mass extinction


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mass extinction

n.
The extinction of a large number of species within a relatively short period of time, as between the Cretaceous and Tertiary Periods when three-quarters of all species on earth, including most dinosaurs, became extinct.

mass extinction

A massive (>15%) and relatively abrupt reduction in the diversity and number of microbes, algae, fungi, protists, plants and animals on the planet.

Seven mass extinctions have have been identified according to the fossil record; the largest occurred in the Early Cambrian period (±500 million years ago) when there was ± 68% reduction in taxa.

mass extinction

any of the several episodes which have occurred throughout the evolution of biological organisms where there has been a period when organisms have disappeared from the fossil record relatively quickly and at a much greater rate than the background extinction. Such mass extinctions may well have resulted from several causes. The demise of the DINOSAURS at the end of the Cretacious (K/T boundary) was probably brought about by the earth being struck by an asteroid, the subsequent effects leading to the extinction of several groups of organisms. Climatic changes (some possibly caused by asteroid/comet impacts) also probably initiated some mass extinctions.
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Unlike other famous mass extinctions that can be tidily linked to discrete, apocalyptic calamities like meteor impacts or volcanic eruptions, there was no known, spectacularly destructive event responsible for the Lau/Kozlowskii extinction.
The warming climate likely would have been one of the biggest culprits in the mass extinction, he said.
As scientists have noted, a mass extinction was achieved when the natural carbon cycle failed to compensate for such discarding.
But is the claim that we are undergoing mass extinction event to rank alongside the five major wipeouts of the last half-billion years justifiable?
Barnosky was the co-author of a study published last year that found an "exceptionally rapid loss of biodiversity over the last few centuries, indicating that a sixth mass extinction is already under way."
* The Permian mass extinction also nicknamed The Great Dying was a die-out when a staggering 96% of species were lost.
"Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now," said Matthew Clarkson, of the University of Edinburgh's School of GeoSciences, who coordinated the study.
Millions of years from now, the planet will be inhabited only by the descendants of those creatures that survive this new mass extinction. And it's not taken for granted that we will be among them.
This increase may represent the recovery and radiation of the conodont fauna after the Late Ordovician mass extinction. Chen et al.
Mass Extinction: Life at the Brink tells that story.
Mass Extinction Looks Like a GMO Field in Iowa The Long Now Foundation - Our planet gets up to no end of apocalyptic-like tricks over time periods when it is nearly all ice, all melting ice, all desert, all sea water, all molten lava, and civilizations come and go, sometimes for geological or climate reasons.
FOR five million years after the worst mass extinction in Earth history, much of the planet was simply too hot for anything to survive, scientists have learned.