How Vertebrates Prevailed Over the Giant Insects

the Scottish Highlands the Appalachian Mountains and the lesser Atlas Mountains are just three relatively small mountain ranges in very disparate parts of the world today but they used to make up a giant mountain range these mountains started forming at the beginning of the Carboniferous and by the end of the period over probably as tall as some of the largest mountain ranges today like the Rockies or the Alps the formation of this range was also the final stage in the formation of Pangaea as it stretched across the center of the supercontinent like a scar marking where the final ocean had closed up in the Carboniferous the dominant land animals were large arthropods with millipedes the size of humans and scorpions larger than cats but at the creation of this new continent our ancestors known as the amniotes birds mammals and reptiles took over as the dominant land animals arthropods did not just come onto land before vertebras became onto land before them on three different occasions the insects arachnids and myriapods which is the group that contained centipedes and millipedes all evolved in the water and they made the journey onto dry land in three separate events long before vertebrates the first out of these three types of animals to ever come to land is hotly debated the earliest fossil evidence of an actual animal in land is either an arachnid or more specifically a scorpion that was found in Wisconsin or a fossilized myriapod that was found in Scotland that are both dated to around 430 million years ago and both of these creatures had developed adaptations to allow them to breathe in land terrestrial plants and microorganisms had formed ecosystems on land for hundreds of millions of years at this point so there would have been plenty of food on the land away from predators for a herbivorous myriapod to graze on and the Scorpions probably carved out a niche eating dead fish and other invertebrates that had been washed up onto land however although these may have been the first animals to go onto land it is likely the advanced land ecosystems with multiple layered few chains did not develop until the mid Devonian and the land animals that were in them were probably never very large but during the Carboniferous land animal started to become big and because the arthropods were the most developed land animal at the time they ended up becoming these big animals so for the only time in history the large a known each were dominated by arthropods in the Carboniferous the environment was humid swampy and for the first time in the Earth's history forested with trees only just having had evolved the majority of these trees were not trees as we know them they were actually giant ferns the trees convergently evolved with ferns are some of the most ancient land plants and don't come from seeds instead reproducing from spores in the Carboniferous they were far more diverse filling many niches that are filled by seed plants today including the tree niche although these large fern trees would never be as dominant as they were in the Carboniferous they clung on until his laces the cretaceous almost 300 million years later in the skies instead of birds there were giant flying insects one of the most common group of these from the period was called paleo dicta opera this group of insects are now completely extinct but were very common in the carboniferous and permian they were some of the first herbivorous flying insects notable because of their oddly shaped mouth that was thought to be used to get juices out of leaves and some species had six wings some members of this group could even grow as large as a magpie but the periods largest flying animal and probably the largest flying insect of all time was Megan Yura Megan era was a dragonfly relative there was the size of a crow it would have been one of the top predators of the Carboniferous probably hunting in a similar way to modern dragonflies swooping down and preying on other flying insects of the period possibly including paleo dicta doctoral the Carboniferous also had giant scorpions like Pohlman a Scorpio that was one of the largest scorpions that ever existed being around 80 centimetres long making it larger than a cat although it had a very large body it actually had very small claws and this can be an indication that it hunted prey much smaller than itself either small arthropods or even small vertebrates it was found in Scotland along with many other scorpions from the period that were also much bigger than they are today this scorpion may have been a giant but it was also unusual for other reasons as well scorpions are nearly always found in dry ecosystems that differed greatly from homeless Scorpios swampy Carboniferous habitat but also palmetto scorpio had very large eyes which showed that it was probably a more visually orientated hunter and one that hunted in a day which is unusual because despite having eyes scorpions have very poor eyesight and are usually nocturnal all of these features as well as the many other scorpions found in the ecosystem show that at this time these animals were more diverse than they are now which was probably because of less competition from vertebrates but also spiders the largest arthropod ever to live on land was after plura there was a giant millipede from an ancient family of myriapods that no longer exists it ranged in size from about 30 centimeters to one species that could grow to over 2 metres long and was one of the largest fully terrestrial animals in the Carboniferous it was once thought that these large creatures were powerful predators like modern-day centipedes but this is now known not to be true to date no after plura specimen has been found with their mouthparts preserved centipedes have very large mouths and if after plura had a similar structure you would think it would have been preserved in at least one of their fossils adding to this some specimens have been found with plant matter in their gut so they were completely herbivorous like millipedes and were probably one of the world's first big grazing animals but because of its large size the only predators in the Carboniferous that would have been large enough to eat them would have been aquatic amphibians so it is entirely possible that they had little to no predators which may explain why they were so successful with many half a meter wide millipede tracks mean found from Scotland to Canada because trees had a vulture recently during the Carboniferous it is thought that the bacteria that breaks down tough tree bark had not yet evolved this would have meant that when a tree died it just compressed over time and would eventually be turned into coal because of this 90% of coal is mined from Carboniferous rock layers and is why the period is called Carboniferous but more importantly bacteria uses oxygen and creates carbon dioxide when breaking down part matter so have large trees were not being broken down a lot oxygen with the left in the atmosphere meaning the oxygen levels at this time were considerably higher than today and this may have been what the giant arthropods oh they're large sizes to insects and myriapods don't have a respiratory system like vertebrates they carry the oxygen the parts of their bodies with blood instead they breathe through a network of tubes called trachea and just let the air run through the body naturally and they don't require a mechanism like a lung to pull the air through this gives them strict size restrictions because they have no way of actually pumping the air through their bodies so eventually they could reach a size where oxygen couldn't get all the way down their tracker the higher oxygen in the Carboniferous would have lift this size limit significantly this may not be the whole story though arthropods take a long time to shed their exoskeleton and they are very vulnerable to predation during these moments and this would have been made significantly worse if they were large animals so it is possible the arthropods were larger in the Carboniferous for higher oxygen levels but also the lower amount of predators and competition but this would change towards the end of the Carboniferous when aquatic vertebrates started to become more terrestrial tetrapods have been walking in and out of the water since the Devonian period but in the Carboniferous there was a new group of them known as Reptil amours there were poised to take the next step of taking permanent residence on the land Reptil morphs are defined as being any animal that is more closely related to amniotes which are birds mammals and reptiles than they are to amphibians a lot of the larger members of this group were probably highly aquatic and lived probably a lot like any other amphibian from the time for instance reptile morphs like chromia Saurus probably lived a lot like crocodiles however many of the smaller reptile morph underwent a small land invasion in the mid Carboniferous many of these small creatures like Jeffy row strikers shared many features with lizards and they may have even had the beginnings of scales however they still had a crucial difference between reptiles and other amniotes they almost certainly still they spawn but this doesn't mean they retire to the water there are many amphibian species today that are able to lay their spawn on land some species of lungless salamander lay their eggs on land placing them in wet leaves or moist soil so they don't dry out although it isn't known if the more terrestrial reptilian wants to lay their eggs like this it is highly likely that at least some of them did laying the spawn out in the forest is dangerous because the eggs are much more vulnerable to drying out they've they were in the water and it would mean that these creatures were unable to move out of the wet ecosystems so there would be strong selective pressures for the eggs to develop to be better suited for dry land from these creatures the very first amniotes evolved they laid amniotic eggs our neurotic eggs have a protective coat that surrounds the fetus called an amnio that holds moisture and makes them a lot less likely to dry out if they are on dry land which of these early lizard-like animals that was the first amniote is not easy to work out and may never be known but in the mid Carboniferous there was a split between these reptile like animals into the synapses they would eventually give rise to the mouse and the sauropsids that would eventually give rise to reptiles and birds because both of these groups are amniotes then their common ancestor must have been an amniote as well so this means that the very early synapse it's like our Tirith iris from the late carboniferous would have been among the first unquestionable amniotes towards the end of the Carboniferous there was a minor extinction event known as the rainforests collapse although the causes of this extinction event are poorly understood it is known that it made the climate considerably drier and the Carboniferous rainforest reduced in size and became less common the amphibians were hit very hard due to the dry conditions and it is thought that the low oxygen levels due to there being less plant life is what brought the extinction of the giant arthropods they were almost completely wiped out by the end of the Carboniferous however because of the way they laid their eggs and they're more resilient skin the amniotes were quite well suited for this new world so by the end of the Carboniferous when Pangaea had formed the amniotes walked away as the dominant land animals and the giant arthropods were confined to one of the earliest chapters of life's history on land thank you for watching a big shout-out to my patrons especially the big contributors like Ken Ham grim Marshall samovars Brandon clop and Green Falls if you really enjoy content like this consider joining the ranks over a patreon

Channel: Moth Light Media

Views: 356,369

Rating: 4.9410729 out of 5

Keywords: Giant Insects, Giant Scorpians, Giant Milipedes, Carboniferous, Before The Dinosaurs, Scorpian, Myriapod, How Creatures Came On Land, Veritbrates, Giant Amphibians, Devonian, Paleontology, Giant Dragon Flies, Jungle, Swamp, Bilogy, Early Prehistory, Paleozoic, 300 MYA, High Oxygen, Pulmonoscorpius, Arthoplerua, Archaeothyris, Reptilomorph, Early vetibrates, Evolution of laying eggs on land, Giant Bugs

Id: K7T9ZURhQxA

Length: 11min 11sec (671 seconds)

Published: Thu Mar 19 2020