AP BIOLOGY

Detailed explanation-1: -A mass extinction is a short period of geological time in which a high percentage of biodiversity, or distinct species-bacteria, fungi, plants, mammals, birds, reptiles, amphibians, fish, invertebrates-dies out.

Detailed explanation-2: -A mass extinction event is when species vanish much faster than they are replaced. This is usually defined as about 75% of the world’s species being lost in a ‘short’ amount of geological time-less than 2.8 million years.

Detailed explanation-3: -These are called mass extinctions, when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1.

Detailed explanation-4: -Based on evidence in the fossil record, scientists have identified major extinction events at the end of these geologic periods: Cretaceous Period-66 million years ago. Triassic Period-201 million years ago. Permian Period-252 million years ago.

Detailed explanation-5: -Cretaceous-Paleogene extinction-66 million years ago The Cretaceous-Paleogene extinction event is the most recent mass extinction and the only one definitively connected to a major asteroid impact. Some 76 percent of all species on the planet, including all nonavian dinosaurs, went extinct.