AP BIOLOGY

Detailed explanation-1: -The Permian extinction, at the end of the Paleozoic Era, eliminated such major invertebrate groups as the blastoids (an extinct group of echinoderms related to the modern starfish and sea lilies), fusulinids, and trilobites.

Detailed explanation-2: -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-3: -The Paleozoic Era began with the Cambrian explosion. It ended with the Permian extinction. During the era, invertebrate animals diversified in the oceans. Plants, amphibians, and reptiles also moved to the land.

Detailed explanation-4: -The supercontinent Pangaea encompassed all of today’s continents in a single land mass. This configuration limited shallow coastal areas which harbor marine species, and may have contributed to the dramatic event which ended the Permian-the most massive extinction ever recorded.

Detailed explanation-5: -Three tests based on fossil data indicate that high rates of extinction recorded in the penultimate (Guadalupian) stage of the Paleozoic era are not artifacts of a poor fossil record. Instead, they represent an abrupt mass extinction that was one of the largest to occur in the past half billion years.