The Cretaceous Extinction Event Essay

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Cretaceous Extinction Event
Causes, Evidence, and Effects on Biodiversity

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
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The effects of the collision were catastrophic. Scientists believe that the asteroid caused a period of cold climate due to dust blocking the heat of the sun, a subsequent period of hot weather, as well as global forest fires. Regardless of what caused the extinction of the dinosaurs, the mass extinction at the end of the Cretaceous set the stage for a rapid rise to dominance of new groups of species during the following time period, the Paleocene, and then later the Cenozoic era. The species group that rose the fastest were the Paleocene Mammals, they would go on to fill many ecological niches left by the dinosaurs.
There have been many hypotheses offered about what caused the K-T extinction, however very few of them have been given serious consideration by the scientific community. The extinction poses a puzzle that paleontologists, biologists and geologists have been trying to solve for over 200 years. Scientific Hypotheses include disease, freezing cold spells, a gamma ray burst (an extremely energetic burst of x-rays released by a super-massive supernova) striking earth, heat waves resulting in populations becoming sterile, and the rise of egg eating mammals. However, since its inception in 1980 by the Walter and Luis Alvarez, the Asteroid Theory has retained much of the focus of the scientific community. This theory states that a meteorite or comet impact could have triggered the K-T event by sending massive amounts of debris into the atmosphere, trapping

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