by Frank Stephenson
It's been called "the mother of all mass extinctions." It happened about 251 million years ago—20 million years before the first dinosaur drew breath.
Earth scientists know it as the Permian mass extinction (so-named because it occurred at the end of Earth's Permian period). Also called "The Great Dying," the massive cataclysm was far more lethal than four other major mass killings recorded in the geologic record, including the one that doomed the dinosaurs.
The event hardly happened overnight—scientists believe the global carnage unfolded over at least a million years. When it was over, an estimated 96 percent of all the planet's marine life, along with 70 percent of all living things on land, was gone forever, never to be replicated. Some scientists believe that it took 30 million years for Earth to fully recover from its effects . . .