Spiny skin, internal skeleton, water vascular system, and suction cuplike structures called tube feet. Most adults have 5-part radial symmetry. Echinoderms Starfish, Sea Urchins, Sand Dollars, Brittle Stars, Sea Cucumbers, Sea Lilies, Feather Stars

Environment Marine Habitats Help control populations of other forms of marine life. Food Source Carnivorous 5-part jawlike structure to scrape algae from rocks Tube feet along their arms to capture floating plankton Pushes its stomach out through its mouth, pours out enzymes and digests the mollusk in its own shell

Maintaining Homeostasis - Internal (Circulation, Respiration, Excretion) Most breathe through the thin-walled tissue in their tube feet Others have small outgrowths called skin gills Circulation through the water vascular system Nitrogen containing wastes are released out the anus Maintaining Homeostasis - External (Response) Have no head….no nervous system. Just a nerve ring around the mouth and radial nerves that connect the ring with the body sections

Movement Determined by the structure of the organisms exoskeleton (either spines or tube feet) Reproduction External fertilization Sexes are separate Evolutionary Milestone Deuterosomes (the first opening in the embryo becomes the anus during embryonic development) they are the first to have true body cavities.

Picture Fig p735 Vocabulary: endoskeleton (734); water vascular system (735)