Permian -- Triassic extinction event (End Permian): 252 Ma at the Permian -- Triassic transition. Earth 's largest extinction killed 57 % of all families, 83 % of all genera and 90 % to 96 % of all species (53 % of marine families, 84 % of marine genera, about 96 % of all marine species and an estimated 70 % of land species, including insects). The highly successful marine arthropod, the trilobite, became extinct. The evidence regarding plants is less clear, but new taxa became dominant after the extinction. The "Great Dying '' had enormous evolutionary significance: on land, it ended the primacy of mammal - like reptiles. The recovery of vertebrates took 30 million years, but the vacant niches created the opportunity for archosaurs to become ascendant. In the seas, the percentage of animals that were sessile dropped from 67 % to 50 %. The whole late Permian was a difficult time for at least marine life, even before the "Great Dying ''.
what was the biggest mass extinction in geologic time
Permian -- Triassic extinction event