mass extinction
noun
plural mass extinctions
: an event in which many living species on Earth experience rapid extinction rates during a relatively short period of geologic time
Unless climate change is curbed, Earth's oceans could see a mass extinction of marine life unlike anything the planet has seen for millions of years …—
Doyle Rice
Doyle Rice[Paleobiologist Anthony] Barnosky calculates that humans are now creating a mass extinction. … As many as 30% of all species may be lost over the next four decades, conservationists estimate.—Gaia Vince
Gaia Vince
specifically
: a rare event in which seventy-five percent or more of all living species on Earth die out within a relatively short period of geologic time and that is usually associated with catastrophic natural phenomena (such as volcanic eruptions or asteroid impacts)
… the most recent of five events in Earth's history that scientists consider mass extinctions, defined by paleontologists as events where more than 75 percent of species vanish within a geologically short period of time, typically less than two million years. —Katarina Zimmer
Katarina Zimmer About 252 million years ago, the vast majority of species on Earth were killed off in the "Great Dying," the worst mass extinction in our planet's history. Up to 96% of all marine species and 70% of land animals were killed off during this event … —Peter Kotecki
Peter Kotecki We are still far from meeting the requirements that paleontologists set for a "mass extinction event" (loss of 75 percent of species globally). However, in geologic time, we are moving towards that reality. —Gabe Allen
Gabe Allen The Triassic mass extinction event took place 200 million years ago, eliminating about 80% of Earth's species, including many types of dinosaurs. —Tammana Begum
Tammana Begum Examples of mass extinction in a Sentence
Recent Examples on the Web
After a meteor contributed to a mass extinction event that killed of all the dinosaurs, only the aquatic and semi-aquatic crocodylomorphs remained.
—Paul Smaglik, Discover Magazine, 16 Apr. 2025
To find answers, a team of scientists studied North America’s fossil record, focusing on the 18 million years before the mass extinction at the end of the Cretaceous period.
—Kimberly Richardson, CNN Money, 15 Apr. 2025
If Earth were to take a direct hit from such a jet, the high-energy particles within it could degrade our ozone layer and lead to a mass extinction.
—Robert Lea, Space.com, 24 Mar. 2025
The team suggested a supernova may have stripped the ozone layer that shields the Earth from damaging radiation, resulting in a chain of events that could cause a mass extinction.
—Katie Hunt, CNN, 20 Mar. 2025
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Paul Smaglik, Discover Magazine, 16 Apr. 2025
To find answers, a team of scientists studied North America’s fossil record, focusing on the 18 million years before the mass extinction at the end of the Cretaceous period.
—Kimberly Richardson, CNN Money, 15 Apr. 2025
If Earth were to take a direct hit from such a jet, the high-energy particles within it could degrade our ozone layer and lead to a mass extinction.
—Robert Lea, Space.com, 24 Mar. 2025
The team suggested a supernova may have stripped the ozone layer that shields the Earth from damaging radiation, resulting in a chain of events that could cause a mass extinction.
—Katie Hunt, CNN, 20 Mar. 2025
See All Example Sentences for mass extinction
Cite this Entry
“Mass extinction.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mass%20extinction. Accessed 1 May. 2025.
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