TRUE: Sea stars have an eye on the end of each arm. (Called an ocellus, it’s one of the simplest eyes in the animal kingdom and has no cornea or lens.)
TRUE: Sea stars have two stomachs. (Food begins in the cardiac stomach and moves to the pyloric stomach.)
FALSE: Sea stars have a water vascular system that filters toxins from the water.
While sea stars do have a water vascular system for movement, it does not filter water. The system consists of tons of tiny tube feet on their underside that suck up and force out water, creating enough hydraulic pressure for sea stars to move across the ground. Since there is no way to filter the water, they are extra vulnerable to water pollution; Think of sea stars next time you are choosing whether to use eco-friendly detergent for your laundry. For more tube feet awesomeness, watch the above video from the Seattle Aquarium.