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Mollusks 6 TH MR. FAIA 4/24/15 GRADE SCIENCE What are Mollusks? Mollusks are: Invertebrates Have soft bodies Unsegmented bodies Often have shells What are Mollusks? Mollusks also have a mantle Thin layer of tissue that covers organs Mollusks include clams, oysters, scallops, snails and octopuses What are Mollusks? The mantle also produces another structure, what do you think is? How do most mollusks move? Where do most mollusks live? What are Mollusks? Mollusks have bilateral symmetry Internal organs are all located in 1 area What are Mollusks? All mollusks have a pair of kidneys Removes waste produced by the cells What organ would most water dwelling mollusks have? It allows them to breath underwater Many mollusks have a radula Tiny ribbon of teeth that acts like sandpaper REVIEW 1) Describe the body of a mollusk. 2) What covers the internal organs? 3) List and describe 3 organs found inside a mollusk. 4) Where can mollusks live? 5) What type of symmetry do mollusks have? Early Mollusks Mollusks have been around about 540 million years Fossil shells were discovered in limestone rocks Types of Mollusks 3 major groups of mollusks Gastropods Bivalves Cephalopods Gastropod Largest group Includes snails and slugs Snails have shells, most slugs do not Can be found almost anywhere on earth Gastropod Can be herbivores, carnivores, or scavengers Snails can use their shell to escape predators or dry conditions Bivalves Means “two shells” Includes clams, oysters, scallops, and mussels Shells are held together by hinges and strong muscles Bivalves Bivalves do not have radula They are filter feeders What other animal(s) have we talked about that are filter feeders? Bivalves Bivalves use their gills to filter food Cilia on the gills move food into the mouth Bivalves Most bivalves either stay in 1 place or move slowly as adults Clams and scallops are the exceptions Bivalves Pearls are formed when sand or grit gets between the mantle and shell The mantle coats the grit Cephalopods Include: Octopus Squid Nautilus Cuttlefish Cephalopods Nautilus has a shell Squid and cuttlefish have a thin shell inside the body Octopus has no shell Cephalopods All cephalopods have tentacles The tentacles have suckers that can taste and touch Cephalopods Excellent Vision Very large nervous system Largest brain of any invertebrate Cephalopods All live in the ocean Swim by jet propulsion http://www.youtube.com/watch?v=AQL89ymGT_s Review What characteristics do most mollusks have in common? List the 3 groups of mollusks. How do bivalves get food? Which cephalopod has a shell? How old are mollusks? Give 2 examples of each type of mollusk. What is a mantle? What is a radula?
