Asteroids.
Mass extinction is when many animals go extinct within a short period of time caused by the same variables/factors leading to the mass extinction.
We are still not sure what caused the mass extinction of the dinosaurs, though an asteroid impact seems to be the popular theory.Scientists believe we may be heading towards another mass extinction event.
The leading theory for the first mass extinction 65 million years ago is a catastrophic event such as an asteroid impact. This event is believed to have led to environmental changes that caused the extinction of the dinosaurs and many other species.
a comet impacting the earth
mass extinction
The k-t extinction marks the transition from the cretaceous to the tertiary period in which it is hypothesized that a meteorite struck the Earth and caused a mass extinction.
"It was the Cretaceous-Tertiary or the K-T Extinction." - WrongThe K-T Extinction was the mass extinction that wiped out the dinosaurs, which was more widely believed to be caused by a heavenly body colliding with the Earth.The mass extinction that involved a large period of glaciation was in truth the Ordovician-Silurian Extinction, which was the earliest mass extinction.The extinction is associated with a period of glaciation. First, sea levels dropped as glaciers formed. Later, as the glaciers melted, the sea level rose. The cause of this glaciation remains a mystery. One suggestion is land plants caused it by absorbing large amounts of carbon dioxide from the atmosphere. The drop in carbon dioxide could then have caused global cooling.
The effect of mass extinction is extinction, death of a mass
asteroid
There were five major extinction events in the past. They are called the Cretaceous-Tertiary (or K-T) extinction event, the late Devonian mass extinction, the Permian mass extinction, the Ordovician-Silurian mass extinction and the Triassic-Jurassic mass extinction event.
the holocene extinction
It has been speculated that the mass extinction of dinosaurs was caused by an asteriod, however there is not enough evidence collected to support this. It is still argued possible though.