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Photo credit: MSC. What is a Mollusk?. Photo credit: NOAA. What are mollusks ? . Invertebrates Soft, unsegmented bodies Often but not always are covered by a shell Mantle – a thin layer of tissue that covers their internal organs
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What is a Mollusk? Photo credit: NOAA
What are mollusks? • Invertebrates • Soft, unsegmented bodies • Often but not always are covered by a shell • Mantle – a thin layer of tissue that covers their internal organs • Foot – an internal organ used for different uses based on the animal (ex. crawling, digging, catching prey)
The Mantle • Mantle secretes the shell and pearly lining • Univalve: 1 shell • Bivalve: 2 shells Photo credits: MSC
Mollusks & Movement • Foot • Muscular organ to move, dig, slide… • Radula • A flexible ribbon of tiny teeth to obtain food Photo credit: USGS
More Mollusk Info. * 100,000 known species * Most are Marine , but can live in fresh water and on land * Importance to man?
Classification • 7 Classes of Mollusks • 3 Major Classes • Gastropods • Snails, slugs, limpets • Bivalves • Clams, oysters, scallops, mussels • Cephalopods • Octopus, squid, nautilus Photo credit: NOAA
Body Structure: • Bilateral symmetry • One way digestive system