1. Phylum Echinodermata

2. Adults exhibit pentamerous radial symmetry !!!
General Characteristics
Adults exhibit pentamerous radial symmetry !!!
Echinoderm larva

3. Possess a water vascular system.
General Characteristics cont.
Possess a water vascular system.
Canals are connected to extensions called tube feet (=podia), located on the oral surface
Important for locomotion, feeding, and gas exchange.
Sexes are separate; gametes shed into the water; fertilization is external

4. Echinoderm Diversity

5. Class Asteroidea
Mouth is located in the center of oral surface which is directed downward
Anus is on top

6. Water then passes through a radial canal extending into each arm
Water Vascular System
On the top surface is the opening of the water vascular system: the madreporite
Water then passes through a radial canal extending into each arm
All along the length of these canals are lateral canals that terminate in a bulb-like structures called ampulla equipped with tube feet
Madreporite  Ring Canal  Radial Canal  Lateral Canal  Ampulla  Tuble foot

7. Nutrition
Mouth leads to a 2-part stomach:
a large cardiac stomach and a smaller pyloric stomach

8. Body is enclosed in a shell or test
Class Echinoidea - Sea Urchins
Lack arms
Body is enclosed in a shell or test
Body surface is usually covered w/ moveable spines

9. Class Holothuroidea (Sea Cucumber)
Lack arms; soft bodied
Some species crawl using podia; others have peristaltic locomotion
Approaching extinction – medicinal properties
… Asia

10. Sunflower Sea Star – regenerating limbs lost to predators