Mollusks Phylum: Mollusca Sea Snail Cockle Shell Green Mussel Octopus

Mollusk Characteristics Soft-bodied invertebrate covered with protective mantle that MAY or MAY NOT form a hard, calcium carbonate shell Soft-bodied invertebrate covered with protective mantle that MAY or MAY NOT form a hard, calcium carbonate shell Have a muscular foot for movement which is modified into tentacles for squid & octopus Have a muscular foot for movement which is modified into tentacles for squid & octopus Complete, one-way digestive tract with a mouth & anus Complete, one-way digestive tract with a mouth & anus Have a fully-lined coelom Have a fully-lined coelom Cephalization - have a distinct head with sense organs & brain Cephalization - have a distinct head with sense organs & brain Have a scraping, mouth-like structure called the radula Have a scraping, mouth-like structure called the radula Go through free-swimming larval stage called trochophore Go through free-swimming larval stage called trochophore

Mollusk Characteristics Body organs called visceral mass lie below mantle Body organs called visceral mass lie below mantle Have circulatory, respiratory, digestive, excretory, nervous, & reproductive systems Have circulatory, respiratory, digestive, excretory, nervous, & reproductive systems Bilaterally symmetrical Bilaterally symmetrical Most have separate sexes that cross-fertilize eggs Most have separate sexes that cross-fertilize eggs Gills are used for gas exchange Gills are used for gas exchange Includes chitons, snails, slugs, clams, and oysters Includes chitons, snails, slugs, clams, and oysters

Class: Gastropoda Single Shell (uni-valve) Snails, conch, abalones, slugs Snails, conch, abalones, slugs Soft, inside body Soft, inside body Radula- mouth that scrapes food Radula- mouth that scrapes food Breathes through skin Breathes through skin Stomach footed Stomach footed Sea Butterfly Oyster Drill

Snail Slug

Class: Cephalopods No shells Head footed mollusks- ten tentacles Head footed mollusks- ten tentacles All salt water All salt water Squid, octopus, cuttlefish, nautilus Squid, octopus, cuttlefish, nautilus Some contain internal shell Some contain internal shell

Chambered Nautilus Octopus Squid

Class: Pelycypoda Hatchet footed- used for movement and to bury in the sand Hatchet footed- used for movement and to bury in the sand All have two shells (bi-valve) All have two shells (bi-valve) Produce three layers to shells Produce three layers to shells 1. Pearly layer- inside layer 2. Prismatic layer- middle layer 3. Horny layer- outside layer Made of calcium carbonate: thin membrane called mantle produces shell Made of calcium carbonate: thin membrane called mantle produces shell Mucus feeder- takes in water and filters microorganisms for food Mucus feeder- takes in water and filters microorganisms for food Breathes by gills Breathes by gills Clams, oysters, scallops, zebra mussels Clams, oysters, scallops, zebra mussels