Mass extinctions have occurred periodically throughout Earth's history, with the most severe being the End Permian extinction 250 million years ago which eliminated 90-95% of species. Other notable mass extinctions include the Ordovician extinction 445 million years ago which impacted 85% of species, the Late Devonian extinction 376 million years ago which impacted 70-82% of species, the End Triassic extinction 200 million years ago which impacted 76% of species, and the K-T extinction 65 million years ago which impacted 60% of species. Approximately 99.99% of all species that have ever lived are now extinct.

1. Mass Extinctions

2. things to note about Extinction Mass extinction vs. background extinction † (dagger symbol) next to a name indicates that organism is extinct Tyrannosaurus rex† Average “lifespan” of species

4. End Ordovician 445 mya Intense glacial activity Sea level changes Circulation & weather disruptions 85%, but no major groups

5. Late Devonian 376 mya Global cooling 70-82% gone

6. End Permian (Permo-Triassic) 250 mya 90-95% eliminated

7. End Triassic 200 mya 76% gone

8. K/T 65 mya 60% lost

9. A final thought… Approximately 99.99% of everything that has ever lived on Earth, over the past 3.6 billion years, is now extinct.