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
Mass Extinctions, Ancient Viruses May Hold Clues to Life’s Origins
Apr 03, 2009 |
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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 ...
Physicists Show that Correlated Environmental Variations Can Quicken Extinctions
Jan 13, 2009 |
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(PhysOrg.com) -- In general, population extinction is a natural process. For one reason or another, an estimated 99.9% of all species that have lived on Earth are now extinct. However, the reasons for a species ...
Killer algae a key player in mass extinctions
Space & Earth / Earth Sciences
Oct 19, 2009 |
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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 ...
A new day dawned fast: Recovery from marine mass extinction happened much faster than thought
Space & Earth / Earth Sciences
Oct 02, 2009 |
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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 ...
Reptiles stood upright after mass extinction
Other Sciences / Archaeology & Fossils
Sep 15, 2009 |
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(PhysOrg.com) -- Reptiles changed their walking posture from sprawling to upright immediately after the end-Permian mass extinction, the biggest crisis in the history of life that occurred some 250 million ...
Extinction runs in the family
Aug 06, 2009 |
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(PhysOrg.com) -- Global calamities like the one that doomed most dinosaurs forever alter the varieties of life found on Earth, but new research shows that it doesn't take a catastrophe to end entire lineages. ...
Crashing comets not likely the cause of Earth's mass extinctions: new research
Space & Earth / Space Exploration
Jul 30, 2009 |
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(PhysOrg.com) -- Scientists have debated how many mass extinction events in Earth's history were triggered by a space body crashing into the planet's surface. Most agree that an asteroid collision 65 million ...
Prehistoric Cold Case Hints of Interspecies Homicide
Other Sciences / Archaeology & Fossils
Jul 20, 2009 |
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(PhysOrg.com) -- The wound that ultimately killed a Neandertal man between 50,000 and 75,000 years was most likely caused by a thrown spear, the kind modern humans used but Neandertals did not, according to ...
54-million-year-old skull reveals early evolution of primate brains
Other Sciences / Archaeology & Fossils
Jun 22, 2009 |
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(PhysOrg.com) -- Researchers at the University of Florida and the University of Winnipeg have developed the first detailed images of a primitive primate brain, unexpectedly revealing that cousins of our earliest ...
Ancient volcano may have caused mass extinction
Space & Earth / Earth Sciences
May 28, 2009 |
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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.
New book suggests Earth perhaps not such a benevolent mother after all
Other Sciences / Archaeology & Fossils
May 20, 2009 |
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(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.
Fossil magnetism helps prove mass extinction theory
Space & Earth / Earth Sciences
May 04, 2009 |
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(PhysOrg.com) -- Were major extinction events real biological catastrophes or were they merely the result of gaps in the fossil record? Research by a team of geologists from the Universities of Bristol, Plymouth, ...
Geoscientist offers new evidence that meteorite did not wipe out dinosaurs
Space & Earth / Earth Sciences
May 04, 2009 |
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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.
Dinosaurs declined before mass extinction
Other Sciences / Archaeology & Fossils
Apr 30, 2009 |
4.1 / 5 (14) |
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Dinosaurs were dying out much earlier than the mass extinction event 65 million years ago, Natural History Museum scientists report in the Proceedings of the Royal Society journal today.
Evidence of the 'Lost World' -- did dinosaurs survive the end Cretaceous extinctions?
Other Sciences / Archaeology & Fossils
Apr 28, 2009 |
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The Lost World, Sir Arthur Conan Doyle's account of an isolated community of dinosaurs that survived the catastrophic extinction event 65 million years ago, has no less appeal now than it did when it was written a century ...
