Sea Stars
CLASS ASTEROIDEA
SPECIES OF Sea Stars
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ANATOMY OF Sea Stars
OVERVIEW
Sea stars are the most classic group of echinoderms! They belong to the class Asteroidea, which means “star-like” in Greek.
THEY REALLY DO LOOK LIKE STARS!
Most sea stars have 5 arms which are broadly connected to their central disc. This is different from brittle stars, which have thinner and longer arms that can be clearly distinguished from their central disc.
TURN YOUR STOMACH INSIDE OUT!
Sea stars roam the intertidal zone with their tube feet, looking for food. Many of them are fearsome carnivores, feeding on molluscs, crustaceans, bristleworms, and even other sea stars! Once they encounter potential prey, some sea stars use a gruesome but effective method to consume their prey. These menacing predators can evert their stomachs, turning them inside out and extending them out of their mouths to swallow their hapless prey whole!
THESE TUBE FEET ARE MADE FOR WALKING!
The underside of each arm of a sea star is lined with rows and rows of tube feet, which are housed within deep, open grooves or channels. By pumping seawater into their tube feet, sea stars use the strong water pressure to move their tube feet and crawl from place to place!