1. http://www.bbc.co.uk/nature/history_of_the_earth

2. Ordovician-Silurian Mass Extinction: 440 million years ago

3. Ordovician-Silurian Mass Extinction 3 rd largest extinction in Earth’s history Actually had two peaks in which the extinction was the greatest over hundreds of thousands of years. During this time, most life on Earth existed in the oceans which is where the most damage occurred. Nearly 85% of sea life was wiped out The reason? The most accepted cause of this extinction was an ice age that not only caused drastic cooling but it caused sea-levels to drop

4. Late Devonian Mass Extinction: 360 million years ago

5. Also known as the “Kellwasser Event” 75% of all species on Earth died out Believed to have been a series of extinctions over millions of years Marine life was the worse affected with coral reefs suffering the most. Actually, coral reefs didn’t rebound until well over a 100 m.y. later! Bacteria was practically the only organism that could survive in the oxygen deprived oceans Unknown cause  theories include climate change, asteroid impact, invasion of new species affecting surrounding ecosystems. Late Devonian Mass Extinction: 360 million years ago

6. Permian Mass Extinction: 250 million years ago

7. Permian Mass Extinction: 250 million years ago Nicknamed “The Great Dying” for being the largest mass extinction in Earth’s history Killed 96% of marine life and 70% of terrestrial vertebrates Most likely happened over millions of years with several waves of extinction, as opposed to one large event Only mass extinction known to affect insects Possible Causes  first phase was probably due to global climate change, then increased volcanism, abundant release of methane which led to anoxia, sea-level change, a possibly a shift in ocean circulation due to climate change.

10. Triassic-Jurassic Mass Extinction: 200 million years ago

11. Triassic-Jurassic Mass Extinction: 200 million years ago 2 to 3 phases of this extinction over 18 m.y. Many animals died out; marine reptiles, amphibians, some reef-building communities About 50% of all life was predicted to have died out Plants, mysteriously, were not affected very much

12. Cretaceous-Tertiary Mass Extinction: 65 million years ago

13. Cretaceous-Tertiary Mass Extinction: 65 million years ago Also known as the K-T Mass Extinction Famous for the death of the dinosaurs Dinos, however, weren’t the only organisms to go extinct Ammonites Many flowering plants (angiosperms) Pterosaurs Theorized that flood basalt eruptions severely affected climate change and caused many of these species to be on the decline well before this extinction Huge asteroid hit in Yucatan Peninsula which pushed these dwindling species over the edge