mass extinction
Scientific-
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.
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The most famous mass extinction included the destruction of the dinosaurs sixty-five million years ago. (See Alvarez hypothesis.)
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The end-Permian mass extinction, the most devastating die-off in Earth's history, struck about 252 million years ago and was followed by extreme global warming.
From Science Daily
Trematosaurids are especially significant because their fossils appear in coastal rock deposits formed less than 1 million years after the end-Permian mass extinction.
From Science Daily
Bodenham's discovery adds another piece to the growing diversity of animals living in this region during the Late Triassic before the Triassic–Jurassic mass extinction event caused by an increase in volcanic activity altering the climate.
From BBC
A deep-water fish called coelacanth similarly survived the mass extinction that wiped out all the dinosaurs that did not evolve into birds, he pointed out.
From Barron's
Scientists have warned that Earth is currently going through another mass extinction -- this one caused by humans.
From Barron's
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
