1. Phylum Echinodermata
Starfish, sea urchins, sand dollars, sea cucumbers, brittle stars, basket stars, sea lilies, feather stars

2. Phylum Echinodermata “Spiny skin” 5800 species
Most exhibit radial symmetry
Most have an endoskeleton of plates call ossicles
Unique water vascular system

4. Starfish
5 or more arms tapering gradually from a central disc.

5. Water Vascular System
Series of canals and tubules for locomotion and food capture
Opens at the sieve plate on the dorsal surface
Controls water pressure in the tube feet

6. Tube Feet
Found in deep groves along the lower surface of the echinoderms rays
Joined by water canal that extends along the starfish rays to the ring canal within the central disc
Uses suction to grip onto things

7. Nutrition and Digestion
Uses tube feet to grab and pry open clams and oysters
Can extrude its stomach through its mouth which is located in the center of the ventral side and begin digestion externally.

8. Repiration/Circulation and Excretion
Skin gills, which are projections of the coelom, allow oxygen to be exchanged through the skin and waste to diffuse out.
Amoebocytes move through the fluid filled coelom and pick up waste. Amoebocytes leave through the skin gills carrying the waste with them.

9. Reproduction Separate sexes
Sexual reproduction through external fertilization
Regeneration
Regenerates lost rays
A ray can grow into a whole new starfish as long as it contains a small portion of the central disc
Ciliated larvae has bilateral symmetry

10. Nervous System
No brain or head, but does contain a nerve ring and nerve net, coordinates movement and transmits information from light sensitive eyespots at the end of each arm

11. Ecological Impact Hard to control
Can destroy a commercial shellfish bed in a short time
Some species eat coral polyps