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mass extinction
- 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.
- Compare background extinction
Notes
Example Sentences
The current rate of species decline is so great globally that many scientists warn humans could be causing the "sixth mass extinction" on Earth.
You’ve heard it before: we’re well into the sixth mass extinction of life on earth.
It's been observed that following these mega-death events, not only is there not nothing, but in fact in the years — actually, the hundreds of thousands or millions of years, because we're talking geological time here — following a mass extinction, there is often an explosion of biodiversity, with surviving species evolving new branches on their evolutionary trees.
It's almost as if the mass extinction process were clearing the way for this wild flourishing of new life you've planted.
If you find yourself mired in a system that’s sucking you ever forward toward mass extinction, a good first step would be to comprehensively and entirely opt out of that system.
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