Biology Chapter 15-4

Biology Chapter 15-4 - A system of canals filled with...

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Chapter 15 Section 4 - Echinoderms Echinoderms “Spiny skinned” invertebrates Starfish, sea urchins, and sand dollars All are marine animals. Live on ocean floor. Some eat shellfish, some eat dead plants and animals, and some eat algae. Although the name echinoderm means “spiny skinned”, the animal’s skin is  not the spiny part.  The spines are on the animal’s skeleton. The echinoderm’s internal skeleton is called an endoskeleton . The skin covers the endoskeleton. Nervous System Echinoderms have a simple nervous system. It is similar to a jellyfish. Around the mouth is a circle of nerve fibers called the nerve ring. In a starfish, there are radial nerves that run from each arm. They control the movement of the arms. At the tip of each arm is a simple eye that senses light. Water Vascular System
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Unformatted text preview: A system of canals filled with fluid. Uses water pumps to help the animal move, eat, breathe, and sense its environment. 1 Kinds of Echinoderms 5 major classes: Sea Stars (starfish) Brittle Stars and Basket Stars Sea Urchins and Sand Dollars Sea Lillies and Feather Stars Sea Cucumbers Brittle and Basket Stars Have long, slim arms Often smaller than sea stars Do not have suckers on their tube feet. Sea Urchins and Sand Dollars round have no arms use tube feet to move Sea urchins eat algae. They chew with special teeth. Sand dollars bury into soft sand. They eat tiny particles of food found there. Sea Lillies and Feather Stars May have from 5 to 200 feathery arms. Stretch and trap small pieces of food. Sea Cucumbers Have no arms. Has soft, leathery body. Has a long, wormlike shape. 2...
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Biology Chapter 15-4 - A system of canals filled with...

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