500
Biologists suspect we're living through the sixth major mass extinction. What are the names of the of the 5 previous extinctions?
End Ordovician, 444 million years ago, 86% of species lost
Late Devonian, 375 million years ago, 75% of species lost. ...
End Permian, 251 million years ago, 96% of species lost. ...
End Triassic, 200 million years ago, 80% of species lost. ...
End Cretaceous, 66 million years ago, 76% of all species lost.