252 Million Years Ago
DescriptionThe Permian-Triassic extinction also know as the Great Dying eliminates up to 96% of marine species and 70% of terrestrial vertebrate, which causes significantly longer than after any other extinction event recovery of life on Earth
RateVery important (8)
Many possible causes have been advanced to account for these extinctions. Some researchers believe that there is a periodicity to mass extinctions, which suggests a common, perhaps astronomical, cause. Others maintain that each extinction event is unique in itself. Cataclysmic events, such as intense volcanic activity and the impact of a celestial body, or more gradual trends, such as changes in sea levels, oceanic temperature, salinity, or nutrients, fluctuations in oxygen and carbon dioxide levels, climatic cooling, and cosmic radiation, have been proposed to explain the Permian-Triassic crisis.