Transcript Mollusks - Mr. Vickers

Sea Snail
Mollusks
Cockle Shell
Phylum: Mollusca
Green Mussel
Octopus
Mollusk Characteristics
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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
Complete, one-way digestive tract with a mouth & anus
Have a fully-lined coelom
Cephalization - have a distinct head with sense organs &
brain
Have a scraping, mouth-like structure called the radula
Go through free-swimming larval stage called trochophore
Mollusk Characteristics
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Body organs called visceral mass lie below mantle
Have circulatory, respiratory, digestive, excretory,
nervous, & reproductive systems
Bilaterally symmetrical
Most have separate sexes that cross-fertilize eggs
Gills are used for gas exchange
Includes chitons, snails, slugs, clams, and oysters
Class: Gastropoda
Single Shell (uni-valve)
Snails, conch, abalones, slugs
 Soft, inside body
 Radula- mouth that scrapes food
 Breathes through skin
 Stomach footed
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Oyster Drill
Sea
Butterfly
Snail
Slug
Class: Cephalopods
No shells
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Head footed mollusks- ten tentacles
All salt water
Squid, octopus, cuttlefish, nautilus
Some contain internal shell
Chambered
Nautilus
Octopus
Squid
Class: Pelycypoda
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Hatchet footed- used for movement and to bury in the sand
All have two shells (bi-valve)
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
Mucus feeder- takes in water and filters microorganisms for food
Breathes by gills
Clams, oysters, scallops, zebra mussels