1. Echinoderms

2. Characteristics Kingdom: Animalia Phylum: Echinodermata
Means “spiny skinned”
Spines are part of the endoskeleton, not the skin!
Radially symmetrical as adults
All live in marine habitat
Eat shellfish, dead plants/animals & algae

3. The Nervous System Simple nervous system (no brain/ganglia)
Nerve ring: circle of nerve fibers around the mouth of an echinoderm
Radial Nerve: runs from the nerve ring to the tip of each arm in sea stars, controlling the arm
Simple eye: located at the end of each arm, it only senses light
The rest of the body is covered with cells that sense changes/chemicals in the water

4. Nervous System (con’t)
Simple Eye

5. Water Vascular System A system of canals filled with fluid.
Uses water pumps to help animal:
move,
eat,
breathe, and
sense its environment
** It’s like hydraulics! And only echinoderms have it.

6. Water Vascular System

7. Kinds of Echinoderms 5 Classes: Brittle Stars & Basket Stars
Sea Urchins & Sand Dollars
Sea Lilies & Feather Stars
Sea Cucumbers
Sea Stars (“starfish”)

8. Brittle Stars & Basket Stars
Look like sea stars, but have long, slim arms
Often smaller than sea stars
No suckers on their tube feet
Move more than other echinoderms

9. Sea Urchins & Sand Dollars
Round
Endoskeleton forms a solid, shell-like structure
No arms, but use tube feet to move
Sea urchins eat algae with special teeth
Sand dollars burrow in the mud and eat food they find there
Named for their coin-like shape

10. Sea Lilies & Feather Stars
5-200 feathery arms
Arms trap food
Sea lilies have a stalk, while feather stars do not
Like sea stars, brittle stars & basket stars, feather stars can re-grow lost arms.

11. Sea Cucumbers No arms Soft, leathery body
Long worm-like shape (unique!)
Move with tube feet

12. Starfish 5 planes of symmetry (Radial)
Eat by pushing their cardiac stomach out through their mouth, and then retracting it. The food moves into the pyloric stomach where digestive glands secrete enzymes to speed up digestion.
Endoskeleton made up of tiny calcium plates called ossicles.

13. Starfish Anatomy