Echinoderms

1. Echinoderms “spiny skin”

2. Echinoderms: Main Characteristics Spiny Skin Exoskeleton Musculoskeletal 5 part radial symmetry Penta-radial Tube feet: Movement Water-vascular system Benthic organisms

3. Classes Asteroidea: Sea Stars Ophiuroidea: brittle stars Echinoidea: sea urchins and sand dollars Holothuroidea: Sea cucumbers Crinoidea: Sea Lilies and feather stars

4. Class Asteroidea : Sea Stars Aster = star, oides = in the form of Large Coelome Circulatory system: use diffusion & cilia to move gas, nutrients and waste Respiratory system: Dermal branchi on skin

5. Diagram the arm of the starfish

6. Asteroidea Digestive System: Mouth on underside Opens into cardiac stomach Folds out of body into prey to secrete enzymes Opens into the pyloric system Nutrients diffuse out of the pyloric stomach Eat: mollusks, crustaceans, polychaetes , coral, detritus

7. The Water Vascular System Who can explain how hydraulics work? Water Vascular System: Made up of a series of water-filled canals that run down the arms from a canal ring in the center Radial canal – ampullae – tubed feet

8. Water Vascular System

9. Asteroidea vs. Ophiuroidea Sea Star vs. Brittle Star Both can regenerate arms Sea Stars: Arms attached to arms Carnivores: Active Predators Brittle Star Arms NOT attached to arms Not active predators: eat plankton

10. Echinoidea: Sea Urchins Same structure, longer spines than starfish Move by means of tube feet Feeding Herbivores, feed on algae and marine plants Grazers Scrape food Roles: Control algae

11. Sea Cucumbers Elongated Body Plan Long sea urchin Tube feet to move Separate sexes Take organic nutrients out of sand Use oral tentacles Defense: release internal organs Tubules called cuvierian tubules: sticky and poisonous

12. Sea urchins and Sea stars feeding in the Antarctic http://dsc.discovery.com/videos/life-the-series-videos/?bcid=73073289001