5 Things to Know About Eyes | Explorer

Hi, I'm Michael Stevens, and these are five facts you need to know about the eye. Research into the evolution of the eye is creating all kinds of technological breakthroughs. Technologies like robots, drones, and cameras that can detect cancer earlier have all benefited from research into the eye.

Eyes didn't evolve linearly in animals like you and me. They didn't evolve from the oldest species to the youngest or from the simplest to the most complex. Instead, the eyes that animals have evolved independently to help them survive. Stereoscopic vision, that is, taking 2D images from our eyes and creating a 3D image in our brains, evolved from our needs to hunt for food.

Humans can see about 10 million different colors. This helps us select mates, but it's nothing compared to what other animals can do. Birds have four color receptors; we only have three, but that's nothing compared to the mantis shrimp, who has 12.

Animals with horizontal rectangular pupils, like goats, are able to physically rotate their eyes inside their heads when they put their heads down to graze. This protects them from predators. They can see what's in front of them while their head is down. It doesn't always work, but it has helped their species stay afloat, and that's what matters.