The sea bed in the deep ocean during the Cambrian period was thought to have been inhospitable to animal life because it lacked enough oxygen to sustain it. But research published in the scientific journal Geology reveals the existence of fossilized worm tunnels dating back to the Cambrian period 270 million years before the evolution of dinosaurs. The discovery, by USask professor Brian Pratt, suggests that animal life in the sediment at that time was more widespread than previously thought. The worm tunnels—burrows where worms lived and munched through the sediment—are invisible to the naked eye. But Pratt “had a...