A Journey Back to the Beginning of Times

the history of our planet started over four and a half billion years ago most of this time there were all sorts of diverse living organisms around the earth's biosphere has come a long way struggling for survival and its history is marked with both periods of vigorous evolution and disastrous extinction events in spite of all ordeals life has not been wiped off the face of the earth quite on the contrary it became a separate factor capable of changing what the planet is like today we invite you to join us on a fantastic journey to the past and see the most crucial milestones in the paleontological history of our earth as well as watch with our own eyes the creatures that used to roam it first we'll go as far back as the archaean the earliest prehistoric eon when living organisms were around we will find out what kind of creatures lived on our planet in those mysterious times then we'll try to understand when and why life left water so hospitable and safe and ventured onto land so forbidding and unwelcoming after that we will see some of the most notable creatures from the times of the dinosaurs and also those who were to succeed them at the end of our journey we will take a look at the most tragic moments in the history of the biosphere on earth which nearly left our planet a barren desert let's get ready and we begin [Music] cosmo the first in outer space giant monsters may have died out on earth but talaria is still languishing under their oppression in the new online strategy game raid shadow legends you will answer arbiter's call and defend the world get your team together and work out a foolproof strategy by carefully selecting heroes according to their special skills for example belinor one of the high elves is pretty strong in a one-to-one combat which makes him indispensable in tackling the strong bosses and del deskarg steals enemy champions buffs so he will come in handy in pvp battles form alliances with other players to beat the mighty bosses and get some cool bonuses the game is continuously updated and so new bosses are created and also you can take part in events to acquire new champs in the latest update for example you get to fight a new hydra rotation follow the link in the description and enjoy a great starting bonus the epic hero tyrell and a whole set of in-game boosters join the battle in raid shadow legends actually our earth has been not the friendliest of places for the greater part of its existence let's cast our mind back to the archaean eon the earliest time when life was known to be around it began four billion years ago and continued for approximately one and a half billion years the early earth had just gone through the second heavy bombardment several thousand tons of rocky debris from the formation of the solar system was hurled to the planet smashing the thin basalt crust that had just formed on the surface of moat and magma even after this ordeal the young earth cooled off again and gained its first lithosphere just a billion years later it became home to the very first living organisms the earth of that period had a comparatively smooth surface tectonic plates that is rocky bodies that create high mountain ridges on collision were simply non-existent at that early time there was no diversity in rocks on the early earth either banks of wars and rocks were in the first stages of formation most of the earth's crust was made up of basalt a rock formed from magma and in essence it is solid lava there was almost no oxygen in the atmosphere in the archaean the concentration of nitrogen was considerably smaller than it is now the earth was shrouded in a dense mixture of water vapor and carbon dioxide with a high percentage of oxides of sulfur phosphorus and other active chemical elements the sun was much dimmer then than it is now according to some estimates its luminosity was even 30 percent less than that of today that is why our planet was quite a murky place the moon still used to find itself in close proximity to it so a day lasted just around 10 hours as for tidal waves they reached up from several dozen to 300 meters as the earth gradually cooled off water in the atmosphere condensed and poured down in torrential rains at first it accumulated in small bodies of water in lowlands this water was sour salty and extremely hot up to a boiling point in some places its composition resembled that of today's geezers paradoxically this seemingly harsh environment proved to be the cradle for primitive life forms that originated and evolved there it goes without saying that first organisms were anaerobic instead of breathing oxygen as we do which was non-existent in the atmosphere at the time first living organisms relied on other sources of energy archaean organisms were not yet able to swim in order to survive they needed a substrate that is why the biosphere of the time was a thin slimy film of not more than a millimeter in width on the bottom of a sour and hot ocean in its coastal area the maximal depth the biosphere reached down was up to 20 meters as the dense atmosphere did not allow sun rays to penetrate deeper the mouths of underwater volcanoes offered habitats to bacteria that were chemotrophs these bacteria didn't need light and fed on other energy sources relying on chemical reactions between sulfur compounds and iron the earth was cooling off sea levels rose the atmosphere became more rarefied and the sun gradually grew in size the coastal area favorable for life was also gradually expanding and by the end of the archaean eon the biosphere was confined to a thin stripe along the coasts and also oasis as it were on the sea bottom near active volcanoes meanwhile all the land rivers and most of the open ocean were still completely devoid of life if an explorer were to visit the earth of that period stromatolites would be the only evidence of life seen with the naked eye these sedimentary limestone formations were created by primordial microorganisms and may reach up to several meters in height there was another problem in that age the amounts of reagents were insufficient and that greatly impeded the evolution of life evolution hadn't yet produced scavenges organisms feeding on dead flesh thus under the influence of gravity and sea currents dead creatures accumulated in cavities on the sea floor hundreds of millions of years later these accumulations were processed by nature into what is now oil fields around three and a half billion years ago there are emerged creatures that were to change the earth beyond recognition some bacteria got the hang of photosynthesis involving oxygen production a billion years later on the border between the archaean and the proterozoic eons their revolution brought about the most global extinction in the history of the planet it is known as the oxygen catastrophe to name but one term i have spoken in more detail about it in an earlier video it is hardly possible to estimate the scale of that event as an overwhelming majority of the creatures didn't get preserved as fossils practically all the diversity of anaerobic life forms that had taken a billion years to evolve vanished off the face of the earth the ancient earth's atmosphere was exceptionally rich in methane as strong greenhouse gas it robustly oxidizes producing carbon dioxide and water during the process with methane's concentration in the atmosphere dropping the temperature on the planet decreased as well as a result of this process there occurred the huronian glaciation the most large-scale ice age in the history of the earth which started 2.4 billion years ago and continued for as long as 300 million years digging is revealed that in some areas ice caps reached as far as the equator with the planet almost totally transformed into a ball of ice it took the earth one and a half billion years to go all the way from boasting boiling lava fields to endless icy deserts the proterozoic eon lasted from two and a half billion years to 440 million years ago life persevered in spite of the cold and evolution although thwarted carried on nevertheless land remained lifeless living organisms concentrated in the coastal area near the equator and what was happening on the continents even though they weren't crawling with life yet land was experiencing something different and interesting in its own way alongside the continents banks of metal oars and new rocks were being formed in the proterozoic eon areas of dry land alternately assumed different aspects and were endless glaciers and stone deserts at one time or another it is hard to imagine but just a measly 500 million years ago the greater part of our planet appeared quite like a martian desert luckily for all the dwellers of our planet the sun was growing brighter and warmer eventually the ice gave in 542 million years ago there began the phanerozoic eon which is the greek for the eon of visible life it was peculiar for periods of active evolution of different species interlaced with mass extinctions at the beginning of the paleozoic era the greater part of land formed a giant supercontinent named gondwana located in the southern hemisphere it had elaborate terrain and covered over a hundred million square kilometers it was comprised of today's africa south america antarctica australia the indian peninsula and some other areas the smaller continents of the day lorentia baltica and siberia were situated near the equator apart from all that there was a great number of smaller islands still up until the silurian period which started approximately 444 million years ago there weren't any life forms to speak of on all these expanses only some simple mosses and lichens were slowly establishing their dominance on land it was only at the beginning of the silurian period that first plants emerged in tidal areas and near rivers and only in the tropical zone of that even in spite of the fact that sea species and plants became more diverse marine life forms still concentrated near the coasts the area populated incrementally expanded just to give you an example the depth of the ocean at which photosynthesis was able to take place in the devonian was just 50 meters which is 10 times as little as it is now in the same period which began 420 million years ago and continued until 358 million years ago the first decomposers emerged organisms decomposing dead flesh as a result their emerged organisms feeding on products of decomposition for example alongside scavenging bacteria there could be found sea sponges at depths of up to 500 meters the next period was the carboniferous period it continued from 358 to 219 million years ago by the time it began the greater part of the tropical zone was covered with tree ferns dense tropical forests did not grow as a mass there were no organisms back then that would help wood decompose that is why bulky trunks of trees didn't trot when they died and didn't pass any nutrients to their descendants they remained lying without decaying and the phosphorus in their bodies so vital for plants couldn't be extracted thus with time lush sapi verger gave way to enormous heaps of dead wood covering enormous stretches of land later they formed rich deposits of coal which is still widely used by mankind in various industries in areas other than the tropics only fungi mosses and lichens could be found they were not able to harden the upper layer of the earth by their roots and as a result rain easily washed it off with rivers turning into muddy streams and lakes becoming putrid swamps dry areas became lifeless deserts it was a time when fishes were vigorously evolving in the seas and rivers although life hadn't yet ventured out into the open ocean algae hadn't learned to float yet and so life was still confined to coastal areas the carboniferous period was followed by the permian period it began 299 and finished 252 million years ago the first amphibians dared to start exploring land and plants spread to conquer subtropics the sea remained populated only in shallow waters close to the coasts the permian period finished with the most massive extinction event in the history of multicellular life according to some estimates up to 96 of marine species and 73 of land species died out it is still not known what caused such a global mortality the triassic period of the mesozoic era promptly made up for the lost time bringing life to a new level during the process for the first time in history of the earth temperate latitudes could boast some woods another revolutionary event took place in the sea where blue green algae emerged a type resembling their today's descendants it was not vital for them to live in a substrate anymore and so photosynthetic microorganisms quickly spread across the upper layer of the global ocean tempted by the food fishes mollusks and arthropods followed it organic leftovers settled on the sea bottom thus sea bottom dwellers were amply supplied with food as well the global ocean was assuming an aspect close to today's the mesozoic era lasted from 250 to 66 million years ago it is subdivided into three periods the triassic the jurassic and the cretaceous this is when dinosaurs thrived admittedly the most well-known prehistoric creatures that became subject of feature and science fiction movies the way these ages are depicted we might get the idea that the earth was covered with tropical forests from the poles to the equator in fact it is completely wrong indeed forests reached northern latitudes but only because the average temperature on the planet was much higher than it is now meanwhile equatorial areas on the contrary suffered droughts with the forests rapidly spreading across the entire earth's surface there were still lots of swamps and deserts around the latters were not only scorching hot and dry as we're used to picturing them but also moderate cool and even humid with no herbaceous plants around soils could not attach themselves to rocky slopes only lichens are able to grow on barren rocks flowering plants became abundant only by the middle of the cretaceous period that is around a hundred million years ago interestingly the first varieties were trees and by the end of the period there emerged plants similar to today's herbs compared to a mighty oak or a giant sequoia regular grass appears insignificant but it is capable of something tree giants aren't by mingling their tiny roots on the ground they help form and strengthen the turf this not only makes soil tougher and prevents it from getting washed off or eroding but also takes care of getting rid of excess water by letting it evaporate and accumulating water when there is a lack of it on emerging herbaceous plants turned deserts into steps prairies and savannas swamps into flood meadows and permafrost areas into tundra and tundra step by the time the cretaceous period was coming to its end the earth had started to resemble the earth of today it was lacking just one important touch mammals this type of animals had been around for a long while but the creatures were not very widespread until the end of the mesozoic era it is still not clear what caused dinosaurs to become extinct a giant meteorite global cooling and other suggestions are listed among the supposed culprits either way these giant saurians vanished thus vacating a special niche for mammals it took them 66 million years to evolve from tiny marsupials into majestic whales dangerous tigers tough camels and amusing bats eventually evolution produced a unique species the only living creature capable of not only adapting to nature but also changing it the being that extracts coal formed of all those dead trees from millions of years ago to warm up one's dwelling the creature exterminating other species for money of a sport the creature turning vast areas into wasteland in pursuit of selfish motives this is homo sapiens or the human life on our planet originated in water this assumption forms the basis of the biogenesis theory today and is practically beyond any doubt in the scientific community it is water in its liquid state that offers the best conditions for life to originate and evolve in however if we were to cast our gaze around we would see various organisms not only in oceans and rivers but also on the planet's surface in the soil in the lower strata of the atmosphere and even in the mouths of volcanoes when and why did life break away from the hospitable ocean and move on to exploring forbidding barren land let's try to get to the bottom of it up until the late proterozoic eon all life on the earth was to be found only in oceans throughout that prehistoric period land on the surface of the planet would alternately be covered first by giant ice caps then by barren lifeless expanses similar to martian landscapes and back again ediacaran the last period in the proterozoic started approximately 635 million years ago and persisted for 94 million years the earth of the time was far from being the most hospitable place if today's human were to experience the environment of that period he or she would very soon pass out due to asphyxiation as oxygen concentration in the air was twice as low back then as it is now landscapes of the diachron period were endless deserts and rocky mountains devoid of any signs of life meanwhile the coastal area of the ocean was crawling with highly unusual creatures not even remotely resembling any of today they were mainly soft-bodied and non-motile that is they couldn't move around and fed of nutritious particles in water these organisms supposedly didn't have either muscles or a developed nervous system or a hard carapace with practically no predators around all these things were by the long and the short of it not yet called for predators emerged at the very end of the ediacaran period at once establishing their dominance in the prehistoric ocean active hunting proved to be a highly effective survival strategy as the soft-bodied non-motile dwellers of the ocean's bottom unable to either escape from the enemy or put up a decent fight or even hide were easy prey in a way the ocean was an endless smorgasbord for first predators full of nutritious food right there for the taking it is hardly surprising that most prehistoric creatures making up the menu didn't last long others had to adapt to deal with the new dangers [Music] approximately 542 million years ago there began a period that was to greatly contribute to changing what our planet was like geological layers of that time are filled with fossils that used to be highly organized living creatures these vines give grounds to suppose that the prehistoric ocean used to be teeming with creatures sporting an impressive outer skeleton or carapace referred to as the cambrian explosion the process heralded a new breakthrough in the history of evolution of life on our planet and the beginning of the phanerozoic eon or the eon of visible life the first period of the phanerozoic eon is called cambrian it started 542 million years ago and continued for about 56 million years trilobites are the most well-known and widespread creatures of the time although these creepy things are not the only ones the cambrian is notable for this was the period when the prey predator system was finally established it goes without saying that in the millions of years that followed natural conditions would interfere with the established food chains with some species dying out and others riding high but the principle stayed predation became a potent incentive for evolution which forced organisms to change in order to be able to deal with new threats as well as to explore new areas so far inaccessible to predators [Music] the cambrian explosion produced a great many completely new forms of organization of living organisms many of them didn't prove to be viable and eventually vanished off the face of the earth others on the other hand brought about a great diversity of new species for example approximately five hundred fifty five hundred thirty million years ago tiny bottom dwellers resembling mollusks known as haiku wellers developed a sturdy notochord going through the entire body these creatures are believed to be some of the most ancient ancestors of today's vertebrates picayas came a bit later these were not very large creatures either they looked like lancelets flatworms or primitive fish proud owners of a sturdy and flexible cord with muscles attached to it they were able to swim by wriggling their entire body in a series of s-shaped movements this manner of swimming proved to be quite effective and fast which allowed early chordates to survive and evolve into higher organized species admittedly almost all paleontological finds dating back to the cambrian are those of marine dwellers as the overwhelming majority of the living organisms of that period lived in the ocean some of these creatures we can see in fossil finds look highly peculiar and even horrifying anomalocaris for example was a giant shrimp measuring up to 60 centimeters in length it was also one of the apex predators in the cambrian period and even though other fines appear rather bleak in comparison they are proof of some really important phenomena among these the most ancient fossil finds of land soils can be mentioned they date back to around 530 million years ago which corresponds to the middle and late cambrian without any specific knowledge in the field one will fail to see anything special in these ordinary looking stones however these prints show that it was around this time that first primitive algae and microorganisms started to venture onto land later having thrived in their lifetime they died and decomposed thus forming a nutritious substrate for their descendants first colonies of microorganisms must have formed in humid and warm places on land in shallow waters for example or in the tidal zone of the ocean with plenty of water and light and with no animals around that would be keen on eating them young algae flourished successfully adapting to the new conditions single cell algae was soon joined by primitive fungi which were not able to synthesize nutrients on their own but could feed on what remained of dead weeds a hundred million years later the symbiosis of fungi and single cell algae produced lichens these undemanding things were to become tip of the spear in exploring great expanses of new territories the ordovician period which followed the cambrian began approximately 485 million years ago and continued for around 42 million years this is when marine life was actively evolving in the ocean mollusks and arthropods were thriving among the latter's euriptarids many of which dwell to the bottom to get around more conveniently these creatures used their jointed limbs this feature would later be an indispensable asset and an important factor in adaptation to life on land apart from these there evolved jawless animals similar to today's lump rays and a bit later their emerged cartilage fish meanwhile plants slowly but surely made their way inland and away from water first multicellular plants emerged which were clearly able to survive on land they left imprints of spores and vessels that delivered water to the upper parts of the plants animals on the other hand still didn't venture out of their regular environment although it is probable that some crustaceans did have a chance to explore coastal areas this period ended in the ordovician silurian extinction event its causes are still not clearly defined yet but according to the most popular theory it was brought about by global ice age and a fall in the level of the global ocean that followed be it as it may up to 50 percent of all the species vanished off the face of the earth as a result of the extinction however life was able to adapt to new conditions and even take it to a completely new level next in line was the silurian period which continued from 444 to 409 million years ago this was when giant arthropods dominated the ocean and it is then that one might come across a euryptorid measuring up to two and a half meters in length fishes also thrived among which large and swift predators over one meter long come to think of it it is hardly surprising that some living creatures preferred to leave the ocean and try to find other safer areas for their habitats and so this is when first arthropods came on shore these were prehistoric europeans and other crustaceans their tough chitinous carapace protected them from exposure to the sun and drying as well as kept their body in shape their small legs allowed them to move around on hard surfaces when out of water it is reasonable to suppose that first arthropods that ventured on land made a point of not getting too far from water their respiratory organs had to remain moist in order to function correctly however the arthropods were greatly tempted by the abundance of plant food that was therefore the taking just beside the sea the safety factor guaranteed by land was another attraction as predators hadn't yet learned to chase their prey if the latter escaped to land gradually these explorers fully adapted to the new conditions and came onto land for good which later made for an incredible diversity of species among insects and spiders as well as other classes of living creatures approximately 419 million years ago the devonian period began which was the most important one in terms of land exploration it lasted for around 60 million years this is when rhinophytes spread all over the planet prehistoric vascular plants and ancestors of mosses and ferns reaching three meters in height they densely covered all humid and warm places of the planet mainly coastal areas of seas and the deltas of rivers flowing into them however neither rhinophytes nor mosses and lichens that emerged later had a proper root system instead of a network of roots that would keep a plant firmly in place they are just primitive root stocks at best that is why soils would quickly get washed into rivers and turn them into muddy streams and their deltas into swamps in these humid places rich in organic matter plants were flourishing giving food to insects and other inhabitants of the earth of that time fish in their turn were attracted to marshy areas by the abundance of insects and their larvae eventually great amounts of putrefying organic matter absorbed oxygen from the water in swamps which affected the breathing of the creatures living there that is why to compensate for the lack of oxygen fish in those waters learned to take gulps of atmospheric air gradually they developed a breathing sac allowing them to survive outside their aquatic habitat simultaneously other appendages were developing thick stalks and trunks of plants growing in marshes offered to fish reliable shelter from larger predators however it was hard for them to make their way through these thickets thin fins were not adequate for the purpose more powerful and muscular limbs were called for that is how the fins of fish dwelling in marshy environments grew longer and developed additional bones that strong muscles were attached to these were first lung fish and in particular psychopterygie eustinopterin is a typical representative of these even though this strong finned fish wasn't keen on settling on land it was already able to breathe atmospheric air and stay out of water for certain periods shallow swamps would often dry out which is why their inhabitants would have to migrate to other more humid places favorable for life and to do this they naturally had to move across stretches of land this is the way acanthostega got about it for example which lived around 365 million years ago in the late devonian one of the first known creatures intermediate between fish and amphibians acantha steger had gills scales and a tail fin just like any other fish at the same time this fascinating creature sported four legs and a breathing sack like that of amphibians that allowed it to breathe atmospheric air unfortunately acanthus steger's limbs were not strong enough to support its weight and its thorax muscles couldn't pump oxygen for too long that is why it stayed mostly in water sometimes crawling from one body of water to take a dunk in another gradually the ability of prehistoric sarcopteryji to breathe atmospheric air improved their fins grew in power and turned into fully fledged pores their appearance underwent great changes for example tiktaalik a prehistoric sarcopterygian amphibian fish that lived at around the same time as a kantha steger had a flat head like that of a frog being anatomically intermediate between fish and amphibians tiktaalik had powerful fins that were able to prop up its body and move it across solid surfaces in addition this amphibian fish could breathe with both its gills and its lungs the way its ossicle is designed is proof of tiktaalik's ability to easily distinguish sounds both on land and in water all these signs show that this creature spent as much time out of water as in it in the carboniferous period which followed the devonian amphibians came onto land for good settling in all sorts of ecological niches in their revolutionary struggle they developed into such animal classes as reptiles and synapsids a great diversity of conditions outside the ocean stimulated and spurred the evolutionary process on as land dwellers are exposed to a much wider range of temperatures and other factors than water dwellers incidentally this question may arise why did animals come onto land only once in the entire history of evolution why didn't a single marine species venture to live on land in the past 350 million years the answer isn't as elaborate as it might seem [Music] marine creatures are adapted to living in an aquatic habitat the overwhelming majority of them are useless and actually helpless when out of water to live in another environment they would need a whole other skeleton structure as well as outer skin or fur or shell for that matter and organs of breathing vision and hearing the proverbial fish out of water is even more helpless than a human in the open sea it is a foregone conclusion that stranded fish is there for the taking for any land creature that would care to have it when coming onto land in the paleozoic period plants arthropods and vertebrates went on to occupy vacant ecological niches they didn't have natural enemies in the new environment while there was plenty of food around the chief negative factor in the new environment was not other creatures but other conditions fortunately the species were able to take their time adapting to them interestingly an example of the other way around is known to us prehistoric ancestors of cetacea went back to living in an aquatic environment at the same time dominating certain ecological niches strange though it may seem on the face of it there is actually nothing controversial about it the fact is that things to adapt to in the terrestrial environment are tougher and more diverse that is why getting back in the water could be a smart move in order to survive whales dolphins and other secondary aquatic inhabitants of oceans seas and rivers are living evidence confirming the fact that evolution is not irreversible if in certain circumstances it is better to take a step back that's what it will do the permian triassic extinction event marked the beginning of the mesozoic a new era in the geologic history of the earth it began approximately 252 million years ago and continued for around 186 million years this was a time when our planet was actively transforming and gradually assuming it's today's looks the most crucial tectonic process of the epoch was the splitting of the single supercontinent pangaea first it broke down into two landmasses laurasia and gondwana which in their turn went on to form the continents we know today with several large mutually independent territories separated by seas and straits the conditions were perfect for independent ecosystems to emerge which gave impetus to new evolutionary adaptations in terms of climate the mesozoic was the warmest era in the entire history of multicellular life forms throughout this era there was no ice shield even at the pearls that would cover the ground for a long term still temperature would drop from time to time which forced both flora and fauna to adapt to the newly imposed conditions the mesozoic comprises three periods and the first one is known as the triassic it began around 252 million years ago and continued for around 51 million years this was the time when tectonic processes in the earth's interior were just starting to break pangaea into separate continents and the supercontinent remained whole for most of the period the ural ridge one of the oldest mountain ridges existing to this day completed its formation in the triassic at the time the mountains were in their solid days and comparatively high the period's climate was relatively dry and hot which is why there were lots of deserts at the time and the area of inland bodies of water diminished there was 10 to 15 percent of oxygen in the air for most of the triassic and then around 215 million years ago its level gave a sudden leap to reach as much as 19 the reasons for this phenomenon haven't been established for certain but it is assumed that it may have had something to do with the evolution and spreading of certain varieties of marine or land plants prehistoric seed ferns accounted for the overwhelming majority of the flora of the day but later on they were gradually ousted by more progressive groups of plants those included psyches ginkgo and prehistoric conifers many of these orders have survived our day although now they're not as diverse as they used to be marine life meanwhile was following its own course of evolution the oceans emptied by the perm triassic extinction were gradually populated by turtles and teleasts and the first ichthyosaurus held the niche of large predators later on they were to become reptiles best adapted to aquatic environment but in the triassic these creatures were still rather primitive an example of these is symbol spondulis which lived 240 to 210 million years ago this giant sea saurian measured 6 to 10 meters in length and date mostly fish this impressive creature had a long thin body half of which was a flexible tail its head was rather large and the elongated sharp muzzle boasted a nice set of small and sharp teeth symbol spondulis's limbs looked like diving fins but it appears they were used only to stabilize body position in water the saurian's skeleton structure suggests that it traveled through water by making wave-like movements and generally speaking was rather clumsy the most common representatives of landfauna of that time were raccosauria prehistoric ancestors of dinosaurs crocodile amorphous and birds as well as other animal species by the middle of the period first dinosaurs evolved from ancient archesauria as independent species but there was still a long and hard struggle for survival up ahead for them it was only by the end of the triassic that dinosaurs started to establish their dominance in the earth's biosphere after sharply growing in size which incidentally coincided with an increase of oxygen in the atmosphere with dozens of films and thousands of books about horrifying saurians anyone today would be familiar with what they looked like at the same time these giants seem to eclipse other species which are by no means less important and interesting for example oligocythus a small creature that lived in the late triassic around 200 million years ago this small and deft little animal was a genus of cyanodance prehistoric animals that differed from mammals in some not very clearly noticeable traits oligocyphus had a thin flexible body measuring around 50 centimeters it grew fur and generally looked like a weasel warm blooded and herbivorous it was widespread on the territories of today's north america europe and china even though it isn't known whether oligocyphus had a pouch on its stomach the structure of its skeleton allows us to assume that its babies were quite small which is typical of today's marsupials it is also highly likely that oligocyphus fed its babies on milk another assumption about these creatures is that they dug boroughs and made homes there they also took great care about their babies which may be evidence of a comparatively high intellect unfortunately these creatures perished at the beginning of the jurassic period supposedly due to lack of food and heightened competition still they remain the oldest prehistoric animals that look like today's mammals most the triassic jurassic mass extinction heralded the end of the triassic period a great number of amphibians some arcusauria other reptiles as well as many plant orders vanished from the face of the earth among the possible reasons for this disaster of volcanic activity a change in the global ocean level and sudden climate change either way the extinction event vacated a number of ecological niches which allowed dinosaurs to establish a firmer position on the evolutionary arena of the earth the next period of the mesozoic was the jurassic it began about 201 million years ago and ended about 145 million years ago which makes it roughly 56 million years long this was a time of large scale tectonic movements and reformations it is in the jurassic that the supercontinent pangaea finally split to form several land masses mutually separated by shallow seas if we look at the map of the earth at the end of the jurassic period we'll be able to distinguish the shapes of some of today's continents although they would be positioned in unexpected places since the new continents were mutually independent their emerged isolated biosystems that is why some animals and plants that were abundant on one continent would be non-existent on another the earth's climate was warm and humid for most of the jurassic period and by its end a comparatively short cooling occurred great areas on land were covered with tropical forests which were for the most part psychists to tresembled palm trees conifers were also widespread their looks were reminiscent of today's cypress trees and pine trees on land meanwhile there started the epoch when dinosaurs positively flourished their diversity was rich and they held most ecological niches while dominating almost every single one of them among these creatures one could come across both small saurians the size of a cat and real giants herbivorous dinosaurs known as sauropoda came to be widespread in the jurassic with some typical representatives like brachiosaurus brontosaurus diplodocus and others they resembled each other very much the largest one titanosaurus measured as much as 25 to 30 meters in length and could weigh over 75 tons an unusual feature typical of sauropoda is the so-called sacral brain a widening in the hind part of the vertebrae that hypothetically could contain 20 times more nervous tissue than cranial brain today it is posited that the sacral cavity was likely to be filled with a glycogen body which was a source of additional nutrition for the giant saurian's nervous system alongside dinosaurs other animal species were evolving as well such as mammals reptiles and darth reports the oceans were richly populated with bivalve mollusks which in many ways resembled their today's descendants the apex predators in the marine food chain were various saurians like ichthyosaurus and pliosaurus looking at a thalmasaurus which lived at the beginning and the end of the jurassic period and comparing it with symbol spondulis which lived earlier it may be hard to believe that these animals are in fact related ancestor symbol spondulous lived 240 to 210 million years ago length 6 to 10 meters elongated body and head badly adapted to aquatic environment descendant of thalmasaurus lived 165 to 145 million years ago length up to 6 meters streamlined body vertical tail well adapted to aquatic environment this marine saurian had a dolphin-like body with an elegant and powerful crescent-shaped vertical tail it is thought that the animal breathed atmospheric air and was able to stay around 20 minutes under water develop speeds of over seven kilometers per hour and dive as deep as 600 meters judging by ophthalmosol's teeth structure its diet consisted for the main part of molluscs including squid the animal's eyes were another distinctive feature in its appearance their diameter measured around 10 centimeters and they were protected by a bony sclerotic ring it is thought that a thalmosaurus could see well in the dark which was a valuable asset for deep water hunt and so the animal was free to dive far down where larger saurian predators couldn't get the last period of the mesozoic era is called the cretaceous it began 145 million years ago and lasted for around 79 million years which makes it the longest one in the mesozoic the continents continued to break apart throughout the entire cretaceous india detached itself from africa and slowly drifted in the direction of asia across the indian ocean south america broke away as well and made its way westwards eventually by the end of the period africa australia greenland north and south america assumed shapes close to those of today while europe and asia were starting to get clearly defined borders the climate in the cretaceous was comparatively cool in the period from 100 to 85 million years ago the average temperature increased somewhat and then cooling continued which persisted till the very end of the era this is exactly when tyrannosaurus and triceratops were around the most widely known dinosaurs and truly distinctive symbols of the mesozoic still the period is much more notable for the spread of flowering plants first trees and then grasses they form turf and so strengthened the soils and made them more fertile while nutritious seeds served as food for a wide variety of species this gave evolutionary impetus to diversification of mammal species and also for some herbivorous dinosaurs but on a smaller scale even though reptiles were dominating in all the ecological niches of that time mammals continued to evolve they grew to be more and more diverse and by the end of the period it was possible to single out separate groups like congulates ulipo typhla predators and primates reponomas which lived around 125 million years ago was one of the largest mammals of the cretaceous its body measured up to 1 meter in length and it weighed 12 to 14 kilograms this creature's appearance may have been similar to today's tasmanian devils its teeth structure suggests that it was a predator but its limbs were short and clumsy so probably this animal was a scavenger incidentally an interesting find was unearthed to archaeological diggings it was rapidnomus's skeleton with bits of a small dinosaur in its abdominal area this may serve as evidence that some mammals of the time could hunt small dinosaur species like cetacosaurus and darkyorn ethys meanwhile large aquatic saurians had long been dominating the seas ichthyosaurus plesiosaurus and mosasaurus however around 1995 million years ago their population sharply dropped after the extinction event brought about by the second oceanic anoxic event which had to do with a sharp decrease of oxygen in the ocean one of the suggested possible reasons is increased under water volcanic activity the end of the cretaceous was probably the coldest time in the mesozoic all living creatures set about adapting to the inexorably dropping temperatures and dinosaurs were no exception around 70 million years ago the territory of today's northern alaska above the arctic circle was inhabited by peculiar dinosaur species this sauron is known as nanuxorus remotely related to the horrifying giant tyrannosaurus rex this dinosaur admittedly resembled it but its size was smaller the body of nanuksaurus measured around 6 meters and it weighed just around a thousand kilos that is approximately eight nine times less than tyrannosaurus rex this shrinking is thought to have had to do with a lack of available food in its habitats forced to survive in the dire conditions of the far north among snowy stretches and in the semi-darkness of the polar night this dinosaur developed some unusual features first of all it is likely that it was warm blooded and incidentally the metabolic processes in its body ran their course remarkably fast for example as is the case with today's birds secondly nanuxoris body was covered with several layers of down and feathers which allowed it to preserve warmth in the severe northern climate this suggests that the northern saurian was probably an active and fast-moving predator but in the conditions of the polar knight traditional ways of hunting prey are not that effective that is why it appears that nanooksaurus had an exceptionally well developed sense of smell and sensitive night vision these assumptions are confirmed by the build of its cranium summer in northern latitudes was short and rather cool so additional sources of warmth were needed for dinosaur eggs so that the babies developed well nanooksaurus is thought to hatch its eggs and to take great care about the young ones studies of fossil finds show that the volume of the brain of this species was rather big potentially this dinosaur was as intelligent as most of today's birds unfortunately these evolutionary adaptations didn't save nanuksaurus from extinction around 66 million years ago the cretaceous paleogene extinction event caused all non-avian dinosaurs to vanish off the face of the earth alongside marine saurians pterosaurs and many other species still the terrifying saurians left their imprint in the history of our planet and the ecological niches vacated by them were promptly occupied by birds and mammals this marked the beginning of the cenozoic era its highest being was the unique creature that came to be known as homo sapiens the self-proclaimed king above all nature its evolution has only just started and time will show what it has in store for this species three-fourths of all living organisms on earth died out in the cretaceous paleogene extinction almost all creatures heavier than 25 kilos ceased to be including practically all non-avian dinosaurs this tragic event heralded the end of the mesozoic and the beginning of the cenozoic the geologic era that is still not over it is divided into three periods of various duration which are different both in terms of climate and diversity of the biosphere the first and longest is known as the paleogene it began around 66 million years ago and continued for 43 million years in the first 10 million years of the paleogene the earth's biosphere was recovering from the hard blow dealt by the mass extinction this geological epoch is referred to as the paleocene since great numbers of dinosaurs and other species of the cretaceous had perished there were lots of vacant ecological niches for the taking these were promptly filled by the new masters of our planet mammals the geography of the earth of that period was drastically different from what we're used to seeing today looking at a map of that prehistoric earth we would already be able to make out the familiar continents but they were positioned slightly differently thus north and south americas were separated by tropical seas while the indian subcontinent was just starting to make for the asian shores the prehistoric ocean known as the tethys still lay between africa and eurasia but was already largely giving way due to the movements of tectonic plates the climate of the epoch was warmer and more stable than today's most of the planet was covered with dense and lush tropical forests the overwhelming majority of the living creatures of the day were quite small thanks to the abundance of vegetable food they quickly propagated and spread across more and more new areas this is when the prehistoric ancestors of most of today's mammals thrived for example the warm forests of the paleogene were inhabited by my acids small and deft predators that looked like martins it is believed that they were the progenitors of all today's rich diversity of mammal predators at around the same time their lived rko seats the prehistoric ancestors of today's whales at the time however they looked more like hippos they hadn't gone to live in the sea yet but had made their first steps in that direction their limbs respiratory organs in the inner rear had already started to adapt to prolonged stays underwater the next deparka planet went through was the ear scene it began approximately 56 million years ago and continued for slightly over 22 million years the contours of the continents had already grown to be quite recognizable india had finally made it to the southern shores of asia and as a result of the collision of tectonic plates giant rock folds formed that is how the himalayas rose the largest mountain range on our planet today even though some species of that time already looked like some we might come across today others were completely different an example of one of these is andrew sarkis one of the largest mammal predators that has ever lived on the earth its skull measured up to 84 centimeters which is roughly one and a half times more than that of the brown bear and its bite is estimated to have been harder than that of any of today's land predators it has been inferred from the deep tooth sockets in andrew sarkis's skull where mandible muscles were attached to which leaves no doubts as to the bite's crushing force reconstruction of its skeleton shows that the animal could measure over 4 meters in length and weigh as much as a ton still interestingly it looks like this giant carnivore fell into the class of primitive ungulates research showed that andrew sarkis's closest relatives were the prehistoric sewer forms hippopotamus and cetaceans studies of a few unearthed fossils of its skull and teeth show that the animal must have been omnivorous and even didn't mind eating carrion unfortunately not many bones and fossils of this fascinating creature have been found and scientists are still at odds as to the structure of its organism habits and relation to other mammal families the oligoscene was the last debuck of the paleogene it is posited that it began around 33.9 million years ago and was over about 23 million years ago which makes it roughly 11 million years long this was a time of global cooling warm tropical forests were gradually superseded by endless prairies covered with grasslands this is when the antarctic glaciation began and an icy shield transformed the green continent of the pole into a lifeless cold desert australia continued to drift away from the other continents while africa on the contrary was making for the north to meet europe after a collision of tectonic plates mountain ranges formed and that is how the alps made their appearance on the map of the world around 26 28 million years ago the super volcano lagarita furiously erupted on the territory of today's colorado in fact it was one of the major volcanic emissions of the entire phanerozoic eon an area of over 30 000 square meters was buried under a layer of hot ash as much as a hundred meters thick all life within a huge radius around the volcano was destroyed completely amazingly life is able to come to terms with any disasters the earth of the time was inhabited by fascinating creatures some of which were not smaller than dinosaurs in size for example indrich etherium a prehistoric herbivore related to rhinos paraceratherium the largest of these reached 4.8 meters in shoulder length which is higher than a large african elephant thanks to their remarkably long neck these giants were able to raise their head up to 7 meters above the ground today's rhino would be able to pass under its enormous progenitor's belly while a human would hardly reach up to touch its knee with our mass reaching 20 tons these giants were the largest land mammals of all times even brontosaurus the most massive of land dinosaurs weighed just around 15 tons it still hasn't been established for certain what endrick ethereum looked like unfortunately not one entire skeleton of these amazing animals has been excavated so far only separate fragments from different animals of the species most scientists agree that in spite of their relation to rhinos enduric ethereum didn't have a massive horn although it may well have had a small nose trunk like today's tapias the trunk would have allowed it to pick juicy leaves off treetops these giant herbivores must have lived in small herds and were constantly on the move around vast stretches of land roaming across their dominions in search of food unfortunately by the end of the oligoscene indrik ethereum had died out completely at around the same time the areas they used to inhabit were explored by prehistoric elephants alongside large predators hyena dance and amphicyonids the latters are also known as bear dogs it is thought that the emergence of new large herbivores would have greatly upset nature's balance and intricate theorem would have been forced to fiercely compete for its food famine and the threat from the new dwellers of the asian prairie gradually led to the herbivores giant's total extinction apart from those mentioned there were some other large predators who were quite common on the earth and the period from 37.2 to 28.4 million years ago and telodons fossilized remains of these creatures have been found all over eurasia being even toed ungulates and telodons resembled wild boars although in terms of evolution these creatures are closer to hippos or even cetaceans measuring up to two meters in length they weighed over a ton a meter long head had huge jaws complete with all sorts of teeth sharp in sizes long fangs and wide flat moles it is likely that intelligence were omnivores with a preference for predation not hampered by their impressive size and bulk they were able to develop remarkably high speeds so chances of outrunning such a monster were quite thin a wild boar the size of a large bull that prefers meat posed a serious threat to any inhabitant of the earth of that time that is why it is hardly surprising that intellidons successfully struggled for their survival for such a considerable time the period in the history of our earth that came next was the near gene it began approximately 23 million years ago and ended just two million five hundred and eighty thousand years ago this is when our planet started to look almost but not quite what it looks like today the continents shifted to their today's positions on the planet's surface and the looks of the most of the plants and animals of the day grew to be familiar to our eye with the earth's climate gradually becoming colder and with droughts occurring more often polar caps were gradually growing which culminated in a global glaciation at the end of the neogene the planet meanwhile was crawling with all sorts of fascinating creatures the deep sea dwellers were terrorized by megalodon a giant shark measuring 15 meters in length and weighing up to 35 tons on land various gomphotheriums could be seen creatures related to today's elephants many of them were the proud owners of four solid tusks as for the animal size some were larger than today's african elephant whereas others were quite modest in comparison around 2.5 million years ago there started the quaternary which is currently the last geologic period in the history of the earth it is remarkable for the emergence and evolution of homo sapiens as well as its prehistoric ancestors for example in the period from one million years ago to a hundred thousand years ago there lived gigantopithecus one of the species of great human-like apes known to science they measured three to four meters in height and weighed over 500 kilograms these creatures lived on the territory of asia and were related to today's orangutans it appears that gigantopithecus would not be able to climb trees like other human-like apes on account of its mass however some of them are known to have dwelt in mountainous areas and made homes and natural grottos caves and ravines even though their diet is believed to have consisted of mainly bamboo bones of herbivorous animals with tooth marks were unearthed in their shelters judging by these finds it is safe to assume that these creatures didn't mind meat and were omnivorous at the very least the gigantopithecus skeleton is similar to that of a gorilla so they were likely to use all four limbs to move around besides these human-like apes had a comparatively large brain which means that they could be relatively intelligent and were probably able to even make primitive working tools unfortunately the population of these amazing giants sharply dropped when the prehistoric ancestors of today's human emerged and spread across the planet by around one to three hundred thousand years ago they had died out completely sadly not many remains of gigantopithecus have been found which greatly impedes studying them as they were spreading across the earth primitive human tribes eliminated many other creatures other giants who supposedly became extinct because of humans were diprotodons which inhabited australia in the period from 1.6 million years ago to around 40 000 years ago these creatures were the largest known marsupials and they were related to wombats and koalas some of these amazing animals reached as much as three meters in length and two meters in shoulder height as for the hamas they weighed approximately three tons this makes diprotodons quite as big as some hippos massive and herbivorous they dwelt on massive woodland and coastal grass-covered plains that abounded in australia before humans had made their appearance there chronologically the extinction of the marsupial giants coincides with first human tribes arriving to this continent still some scientists maintained that the extinction was caused not by hunting but an anomaly of the earth's magnetic field together with a local temperature decrease the heightened radiation background coupled with cooling slowed down plant growth which led to farming among the herbivores thus it appears that by and large the tragedy was inevitable and the humans simply brought it to a close faster the last ebook of the quaternary the holocene heralded a robust development of the human civilization when homo sapiens spread across the entire planet and dominated all the other inhabitants of our earth the downside of this evolution is manifested in a number of industrial disasters and irreversible changes in nature's balance for example it is due to human activity that the greenhouse gases concentration in the earth's atmosphere is getting worse every year this may globally negatively affect all living things on our earth from simplest bacteria to elaborate multicellular organisms unfortunately the number of fascinating creatures living on our earth is going down every year it is particularly poignant to realize that they perish because of human stupidity or ovaries uncontrolled hunting irresponsible land development and indifference to the environment have already made scientists speak of a new sixth great extinction event whose consequences are potentially just as grave as those of the previous five will mankind stop before it eliminates itself how long should it take our planet to recover from the consequences of the technological progress and will nature produce radically new life forms that would weather this crisis just like it happened before we can hardly realistically answer these questions [Music] the evolution of life on earth was anything but linear there were periods of higher diversity as well as periods of almost total extinction this was deduced following the analysis of fossils unearthed at paleontological digging sites in the past 540 million years there have been five major and about 20 minor extinction events however the most global crisis of our planet's biosphere occurred much earlier approximately 2.1 billion years ago the first living organisms are posited to have appeared on earth rather early approximately but not quite four billion years ago that is about 400 million years after the planet's surface had become more or less suitable for life even so the earth of that period can't have looked hospitable barren rocks dense clouds frequent storms and earthquakes and an atmosphere devoid of oxygen made up of mostly nitrogen methane and carbon dioxide this was the age of primitive microorganisms archaea and bacteria most of which used an oxygenic photosynthesis that is a kind of photosynthesis where oxygen is not produced apart from these creatures it is thought that there were many forms falling in between that couldn't be classified as either living beings or not living objects with a satisfying degree of certainty about 2.7 billion years ago their emerged oxygenic photosynthesis the kind of photosynthesis familiar to us where oxygen is produced this form is still used by the overwhelming majority of plants and unicellular algae anaerobic organisms cannot live in an oxygen-rich environment that is why ancient algae used oxygen as a weapon they released it as a byproduct of their life activity and this waste killed their competitors this way algae not only protected their turf but also spread further to cover larger areas to dwell on at first oxygen was spent on oxidation of rocks in habitats of aerobic organisms colonies in this manner oxygen pockets were formed small areas of oxidized minerals gradually oxygen went on to spread in the atmosphere oxidizing methane sulphur compounds and iron not able to exist in an environment rich in oxygen most anaerobic organisms died out with those of them remaining around confined to underground pockets where oxygen didn't reach thus the tables were turned in the biosphere with the oxygen breathing organisms becoming the majority and spreading across larger areas and the former planet owners forced to remain in some limited areas with the spread of the new organisms the content of gases like methane and carbon dioxide in the atmosphere dropped methane oxidized forming water and eventually carbon dioxide with the latter taking active part in photosynthesis all this reduced the greenhouse effect and the earth's surface considerably cooled the so-called huronian glaciation started approximately 2.1 billion years ago and continued for about 300 million years until the sun's luminosity and tectonic makeovers had heated up the earth this was a time when single cell microorganisms were evolving extremely slowly constantly thwarted by an occasional prolonged global ice age the period has earned a great number of nicknames like the great oxidation or oxygenation event oxygen catastrophe and oxygen crisis to name but a few even though not really swift this event was definitely large scale and global practically all the biodiversity of the non-oxygen period was eliminated and evolution was greatly hampered by global glaciation for a good billion years however in the aftermath there emerged a more energy efficient method of nutrition approximately 540 million years ago the phanerozoic eons started sometimes referred to as the period of visible life it was peculiar for vigorous evolution of multicellular species and in fact it is actually still in progress many creatures of that age looked really bizarre and didn't resemble any of their today's descendants suddenly about 450 million years ago some unknown factor abruptly interfered with the act of evolution of life forms the proposed causes include a cosmic gamma-ray burst volcanic activity and even a large celestial object impact as it is from 25 to 50 percent of all living beings became extinct within seven million years this series of extinction events dubbed the ordovician silurian extinction was hard on trilobites mollusks and some other marine invertebrates of the time the late paleozoic era that followed this extinction event heralded active evolution of flora on land the first amphibians and reptiles emerged in that time too fishes were actively evolving establishing their dominance in all fresh water and saline bodies of water approximately 372 million years ago the so-called devonian extinction started it occurred in several stages that were alternately followed by comparatively peaceful periods peaceful they may have been but even so the extinction rate of species was higher than average the most likely reason for this extinction is posited to be this land plants of the time sported long and powerful roots which enabled them to extract nutrients from much deeper down in the soil than before when waters seeped through soils that were loosened by plants roots great amounts of nutrients were washed into the ocean as a result algae were positively thriving there in the abundance of food and light the rotting of these algae reduced oxygen dissolved in the water and the organisms inhabiting the sea bottom were simply smothered with nothing to breathe in the aftermath about 70 percent of the marine species of that time are estimated to have died out including practically all species forming coral reefs this triggered global irreversible changes in the biosphere of the global ocean many genera and families vanished completely and the vacated space was filled by others in the carboniferous period which followed tree ferns exploded in numbers all over the planet's surface also there emerged gymnosperm trees and conifers it is in this period that rich deposits of coal were formed which is still widely used by mankind and various industries speaking about the fauna this was the time when insects thrived that's when the giant millipede arthropleura was around which measured two and a half meters the meganura a giant dragonfly with a wingspan of up to one meter and the boom in a scorpius a scorpion measuring 70 centimeters the insects were of these unbelievable sizes on account of exceptionally high concentrations of oxygen in the atmosphere which at that time reached a staggering 35 percent the permian triassic extinction event also informally referred to as the great dying occurred about 251 253 million years ago marking the transition from the permian to the triassic period it proved to be the most massive and global in the entire history of multicellular life digging show that up to 95 percent of marine species and up to 70 percent of land species vanished from the face of the earth as a result interestingly this disaster was rather swift by geological standards it took just up to 200 000 years later it would take not less than 50 million years for biodiversity to recover for land species and about a hundred million years for marine species trilobites a great number of marine and vertebrates and microorganisms were on the verge of extinction insects shrank in size they stopped looking like horror film creatures on the loose and instead assumed in appearance of today's tiny and numerous creatures the reasons for the permian triassic extinction event still haven't been established with certainty among the proposed hypotheses we may single out robust volcanic activity as one of the most likely ones others worth mentioning are a collision of our earth with a large celestial object climate change and active methane emissions following biological or tectonic activities there is no single answer to this question yet in the triassic period which followed the permian triassic extinction event vertebrates vigorously evolved this is when archosaurs emerged the prehistoric saurians crocodiles and dinosaurs were to evolve from the triassic period also produced first mammals although they were not so widespread at that time about 200 million years ago the triassic jurassic extinction event began sometimes called the end triassic extinction having lasted for approximately 10 000 years it marked the transition from the triassic to the jurassic period the event claimed about half of known species on the earth of that time they included various reptiles and amphibians that vacated a number of ecological niches this allowed dinosaurs to establish their dominance on the planet and sustain it for the next 130 million years incidentally the reasons for the untriagic extinction event are not known either and in fact there isn't a single hypothesis today that would sound sufficiently convincing the jurassic and cretaceous periods that followed the triassic jurassic extinction event were the times when dinosaurs thrived and flourished but these giant saurians were not the sole inhabitants of our planet at the time this is when the forefathers of today's birds flowering plants and corals evolved as well as small furry warm-blooded animals mammals even though these small creatures didn't look quite as impressive compared to tremendous dinosaurs in all their glory they firmly held their ecological ground and steadily progressed in their revolution mammals got their chance at the end of the cretaceous period that is about 66 million years ago what occurred then was the most well-known and a rather large-scale mass extinction event referred to as the cretaceous tertiary extinction event according to the first and most popular hypothesis the extinction was caused by a giant celestial object impact everyone would have heard of a meteorite supposedly killing off all dinos nevertheless there is no hard evidence in favor of this version either way the upshot was that all dinosaurs died out alongside a great number of conifers algae and mollusks the cretaceous tertiary extinction event heralded the beginning of a new geologic era the cenozoic which is still in progress throughout this era mammals birds and flowering plants have been actively evolving and spreading across the earth mammals settled all over the planet inhabiting it literally everywhere from tropical areas to ice caps of the poles and from the depths of the oceans and the planet's interior to air currents up high eventually evolution produced mankind even though you would expect people today to be enlightened enough there are still those who do not believe in evolution however the theory of evolution is not something to believe in it is a scientific theory based on facts the theory of the evolution of species has come a long way and has undergone serious revisions since its original version proposed by charles darwin back in 1859 still the basic principles of the theory are the same and to date the theory of evolution is the only serious scientific theory that accurately describes the process of the evolution of species and the origin of new creatures according to some scientists we are now living in the epoch of the sixth mass extinction event they also call it the holocene or anthropocene extinction thousands of species have died out in the past 10 000 years around 900 species have vanished from the face of the earth in the past 500 years today about 40 of amphibian species and 25 percent of mammal species are under the threat of extinction and it looks like one of the chief reasons for this is human activity the history of life on earth is still being recorded the primordial struggle for survival is going on even at this moment and we cannot say with any certainty what our planet will look like in hundreds of millions of years perhaps its surface will be covered with lifeless deserts and humans will refer to another planet as their home the universe is full of other worlds which are quite out of bounds right now but nevertheless so attractive to humans who have always been keen on seeing beyond the horizon so far we have made only the first timid steps in exploring the boundless universe and there are all sorts of countless secrets waiting for us up ahead you

Channel: Kosmo

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Keywords: Earth, dinosaurs, what was the prehistoric earth like, earth before dinosaurs, earth with dinosaurs, earth before humans, global extinctions, planet, life, mankind, humanity, dinosaurs perished, prehistoric animals, prehistoric plants, continents, supercontinent pangeia, apocalypse, first humans, life in water, life on land, science, popular science, film, video, global cooling, ancient human, first dinosaurs, evolution, how life came to be, facts, ice age, cosmo, kosmo, calamities, cataclysms

Id: RUdnvm7-Z2U

Length: 84min 8sec (5048 seconds)

Published: Sun Feb 27 2022