Causes of Earth's mass extinctions
The Meteor Crater impact event killed off most plant and animal life in the near vicinity, but it was nothing compared to our planet's mass extinctions.
By
Liz Kruesi Òš|Òš
Published: Monday, June 26, 2006
In Earth's modern history (meaning the time since complex life evolved on Earth), there have been five mass extinctions. These "big five" are the End Ordovician (roughly 440 million years ago), the Late Devonian (roughly 365 million years ago), the End Permian, or Permian-Triassic, (250 million years ago), the End Triassic (210 million years ago), and the Cretaceous-Tertiary (65 million years ago). Scientists say they know roughly when each occurred, but figuring out what caused each one is another story.