A strange layer in the fossil record contains evidence that fern populations exploded following the mass extinction that ended the Cretaceous period. Scientists want to know why.
Today’s extinction rates are sky-high. But scientists debate if that’s sufficient evidence to conclude that Earth is undergoing a mass extinction event—or whether that’s even a helpful designation.
Extinction is a natural part of life on Earth. But occasionally, extinction rates have surged far beyond usual levels, driving mass extinction events that have reshaped the trajectory of life.
More than two-thirds of mammals in Africa and the Arabian Peninsula went extinct during the Eocene-Oligocene transition some 30 million years ago, a study finds.