3Unifying Characteristics Spiny SkinInternal Skeleton – “endoskeleton”Water vascular systemMuscular tube feet (suction cup feet)Pentaradia Symmetry5 rays of symmetry
4Water Vascular SystemMadreporite - sieve-like opening to the water vascular system
5Water Vascular System Functions: Respiration Circulation Movement Ring & Radial CanalsTube FeetCirculationMovement
6Tube FeetEach tube foot is basically a suction cup, muscles pull up the centre of the cup causing suctionMany feet working together can exert huge force, allowing “walking” and attacking
7Groups of Echinoderms Sea Urchins and Sand Dollars Brittle Stars Grazers and DetrivoresSolid plates protect internal organsBrittle StarsFilter feeders and DetrivoresSlender/Flexible arms – detach and distractSea CucumbersDetrivoresEviscerate themselves as defence!Sea StarsPredatoryRegenerative if dismembered!Sea Lilies and Feather StarsFilter FeedersFeather dusters of the sea
8Sea Urchins and Sand Dollars Grazers and DetrivoresSolid plates protect internal organs
9Brittle Stars Filter feeders and Detrivores Slender/Flexible arms – detach and distract
10Sea CucumbersDetrivoresEviscerate themselves as defence!