Echinoderms are more closely related to chordates (our own phylum) than any other animal phylum: 

1. What features of echinoderms supports this observation? 

2. Echinoderms lack cephalization. What characteristics of this group de-emphasize the need for a head? 

3. What part of the water vascular system extends into each arm? 

4. Are echinoderms radial or bilateral in symmetry? Explain your answer. 

5. How would you distinguish the oral and aboral sides of a sea star?