ft without a doubt this was the biggest species alive at the time and one of the most intimidating fish to have ever lived its colossal

head housed guillotin like teeth and experts reckon it had a stronger bite than a saltwater crocodile for context saltwater crocs have the most powerful bite of any living creature but dun closius had more than double that I mean just look at that jaw fish weren't the only thing getting super sized either on land plants started bulking too the culmination of all prior evolution the first wooded trees sprang up with complex root systems branches and height they formed the original forests which produced a whole load more oxygen for the atmosphere while absorbing huge amounts of carbon

dioxide all this meant the terrestrial ecosystem became even more inviting for new life and so finally the vertebrates took notice see certain species of fish like lung fish had been spending more and more time in Shallow Waters and some had even flopped onto land for brief periods but in the devonian everything changed they evolved the most interesting representation of this is Tick talik the earliest known vertebrates that could breathe out of the water this freaky looking fella had the characteristics of fish amphibians and reptiles a bizarre Middle Ground between the worlds of land and sea

while it still lived mostly under water it was capable of clamoring onto land when needed and then we have the ichio stegga the first of the tetrapods animals with four fully fledged limbs like us though they too spent most of their time in the water the world would never be the same again meanwhile the arthropods that were living on land already started to diversify wingless insects and spiders developed and spread for those creatures still confined to the Seas though things were about to get a whole lot worse as the devonian period neared its end oxygen

levels in the oceans began to decline harshly without oxygen to keep them alive immense swaths of marine creatures died out the long lasting trilobites and sea scorpions were decimated and although some survived their populations would never recover dominant species like the the duncle OAS on the other hand were completely eradicated and up to 70% of all invertebrate species died out we aren't entirely sure what caused the sudden drop in oxygen but scientists reckon it probably involved trees huh now hear me out trees in this era reached up to 130 ft tall so needed deep root

systems to support them but Roots don't just anchor plants and absorb nutrients they also affect the Earth around them altering rocks and creating nutrient-rich soil the problem this soil covered the planet so thinly that much of it washed off into rivers and oceans taking all its nutrients with it this fueled a series of huge algae blooms in the water and as all this new algae photosynthesized it removed oxygen from the water not good for anything living in there man who knew that plants could be resp responsible for so many deaths I'd keep an eye on

your succulent if I were you and while life underwater was devastated however the land dwellers continued to thrive marking a palpable shift in the balance of power the era that came next the Carboniferous showcased the sheer dominance that life on land had cultivated starting 359 million years ago the Carboniferous period saw terrestrial plant life flourish and multiply even more forming vast jungles and murky swamplands that covered most of the planet this incredible amount of foliage caused the oxygen in the atmosphere to reach levels completely unheard of before or since and it had some crazy effects

on the animals of the day remember the arthropods that first invaded the land back in the saluan well by now they'd had a very long time to evolve and adapt and they were every everywhere when oxygen in the air skyrocketed they were given their latest upgrade see arthropods take in oxygen through small holes in their body with more oxygen up for grabs and huge amounts of available food in the form of these new plants they grew absolutely enormous take the arthr plura a millipede the size of a car seriously this thing could have reached a

terrifying 8 and 1/2 ft long fortunately for any smaller Critters around at the time millipedes have always been vegetarians wooo not that many creatures were exactly small even among those with wings the aptly named megaera was one of the largest flying insects to ever live with a Wings span of 2 and 1/2 ft that's about the same size as an American crow the tetr pods also exploded in diversity both on land and in the water the early amphibian Diplo Callis evolved in this era and was a complete weirdo this 3ot long freak sported a strange

Boomerang shaped head that experts suggest could have helped it to glide through the water or deter Predators it'd be hard for anything to swallow this guy but it was outside of the water that the tetrapods made the next giant leap see no matter how much time they'd been spending on land they were still forced to return to the water to give birth that was until an incredible evolutionary adaptation changed everything terrestrial tetr pods started laying eggs with hard shells these fancy new eggs were able to keep amniotic fluid inside their walls negating the need to

be laid directly in water and the shells also protected the young inside from predators with that tetr pods would uncouple themselves from Life in the water for the first time ever these were the very first amniotes the ancestors of most modern land animals plus were only a few hundred million years out from the first omelet it's pretty lucky that the tetrapods developed this amazing adaptation when they did because the end of the Carboniferous period would change the planet entirely again see Earth's various land masses have been gradually shifting over the preceding millions of years until

around 335 million years ago go they all collided together and formed one super continent Pangia but what exactly did this mean for life on Earth well the Lush rainforests that covered the planet suddenly found themselves struggling they became fragmented and Scattered and the formation of the supercontinent meant that trees that once had access to copious water now found themselves Inland and quickly dried up this destroyed habitats and consequently lowered the incredible oxygen levels in the atmosphere coupled this with dropping temperatures and a wave of oncoming glaciation and the rainforests were done for the formation of

Pangia had started a domino effect that brought the Carboniferous period crashing down around 299 million years ago in its wake was a much drier less forested World largely unrecognizable from what had come before many species went extinct due to this massive climate change including the giant arthropods who relied on lots of oxygen but the amniotes stayed strong with no need to return to water to reproduce and a scaly body to prevent water loss the stage was set for them to take over the world split into synapsids the group that would become mammals and ssids the

group that would evolve into reptiles and birds it was all coming together the next era the perian began with a rise in temperature the glaciers that had formed at the end of the previous period slowly melted away with the most Inland areas becoming dry deserts and the supercontinent would only get hotter as the period went on life was difficult so the animals that thrived were the ones capable of conserving water most effectively those synapsids and ssids I mentioned earlier had Diversified and spread across Pangia becoming the dominant land animals but it was these synapses that

truly ruled the perian they were slowly but surely evolving and becoming more like mammals demetron was one such creature a big mean boy probably the most iconic animal of the time this thing was so menacing that it's often misconstrued as a dinosaur in reality it's more closely related to you and me it was the top predator of the early peran reaching intimidating lengths of 15 ft it'd be tough not to be top dog when you're as big as an SUV consensus is still split on what that big old sale was used for some scientists say

it helped regulate body temperature While others believe it was used to attract potential mates personally I think it was a handy place to hang Christmas decorations despite enjoying great success dimetrodon did eventually die out though after its 16 15 million year tenure taking the crown as the middle to late perian Apex PR was another group of synapsids the gorgonopsians no they're not Star Trek villains these ugly mugs weren't as big as dimetrodon the largest species Ino strand CIA came in at only 11 ft long but they were deadly gorgonopsians had a mouth filled with 6in

long saber likee canines probably used to Shear the skin off their prey that's freaking terrifying and they'd have turned these teeth on animals like the lumbering sarup said scutosaurus Slow armored herbivores that had to walk for miles to hunt down scant vegetation but enough of the lame scutosaurus the perian era also gave birth to the greatest animal to ever live you ready okay let me introduce you to the Cody linkis damn just look at his tiny little head no neck at all on that lad what an adorable little plant munching freak but don't get to

attached to him remember when I said that the perian would only get hotter I meant it over the course of a million years a series of extensive volcanic eruptions began to tear through what is now Siberia these eruptions spread unbelievable amounts of burning hot lava across the planet I'm talking giant Lava Beds half the size of of the United States all spewing colossal amounts of carbon dioxide into the atmosphere all this CO2 trapped heat within the ozone layer raising the Earth's temperature dramatically and forcing animals to adapt or die marine animals fared no better than

those on land the ocean absorbed some of the carbon dioxide making the water dangerously acidic then the hotter temperatures ignited wildfires on land that burned down what foliage remained incinerating forests and exposing previously hidden rocks these quickly eroded and the nutrients Left Behind ran off into the ocean unwittingly causing an explosion of Life a awesome I was getting worried so things all turned around right well no actually the overwhelming number of new life forms turned out to be less a blessing and more of a curse they absorbed what little oxy remained in the sea suffocating

any creatures that had survived the initial Onslaught oh man by the end of the peran around 251 million years ago this apocalyptic event had reached a fever pitch since termed the great dying it was the single most devastating mass extinction the world has ever seen and the closest life has ever come to disappearing entirely a shocking 70% of land animals and 90% % of sea creatures were wiped from the face of the Earth yikes the tiny number of beasties that survived these end times were left with a husk of a world all the periods of

prehistory we've covered so far were grouped into an overarching era known as the Paleozoic meaning ancient life with the great dying it wasn't just the perian that ended but the entire Paleozoic with it that's a nearly 300 milliony year span but history didn't just end oh no life went on the Mesozoic was here the era that would eventually Herald the arrival of the dinosaurs but not quite yet the Mesozoic Era began far more humbly with the Triassic period the first 5 million years of which life spent slowly recovering to the point new dominant species would

emerge again this new world was a supreme difficult place to live and the few species that stood a chance would need to be pretty darn resilient most of the synapsids sadly didn't have what it takes they were utterly devastated by the great dying and though a handful did survive to eventually evolve into modern mammals they'd take a backseat for a long time the sarup SIDS on the other hand well they were perfectly suited given their ability to survive away from water due to their hard shelled eggs and retain moisture with those scales they not only

recovered they utterly dominated the planet indeed the Triassic saw sarup SIDS diversify and evolve at a rapid rate never seen before some took to the empty oceans evolving into the very first marine reptiles like iosaur bizarre and terrifying fish-like beasts that hunted using some of the largest eyes in the animal kingdom alongside them the plesiosaurs would eventually Patrol the Seas too these equally bizarre creatures had monumentally long necks that could have helped them hunt more stealthily both marine reptiles would Thrive for hundreds of millions of years other creatures like the strange drepanosaurus evolved to live

in trees possibly acting similarly to Modern lemur and sloths and hanging from their tails like an i i draan aurus had a super long claw for poking around inside insect nests attached to tree branches so yes this thing was essentially a monkey lizard but trees weren't the final frontier for these newly evolved reptiles oh no some began to evolve flight to start with this took the form of some weird experiments like the Sher of opter unlike pretty much every flying animal we know of this little reptile had wings on its high H limbs instead of

on its front because of this it couldn't actually fly instead it was only capable of a sort of clumsy Glide unsurprisingly this design didn't carry through to modern day by the tail end of the Triassic however this evolutionary trait had been perfected with theasaurus hollow air-filled bones meant these skybound reptiles were light enough to sustain flight and their wings ran all the way down from their forearms across the length of their bodies to their ankles in other words these babies put sherov opter to shame but now we've covered the Sea and the sky let's get

into the meat and potatoes what was happening back on dry land well with the once dominant synapsids largely extinct the ssids there had evolved into a new subclass known as archosaurs to take their place and they were super successful you see archosaurs had a very efficient respiratory system that allowed them to survive in harsher conditions oxygen was probably in limited Supply during the Triassic due to the sheer amount of CO2 in the atmosphere after the great dying so this superb respiratory system allowed arkosaurus to excel where other species couldn't but that's still not all archosaurs

also made rapid progress toward upright limbs it might seem like a stupid thing to get excited about but it granted them a big Advantage see tetr pods with limbs that stretch outward like modern lizards move by flexing their bodies sideways this shunts stale air from lung to lung rather than expelling it to make room for fresh air making it impossible for them to breathe and walk at the same time but with upright limbs not a problem archosaurs had it covered one particularly formidable member of the group was the horrifying postos sucus a 15-t monster that

ruled as apex predator this fanged fiend resembled a cross between a T-Rex and a crocodile a terrifying combo that nobody needed least of all the poor creatures it would prey on which was pretty much everything experts reckon postas suus stocked its prey on all fours but when close enough could have risen up on its high legs to bite their neck or spine thanks Eggheads you made this thing even creepier in fact it was so fearsome that when dinosaurs did finally come into The Fray postas suus firmly held its own wait what was that I just

said dinosaurs oh yes archosaurs took over the world all right but in the middle of the Triassic there was one more advancement that turned the planet on its head there in the wastes appeared some seemingly unremarkable breeds of archosaur unremarkable however they were not these were the very first dinosaurs with all the advantages of their Brethren as well as an incredibly fast breeding rate they were set up to conquer the globe and Usher in a new age but that's for a different video right yeses that was a whole lot of history what did you find

the most interesting and do you want to follow followup video if so let me know in the comments below and I'll see you next time thanks for watching [Music]