Extinction : How Life on Earth Nearly Ended 250 Million Years Ago - Updated Edition

Omtale

Some 250 million years ago, the earth suffered the greatest biological crisis in its history. Around 95 percent of all living species died out--a global catastrophe far greater than the dinosaurs' demise 185 million years later. How this happened remains a mystery. But there are many competing theories. Some blame huge volcanic eruptions that cover