Related topics: climate change , dinosaurs , conservation
Extinction
hideIn biology and ecology, extinction is the end of a species or group of taxa. The moment of extinction is generally considered to be the death of the last individual of that species (although the capacity to breed and recover may have been lost before this point). Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "re-appears" (typically in the fossil record) after a period of apparent absence.
Through evolution, new species arise through the process of speciation—where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche—and species become extinct when they are no longer able to survive in changing conditions or against superior competition. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils, survive virtually unchanged for hundreds of millions of years. Extinction, though, is usually a natural phenomenon; it is estimated that 99.9% of all species that have ever lived are now extinct.
Prior to the dispersion of humans across the earth, extinction generally occurred at a continuous low rate, mass extinctions being relatively rare events. Starting approximately 100,000 years ago, and coinciding with an increase in the numbers and range of humans, species extinctions have increased to a rate unprecedented since the Cretaceous–Tertiary extinction event. This is known as the Holocene extinction event and is at least the sixth such extinction event. Some experts have estimated that up to half of presently existing species may become extinct by 2100.
For more information about Extinction, read the full article at
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News tagged with extinction
Superior Super Earths
Space & Earth / Space Exploration
Nov 30, 2009 |
4.6 / 5 (55) |
15
Super Earths are named for their size, but these planets - which range from about 2 to 10 Earth masses - could be superior to the Earth when it comes to sustaining life. They could also provide an answer to ...
Volcanic eruptions wiped out ocean life 93 million years ago
Space & Earth / Earth Sciences
Jul 16, 2008 |
3.8 / 5 (38) |
8
University of Alberta scientists contend they have the answer to mass extinction of animals and plants 93 million years ago. The answer, research has uncovered, has been found at the bottom of the sea floor where lava fountains ...
Mass Extinctions, Ancient Viruses May Hold Clues to Life’s Origins
Apr 03, 2009 |
4.7 / 5 (30) |
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(PhysOrg.com) -- Mass extinctions occur repeatedly, though irregularly, throughout Earth’s history, and occasionally these extinctions have been devastating to life on our planet - or have they? Extinction ...
New Blow for Dinosaur-Killing Asteroid Theory
Space & Earth / Earth Sciences
Apr 27, 2009 |
4.4 / 5 (29) |
14
(PhysOrg.com) -- The enduringly popular theory that the Chicxulub crater holds the clue to the demise of the dinosaurs, along with some 65 percent of all species 65 million years ago, is challenged in a paper ...
Canada's shores saved animals from devastating climate change 252 million years ago
Space & Earth / Earth Sciences
Oct 01, 2008 |
4.5 / 5 (26) |
7
The shorelines of ancient Alberta, British Columbia and the Canadian Arctic were an important refuge for some of the world's earliest animals, most of which were wiped out by a mysterious global extinction event some 252 ...
Geoscientist offers new evidence that meteorite did not wipe out dinosaurs
Space & Earth / Earth Sciences
May 04, 2009 |
4.5 / 5 (21) |
28
A Princeton University geoscientist who has stirred controversy with her studies challenging a popular theory that an asteroid wiped out the dinosaurs has compiled powerful new evidence asserting her position.
New book suggests Earth perhaps not such a benevolent mother after all
Other Sciences / Archaeology & Fossils
May 20, 2009 |
4.1 / 5 (21) |
15
(PhysOrg.com) -- In the past 50 years it has become commonplace to think of Earth as a nurturing place, straining mightily to maintain equilibrium so that life might continue and flourish.
Scientists offer new theory for largest known mass extinction
Space & Earth / Earth Sciences
Mar 30, 2009 |
4 / 5 (21) |
5
The largest mass extinction in the history of the earth could have been triggered off by giant salt lakes, whose emissions of halogenated gases changed the atmospheric composition so dramatically that vegetation ...
New report details historic mass extinction of amphibians
Biology /
Aug 11, 2008 |
4.4 / 5 (19) |
1
Amphibians, reigning survivors of past mass extinctions, are sending a clear, unequivocal signal that something is wrong, as their extinction rates rise to unprecedented levels, according to a paper published ...
Ancient volcano may have caused mass extinction
Space & Earth / Earth Sciences
May 28, 2009 |
4.3 / 5 (18) |
0
A previously unknown giant volcanic eruption that led to global mass extinction 260million years ago has been uncovered by scientists at the University of Leeds.
Geologic Findings Undermine Theories of Permian Mass Extinction Timing
Space & Earth / Earth Sciences
Mar 02, 2009 |
4 / 5 (19) |
3
(PhysOrg.com) -- New scientific findings by geologist Robert Gastaldo of Colby College in Waterville, Maine, and colleagues call into question popular theories about the largest mass extinction in Earth's ...
Killer algae a key player in mass extinctions
Space & Earth / Earth Sciences
Oct 19, 2009 |
4.4 / 5 (17) |
4
Algae, not asteroids, were the key to the end of the dinosaurs, say two Clemson University researchers. Geologist James W. Castle and ecotoxicologist John H. Rodgers have published findings that toxin producing ...
Down Under dinosaur burrow discovery provides climate change clues (w/ Video)
Other Sciences / Archaeology & Fossils
Jul 10, 2009 |
4.6 / 5 (16) |
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On the heels of his discovery in Montana of the first trace fossil of a dinosaur burrow, Emory University paleontologist Anthony Martin has found evidence of more dinosaur burrows - this time on the other ...
Research identifies brain cells related to fear
Jul 11, 2008 |
4.3 / 5 (16) |
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The National Institute of Mental Health estimates that in any given year, about 40 million adults (18 or older) will suffer from some form of anxiety disorder, including debilitating conditions such as phobias, panic dis ...
A new day dawned fast: Recovery from marine mass extinction happened much faster than thought
Space & Earth / Earth Sciences
Oct 02, 2009 |
4.8 / 5 (14) |
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(PhysOrg.com) -- In 1979, Luis Alvarez and his collaborators stunned the world with their discovery that an asteroid impact 65 million years ago probably killed off the dinosaurs and much of the the world's ...
