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					| The Permo-Triassic Extinctions |  
					| Lecture 22 4/22/98
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					| |  | Today we examine the largest extinction event in the earth's history. | 
 |  | The Permo-Triassic extinction is focused on the marine biosphere. | 
 |  | Land plants and animals are less affected by the extinction. | 
 |  | The causes for the extinction remain unclear. | 
 | Permo-Triassic Extinctions | 
 |  | 90-95% of fossil organisms | 
 |  | focused on marine organisms | 
 |  | Number of marine families is halved | 
 |  | extinctions focused at species level | 
 |  | stratified, anoxic oceans | 
 |  | sudden increases CO2 levels in shallow waters | 
 
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