A twist in the story of volcanic eruptions and mass extinctions

An emerging scientific consensus is that gases—in particular carbon gases–released by volcanic eruptions millions of years ago contributed to some of Earth's greatest mass extinctions. But new research at The City College ...

Why bumble bees are going extinct in time of 'climate chaos'

When you were young, were you the type of child who would scour open fields looking for bumble bees? Today, it is much harder for kids to spot them, since bumble bees are drastically declining in North America and in Europe.

DNA extracted in museum samples can reveal genetic secrets

DNA in preserved museum specimens can allow scientists to explore the history of species and humanities impact on the ecosystem, but samples are typically preserved in formaldehyde which can damage DNA and make very difficult ...

An evolving understanding of extinction

Few things related to science capture the imagination more than the magic of worlds past. This includes the origins of life, dinosaurs, mass extinctions, meteorite impacts, and the evolution of our species. Understanding ...

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Extinction

In 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.

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