GEOLOGY

Detailed explanation-1: -About 250 million years ago, at the end of the Permian period, something killed some 90 percent of the planet’s species. Less than 5 percent of the animal species in the seas survived.

Detailed explanation-2: -Scientists estimate about 90% of the plant and animal species on Earth during the Permian Period were extinct by the end of the period.

Detailed explanation-3: -Who became extinct? Important groups of marine animals disappeared at the end-Permian extinctions. Trilobites, which had lived in the oceans for more than 250 million years, were lost, along with tabulate and rugose corals.

Detailed explanation-4: -Scientists have debated until now what made Earth’s oceans so inhospitable to life that some 96 percent of marine species died off at the end of the Permian period. New research shows the “Great Dying” was caused by global warming that left ocean animals unable to breathe.

Detailed explanation-5: -Permian-Triassic extinction-252 million years ago The cataclysm was the single worst event life on Earth has ever experienced. Over about 60, 000 years, 96 percent of all marine species and about three of every four species on land died out.