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
The last European hadrosaurs lived in the Iberian Peninsula
Other Sciences / Archaeology & Fossils
Nov 05, 2009 |
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Spanish researchers have studied the fossil record of hadrosaurs, the so-called 'duck-billed' dinosaurs, in the Iberian Peninsula for the purpose of determining that they were the last of their kind to inhabit ...
Bacteria expect the unexpected: Scientists observe the emergence of a new adaptation strategy
Nov 04, 2009 |
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Organisms ensure the survival of their species by genetically adapting to the environment. If environmental conditions change too rapidly, the extinction of a species may be the consequence. A strategy to ...
Over 1,000 fish species 'threatened with extinction'
Nov 03, 2009 |
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More than 1,000 freshwater fish species are threatened with extinction, reflecting the strain on global water resources, an updated global "Red List" of endangered species showed Tuesday.
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 ...
The first neotropical rainforest was home of the Titanoboa
Other Sciences / Archaeology & Fossils
Oct 12, 2009 |
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Smithsonian researchers working in Colombia's Cerrejón coal mine have unearthed the first megafossil evidence of a neotropical rainforest. Titanoboa, the world's biggest snake, lived in this forest ...
Conservation targets too small to stop extinction: study
Oct 12, 2009 |
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(PhysOrg.com) -- Conservation biologists are setting their minimum population size targets too low to prevent extinction, according to a new study led by University of Adelaide.
Researcher studies monkeys in Africa to better understand virus evolution
Medicine & Health / HIV & AIDS
Oct 07, 2009 |
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(PhysOrg.com) -- Despite the importance of AIDS in human health, scientists still know very little about the diversity and ecology of AIDS-like viruses in nature.
Study: Endangered AK beluga whale group declining
Oct 07, 2009 |
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(AP) -- A government study found that a group of endangered beluga whales in Alaska is declining, raising concern that bolstered protection for the animals is not coming quickly enough.
Dinosaur-Killer was Soft on Algae
Space & Earth / Earth Sciences
Oct 02, 2009 |
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The asteroid impact that many researchers claim was the cause of the dinosaur die-off was bad news for marine life at the time as well. But new research shows that microalgae - one of the primary producers ...
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 ...
Hundreds of dinosaur nests found in India
Other Sciences / Archaeology & Fossils
Oct 02, 2009 |
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(PhysOrg.com) -- Geologists have discovered hundreds of fossilized nests each containing clutches of eight dinosaur eggs. The eggs were located in sand banks in Tamil Nadu in Southern India.
Researchers use computational models to study fear
Medicine & Health / Neuroscience
Sep 30, 2009 |
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The brain is a complex system made of billions of neurons and thousands of connections that relate to every human feeling, including one of the strongest emotions, fear. Most neurological fear studies have been rooted in ...
10 percent of world's major species at threat: report
Sep 29, 2009 |
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Almost 10 percent of the world's mammals, birds, reptiles, amphibians and fish are in danger of extinction due to climate change and other factors, according to an Australian report released Tuesday.
Fanged frog, 162 other new species found in Mekong
Sep 25, 2009 |
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(AP) -- A gecko with leopard-like spots on its body and a fanged frog that eats birds are among 163 new species discovered last year in the Mekong River region of Southeast Asia, an environmental group said ...
'McDonalization' of frogs: Frog fungus hammering biodiversity of communities
Sep 22, 2009 |
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Sometimes to see something properly, you have to stand farther back. This is true of Chuck Close portraits where a patchwork of many small faces changes into one giant face as you back away.
