The most recent of these, the K-T extinction, 65 million years ago at the end of the Cretaceous period, is best known for having wiped out the non-avian dinosaurs, among many other species.
Introduction of new competitor species are also a factor in extinction and often accompany habitat degradation, as well.
Today, extinction as a fact is accepted by almost all religious faiths, and views of God's nature and the relation between God and creation have been modified accordingly.
Some scientists speculate that there soon may be a loss of species 1,000 times the normal or background rate of extinction (CBC 1999).
Major climate changes, such as ice ages or asteroid impacts, and subsequent habitat degradation have been cited as major factors in many major extinctions in the past.
Most of these modern extinctions can be attributed directly or indirectly to human effects.
The history of extinction in "deep time" prior to humans comes from the fossil record.
The rate at which extinctions occurred prior to humans, independent of mass extinctions, is called the "background" or "normal" rate of extinction.
Regarding the possibility of extinction, small populations that represent an entire species are much more vulnerable to these types of effects.
Genetic and demographic phenomena affect the extinction of species.
Pseudoextinction, also called phyletic extinction, can sometimes apply to wider taxa than the species level.
Extinction has occurred throughout the history of living organisms and is usually a natural phenomenon.
Pseudoextinction for taxa higher than the genus level is easier for which to provide evidences.
The Permian-Triassic extinction alone killed off about 90 percent of marine species and 70 percent of the terrestrial vertebrate species alive at the time.
There have been at least five mass extinctions in the history of life prior to humans, and many smaller extinction events.
The moment of extinction is generally considered to be the death of the last individual of that species or group.
Just as extinctions reduce biodiversity by removing species form the earth, new species are created by the process of speciation, thus increasing biodiversity.
Pseudoextinction is a term used by paleontologists to refer to a situation whereby the parent species is extinct but daughter species or subspecies are still alive.
Some consider that humans are now playing a role in extinction "that previously was reserved for asteroids, climate changes, and other global-scale phenomena" (CBC 1999).
Extinction therefore becomes a certainty when no surviving specimens are able to reproduce and create a new generation.
Effects that cause or reward a loss in genetic diversity can increase the chances of extinction of a species.
According to the World Conservation Union, 784 extinctions have been recorded since the year 1500, the arbitrary date selected to define "modern" extinctions, with many more likely to have gone unnoticed.
Until recently, it had been universally accepted that the extinction of a species meant the end of its time on Earth.
Pinpointing the extinction or pseudoextinction of a species requires a clear definition of that species.
Extinction (or replacement) of species by a daughter species plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould and Niles Eldredge (1986).
Olivia Judson is one of few modern scientists to have advocated the deliberate extinction of any species.
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the Cretaceous–Tertiary (K–T) extinction, was a mass extinction of some three-quarters of the plant and animal species on Earth that occurred over a geologically short period of time, approximately 66 million years ago.