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Extinctions are a normal part of the evolutionary process, and the background extinction rate is a measurement of "how often" they naturally occur.Normal extinction rates are often used as a comparison to present day extinction rates, to illustrate the higher frequency of extinction today than in all periods of non-extinction events before it.
Permian–Triassic extinction event 252 Ma Large igneous province (LIP) eruptions [ 23 ] from the Siberian Traps , [ 24 ] an impact event (the Wilkes Land Crater ), [ 25 ] an Anoxic event , [ 26 ] an Ice age , [ 27 ] or other possible causes
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth.Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms.
The causes of these extinctions are varied — land-use change, habitat loss, deforestation, intensive farming and agriculture, invasive species, overhunting and the climate crisis — but all ...
Limited geographic range is the most important determinant of genus extinction at background rates but becomes increasingly irrelevant as mass extinction arises. [45] Limited geographic range is a cause both of small population size and of greater vulnerability to local environmental catastrophes.
The Cretaceous–Paleogene (K–Pg) extinction event, [a] also known as the K–T extinction, [b] was the mass extinction of three-quarters of the plant and animal species on Earth [2] [3] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs.
Despite the world's last captive thylacine dying in 1936, the secretive animal wasn't declared extinct until 1986. More recently in 2007 the Baiji dolphin , a rare river dolphin native to China ...
At the time of the extinction, around 100 marine families became extinct, covering about 49% [20] of genera (a more reliable estimate than species). The brachiopods and bryozoans were strongly impacted, along with many of the trilobite, conodont and graptolite families. [10] The extinction was divided into two major extinction pulses.