Why Was the Great Dying So Bad?

the ending of the Permian period 252 million years ago gave way to the Mesozoic Era more popularly known as the age of the dinosaurs the Mesozoic made up of the Triassic Jurassic and Cretaceous periods saw the evolution of all sorts of iconic animals and in many ways it was during this era of time that the world we know today found its Beginnings the first mammals birds lizards snakes Turtles and many modern amphibian groups all originated during this massive stretch of deep time however the start of the Mesozoic was a time of great upheaval and unimaginable Devastation as the boundary between the Permian and the Triassic also marked the most severe mass extinction event in the history of Life the imaginatively named Permian Triassic mass extinction or more dramatically the great dying now I've actually been lucky enough to stand on this boundary itself back when I was invited to join an expedition in South Africa to search for fossils in the Kuru semi-desert the feeling of standing on this divider was a profound one knowing how much Carnage and death these rocks represented and despite it all happening over 250 million years ago I couldn't help but feel a little sad for all the Magnificent species that were wiped from the face of our world estimates for the severity of this event vary with some studies putting an extent of marine species Extinction at about 81 whereas others put it at an even more extreme 94 percent the four-legged backbone inhabitants of the land at this time the tetrapods which includes our own ancestors may have experienced an 89 loss of Genera over the last million years of the Permian period and it was also only the second ever mass extinction of plants as well as the only mass extinction to have severely affected insects they also appear to have been distinct pulses of Extinction with different timings of Extinction for terrestrial and marine organisms although the specifics are still debated it seems as though the terrestrial Extinction occurred sooner than the Marine One and the stresses to the Marine environments happened first in higher latitude regions before the lower latitudes so there's no denying that this was a truly terrible time to be alive and the odds for a lot of animals around at this time were that they would not be making it through to the following Triassic period indeed the tetrapods living on the land before the extinction event were very different to the ones found after and the terrestrial ecosystems of the planet which had been dominated by groups of animals related to our ancestors called synapsids would eventually give way to the crocodile relatives and of course the dinosaurs a total restructuring of vertebrate life on land happened after this Extinction and the planet was never the same again so why did the PT Extinction wipe out so much of the life that inhabited this Permian World why was the Great dying quite so bad well it has a lot to do with the specific geological conditions of the volcanism considered responsible for this destruction it was first noticed in the 1990s that there might be a potential link between this notable decline in diversity of various groups and the rapid eruption of incredibly widespread flood basalts in Siberia which occurred at around the same time these flood basalts which are still clearly visible today in eastern Siberia are the result of a huge volume of lava spreading over the surface of the Permian Earth as a large igneous Province a so-called lip became in place what this means is that a massive amount of igneous material quite quickly Rose to the surface of the Earth over a very wide area resulting in both intrusion with a magma being forced into rocks underground and melting them as well as Extrusion finding its way to the surface and spreading out as lava while there appears to be somewhat of a correlation between the formation or emplacement of the these lips and some of the major mass extinctions throughout the history of Life on our planet it's not always a perfect clear cause and effect relationship however but in the case of the end Permian Extinction all the current evidence points to the Siberian trap's large igneous Province as being the main driver of the destruction but if lips have been the cause of at least some other mass extinctions too what made the Siberian ones quite so deadly that's where the geology of the region this volcanism happened in comes into play millions and millions of years earlier huge volumes of evaporating water left behind mineral deposits called unsurprisingly evaporites these evaporite deposits were then covered by successions of sediment over millions of years being buried far underground in addition to these evaporoids there were also layers of sediments that were particularly rich in concentrated organic material so why is this important well as it turns out the presence of these deposits was a complete disaster for life on Earth when the lip started to come into contact with them three different phases of activity have been identified as having happened when the Siberian traps formed the first stage beginning just before about 252.24 million years ago involved a lot of extrusive and explosive volcanic activity with a lot of pyroclastic eruptions as well as incredible volumes of lava pouring out onto the surface now you might imagine that this would have a pretty devastating effect on the planet and indeed any living things in the vicinity of these eruptions would have been getting pretty toasty and there is some evidence for changes in the carbon cycle as well as peaks in the concentration of mercury and the sediments laid down at this time at a site in Canada an unmistakable signal of increased volcanism however there seems to have been less of an effect on global conditions at this time than we might have expected it's at about this time that the earlier terrestrial Extinction we talked about before seems to have been occurring and the mass extinction of plants was taking place one of only two Mass plant extinctions to have happened in the history of their evolution there seems to have been a lot of stress on the terrestrial ecosystems at this time resulting in their eventual collapse and turnover however the Marine realm was still largely unaffected by these events but even more destruction was still on the way and the marine life of the Permian would soon get its fair share of the extinction the second stage of the Siberian traps in placement started around 251.9 million years ago after about 300 000 years of State 1 eruptions this second phase was very interesting the extrusive eruptions of vast quantities of lava onto the surface stopped and instead extensive underground complexes of magma were forced in between the sedimentary layers that made up The Rock here this is where everything went South for the marine organisms of the Permian when the magma intruded into the sedimentary rocks under the surface they came into contact with those evaporite and organic Rich deposits and disaster follow due to the effect of contact metamorphism vast quantities of gases specifically halocarbons and greenhouse gases were mobilized from these deposits and escaped to the surface as evidenced by pipe and vent structures that indicate these gases violently exploded up from underground and into the atmosphere once they'd been released Havoc was Unleashed upon the environment Halo carbons are associated with ozone depletion and so the vast quantities of these gases in the Permian atmosphere likely brought about the collapse of the ozone layer while the greenhouse gases released from the organic Rich rocks carbon dioxide and methane would have resulted in global climate change including Rising temperatures acidification of the oceans and widespread Oceanic anoxia this is when the Marine Extinction happened the worst Marine extinction of the past half a billion years the last of the trilobites were wiped from the face of the planet along with many other groups of not quite so well-known organisms as conditions in the ocean all across the planet deteriorated the world would forever be a changed place after this event the third stage of Siberian traps activity then began around 251.48 million years ago and was characterized by a continued intrusion of magma underground as well as a resumption of lava being erupted onto the surface however records of carbon Isotopes form this time indicate that they began to return back to pre-extinction levels suggesting some recovery of environmental conditions although many details of the Permian Triassic mass extinction event are still heavily debated and the timings of when different organisms died out as well as exactly when various volcanic events occurred or the subject of a great deal of discussion it seems quite apparent that the excessive severity of the great dying has a lot to do with the underlying geology of the Siberian traps it's quite alarming to think that the history of Life on our planet could have been entirely different if it weren't for the specific region the Siberian traps formed in and making this such a destructive Extinction the world could have remained a very different place but luckily for us at least those good old evaporites and organic Rich deposits changed the course of evolutionary history the great dying also has some very serious and quite worrying lessons for our future too the release of vast quantities of greenhouse gases and depletion of the ozone layer are all too familiar threats to our modern world and the fact that such dramatic consequences can be seen in the record of past life on Earth really should be be of concern to humans as a species and then there's the fact that the change in global temperatures at the end of the Permian was actually happening at a much slower rate than what we see today which is a pretty terrifying Prospect but that just goes to show the importance of paleontology as a science and its relevance to us today the past really is the key to the present sometimes anyway I really hope you enjoyed watching this video this was actually inspired by some coursework I had to do for my University degree recently in which I undertook a literature review on the use of proxies for the Permian Tri sigmas Extinction and so I thought I may as well link to that in the description below in case anyone wanted to read it and maybe decide what grade I should get for it I don't know I just enjoyed reading about our current understanding of this event and realizing that there's still a lot that needs to be found out about it well I really hope you enjoyed watching this video and learned something new thank you again for all the support you've been showing us recently with our new boner heads project we've already been enjoying making them for you and we've got some great videos planned for you this year including the rest of our South Africa series anyway a huge thank you to our patreon supporters especially our dinosaur tier supporters amandival Nordic archieanthus Clara Middleton Daniel Ingraham Drew srivastava Gary Arrington gyotus Greg Silvernail Corey Peterson loxypoo mendic and Friar Mike Pace monitor man Nicole Bueno Persian Boy Ralph Balzac Robert Thomas and Steve Bradshaw if you would like to find out more about our world its history and the wonderful life that surrounds us all please feel free to subscribe to the channel if you think we deserve it and if you would like to see more from us foreign

Channel: Ben G Thomas

Views: 203,971

Keywords: Biology, Science, Paleontology, Palaeontology, Dinosaurs, Animals, Nature, Wildlife, Ben, Thomas, Prehistory, Anatomy, Fossil, Bones, News, 7Daysofscience, Days, of

Id: V62l2wzpuAQ

Length: 10min 13sec (613 seconds)

Published: Sun Mar 12 2023