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Million Years Ago 65 Million Years
2,114 wordsThe "Nemesis Theory" was an outgrowth of the discovery of Alvarez et al. , that the impact of a large (10 km diameter) comet or asteroid was responsible for the great mass extinction that took place 65 million years ago. Studies of the fossil record by Dave Raup and Jack Sepkoski shows that this was not an isolated event, but one of several mass extinctions that appear to occur on a regular 26 million year cycle. Their original paper analyzed marine fossil families, and was published in the Proc...
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The End Permian Mass Extinction
3,001 words... verify the Chinese reports of iridium and they are fruitless. Anomalies can cause a build up of iridium in one place which would lead to what the Chinese have discovered (Erwin, 1993). Cosmic Radiation Global Cooling Global Warming Salinity The hypothesis that salinity decrease caused the mass extinction of oceanic life was first formed by Beurlen in 1956 (Maxwell, 1989). Evidence for this phenomena was based mainly on stenohaline groups such as the bryozoans, ostracods and corals which were...
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Million Years Ago Permian Extinction
1,401 wordsAnthropology Is human extinction possible? Why does this happen? What causes a species to be extinct? Can human race prevent it? To answer these questions we must first define what extinction means, what types are there and why do they occur. As extinction is a continual product of natural selection, since the dawn of competition spawned by the first meiosis event, natural selection has altered all life on earth, precariously engaging in life experiments some that work and some that dont. Those ...
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Million Years Ago Mass Extinction
10,014 wordsEarth probably began Extinction Introduction Earth probably began about 4. 5 billion years ago. A history of this life on Earth is recorded in fossil remains and traces of past life. It is a record of evolution for both life and the planet. Life and the planet have co-evolved, with life causing changes to the planet which in turn drive changes in life. The Fossil Record A history of these changes is recorded in the layers or strata of rock laid down over the millions of years, and by changes in ...
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Million Years Ago 65 Million Years
1,623 wordsThe first question that must be posed when trying to crack the mystery of the mass extinction is to ask, throughout history were there any other occurences of this magnitude? The answer is a resounding yes. Altogether over time there has been about eight mass extinctions to large land dwelling vertebrates. The most recent was about ten thousand years ago, killing most of the giant mammals like mammoths, mastodons, super-large camels, saber-toothed tigers, and others (Bakker 428). The second ques...
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Permian Extinction Mass Extinction
6,021 wordsThe End Permian Mass Extinction Introduction Think of a world which existed 290 million years ago. As you look out over the trade 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 ...
Free research essays on topics related to: carbon dioxide, extinction, mass extinction, permian extinction, oceanic crust
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