mass extinction

Scientific  

1. The extinction of a large number of species within a relatively short period of geological time, thought to be due to factors such as a catastrophic global event or widespread environmental change that occurs too rapidly for most species to adapt. At least five mass extinctions have been identified in the fossil record, coming at or toward the end of the Ordovician, Devonian, Permian, Triassic, and Cretaceous Periods. The Permian extinction, which took place 245 million years ago, is the largest known mass extinction in the Earth's history, resulting in the extinction of an estimated 90 percent of marine species. In the Cretaceous extinction, 65 million years ago, an estimated 75 percent of species, including the dinosaurs, became extinct, possibly as the result of an asteroid colliding with the Earth.

2. Compare background extinction

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mass extinction Cultural  

1. Any of several events in the Earth's past in which large numbers of species (in some cases, up to eighty percent) became extinct.

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Discover More

The most famous mass extinction included the destruction of the dinosaurs sixty-five million years ago. (See Alvarez hypothesis.)

Example Sentences

Mass extinction lurks beneath the surface of the sea.

From Salon • Jun. 17, 2022

Mass extinction, deforestation, eroding soils and melting ice shelves — climate change, he said, would soon bring with it an Old Testament plague of droughts and floods.

From New York Times • May 26, 2022

Mass extinction is the ultimate crisis, doom of all dooms, the disaster toward which all other disasters flow.

From New York Times • Jan. 6, 2021