1. Echino= Spiny Derm = Skin
Echinoderms!
Echino= Spiny
Derm = Skin

2. Examples Ateroidea- Sea Stars Echinoidea- Sea Urchins, Sand Dollars
Holothuroidea- Sea Cucumbers
Ophiuroidea- Brittle Stars
Crinoidea- Feather stars, sea lillies

3. Sea Star Body Plan

4. Sea Star Anatomy 101
Sea stars have delicate skin stretched over a calcium- rich endoskeleton of spiny plates
Adults have 5 parts and radial symmetry
Absorb Oxygen through skin (brown spots)
Eyespot: At the end of each ray to detect light
Tube feet: With suction cups on bottom attach to surface and muscles pull sea star against them to haul itself along
Ampulla: Water-filled sack that contracts to extend tube feet.

5. Sea Star Anatomy 102
Madreporite: Sieve to allow water to enter vascular system
Ring Canal: Circular vascular tube that connects the madreporite to the arms (radial canal)
Stomach: Turns inside out, secretes digestive fluid, takes hours to fully digest
Anus: Releases waste out the top of the body
Digestive glands: Make digestive fluid
Gonads: Produce eggs/sperm, each arm has a set.

6. Sea Star Anatomy 103
Pedicellaria: Tiny pinchers on the skin surface to keep barnacles and other organisms from hitching a ride

7. Regeneration
Pieces of sea star can grow into a whole sea star if there is a piece of the radial canal.

8. Sea Urchins
Aristotle’s Lantern: 5 teeth

9. Sea Urchins Cont. Keyholes/Pores
Helps sand move up the body so that it can cover itself easier
Also can help move mucus toward the mouth

10. Elongated Echinoderms

11. Sea Cucumbers Live near rocky shores & on ledges
Leather body covering, very flexible