Ancient predatory worms have scientists rethinking the history of life on Earth

500 million years ago, the world was a very different place. During this period of time, known as the Cambrian period, basically all life was in the water. The ocean was brimming with animals that looked pretty different from the ones we recognize today — including a group of predatory worms with a throat covered in teeth and spines. Researchers thought these tiny terrors died out at the end of the Cambrian period. But a paper published recently in the journal Biology Letters showed examples...