GEOLOGY
THE PERMO-TRIASSIC EXTINCTION EVENT
At the end of the Paleozoic Era, the largest mass
extinction in history wiped out approximately 90% of all marine
animal species. The Permo-Triassic
extinction event was largest extinction event known
in the 4.5 Billion year history of the Earth. This event occurred approximately
245 Million Years ago and about 50% of all animal families became extinct at this
time.
At the end of the Paleozoic Era so many organisms became extinct that the
contrast between life before and after this event was recognized early on as
a basis for the division of the Paleozoic and Mesozoic Eras.
Nobody really knows exactly why organisms, present on the Earth before
man, went extinct. Several possibilities are:
Competition and predation from other organisms
Changes in the physical environment that the organism was not able to adapt to.
Chance events such as meteor impacts, volcanism, etc...
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