1. Animals Chapter 2 Section 5 (p. 73-76)
Echinoderms

2. Vocabulary Echinoderm: Endoskeleton: Water vascular system:
radially symmetrical invertebrate that lives on the ocean floor
Endoskeleton:
spiny internal skeleton made of plates that contain calcium
Water vascular system:
fluid-filled tubes within the echinoderm’s body

3. The “Spiny Skinned” Animals
Echinoderms consist of
Sea stars
Sea urchins
sand dollars
Sea cucumbers
Characteristics
Radially symmetrical
Invertebrate
Live on the ocean floor

4. The “Spiny Skinned” Animals
Skin supported by an endoskeleton
Well numerous plates
Well defined rows

5. The “Spiny Skinned” Animals
Adult echinoderms have unique radial symmetry
Multiples of five
Arranged like the spokes on a wheel

6. Internal Fluid System Water Vascular System
Fluid filled tubes within the body
Tubes contract squeezing water to tube feet
External parts of the water vascular system

7. Water Vascular System Ends of tube feet are sticky
Small sticky suction cups when water filled
This enables tube feet to grip the surface
Tube feet used to move slowly along ocean floor

8. Radial Symmetry Echinoderm has not have a front with sense organs
Respond to food, mates or predators from any direction

9. Reproduction Either male or female Female releases eggs into sea water
Male releases sperm
Eggs fertilized in the water
Eggs develop into tiny swimming larvae
Undergo metamorphosis and become adults

10. Sea Stars Predators Use arms and tube feet to capture prey
Eat mollusks, crabs and other echinoderms
Use arms and tube feet to capture prey
Pulls closed shells apart
Forces stomach though its mouth and into the shell
Digestive chemicals break down the food
Sucks the food into its stomach

11. Sea Stars Regeneration:
Can regrow an arm if lost
Some sea stars reproduce by splitting into many parts
Regrow the missing parts

12. Brittle Stars Close relative to sea star Five long skinny arms
Flexible joints
Can regenerate limbs
Tube feet have no suction cups
Used for catching food, not moving
Move by moving arms on ground

13. Sand Dollars Have no arms Look like large coins
Flat bodies covered with spines
Used to burrow in sand

14. Sea Urchins Body covered with movable spines
Spines cover central shell
Move by using bands of tube feet that extend between spines
Five teeth project from mouth
Scrape algae, crush coral and mollusk shells
Dig into crevises to hide

15. Sea Cucumber Look like leathery skinned cucumber
Live on sandy or rocky ocean floor
Colors: red, brown, blue or green
Soft flexible bodies
Tube feet on the underside
Used for crawling

16. Sea Cucumber Mouth at one end surrounded by tentacles Filter feeder
Lengthens tentacles to sweep food to mouth
Retracts tentacles back into body