Friday, March 19, 2004
Extinction
Cretaceous-Tertiary extinction (about 65 million years ago)
- The last mass extinction wiped out the dinosaurs and nearly half of the main groups of marine animals. Most likely cause was a collision with a large asteroid.
Triassic extinction (199m to 214m years ago)
- Killed nearly half of the major groups of marine wildlife. Believed to have been caused by undersea volcanoes.
Permian-Triassic extinction (about 251m years ago)
- The worst mass extinction, wiping out up to 95 per cent of species. Probably caused by volcanic eruptions or an asteroid.
Late Devonian extinction (about 364m years ago)
- Death toll estimated to be 22 per cent of marine families and 57 per cent of marine genera. No one knows why it happened.
Ordovician-Silurian extinction (about 439m years ago)
- Killed a quarter of marine families, including some bizarre creatures such as Hallucigenia (right). Believed to have been caused by a fall in sea levels as glaciers formed, then rising sea levels as glaciers melted. - Independent UK
Speaking of Hallucigenia sparsa, check that sucker out.
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