LIFE ON THE EDGE: SURVIVING EARTH'S GREATEST EXTINCTIONS

Something almost exterminated all life. Not the majority. Not ninety-nine percent. Everything. Every organism. Every cell. Every form of life on Earth. The culprit was neither asteroid nor volcano. It was oxygen. The same gas that makes our existence possible. Two and a half billion years ago, oxygen was the deadliest poison. It poisoned oceans. Transformed atmospheres. Froze the planet.