They even managed to survive during times when the ocean lost its oxygen - including one such event in the Cretaceous period when many other, larger, species died out. As a refuge, sharks moved deeper underwater, say experts. And while there, they had another cunning trick. ⁠ ⁠ Some evolved the ability to glow in the dark. Sharks are older than trees. Sharks have existed for more than 420 million years, whereas the earliest tree lived around 350 million years ago.⁠ ⁠ _____⁠ ⁠ Source: New Scientist⁠ ⁠ ⁠ ⁠ #shark #sharks #evolution #evolve #science #biology