Pre-lab Mrs. Trotter Vian Middle School Starfish (also known as Sea Stars)

Not real fish No backbone No fins

Kingdom-Echinodermata Have spiny skins Usually have 5 appendages There are over 6,000 species Radially symmetrical Echinoderm in Greek means “spiny skin”

Symmetrical As larvae they are bilaterally symmetrical As they mature they become radially symmetrical

Endoskeleton Spines – with canals located inside

Ray Each arm is called a ray Usually have 5 Has the ability to regenerate an entire organism IF is has one whole ray and at least a piece of the central disc (very slow- could take an entire year to regenerate)

Eyespot Each ray of a starfish has a light sensitive organ You can see it by spreading the tube feet at the tip of the ray It can’t see like you or I It only detects light and the direction it is coming from This gives them somewhat of an idea of where they are going

Anus Very inconspicuous Located on the dorsal or upper side in the center of the disc

Mouth In the center on the underside or ventral side

Feet Hundreds of tiny feet Tube fee or podia Suckers located on the ends of feet Capture and hold prey (clams) Capture and hold prey (clams Hold onto rocks in swift currents

How to dissect the specimen The dissection