AP BIOLOGY

Detailed explanation-1: -You probably know sea stars as starfish, the name sea stars are commonly known by. But sea stars aren’t really fish. Sea stars, like sea urchins and sand dollars, do not have backbones, which makes them part of a group called invertebrates.

Detailed explanation-2: -Sea stars are invertebrates related to sea urchins, sea cucumbers and sand dollars, which are all echinoderms. Echinoderm means spiny skin-a reference to their hard, calcified skin, which helps to protect them from predators. Sea stars have rows of tiny tube feet extending from the grooved surface on their underside.

Detailed explanation-3: -Starfish, like their close relatives sand dollars and sea lilies, are invertebrates, animals without backbones. It’s no wonder scientists prefer to call them “sea stars.” Starfish are certainly not the speediest creatures in the ocean, but they have a fascinating way of moving.