IntroductionThink of a world which existed 290 million years ago. As you look out over the terane in front of you, you think that you are on an alien planet. You see volcanoes spewing ash and lava. Beside them is the ocean which is swarming with many different species of echinoderms, bryozoans and brachiopods. As you look down onto the sea floor you are amazed at the countless number of starfish and urchins. Some animals leave you can't even describe and you have no idea even what phylum they belong to.
This is a world at its height in diversity of oceanic species. Millions of wonderous species existed at this time in the ocean and most of them will never appear again in earth's history. In the geologic time scale, a million years means nothing but this time things are different. In the blink of an eye things now look vastly different.
The world once again looks alien but it looks worse than before. The sky is dark. Oceans are no longer teaming with life. The stench of rotting flesh and plants hangs in the air.
The ground trembles under your feet. You feel an intense heat burning you face. You look up and see one of the greatest show of force mother nature has ever shown. Whole mountains are being thrown in the air. Lava and debris are everywhere. You ask yourself, what has happened?
Will life ever exist on earth again?The above paragraph is a primative example of what the end of the Permian period could have looked like. Marine life was devastated, with a 57% reduction in the number of families (Sepkoski, 1986) and an estimated 96% extinction at the species level (Raup, 1979). Oceanic life suffered the most but terrestrial life forms were also greatly affected. There was a 77% reduction in the number of tetrapod families (Maxwell and Benton, 1987). All major groups of oceanic organisms were affected with the crinozoans (98%), anthozoans (96%), brachiopods (80%) and bryozoans (79%) suffering the greatest extinction (McKinney, 1987).
The end of the Permian and beginning of the Triassic periods marked the single greatest extinction event the world has ever faced.Timing of the ExtinctionThere are many questions regarding the timing of the extinction at the end of the Permian. One of the main questions was the even a catastrophy or gradual. There is evidence for both senarios. Some of the evidence supports an ectraterrestrial even such as a metior.
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..., Palaeoclimatology, Palaeoecology, 102: 215-237.Xu Dao-Yi, and Yan Zheng., 1993, Carbon isotope and iridium event markers near the Permian/Triassic boundary in the Meishan section, Zhejiang Provence, China. Palaeoecology, 104: 171-176.Xu, D.-Y., Ma, S,-L., Chai, Z.-F., Mao, X.-Y., Zhang, Q.-W. and Yang, Z.-Z., 1985, Abundance variation in iridium and trace elements at the Permian/Triassic boundary at Shangsi in China, Nature, 314 (6007): 154-156.Xu, D.Y., Zhang, Q.W., Yan, Z., Sun, Y.Y., Chai, Z.F., and He, J.W., 1989. Astrogeological Events in China. Geological Publishing House, Beijing, Von Nostrand Reinhold, New York and Scottish Academic Press, Edinburg, 264pp.These sources mostly have come from the University of Alberta. I used the "Gate" and databases to get periodicals and books. Some of the sources came from the internet. I emailed some of the authors and they sent their papers to me by email. Some I got from web sites. I have no web sites posted in my sources because all the only information I took was when the paper and its source was displayed. I didn't quote or use internet sources because they are not reliable and most are based on opinions and not science.
The Permian-Triassic Extinction is a mass extinction that occurred between the Permian and Triassic geologic time periods approximately 250 million years ago; it is the deadliest of all extinctions that have occurred on Earth. In addition, during the Permian-Triassic extinction the continents of today existed as one supercontinent known as Pangaea. This was the first time in history where continental or land mass exceeded that of the ocean. This was also before dinosaurs of the Triassic period roamed Earth, during this time animals such as the therapsids, and Synapsids such as the Pelycosaurs, insects and amphibians also occupied Earth. Fauna that existed during the Permian period includes Gymnosperms, or seed producing plants such as the Conifers. Other animals that existed during this time include marine life such as brachiopods (clams), bryozoans (coral-like skeletons), bony fish and sharks, as well as crinoids (sea urchin like creatures). According to National Geographic, about 90 percent of all the animals and fauna of this period perished, the marine life was hit the hardest wi...
“...99.9 per cent of all [species] that have ever existed are now extinct.” (Benton 1) After one hundred and sixty million years of domination, the reign of the dinosaurs ended in fire and ice. Sixty five million years ago, the largest volcanoes in the history of the Earth erupted across what is now India, effectively annihilating the dinosaurs by spewing out noxious gas and ash, that effectively blocked out the sun killing off most vegetation and breaking the food chain, leaving the dinosaurs to starve. Compared to other groups of animals the dinosaurs were the most vulnerable to such a climatic event and the result was the end of the dinosaurs’ glorious evolutionary history.
So what killed the dinosaurs? Without having any background education in science it is hard for the general public to comprehend such matters and they rely on the knowledge of the scientists in this field. Although there has been much research on the subject nobody has come up with a conclusive answer. And we are left to read the countless articles, all having their own opinions as to the mass extinction. One such theory is that a shift in the solar system could have caused the mass destruction. According to an article published in Nature magazine,
As the decades pass, technological advances have enabled researchers, entrepenures and pondering minds the ability to discover more and more about every aspect of our very existence. Over the past three decades the evolutionary tree of life has been expanded at least seven times over. Major advances have been made in the area of evolution to open the eyes of many to the extensive history of the earth. For the very first time, we have tangible knowledge that life evolved and grew to become a flourishing success during the young ages of the Earth. By 3.5 million years ago life was already well advanced. Before this breakthrough no one could have thought that life occurred so amazingly early, that Earth was inhabited by a huge array of tiny life forms through t the first four-fifths of it’s existence, and no one deduced that evolution itself evolved over geologic time.
The Permian Triassic extinction was an event of cataclysmic disaster and almost the extinction of all species on planet earth. The Permian Triassic extinction is said to have occurred millions of years ago, geologist have estimated that its occurrences happened about 248 million to 286 million years ago. This rare occurrence of events proceeded the Triassic geologic periods and the Paleozoic and Mesozoic eras. This mass disaster was the largest dissipation of living life on planet earth; it is believed to be even superior to other crises such as the Ordovician and Devonian events and the conclusion of the cretaceous era that came upon the dinosaurs.
Throughout history, the world and its inhabitants have been subject to great change. Whether these changes are biological, ecological or geological they are all influenced by certain factors at play. Great changes take time to observe, usually longer than one's life would allow. The longer the change, the harder to identify the exact cause. When it comes to the species that inhabit the earth, it is notable that some species that lived and thrived long ago are now simply gone. The extinction of entire species of birds, mammals and amphibians occurs throughout time here on earth but the exact cause for their disappearance has been debated. In chapter two of "Twilight of the Mammoths" written by Paul S. Martin, the theories of extinction are challenged.
Throughout history our world has undergone and experienced all sorts of changes that have shaped the world into what we see it today. The most significant events included disasters like the extinctions of organisms. Out of all the extinctions, the most influential was the Permian Mass Extinction. During the Paleozoic era roughly eighty five percent of living species died and became extinct due to the Permian mass extinction. This illustrates how severe an event like the Permian mass extinction actually was. With such a prodigious magnitude, it’s important to note the consequences and results that aroused. In this case the most devastating consequence was its influence and alternation on the history of life. In addition, it is crucial to see the factors responsible for causing such immense extinctions, ultimately leading to what we call the Permian Mass Extinction.
The Permian Period occurred around 298 million years ago. It stretched from the Carboniferous Era to the Triassic. Sir Roderick Murchison in the early 1800’s noticed a differentiation among the overlay of the rock formation in the Ural Mountains in Russia. These rocks differed from the older Carboniferous rocks in Britain, and seemed younger than the Triassic rocks of Europe. Murchison named this differentiation after the prehistoric kingdom of Perm, thus the Permian Period.
Audesirk, T. (2003). Life on Earth. In (Ed.), (3rd ed., pp. 581-620). New York: Pearson Custom Publishing - Prentice Hall, Inc..
The most significant event of the Cretaceous era came at its end. Nearly 65 million years ago, the second most severe mass extinction in earth’s history occurred. This resulted in the loss of around 80% of species living at the time. Though nowhere near as severe as the end-Permian mass extinction, the end-Cretaceous extinction is the most well known mass extinction event. This is due to the violent event that caused it the extinction, as well as the chapter of earth’s history that it closed: the Dinosaurs. The Cretaceous Event ( often shortened to K-T event) Of the animals that were killed off were the flying reptiles (pterosaurs) and the last few mosasaurs and plesiosaurs, both early marine reptiles. Many mollusks and species of microscopic plankton were killed. Terrestrial plants suffered mass extinction as well. Almost 60% of terrestrial plants were lost. This led to high extinction rates among insect populations, especially insects that were highly specialized to feed on just a few types of plants had it the worst. It took approximately 9 million years for the global insect populations to recover from the Cretaceous extinction. Immediately after the extinction, the earth saw an explosion of short term species who respond well to fire, or other external disturbance. Evidence of the catastrophe comes from a thin rock layer deposited worldwide just after the impact. It is dominated by fossil plants whose descendants recover quickly after fires of other disturbances, such as Fire Weed in Alaska. The causes of the Cretaceous extinction are still being debated by paleontologists. Scientists agree that the main cause of the extinction was a...
living on earth disappeared. So how did these dominant creatures just die off? Was it a
Almost 23% of all families, 48% of all genera (20% of marine families and 55% of marine genera) and 70% to 75% of all species went extinct (Beaz). Although the cause of this mass extinction is debatable, many speculate that global warming was the killer. Because Pangea was breaking up into Laurasia and Gondwanaland, there was widespread volcanic activity caused by the rifting, increasing atmospheric carbon dioxide. The massive release of this greenhouse gas increased global air temperatures and resulted in acidified oceans along with rising sea levels. If this is the case, the life in the ocean would have died at a significant rate. Many families of brachiopods, gastropods, bivalves, and marine reptiles became extinct (Rafferty). An important trace fossil known as the phylloceratid ammonoid was able to survive, and they gave rise to the explosive radiation of cephalopods later in the Jurassic Period, as well as evolved into many different forms during the later Cretaceous (End Triassic Extinction). This extinction event ranks fourth in severity of the five major extinction events over geologic history
Similarly, the fossil record reveals profound changes in the kinds of living things that have inhabited our planet over its long history. Trilobites that populated the seas hundreds of millions of years ago no longer crawl about. Mammals now live in a world that was once dominated by reptilian giants such as Tyrannosaurus rex. More than 99 percent of the species that have ever lived on the earth are now extinct, either because all of the members of the species died, the species evolved into a new species, or it split into two or more new species.
Among the species that perished were the dinosaurs, pterosaurs, belemnoids, many species of plants, except ferns and seed-producing plants, ammonoids, marine reptiles and rudist bivalves. Severely affected organisms included planktic foraminifera, calcareous nannnoplankton, diatoms, dinoflagellates, brachiopods, mollusca, echinoids and fish. Mammals, birds, turtles, crocodiles, lizards, snakes and amphibians fared much better and were mostly unaffected by the End-Cretaceous mass extinction (“The End-cretaceous (K-T) Extinction”, accessed 2000...
The most popular theory of dinosaur extinction, the asteroid theory, says that dinosaurs died out because of a single, giant asteroid. They say that the asteroid that struck the earth near the Gulf of Mexico went 43,000 mph and spanned six miles wide (Erdman). When it hit the Earth the asteroid it left an enormous crater that measured 24 miles deep and 125 miles wide (Erdman). Just the impact of the asteroid destroyed the forests and landscape of the majority of North America due to its massive shock wave (Erdman). Many species went extinct when the asteroid hit, these species include dinosaurs, ammonites (certain ocean dwelling creatures), pterosaurs, and some plant groups dinosaurs, ammonites (mollusks related to the octopus and the chambered nautilus), pterosaurs, and certain plant groups. Although devastating, the asteroid did not wipe out all of the animals on Earth, it didn’t exterminate fish, frogs, turtles, birds, mammals and croco...