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- Extinction: The death of an entire
species, the fact of becoming
extinct.
- Extinct: Having no living members, as is
the case with many organisms
known only from fossils.
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In
biology and
ecology, extinction
is the total and irreversible ceasing of existence or
disappearance a group of related
organisms (
species or higher
taxa), from a given
local habitat, geographic
area, or globally in the entire world (The term extinction is
also applied to the condition that occurs when the number of
individuals in a population
falls below the level that will allow for sustainable
reproduction or when
no living representatives of a species exist in the wild).
The moment of extinction is generally considered to be the death
of the last individual of that species.
Extinction is both a natural
(dinosaurs, trilobites) and human-induced
process (dodo, moa,
Thylacine); it is
estimated that 99.9% of all species that have ever lived are now
extinct. Extiction can result from various human activities,
including the destruction of habitats or the
overexploitation of
species that are hunted or
collected as a resource, but the most effective agent in the
extinction of species is the pressure of other species.
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