1. Echinodermata
“spiny skin”

2. Complete digestive system
Some are carnivorous, scavengers
Filter feeders, deposit feeders

3. 5 Classes Asteroidea – starfish Ophiuroidea – brittle stars
Echinoidea – sea urchin, sand dollar
Holothuroidea – sea cucumber
Crinoidea – sea lily

5. Asteroidea Starfish Arms extend from body, from central disk
Majority have 5 arms, can have up to 40
Some with structures called pedicellariae. Claw shaped used to remove organisms from settling on the surface.

6. Circulatory system Open circulatory system
Water vascular system. Transports oxygen through the body.
No heart.

7. Regeneration and Reproduction
Can regenerate arms
Some reproduce asexually
Most reproduce sexually. Separate sexes
Free spawners – release sperm and egg into water

8. Nervous system Nervous system allows for sensing the environment
Sensory cells – sense light, contact, chemicals, and water current

9. Feeding and Digestion Scavengers and carnivores
Feed on snails, clams, oysters, sand dollars
Complete digestive system
2 stomachs : cardiac stomach and pyloric stomach
Grasp prey with arms, evert cardiac stomach and secrete enzymes on prey to digest then suck them up

11. Class Ophiuroidea Brittle stars, basket stars
Not true sea stars but have similar body plan
The arms can measure over 3 feet across
Can live in tide pools to deep sea
Live in cold and warm water

12. Reproduction and Regeneration
Mostly reproduce sexually
Asexual by division or regeneration
Can regenerate lost limb

13. Feed on small organisms or can filter feed
Nervous system similar to starfish
Have no eyes only sense organs
Some can change color

15. Class Echinoidea Sea Urchin and Sand dollar
Sea urchin spines – some are barbed and some are hollow with venom
Sea urchins that have venom – dangerous to predators and swimmers

16. Reproduction Separate sexes Release sperm and egg into water
Some female sea urchins brood young externally
Most sand dollars have separate sexes but some are hemaphrodites

17. Feeding and Digestion Sea Urchin – herbivores, deposit feeder
Feed on algae
Well developed digestive system. Can process indigestible materials
Sand dollar – mouth and anus on the same surface (aboral surface)
Bury into sand allowing only mouth exposed to water current
Filter feeder
Capture particles by sticky mucous on tube feet.

18. Class Holothuroidea Sea cucumber Found all over the world
Range in size 3cm to 1 m long
Look like a worm
10 to 30 tentacles surrounding mouth
No skeletal structure. Body wall of muscle for support
Slow moving
Defense – ejecting intestines to confuse predators

19. Reproduction and feeding
Only sexual reproduction
Most fertilize externally
Few with internal fertilization and development
Some brood eggs in the tentacles
Deposit feeders
Trap particles on mucus covered tentacles and push into mouth to ingest

20. Crinoidea Sea lily, feather star Smallest class Common on coral reefs
2 body regions: 1) calyx – most organs contained. 2) Rays – use for feeding
Both mouth and anus found on oral surface
Filter feeders
Sexual reproduction
Regenerate lost body part

21. Economical Importance
Starfish – use as lime for farmers
Brittle star – once as food source, now more ornamental
Sea urchin – used for food, sushi
Sand dollar – ornamental
Sea cucumber – food and medical properties (cancer and arthritis)