mollusca notes
DESCRIPTION
Outline of characteristics and classification of Phylum MolluscaTRANSCRIPT
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