Phylum Echinodermata

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

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

Echinoderm Diversity

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

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

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

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

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

Sunflower Sea Star – regenerating limbs lost to predators