Starting a new feature here! Every Monday, they’ll be a little overview of each of the five big mass extinctions, To start off, we’re going to do a bit of a general overview.
Around 99% of all species that have ever lived on Earth are extinct.1 However, this extinction rate is far from constant, as organisms are forced to adapt to new changes in their environment–which may suddenly be caused by catastrophic events.
Throughout Earth’s history, there have been five major categorized mass extinctions, where 50-90% of all living species have been wiped out in a rapidly short amount of geologic time.2 The causes of some of these extinctions are still a mystery, but rapid climate change, intense volcanism, and meteorite impacts have been accepted as triggers for massive die-offs.
Almost everyone is aware of the End-Cretaceous (K/T or K/Pg) mass extinction due to an endless fascination with dinosaurs, but that one was actually the least catastrophic. Here’s a look at the big five to see how they rank up:
CHRONOLOGICAL ORDER
1. End-Ordovician (440 Ma)
2. Late Devonian (365 Ma)
3. End-Permian (250 Ma)
4. End-Triassic (200 Ma)
5. End-Tertiary (65 Ma)
ORDER OF SEVERITY [most to least]
1. End- Permian (250 Ma)
2. End-Ordovician (440 Ma)
3. Late Devonian (365 Ma)
4. End-Triassic (200 Ma)
5. End-Cretaceous (65 Ma)
Be sure to check back next Monday to learn about the End-Ordovician mass extinction!
Emily Zawacki, Ph.D. 