2 INVERTEBRATESAre animals which do not have a skeletonSize Most are very small, some such as giant squidsBody shape Most invertebrates are symmetrical but somehave irregular bodies.Body covering Many bodies are protectec by shells orexoskeletonsIn the seaIn fresh waterOn landThe invertebrates liveCan moveAttach themselves to rocks or the sea floorParasites: Live inside other animalsAre oviparousInvertebrates
3 INVERTEBRATES GROUPS Sponges Have irregular bodies. They cannot move Cnidarians Have jelly-like bodies. They have tentacleswhich can sting you.Worms Have long, sofl bodies. Some are cylindrical, and othersflat. Many are parasites.Echinoderms Are symmetrical. They have a skeleton made up ofhard plates.Arthropods Are covered by a hard exoskeleton. Some are aquatic.Molluscs Have a soft body. Many are covered by one or two shells
4 ARTHROPODS Arthropods have an external exoskeleton Made up of many small platesThe exoskeleton is rigid.From time to time the Arthropods sheds it ,andgrows a new ,flexible one.As a result arthropods growARTHROPODS GROUPSINSECTS Insects body is divided in three parts.the thoraxhas six legsARACHNIDS Have eight legs . Body divided in abdomen andcephalothoraxCRUSTACEANS Have ten or more legs . Body divided in abdomenand cephalothoraxMYRIAPODS Have long bodies with many legs. The head has onepair of short antennae.