Why some species died out and others didn’t during the Earth’s second largest mass extinction has been revealed in a new study.
It coincided with a short but intense ice age and California Institute of Technology (Caltech) researchers believe that species died out if large portions of their habitat were lost to ice sheets and falling sea levels.
Those that had always been confined to warm tropical waters were also most likely to go extinct as a result of the rapid climate change.
It has long been agreed that this even extinction was related to climate change, but exactly how the climate change produced the extinction has not been known.
The work – performed by scientists at Caltech and the University of Wisconsin, Madison – is described in a paper currently online in the early edition of the Proceedings of the National Academy of Sciences.
The researchers combined information from two separate databases to overlay fossil occurrences on the sedimentary rock record of North America around the time of the extinction, an event that wiped out about 75 per cent of marine species alive then.