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Extinction

1. Cretaceous-Tertiary extinction
 Time – About 65 million years ago.
 Extinction Rate – 16% of marine families, 47% of marine genera, and 18% of land vertebrate families, including the dinosaurs.
 Possible Causes – Probably caused by an asteroid that created the Chicxulub crater. Other theories involve gradual climate change or flood like volcanic eruptions of basalt lava from the Decan Traps.
2. End Triassic extinction
 Time – Roughly 199 million to 214 million years ago.
 Extinction Rate – 22% of marine families, 52% of marine genera, and the vertebrate deaths are unclear.
 Possible Causes – Likely caused by massive floods of lava erupting from the central Atlantic magmatic province. This volcanism may have led to deadly global warming.
3. Permian-Triassic extinction
 Time – About 251 million years ago.
 Extinction Rate – 95% of all species, 53% of marine families, 84% of marine genera, and an estimated 70% of land species including plants, insects, and vertebrate animals.
 Possible Causes – It is suspected to have been caused by a comet or asteroid impact but no direct evidence has been found. Another theory is that it was caused by flood volcanism from the Siberian Traps, which led to rapid loss of oxygen in the seas. Some people believe that these two events are linked and that the impact may have caused the volcanism.
4. Late Devonian extinction
 Time – About 364 million years ago.
 Extinction Rate – 22% of marine families, and a small percent of marine genera, little is known about this event's on land organisms at that time.
 Possible Causes –The cause of this event is unknown.
5. Ordovician-Silurian extinction
 Time – About 439 million years ago.
 Extinction Rate – 25% of marine families and...