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Phylum MolluscaPhylum Mollusca
Phylum MolluscaPhylum Mollusca ProtostomesProtostomes Lophotrochozoan group Lophotrochozoan group Eucoelomates Eucoelomates
(coelomates)(coelomates)
Tridacna squamosa
Tridacna gigas
Phylum MolluscaPhylum Mollusca Soft BodiedSoft Bodied ShelledShelled
Some withoutSome without CephalizationCephalization
Sensory organsSensory organs MouthsMouths
Body DivisionsBody Divisions Visceral MassVisceral Mass Head-FootHead-Foot MantleMantle
Tonicella lineata
Phylum MolluscaPhylum Mollusca Complete digestive tractComplete digestive tract Digestive glandsDigestive glands Specialized feeding Specialized feeding
structuresstructures Circulatory system Circulatory system
Heart (2 chambers)Heart (2 chambers) Open system in most Open system in most
groupsgroups Closed in cephalopodsClosed in cephalopods
Coelom restricted to pericardium in Coelom restricted to pericardium in most casesmost cases
Octopus briareus
Phylum MolluscaPhylum Mollusca Advanced nervous Advanced nervous
systemsystem BrainBrain Sensory organsSensory organs
Eyes (simple and Eyes (simple and camera)camera)
Sensory papillae Sensory papillae Excretory systemExcretory system
Kidney-like nephridiaKidney-like nephridia ReproductionReproduction
Monoecious and Monoecious and dioeciousdioecious
External developmentExternal development External & internal External & internal
fertilizationfertilization
Mollusc PhylogenyMollusc Phylogeny
~50-80K ~50-80K extant speciesextant species
~40K extinct ~40K extinct speciesspecies
Fossil records Fossil records from from precambrian precambrian period of period of proterozoic proterozoic eon (>570my eon (>570my BP)BP)
Mollusc Mollusc PhylogenyPhylogeny Mantle Mantle
secreting secreting shellshell
Muscular footMuscular foot Chambered Chambered
heartheart
Mollusc TaxonomyMollusc Taxonomy
Major classesMajor classesPolyplacophora Polyplacophora
ChitonsChitons
Chiton tuberculatusChiton tuberculatus lives in the rocky lives in the rocky intertidal zones eat intertidal zones eat algae with its radulaalgae with its radula
8 shell plates8 shell plates
Mollusc TaxonomyMollusc Taxonomy
Major classesMajor classes Polyplacophora Polyplacophora
GastropodaGastropodaSubclasses:Subclasses:ProsobrancProsobranchiahia
Shelled Shelled marine marine gastropodsgastropods
Atlantic triton’s trumpet Atlantic triton’s trumpet ((Charonia variegataCharonia variegata))
Tiger cowrie (Tiger cowrie (Cypraea tigrisCypraea tigris))
Mollusc TaxonomyMollusc Taxonomy
Major classesMajor classes Polyplacophora Polyplacophora
GastropodaGastropodaSubclasses:Subclasses: ProsobranchiaProsobranchia
OpisthobranOpisthobranchiachia
Sea slugs Sea slugs (marine)(marine)
zebra sea goddesszebra sea goddess((Hypselodoris zebraHypselodoris zebra))
Spotted sea hare (Spotted sea hare (Aplysia dactylomelaAplysia dactylomela))
Phidiana hiltoni
Mollusc TaxonomyMollusc Taxonomy
Major classesMajor classes Polyplacophora Polyplacophora
GastropodaGastropodaSubclasses:Subclasses: ProsobranchiaProsobranchia OpisthobranchiaOpisthobranchia
PulmonataPulmonata Terrestrial Terrestrial
snails/slugssnails/slugs Freshwater Freshwater
snailssnails
Helminthoglypta walkeriana
Giant banana slug (Ariolimax columbians)
Mollusc TaxonomyMollusc Taxonomy Major classesMajor classes
PolyplacophoPolyplacophora ra
GastropodaGastropoda
BivalviaBivalvia Clams, Clams,
oysters, oysters, mussels, mussels, scallopsscallops
Bay scallop (Aequipecten irradians)
Edible mussels (Mytilus edulis)
Ostrea edulis
Mollusc TaxonomyMollusc Taxonomy
Major classesMajor classes Polyplacophora Polyplacophora GastropodaGastropoda BivalviaBivalvia
CephalopodaCephalopoda Octopus, squid, nautilusOctopus, squid, nautilus
Giant cuttlefish (Giant cuttlefish (Sepia latimanusSepia latimanus))
Nautilus sp
Octopus sp
Mollusc TaxonomyMollusc Taxonomy
Major classesMajor classes Polyplacophora Polyplacophora GastropodaGastropoda BivalviaBivalvia CephalopodaCephalopoda
Minor classesMinor classes MonoplacophoraMonoplacophora SolenogastresSolenogastres CaudofoveataCaudofoveata
Generalized Mollusc AnatomyGeneralized Mollusc Anatomy
Gastropod Feeding Gastropod Feeding ApparatusApparatus
Respiration: GillsRespiration: Gills
Shell Structure & FormationShell Structure & Formation
A Pearl Among the SwineA Pearl Among the Swine
Mollusc Reproduction & Mollusc Reproduction & DevelopmentDevelopment Indirect developmentIndirect development
Larval stagesLarval stages Trochophore larvaTrochophore larva
Free swimming, ciliated, shell formation Free swimming, ciliated, shell formation beginsbegins
Veliger larvaVeliger larva Free swimming, ciliated velium forms, Free swimming, ciliated velium forms, Shell/body torsion occursShell/body torsion occurs
SpatSpat Metamorphic form between veliger and Metamorphic form between veliger and
juvenilejuvenile Shell elaboratesShell elaborates
Trochophore LarvaTrochophore Larva
Gastropod Veliger LarvaGastropod Veliger Larva
Velia
Mouth
Shell
Zygote
Trochophore
Veliger
Spat
Juvenile
Adult
Adult AbaloneAdult Abalone
Class Polyplacophora - chitonsClass Polyplacophora - chitons
Polyplacophoran AnatomyPolyplacophoran Anatomy
Class Class GastropodaGastropodaThe Shell GameThe Shell Game
Class Gastropoda - TorsionClass Gastropoda - Torsion
Gastropod Shell Gastropod Shell CoilingCoiling
Gastropod Gastropod Gill/Mantle Cavity Gill/Mantle Cavity EvolutionEvolution
Generalized Gastropod Generalized Gastropod AnatomyAnatomy
Marine GastropodsMarine Gastropods
Cowries
Marine GastropodsMarine Gastropods
Sea Hare – Aplysia sp
Marine Gastropods - Marine Gastropods - NudibranchNudibranch
Terrestrial Gastropods Terrestrial Gastropods - Pulmonata- Pulmonata
The mantle cavity The mantle cavity serves as a “lung”serves as a “lung”
Glandular Glandular epidermisepidermis Secrete mucus Secrete mucus
(slime) upon which (slime) upon which gastropod glidesgastropod glides
Terrestrial Gastropod - Terrestrial Gastropod - PulmonataPulmonata
Slugs lack Slugs lack shellsshells
Mantle thickenedMantle thickened PneumostomePneumostome
Air intake into mantle cavityAir intake into mantle cavity
PneumostomePneumostome
Phylum Mollusca, Class Phylum Mollusca, Class BilvaliaBilvalia Two shellsTwo shells Incurrent & excurrent siphonsIncurrent & excurrent siphons No cephalizationNo cephalization
Generalized Bivalve AnatomyGeneralized Bivalve Anatomy
Generalized Bivalve Anatomy Generalized Bivalve Anatomy (XS)(XS)
Bivalve Anatomy (Sagittal)Bivalve Anatomy (Sagittal)
Bivalves are Typically Filter Bivalves are Typically Filter FeedersFeeders
Bivalve Life CycleBivalve Life Cycle
Glochidia – Unique Larval Stage of Glochidia – Unique Larval Stage of Freshwater BivalvesFreshwater Bivalves
Internal fertilization Internal fertilization Early development in Early development in
brood chamber brood chamber (region of mantle (region of mantle cavity)cavity)
Release of glochidia Release of glochidia veliger larvaeveliger larvae
Glochidia attach to Glochidia attach to gills of fish and are gills of fish and are distributeddistributed
Phylum Mollusca, Class Phylum Mollusca, Class CephalopodaCephalopoda Closed circulatory systemClosed circulatory system
Shell: lost in Octopus, extremely Shell: lost in Octopus, extremely reduced and enclosed in mantle in reduced and enclosed in mantle in squid, planar spiral in Nautilussquid, planar spiral in Nautilus
CephalizationCephalization eyeeye Beak around Beak around
mouthmouth Tentacles/armsTentacles/arms
Cephalopod AnatomyCephalopod Anatomy
Squid are the largest Squid are the largest CephalopodsCephalopods
Nautilus AnatomyNautilus Anatomy
Cephalopod EyeCephalopod Eye
MatingMating
Direct Development in Direct Development in CephalopodsCephalopods
Color & Morphology Changes for Color & Morphology Changes for CamouflageCamouflage
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