Phylum MolluscaPhylum Mollusca

By Mr. “AFC North Champs” By Mr. “AFC North Champs” ChapmanChapman

Phylum: MolluscaPhylum: MolluscaThe Soft-bodied AnimalsThe Soft-bodied Animals

Phylum: MolluscaPhylum: Mollusca• Has about 100,000 speciesHas about 100,000 species• Bilateral symmetry and TriploblasticBilateral symmetry and Triploblastic• Mollusk bodies have three regionsMollusk bodies have three regions

– Head-footHead-foot– Visceral massVisceral mass– mantlemantle

Body RegionsBody Regions• Head-FootHead-Foot – is elongated with an – is elongated with an

anterior head, containing the mouth anterior head, containing the mouth and certain nervous and sensory and certain nervous and sensory structures, and an elongate foot structures, and an elongate foot used for attachment and locomotion.used for attachment and locomotion.

Body RegionsBody Regions• Visceral MassVisceral Mass – the area that – the area that

contains the organs of digestion, contains the organs of digestion, circulation, reproduction, and circulation, reproduction, and excretion and is positioned above the excretion and is positioned above the head-foot.head-foot.

Body RegionsBody Regions• MantleMantle – is attaches to the visceral – is attaches to the visceral

mass surrounds the body and secretes mass surrounds the body and secretes the calcareous shell (limestone).the calcareous shell (limestone).

CharacteristicsCharacteristics

• Mantle cavity Mantle cavity functions infunctions in::– ExcretionExcretion– Gas exchangeGas exchange– Elimination of Elimination of

digestive wastesdigestive wastes– Release of Release of

reproductive reproductive productsproducts

CharacteristicsCharacteristics• RadulaRadula

– Is a rough structure Is a rough structure on the tongueon the tongue

– Contains rows of Contains rows of curved teeth curved teeth

• Open circulatory Open circulatory systemsystem– Except Except

CephalopodesCephalopodes• CoelomCoelom

Important WordsImportant Words• DeuterostomesDeuterostomes – is when the anus – is when the anus

develops before the mouthdevelops before the mouth

• ProtostomesProtostomes – is when the mouth – is when the mouth develops before the anusdevelops before the anus

ClassesClasses• There are 8 classes, but only three that There are 8 classes, but only three that

are important to us.are important to us.• Class: Gastropoda “Stomach Foot”Class: Gastropoda “Stomach Foot”

– Snails and slugsSnails and slugs

ClassesClasses• Class: Bivalvia “2 valves (shells)”Class: Bivalvia “2 valves (shells)”

– Mussels, clams, oystersMussels, clams, oysters

ClassesClasses• Class: Cephalopoda “Head Foot”Class: Cephalopoda “Head Foot”

– Squids, octupus, nautilus, cuttlefishSquids, octupus, nautilus, cuttlefish

THEEND