Bizarre creatures like Dimetrodon ruled the world on land for about 60 million years. Their success came to a sudden and dramatic end 252 million years ago, when life crashed into a deep abyss from which it almost never recovered.
This was the single bleakest, most serious ever threat to prehistoric life on Earth, a time known as the Permian Mass Extinction.
By now all the Earth's landmasses had collided, forming a massive single supercontinent, Pangaea (the name comes from two Greek words: pan meaning "all", and gea, meaning "the Earth").
When enormous continental landmasses crash and collide, one thing is certain: there will be a huge increase in the number and violence of volcanoes. Experts think this is one reason why such a horrific mass extinction occurred 252 million years ago. An enormous super-volcano, located somewhere in what is now northern Russia, exploded with unprecedented fury. Initially it flooded about 200,000 sq km of land in Siberia with boiling hot lava (forming the Siberian Traps – an area larger than Florida). Then, amazingly, it kept erupting for more than a million years.
This massive eruption devastated the Earth's environment, triggering a catalogue of disasters. Even though the Permian Mass Extinction took place over an estimated 80,000 years, only the very toughest, most well-suited creatures survived the darkness and the enormous swings of temperature. Only those which luck had blessed with specific genetic differences that improved their chances of survival in those extreme conditions lived on. Everything else perished.
These were desperate times for the Earth, her life-support systems ailing from a string of unmanageably chaotic events.