Ancient diggers may have stirred up evolutionary forces
Worms may have first burrowed into mud more than 550 million years ago. The tunnels they apparently created, preserved in fossilized sediments and reported in a new study, could be the oldest example of animals significantly churning up the ground.
That newly plowed seafloor in turn might have helped to spur the rise of new kinds of macroscopic life late in the Ediacaran period — just before the Cambrian explosion produced most of the major animal groups around today.
“We think that Ediacaran organisms diversified as a reaction to habitat remodeling by … burrowing,” says Dima Grazhdankin, a paleontologist at the A.A.