the permian period ended in the greatest extinction of the
The Permian -- Triassic (P -- Tr or P -- T) extinction event, colloquially known as the Great Dying, the End-Permian Extinction or the Great Permian Extinction, occurred about 252 Ma (million years) ago, forming the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras. It is the Earth's most severe known extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct. It is the only known mass extinction of insects. Some 57% of all biological families and 83% of all genera became extinct. Because so much biodiversity was lost, the recovery of land-dwelling life took significantly longer than after any other extinction event, possibly up to 10 million years. Studies in Bear Lake County near Paris, Idaho showed a relatively quick rebound in a localized marine ecosystem, taking around 2 million years to recover, suggesting that the impact of the extinction may have been felt less severely in some areas than others.