Search results
Results from the WOW.Com Content Network
In the 1980s, Jack Sepkoski identified the Triassic-Jurassic boundary drop in biodiversity as one of the "Big 5" mass extinction events. [1] After the discovery that the Cretaceous-Palaeogene extinction event was caused by a bolide impact, the TJME has also been suggested to have been caused by such an impact in the 1980s and 1990s.
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 .
A growing number of scientists believe a sixth mass extinction event of a magnitude equal to the prior five has been unfolding for the past 10,000 years as humans have made their mark around the ...
Dresbachian extinction event: 502 Ma: End-Botomian extinction event: 517 Ma: Precambrian: End-Ediacaran extinction: 542 Ma: Anoxic event [45] Great Oxygenation Event: 2400 Ma: Rising oxygen levels in the atmosphere due to the development of photosynthesis as well as possible Snowball Earth event. (see: Huronian glaciation.)
Mass extinctions are characterized by the loss of at least 75% of species within a geologically short period of time (i.e., less than 2 million years). [18] [51] The Holocene extinction is also known as the "sixth extinction", as it is possibly the sixth mass extinction event, after the Ordovician–Silurian extinction events, the Late Devonian extinction, the Permian–Triassic extinction ...
Coextinction refers to the loss of a species due to the extinction of another; for example, the extinction of parasitic insects following the loss of their hosts. Coextinction can also occur when a species loses its pollinator, or to predators in a food chain who lose their prey. "Species coextinction is a manifestation of one of the ...
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.
Of the 1,189 migratory creatures studied, more than one in five are threatened.