If you think asteroid strikes are scary, I've got some bad news for you. The most deadly events on Earth are caused by . . . Earth. New evidence suggests that underwater volcanoes may have wrecked our planet for thousands of years, and ultimately allowed dinosaurs to rule the world.
How the dinosaurs died is maybe the most well-known story in all paleontology, but the dinosaurs' origins are more obscure. Dinosaurs might well have gotten their chance to rule the planet from the very thing that later killed them off.
Sharks weren't always the huge, vicious alpha predators that they are today. Hundreds of millions of years ago, they were just another tiny little harmless fish species hanging out in lakes and rivers. So yeah...things have changed slightly since then.
About 230 million years ago, a tiny meat-eating dinosaur roamed South America looking for prey. It measured just four feet from long from head to tail, but it was the ancestor of all meat-eating dinosaurs, including the fearsome Tyrannosaurus rex.