Transcript Echinoderms
Echinoderms Sea Stars, Sea Urchins, Sand Dollars, Sea Cucumbers Kingdom Animalia, Phylum Echinoderms Greek: Echinos = “spiney”; dermos = “skin” Types of Echinoderms • They lack body segmentation. • There are more than 6000 species. Penta-Radial Symmetry in adults. Bilateral Symmetry in larva. Penta means: ______________ •Made of calcium carbonate plates and spines. Water-vascular System • A system of fluid-filled tubes that work together to enable echinoderms to move, get food, and circulate. • Tube foot: small, muscular fluid filled tubes that end in suction-cuplike structures. • • • • Three essential body functions. 1) Respiration 2) Movement 3) Digestion ____________: Living ____________,muscles that pull up the centre of the cup causing suction. Many feet working together exert force allowing it to “walk” and attack. Feeding and Digestion • Use tube feet (living suction cups) • Many sea stars push their _________ out of their mounts and onto the prey, they then spread digestive enzymes over the food to bring into the mouth. • Sea urchins use ____________s to scape off algae. • Others extend arms and trap food. Respiration • Diffustion • Some use tube feet to diffuse oxygen into the body. • Some use thin-skinned gills. • Sea cucumbers have branched tubes. Response • Nerve Ring that surrounds mouth with branching nerve • Nerve Cord connecting to other body parts. Reproduction + Development • Sexual • Females shed eggs and males shed sperm for external fertilization. • Fertilized eggs turn into free swimming larvae. Echinoderm Diversity Sea Star Anatomy Sea Urchins • Sea Urchins look like big pin cushions. • They use these spines for protection against predators. • The spines also act like stilts to keep their bodies up off the ground so the tube feet can pull them around! • They eat mostly algae. • They live mostly attached to rocky crevices, which protect them from waves and tide surges. • They have become a popular item to eat and are being harvested in alarming numbers. Sand Dollars • Are found on the sandy shore or muddy bottoms. • They feed standing on edge with their tube feet acting as filters. • The star pattern seen on top of the sand dollars is actually caused by special breathing tube feet! • The mouth is found on the under side of the animal. Sea Cucumbers • Sea cucumbers have tentacles at their mouth openings to grab and hold food. • Radial symmetry and spiny bodies like all other echinoderms. • When provoked, or annoyed, Sea cucumbers throw out their intestines to entangle, frighten, or confuse their predator. Then the intestines are regenerated. • They are filter feeders. • Sea Cucumbers are considered a delicacy in Asian cultures.