1. Echinoderms
Phylum Echinodermata

2. Include sea stars, sea urchins, sea cucumbers

3. Have radial symmetry based on 5 parts (similar parts surrounding central axis) Planktonic larvae has bilateral symmetry
Considered to have oral/aboral sides, NOT dorsal/ventral

4. Body Structure Have a water vascular system-water filled canals
Tube feet-muscular extensions of these canals usually end in suckers used for attachment & locomotion

5. Ampullae-muscular sacs that sometimes fill tube feet with water
Madreporite-connects vascular system to outside on aboral (top) surface
Also has gonads & digestive system
No heart, brain or eyes

6. Complete digestive tract-stomach, digestive gland & anus
Endoskeleton-covered by a thin layer of tissue
Surface covered with bumps & spines giving them their name-”spiny skinned” (echinodermata)

7. Five classes 1)sea stars 2)brittle stars Class: Asteroidea
Subclass:Ophiuroidea

8. 3)sea urchins & sand dollars Class: Echinoidea
4)sea cucumbers
Class: Holothuroidea
3)sea urchins & sand dollars
Class: Echinoidea

9. 5)feather stars & sea lilies
Crinoidea

10. Sea stars (starfish) 5 arms to 50 Most are
predatory- bivalves, snails,
barnacle, etc.

11. Sunflower Star

12. Cushion Star

13. Brittle Stars Arms very long & flexible -tube feet lack suckers
Eat particles of
organic matter
passed from feet to mouth
More species than
any other group of
echinoderms

14. Basket Star (Brittle Star)

15. Brittle Stars

16. Sea Urchins & Sand Dollars
Filter feed on drifting plant/animals
Deposit feeders
that live on bottoms
using tube feet
lined with mucus to
pick up particles

17. Sea Urchins

18. Sand Dollars

19. Sea Cucumbers Wormlike, lack spines Tube feet around mouth reach
out and pick up
organic material
Escapes by
ejecting digestive
system distracting
predators

20. http://www. youtube. com/watch
Sea Cucumber

21. Feather stars & Sea lilies
5 to 200 arms
due to the
branching
Mucus helps
in catching food
Some attach to
bottom, some crawl
on surfaces in
shallow to deep water

22. Sea Lilies (with Stalks)
Feather
Stars (no
Stalks
Sea Lilies (with Stalks)

23. Biology Sexes are separate in most echinoderms External fertilization
Spawning occurs at once to increase survival

24. Echinoderms can use regeneration to replace missing parts
In some sea stars a severed arm can grow into a complete individual