1. Invertebrate Diversity
Chapter 23
Invertebrate Diversity

2. 23.6 Echinoderms
A. What are echinoderms?
spiny-skinned animals with five-part radial symmetry, an internal skeleton, a water vascular system, and suction cup-like structures called tube feet
live in the ocean

3. B. Body Plan of Echinoderms
1. five symmetrical parts organized around a center
2. water vascular system: internal network of fluid-filled canals
a. madreporite: connects system to the outside

4. B. Body Plan of Echinoderms
b. ring canal: circles the digestive system in center
c. radial canals: extend into each body segment
d. tube feet: attached to radial canals; act like suction cups

5. Echinoderm anatomy

6. 2. Respiration: occurs through tube feet
23.6 Echinoderms
C. Form & Function
1. Feeding: use tube feet to pry open bivalve mollusks; some eat algae; others eat detritus
2. Respiration: occurs through tube feet
3. Internal Transport: digestive glands and body fluids

7. 6. Movement: tube feet and muscles
23.6 Echinoderms
C. Form & Function
4. Excretion: tube feet
5. Response
a. no head; primitive nervous system
b. eyespots sense light or dark
c. Protection: hiding; spines ineffective defense
6. Movement: tube feet and muscles

8. Tube Feet

9. C. Form & Function 7. Reproduction 23.6 Echinoderms
a. sexual; separate sexes or hermaphrodites
b. asexual; regeneration abilities

10. Regeneration

11. Regeneration

13. Brittle Star

14. Sea Urchin

15. Sea Urchin Skeleton

16. Sand Dollar and Sand Dollar Skeleton

17. Sea cucumber

18. Sea cucumber

19. Feather star

20. Feather star

21. Crinoid