(Ex. Sea Stars, Sea Urchins, Sand Dollars, Sea Cucumbers) Echinoderms (Ex. Sea Stars, Sea Urchins, Sand Dollars, Sea Cucumbers)

Generalities: Echinoderms belong to the Phylum Echinodermata Echinoderms have spiny skins. They have radial symmetry. They lack body segmentation. There are more than 5000 species of Echinoderms.

Types of Echinoderms

Sea Stars- Starfish Most starfish have 5 “arms”or rays. Starfish have tube feet for locomotion, and strong suction to hold them in place. They also have a water vascular system that enables them to store water in their tube feet so they can survive while the tide is out. They breathe through small gills in their skin. Their mouths are located on the underside of their bodies. Starfish can regenerate. (must have the central disc attached).

More Starfish Stuff Sea Stars are carnivorous,they eat mostly shellfish, snails, and barnacles. They use their tube feet to open the shells and then throw their own stomachs out into the shell to digest the meat before it’s brought back into its body! There are lots of different types of Sea Stars, about 2000 different kinds. Most Sea Stars have spiny skin.

Sea Star Anatomy

Sea Urchins Sea Urchins look like big pin cushions. They use these spines for protection against predators. They eat mostly algae. They live mostly attached to rocky crevices, which protect them from waves and tide surges.

Sea Urchin Anatomy

Sand Dollars Are found on the sandy shore or muddy bottoms. They feed standing on edge with their tube feet acting as filters. The star pattern seen on top of the sand dollars is actually caused by special breathing tube feet! The mouth is found on the under side of the animal.

Sea Cucumber Some Sea cucumbers are quite poisonous, and the poison has been used as an inhibitor of Cancer growth. Sea Cucumbers secrete a sticky glue as a defense mechanism that has been used as a bandage to bind wounds.

Sea Cucumber Anatomy