Earth has experienced five recognised mass extinctions. The Ordovician-Silurian mass extinction of 443 million years ago saw 83 per cent of sea life wiped out. In the Late Devonian mass extinction which followed 90 million years later three quarters of life on Earth became extinct . The Permian mass extinction of 248 million years ago was nicknamed The Great Dying as 96 per cent of species died out. Then 48 million years later half of Earth’s species were wiped out by climate change and asteroid impacts. The final one marked the end of the dinosaurs.