The Great Dying: The Causes and Evolutionary Effects of the Permian-Triassic Extinction
In the early nineteenth century, the famous French paleontologist and anatomist Georges Cuvier was convinced that the Earth and its species were not susceptible to evolution. In reference to the paleontological phenomenon that was the recently-discovered fossil record, Cuvier proposed that the Earth had undergone a series of great catastrophes (later termed “punctuated equilibrium”), and attributed the different time periods as intervals of major catastrophes, the last of which was the Genesis flood (Turner 1984). In Cuvier’s mind, the Earth was repopulated by remaining species that had survived the crisis. His theory thus supported Carl Linneaus’ idea that
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For centuries, the colossal evidence of faunal turnover has made it an important occurrence. The magnitude of the species-level extinction wasn’t known until Raup (1979) estimated that as many as 96% of all marine species may have died out. His procedure, which has since been thrown out, was to determine the percent of extinction for the higher taxonomic groups by referring to the general fossil record. He then employed the rarefication curve technique to calculate the percent of species extinction through the disappearance of higher groups (Briggs 1990). It has been subsequently discovered that that the fossil record as a whole cannot be used for entire analyses (Smith and Patterson 1988), but Raup’s numbers hold up nonetheless. Both Bergstrom (2009) and Benton (2005) confirmed Raup’s estimate of 96%. Further, an estimated 70% of all terrestrial vertebrates became extinct as well (Sahney 2008). Occurring 250 million years ago, the extinction reduced a record high of Palaeozoic species diversity to the lowest post-Ordovocian value of the entire Phanerozoic (Allison and Briggs 1993). The effects of the P/T extinction were also not attained again until the Cretaceous period (Benton 1995).
The diversity
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Jablonski (1994) calculated and compared the extinction events with one another to illuminate the stark difference between the P/T extinction (labeled “End-Permian” in the experiment) parallel to others. With End-Permian’s calculated species loss at 95%, the second-highest is the end of the Ordovician extinction with 85%. In the observed extinction of families, End-Permian reports an estimated 51%. The next highest estimate is End-Ordovician with 26%, and the End-Cretaceous which receives the lowest of 16%. The trend continues with the observed extinction of genera, with End-Permian at an estimated 82%, and End-Ordovician at 60%. In all of those metrics weighing biological loss, the P/T extinction is ahead by a minimum of 10% (Benton
In this paper Martin is arguing that late quaternary or near time extinctions where caused by human activity or as he calls it “overkill”. Martin recognizes that there have been many forces that have triggered extinctions in the planet on the past but disagrees with the idea that near time extinctions where caused by some commonly believed causes like climate change, disease or nutrient shortage. He argues that the arrival of humans to different continents, islands and the subsequent excessive hunting, the introduction of diseases and other competitors and predators was the cause of extinction of a great number of species “As our species spread to various continents we wiped out their large
In Charles Darwin’s life he had helped make a significant advancement in the way mankind viewed the world. With his observations, he played a part in shifting the model of evolution into his peers’ minds. Darwin’s theory on natural selection impacted the areas of science and religion because it questioned and challenged the Bible; and anything that challenged the Bible in Darwin’s era was sure to create contention with the church. Members of the Church took offense to Darwin’s Origins of Species because it unswervingly contradicted the teachings of the book of Genesis in the Bible. (Zhao, 2009) Natural selection changed the way people thought. Where the Bible teaches that “all organisms have been in an unchanging state since the great flood, and that everything twas molded in God’s will.” (Zhao, 2009) Darwin’s geological journey to the Galapagos Islands is where he was first able to get the observations he needed to prove how various species change over t...
In order to better understand these "implications," it is necessary to define and explain the major theories regarding North American megafaunal extinction. The two most widely supported theories are those of environmental change and overkill. Two theories finding less support within the field are those of hyperdisease and "keystone herbivores."
Charles Lyell was a British lawyer and one the smartest geologist known in his time. He was known as the author of the Principles of Geology, which helped popularize the theories and concepts of uniformitarianism. The Principles of Geology was the first book written by Lyell and explained the changes of the earth’s surface. He used the research and information in the book as his proof to determine that the earth was over 6,000 years old. The central argument in his book was “the present is the key to the past”, this meant that to find out what happened in the past you had to look at what was happening now. It explained that changes which happened in the past, were happening in the present, and will happen in the future. Lyell’s book was later published into three volumes from 1830-1833. After the publication, it gave him credentials as an important geological theorist. His book later influenced a young Charles Darwin. Lyell’s influential book led Darwin to follow his principles and they later became friends. Darwin began to explore the changes that happen on the earth and develop his theories of evolution, though Charles did not completely endorse Darwin’s theory of evolution. Lyell was a devout Christian and Darwin’s theory of evolution did not line up with his Lyell’s beliefs with natural selection. Darwin continued his research and beliefs of his own and became a scientist working with his theories of evolution.
The eradication of species numbers average at a toll close to one hundred percent of earths total living creatures. “It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct” (Sahney, and Benton 759). Not only where marine and terrestrial species effected but this catastrophic event is the only recogni...
Throughout Earth’s history there have been many changes. These changes have consisted of temperature fluctuations, atmospheric differentiations, extinctions of various plant and animal life, etc. Over time everything seems to have evolved in some way form or fashion. However, the Permian Era extinction was different from all the rest. This extinction affected every form of life, but especially the marine life. Researchers have stated that 93-97% of all Earths species went extinct during this period of time. This essay will explain how a once blossoming progressive era turned into Earths most catastrophic event.
[1] This problem with the theory of evolution was addressed by Stephen Jay Gould and other evolutionists. They postulated the punctuated equilibrium theory of evolution, which does not predict the numerous fossils predicted by the orthodox theory of evolution.
The disaster theory, Gould claims, is an example of good science. It has testable evidence and has an impact on studies in other fields of science, it develops further and explains why the extinction of dinosaurs occurred simultaneously with other events. This theory suggests that a large comet hit the Earth sixty five million years ago, causing the cloud of dust to rise into the sky and to block sunlight. As a result, world temperatures went down significantly, the ice age bega...
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...
The K-T Extinction occurred 65 million years ago. Many species perished in that extinction. Today evidence for this extinction can be seen in the fossil record. Biological, botanical and geological evidence at the Cretaceous – Tertiary Boundary show that some enormous event occurred that caused mass extinction of life on the Earth. Controversy about the cause of the K-T extinction exists with two main theories currently being in favour. One theory is called Intrinsic Gradualism and believes the cause of the K-T Extinction was a slow and gradual Earth generated event, caused by intense volcanic activity and the effect of plate tectonics. The second theory is known as Extrinsic Catastrophism and proposes that the K-T Extinction was caused by a sudden and violent catastrophic event such as the Earth being struck by a meteor or asteroid. The K-T Extinction supports the concept of Punctuated Equilibrium in evolution because surviving species evolved and others were exterminated. This creates the stepladder effect of evolution seen in the fossil record .
of species due to a variety of causes. Included is out competition, depletion of resources
middle of paper ... ... The Web. 13 Mar. 2014. The 'Standard' of the 'Standard'. Dinosaurs: Climate Change and Biodiversity."
Gould, Stephen Jay. "Evolution as Fact and Theory." The Norton Mix. Editor Katie Hannah. New York: W.W. Norton & Company, 2010. 110-119.
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
Lotze, Heike K., Marta Coll, Anna M. Magera, Christine Ward-Paige, and Laura Airoldi. "Recovery of Marine Animal Populations and Ecosystems." Trends in Ecology & Evolution 26.11 (2011): 595-605. Print.