MolluscaMollusca

4 classes near shore4 classes near shore Gastropoda- The snailsGastropoda- The snails Polyplacophora- ChitonsPolyplacophora- Chitons Bivalva-Two shelledBivalva-Two shelled Cephalopoda- Squid & octopeCephalopoda- Squid & octope

Molluscan BodyMolluscan Body

Soft bodies Soft bodies Two main parts: head-foot, visceral Two main parts: head-foot, visceral

massmass Visceral mass: Organ systemsVisceral mass: Organ systems Head-foot: Head, foot, sensory,and Head-foot: Head, foot, sensory,and

footfoot Visceral mass is covered by the Visceral mass is covered by the

mantle which forms the shellmantle which forms the shell Radula- teethRadula- teeth

FeedingFeeding

Herbivores, Herbivores, carnivores,filter, carnivores,filter, detritivores or detritivores or parasites parasites

Use of a siphon or Use of a siphon or radularadula

MolluskMollusk

GastropodsGastropods

Examples: snails, whelks, cowriesExamples: snails, whelks, cowries Muscular footMuscular foot Micro to 3 feet longMicro to 3 feet long Foot acts as doorFoot acts as door Some scrape algae from rocksSome scrape algae from rocks Conchs eat seagrassesConchs eat seagrasses

Gastropods cont.Gastropods cont.

Some have a radula covered with Some have a radula covered with toxinstoxins

Most have separate sexesMost have separate sexes Internal fertilization for mostInternal fertilization for most

Slipper snailsSlipper snails

HermaphroditicHermaphroditic Stacked on top of each otherStacked on top of each other Young are always maleYoung are always male Can stay male or change to femaleCan stay male or change to female Cannot go back to maleCannot go back to male

ChitonsChitons

Flat bodies- low profileFlat bodies- low profile 8 plates8 plates Eats algaeEats algae Found on intertidal rocksFound on intertidal rocks LethargicLethargic

BivalvesBivalves

Two shells Two shells Muscles hold Muscles hold

them togetherthem together No headNo head No radulaNo radula

FeedingFeeding

Cilia form currents to fill body Cilia form currents to fill body cavity with watercavity with water

Mucus traps food on the gillsMucus traps food on the gills

CephalopodsCephalopods

Soft bodied Soft bodied mollusk.mollusk.

Foot is divided Foot is divided into tentacles or into tentacles or arms.arms.

Octopi, squids, Octopi, squids, cuttlefish, and cuttlefish, and nautiluses.nautiluses.

Squids, Octopods, and Squids, Octopods, and CuttlefishCuttlefish

Bulky bodiesBulky bodies 8 arms, 2 8 arms, 2

tentaclestentacles ChromatophoresChromatophores Jet propulsionJet propulsion Ink glandInk gland

CuttlefishCuttlefish

NautilusNautilus