The Big Five Extinctions. Around 252 million years ago, ... there have been particularly notable disasters—mass extinctions and slightly lesser extinction crises.

The Big 5. These five mass extinctions have happened on average every 100 million years or so since the Cambrian, although there is no detectable pattern in their particular timing.

Five big mass extinction events are recognized by paleontologists. At the end of the Ordovician some 443 million years ago, when an estimated 86% of all marine species disappeared.

They are known ominously as the Big Five — the five greatest mass extinctions over the past 500 million years, each of which is thought to have annihilated anywhere from 50 to 95 percent of all ...

By simulating the movement of two continent-sized Big Lower-Mantle Basal Structures, or BLOBs, researchers may have uncovered ...

While the causes of the “big five” mass extinctions varied, understanding what happened during these dramatic chapters in Earth’s history — and what emerged in the aftermath of these ...

A new study explores one of the 'big five' mass extinctions, the Permian-Triassic event, revealing unexpected results about the types of animals that were most vulnerable to extinction, and the ...

Biologists suspect we’re living through the sixth major mass extinction. Earth has witnessed five, when more than 75% of species disappeared. Palaeontologists spot them when species go missing from ...

The "Big Five" mass extinctions are numbered. The shaded bands show the "recovery interval" -- the interval from the highest extinction rate (the peak on the middle graph, ...

While the causes of the “big five” mass extinctions varied, understanding what happened during these dramatic chapters in Earth’s history — and what emerged in the aftermath of these ...

(CNN) — No species lasts forever — extinction is part of the evolution of life. But at least five times, a biological catastrophe has engulfed the planet, killing off the vast majority of ...