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Invertebrates - Animals Without Backbones

Science, Grade 4

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sand dollar starfish clam foot hard shell earthworm dragonfly flat worm lobster spider hydra tentacle bud - new hydra Scientists classify animals into two major groups, vertebrates and invertebrates. Invertebrates are animals that do not have a backbone. Many invertebrates do not have hard body parts either, though some do. There are many different invertebrates living on Earth. In fact, most of the organisms living on Earth are invertebrates. Scientists classify invertebrates into broad groups called phyla, based on their symmetry and body plan. The major groups of invertebrates are cnidarians, echinoderms, mollusks, worms, sponges, and arthropods. Jellyfish (a cnidarian) have soft bodies and long stinging tentacles that are poisonous. Sea anemones look like flowers in the sea and live attached to objects on the ocean floor. Coral reefs are a mass or ridge of living coral that need sunshine and warm waters to survive. Coral reefs live in warm, shallow sea waters. Coral reefs provide a protective living environment for a large variety of invertebrate marine life. Crustaceans are arthropods and include crabs and lobsters. They have hard external shells that protect their soft bodies. They show bilateral body symmetry. nautilus - mollusk jellyfish fly shrimp - crustacean octopus- mollusk Cnidarians include hydra, jellyfish, and sea anemones. All cnidarians have stinging cells which they use to catch food. Arthropods are the largest animal phylum. Arthropods’ skeletons are on the outside of their bodies. All arthropods have segmented bodies and jointed legs. Insects, crabs, centipedes, millipedes, and spiders are all examples of arthropods. Worms are invertebrates that have long, soft bodies and no legs. Roundworms, such as earthworms, have segmented bodies which mean their bodies are divided into sections. Flatworms, such as tapeworms, have flat simpler bodies. Mollusks have soft bodies and most have shells. Snails, clams, and octopus are types of mollusks. Mollusks move by using a structure called a foot. Its foot produces slime that helps them move easier along the ground. Echinoderms are invertebrates that live in the ocean. Examples include starfish, sea urchins, sand dollars, and sea cucumbers. Echinoderms show radial symmetry. Invertebrates - Animals without Backbones © Copyright NewPath Learning. All Rights Reserved. 94-4402 www.newpathlearning.com Animal Kingdom Invertebrates Phylum • Cnidarians • Arthropods • Worms • Mollusks • Echinoderms • Porifera

Describe the following: Cnidarians ________________________________________________ __________________________________________________________ Arthropods _______________________________________________ __________________________________________________________ Roundworms ______________________________________________ __________________________________________________________ Flatworms ________________________________________________ __________________________________________________________ Mollusks _________________________________________________ __________________________________________________________ Echinoderms ______________________________________________ __________________________________________________________ Crustaceans _______________________________________________ __________________________________________________________ What are invertebrate animals? _____________________________________ _________________________________________________________________ _________________________________________________________________ How are invertebrate animals classified? ______________________________ _________________________________________________________________ _________________________________________________________________ What is a Coral reef? _________________________________ ___________________________________________________ ___________________________________________________ Key Vocabulary Terms • anemone • mollusk • arthropod • nautilus • classify • octopus • cnidarian • roundworm • crustacean • shrimp • echinoderm • spider • flatworm • sponge • insect • starfish • invertebrate • symmetry • jellyfish • tentacles Animal Kingdom Invertebrates Phylum • Cnidarians • Arthropods • Worms • Mollusks • Echinoderms • Porifera Invertebrates - Animals without Backbones © Copyright NewPath Learning. All Rights Reserved. 94-4402 www.newpathlearning.com \|xiBAHBDy01719mzV

Invertebrates - Animals Without Backbones

Science, Grade 4

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