Dubbed "the Great Dying" or "the mother of all mass extinctions," the catastrophe occurred around 250 million years ago at the end of the Permian era.
The event may have unfolded over millions of years, and an increasing number of clues testify to its severity, include the discovery worldwide of eerie, fossilised, mutant plant spores. What is unclear, though, is what caused it.
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| Paleontologists uncover the bones of a "Southern Elephant" (archidiskodon meridionalis) in Stavropol, 2007. Scientists on Sunday said they had ruled out a key hypothesis to explain Earth's greatest extinction, when 95 percent of marine species and 70 percent of land species were wiped out. |
British researchers, reporting on Sunday in the journal Nature Geoscience, ruled out a leading theory that the oceans became starved of oxygen and rich with sulphide, causing marine life to die out.
