Mollusks ZOOLOGY SBC Bill Palmer What is a

Mollusks ZOOLOGY SBC Bill Palmer

What is a Mollusk? Oysters, Clams, Snails, Slugs, Squid, Octopus Most are Marine, some freshwater, some terrestrial

What is a Mollusk? Some have a hard shell Bilateral Symmetry All have a mantle (membrane that surrounds the internal organs

How Mollusks Feed? Snails have a radula-teeth that scrape food Octopus and squid use radula to pull food into their mouths Bivalves (clams, oysters, mussels are filter feeders)

How do Mollusks Reproduce? Separate sexes-reproduce sexually Eggs and sperm are released into water and fertilization takes place in water Snails mate

How does the nervous system of Mollusks work? Simple nervous system Most have eyes (snails, squid) Scallops have many eyes

How does the Mollusk circulation system work? Three-chambered heart Open circulation system

How does the Mollusk Respire? Most have Gills Land snails and slugs have primitive lungs

How does the Mollusk Excrete? Mollusks have nephridia (kidneys)

How are Mollusks Classified? Gastropods One-shelled mollusk Stomach-footed mollusks Some have no shell (slugs) Abalones, snails, conches, periwinkles Protected by mucus May incorporate nematocysts of cnidarians

How are Mollusks Classified? Bivalves Two-shelled mollusk Most marine, some freshwater Use foot for burrowing 1 mm to 1. 5 meters (giant clam=5 ft) in length Filter feeders

How are Mollusks Classified? Cephalopods Head-footed mollusks All are marine Octopus, squid, cuttlefish, chambered nautilus Most evolved of all mollusks Foot is modified into tentacles with suckers Beak-like jaws Jet propulsion

How are Mollusks Classified? SQUID

How are Mollusks Classified? OCTOPUS

How are Mollusks Classified? CHAMBERED NAUTULIS CUTTLE FISH

Wrap-up 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Why is mucus important to a snail? How does the clam move? How does the cuttlefish move? How does the slug move? What is unique about the squids eyes? How many tentacles does an octopus have? Squid? What can a bivalve tell us about its environment? What do snails feed on? Why must all bivalves exist in a moist environment Complete the dichotomous key on page 746 Orca Book