Vocabulary0ssicle = protective spines on a sea

star

Ampulla = a bulb-like sac at the base of a tube foot that functions in movement

Bipinnaria = free swimming larva

VocabularyPedicellariae = pincer-like structure

that protects and cleans body surface

Madreporite = sieve-like plate on the abdomen where water enters

General Characteristics

A. Undergo Metamorphosis - Bipinnaria to bottom-dwelling adult

B. Endoskeleton = internal skeleton

C. Water Vascular System - aids in movement and feeding

General Characteristics

D. Tube Feet = help with movement, feeding, respiration, excretion

E. Nervous System - no head or brain

F. Fossils - date back to Cambrian period (over 500 million years ago)

G. Radial Symmetry

Reproduction

A. Asexual = regeneration (if part of central disk is attached)

B. Sexual = releases eggs from holes under arm; eggs form tiny swimming larvae; larvae settle on bottom & develops into sea star

Water Vascular System

(network of canals where muscle contraction permits movement)

A. Water enters sieve plate; passes through madreporite and down a canal

B. Radial canals carry water to tube feet

Water Vascular System

C. Muscles contracts forcing water into ampulla; creates suction; suckers grip surface

D. Ampullae contracts; water enters feet, releasing grip and feet extend

Other Echinoderms

A. Crinoidea “lily-like”= sea lilies and feather stars

EchinodermsB. Asteroidea “star-like” = starfish; live

in coastal waters and rocky shores

EchinodermsC. 0phiuroide “snakelike” = largest

class; basket stars and brittle stars

EchinodermsD. Echinoidea “hedgehog like” = sea

urchins & sand dollars

EchinodermsE. Holothuroidea = soft bodies;

armless sea cucumbers