Around 250m years ago at the end of the Permian era the Earth experienced its most dramatic loss of life, when an estimated 95% of marine species and 70% of land animals were wiped out. Scientists are uncertain what caused the extinction, but many suspect rapid environmental upheaval caused by vast volcanic eruptions were at least in part to blame.
Scientists at the Field Museum of Natural History, in Chicago, used a new database of fossil records to study how lifeforms in the oceans changed over 545m years. Instead of finding a gradual rise in different species, they spotted a sudden explosion in marine life shortly after what paleontologists call "the great dying".
more: The Guardian