How many mass extinctions are recorded in the fossil record?

1 Answer
Oct 7, 2015

There have been five mass extinction that we know of.


There have been five mass extinctions that we are aware of, and scientists recently determined we are in the middle of a sixth mass extinction event
(Ceballos et al., 2015).

The first occurred 443 million years ago (mya) during the end of the geological time period known as the Ordovician. An estimated 85% of marine life went extinct during this time. An ice age is thought to be the cause of this event.

The second mass extinction occurred in the late Devonian, 359 mya. During this extinction event, the cause of which is still debated, 75% of all species died.

The third event was the Permian extinction event, during which 96% of all species on the planet went extinct. This happened 248 mya. This is widely considered the greatest mass extinction event of the earth's history.

The fourth event was the Triassic-Jurassic event which happened 200 mya. Half of all species went extinct.

The fifth extinction event is perhaps the most well known, as this is when the dinosaurs went extinct. The Cretaceous-Tertiary extinction occurred 65 mya and is also known as the K/T extinction event.

BBC Nature has an excellent series of webpages on mass extinctions that is worth checking out.

Read about the sixth mass extinction here .