Phylum MolluscaPhylum Mollusca

- From mollus meaning “soft”- From mollus meaning “soft”

ClassificationClassification

Kingdom- Animalia Phylum- Mollusca

4 classes:

Kingdom- Animalia Phylum- Mollusca

4 classes:

1. Class- Gastropoda -“stomach foot”

1. Class- Gastropoda -“stomach foot”

Has one shell or noneEx. Snails, slugs, sea slugs

Snail Conch

Slug Whelk Abalone

2. Class Bivalvia - “Two Shells”

2. Class Bivalvia - “Two Shells”

Ex. Clams, mussels, oysters, scallops

Ex. Clams, mussels, oysters, scallops

Clam Mussel

Scallop Oyster

3. Class Cephalapoda -“head foot”

3. Class Cephalapoda -“head foot”

No shell or one Ex. Squid, octopus, nautilus,

cuttlefish

No shell or one Ex. Squid, octopus, nautilus,

cuttlefish

OctopusSquid

Nautilus

4. Class Polyplacophora -“many plates”

4. Class Polyplacophora -“many plates”

Mantle made of 8 dorsal plates Ex. Chitons

Mantle made of 8 dorsal plates Ex. Chitons

CharacteristicsCharacteristics

Eucoelomate - True body cavity Hollow body cavity, Lined with

peritonium (endodermis) Bilateral symmetry Most have Mantle

Secretes shell - grows with organism Site of Respiration in terrestrial

mollusks

Eucoelomate - True body cavity Hollow body cavity, Lined with

peritonium (endodermis) Bilateral symmetry Most have Mantle

Secretes shell - grows with organism Site of Respiration in terrestrial

mollusks

HabitatHabitat Aquatic-

Marine: Sea slugs (Nudibranchs), clams, oysters,

scallops, mussles, conch, whelk, squid, octopus, cuttlefish

Fresh water: Clams, mussles, snails

Terrestrial - Snails, slugs

Aquatic- Marine:

Sea slugs (Nudibranchs), clams, oysters, scallops, mussles, conch, whelk, squid, octopus, cuttlefish

Fresh water: Clams, mussles, snails

Terrestrial - Snails, slugs

OrganizationOrganization

Tripoblastic - 3 tissue layers Many Organ systems

well-defined circulatory, respiratory, excretory, and digestive systems

Tripoblastic - 3 tissue layers Many Organ systems

well-defined circulatory, respiratory, excretory, and digestive systems

RespirationRespiration

Aquatic- gills Terrestrial- mantle and some with

primitive lungs

Aquatic- gills Terrestrial- mantle and some with

primitive lungs

DigestionDigestion Complete digestive tract

mouth and anus Radula

Rasping “file” with hundreds of tooth like structures

Feeding Patterns - filter feeders, herbivores, carnivores

Complete digestive tract mouth and anus Radula

Rasping “file” with hundreds of tooth like structures

Feeding Patterns - filter feeders, herbivores, carnivores

CirculationCirculation Some - Open Circulatory System

Blood flow doesn’t always stay in vessels

Ex. Gastropoda and bivalvia

Some - Closed circulatory system Blood flow stays within the vessels Ex. Cephalopoda

All have hearts

Some - Open Circulatory System Blood flow doesn’t always stay in

vessels Ex. Gastropoda and bivalvia

Some - Closed circulatory system Blood flow stays within the vessels Ex. Cephalopoda

All have hearts

CephalizationCephalization

Brain with nervous system Gastropoda and Cephalopoda Exception Bivalvia no head=no brain

Sensory cells All have - Touch, smell, taste, balance Some have - True eyes

Cephalopoda and some Gastropoda

Brain with nervous system Gastropoda and Cephalopoda Exception Bivalvia no head=no brain

Sensory cells All have - Touch, smell, taste, balance Some have - True eyes

Cephalopoda and some Gastropoda

LocomotionLocomotion

Muscles are present Some sessile (mussels and oysters) Some use foot to burrow, crawl/ drag Some use tentacles to creep Some swim Some flutter away (scallops)

Muscles are present Some sessile (mussels and oysters) Some use foot to burrow, crawl/ drag Some use tentacles to creep Some swim Some flutter away (scallops)

ReproductionReproduction

Almost all dioecious Some release sperm or eggs into

water Some use internal fertilization

Almost all dioecious Some release sperm or eggs into

water Some use internal fertilization

Ecological RolesEcological Roles Food for many Destruction *can destroy engines and docks Cuttlebone used for parakeet beak health Jewelry / Decoration

Abalone - mother of pearl Pearls - necklaces, rings, earrings

Medical research - black pearls don’t get cancer

Food for many Destruction *can destroy engines and docks Cuttlebone used for parakeet beak health Jewelry / Decoration

Abalone - mother of pearl Pearls - necklaces, rings, earrings

Medical research - black pearls don’t get cancer