The end Permian extinction as yett was the most devastating to organisms in Earth history. Some 70% of terrestrial species and 85% of ocean species became extinct. This paper explores the two major hypotheses that relieve oneself been suggested to explain this event.
single hypothesis that has been proffered to explain this mass extinction is the catastrophic asteroid impact hypothesis. There is evidence that an asteroid or comet could gift impacted the Earth causing a sudden enormous extinction event. The following is a brief description of the agile consequences of an asteroid impact on Earth. As a comet or asteroid entered the Earths breeze, the vaporized material would react over clipping and form small particles in the Earths stratosphere (Knoll, Bambach, Canfield, and Grotzinger (1996). These dust particles would then cease out the sun. The darkness would probably last a level best of a few months. The darkness would limit photosynthesis effectively cleanup position off many plants that could no longer produce decent life-sustaining energy. It follows then that the herbivores that feed on these plants would also pop to die moving on right down the viands chain.
The first piece of evidence for this hypothesis derives from limestone deposits that were discharged into the atmosphere.
A discharge of large masses of limestone released enormous amounts of CO2 into the atmosphere when the deposits were freed from the ocean. This was postulated to have been eventd by an impact by the asteroid (Retallack, Seyedolali, Krull, Holser, Ambers, and Kyte (1998). This would cause global warming for periods of several thousands of years. This warming effect is even worse because the asteroid would have had to hit limestone covered by water, so that a large amount of water would have vaporized. Water vapor acts as a strong glasshouse gas. The asteroid, during its travel through...
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