#ectinction

Earth’s first major extinction was worse than we thought

Fossil finds suggest nearly 80% of life on Earth died some 550 million years ago.

About 570 million years ago, life was confined to the seas. Large, strangely shaped invertebrates attached themselves to the sea floor, their fleshy fronds collecting nutrients that drifted by. These bizarre life forms, known as the Ediacaran biota, eventually disappeared. But researchers have long debated whether their die-off was truly cataclysmic. New research published in January in Geology now offers a reappraisal of the extinction that claimed many of these creatures, known as the Kotlin Crisis—and reveals that it may have been far more extensive than previously thought, extinguishing a similar percentage of species as the asteroid-driven calamity that killed the dinosaurs 66 million years ago. Although the Kotlin Crisis killed fewer total organisms than the Great Dying, the mass extinction that wrecked Earth approximately 252 million years ago, “the extinction rivals its [later and more famous] counterparts in terms of percentage of animals lost,” says Shuhai Xiao, a paleobiologist at Virginia Tech who was not involved with the research. The discovery helps clarify our messy and incomplete understanding of the rare Ediacaran biota...