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Questions and Answers
All members of the phylum Mollusca have radial symmetry.
All members of the phylum Mollusca have radial symmetry.
False (B)
A flexible tongue-like structure with abrasive teeth that point backward is called a chromatophore.
A flexible tongue-like structure with abrasive teeth that point backward is called a chromatophore.
False (B)
Mollusks are divided into classes based on the characteristics of their foot.
Mollusks are divided into classes based on the characteristics of their foot.
False (B)
Nudibranchs are marine gastropods that lack a shell.
Nudibranchs are marine gastropods that lack a shell.
Bivalves are the only molluscs that do not possess a foot.
Bivalves are the only molluscs that do not possess a foot.
Bivalves lack a distinct head and there are no specialized sense organs.
Bivalves lack a distinct head and there are no specialized sense organs.
The fertilized egg of a clam develops into a pinnula larva.
The fertilized egg of a clam develops into a pinnula larva.
Most clams have separate sexes.
Most clams have separate sexes.
Cephalopods have a complex brain and well-developed sense organs.
Cephalopods have a complex brain and well-developed sense organs.
What class do nudibranchs, snails, and slugs belong to?
What class do nudibranchs, snails, and slugs belong to?
What class do squid, octopus, nautilus, and cuttlefish belong to?
What class do squid, octopus, nautilus, and cuttlefish belong to?
What class do chitons belong to?
What class do chitons belong to?
What class do tusk shells belong to?
What class do tusk shells belong to?
What class do clams, oysters, scallops, and mussels belong to?
What class do clams, oysters, scallops, and mussels belong to?
What class of mollusk is intelligent, with a well-developed nervous system?
What class of mollusk is intelligent, with a well-developed nervous system?
What class of mollusk has no distinctive head?
What class of mollusk has no distinctive head?
What classes of mollusk have an open circulatory system?
What classes of mollusk have an open circulatory system?
What class of mollusk has a closed circulatory system?
What class of mollusk has a closed circulatory system?
What class of mollusk has external shells present in some species?
What class of mollusk has external shells present in some species?
What class of mollusk has all carnivorous species?
What class of mollusk has all carnivorous species?
What class of mollusk uses radula in feeding?
What class of mollusk uses radula in feeding?
What class of mollusk all use gills for both respiration and food collection?
What class of mollusk all use gills for both respiration and food collection?
What class of mollusk bites prey with a beak?
What class of mollusk bites prey with a beak?
What class of mollusk has a shell that contains 8 overlapping plates on the dorsal surface?
What class of mollusk has a shell that contains 8 overlapping plates on the dorsal surface?
What class of mollusk has a pair of tentacles on their head?
What class of mollusk has a pair of tentacles on their head?
What class of mollusk uses excretory structures called nephridia?
What class of mollusk uses excretory structures called nephridia?
What class of mollusk are all marine species?
What class of mollusk are all marine species?
What class of mollusk is known for their great camouflage abilities?
What class of mollusk is known for their great camouflage abilities?
What class of mollusk undergoes torsion?
What class of mollusk undergoes torsion?
What class of mollusk swims by jet propulsion?
What class of mollusk swims by jet propulsion?
What kind of shell does a squid have?
What kind of shell does a squid have?
Describe the foot of a cephalopod.
Describe the foot of a cephalopod.
What purpose does the foot of a cephalopod serve? How is the foot adapted for this purpose?
What purpose does the foot of a cephalopod serve? How is the foot adapted for this purpose?
What are some other animals in the cephalopod class?
What are some other animals in the cephalopod class?
What class do snails belong to?
What class do snails belong to?
What shell do gastropods have?
What shell do gastropods have?
Describe the foot of a gastropod.
Describe the foot of a gastropod.
What is the foot of a gastropod used for and how is it adapted for this?
What is the foot of a gastropod used for and how is it adapted for this?
What are some other animals in the gastropod class?
What are some other animals in the gastropod class?
What class does a clam belong to?
What class does a clam belong to?
Describe the shell of bivalves.
Describe the shell of bivalves.
Describe the foot of a bivalve. What purpose does it serve? How is this foot adapted for its purpose?
Describe the foot of a bivalve. What purpose does it serve? How is this foot adapted for its purpose?
What are some of the other animals in Bivalvia?
What are some of the other animals in Bivalvia?
Free swimming ciliated larva found in molluscs.
Free swimming ciliated larva found in molluscs.
Body symmetry in which the right and left sides mirror one another.
Body symmetry in which the right and left sides mirror one another.
Layer of soft tissue that covers the visceral mass.
Layer of soft tissue that covers the visceral mass.
Structure made of calcium carbonate that protects the soft bodies of some mollusks.
Structure made of calcium carbonate that protects the soft bodies of some mollusks.
Structures found in aquatic molluscs that are specialized for gas exchange.
Structures found in aquatic molluscs that are specialized for gas exchange.
The process occurs during gastropod larval development and results in the 180-degree twisting of the visceral mass.
The process occurs during gastropod larval development and results in the 180-degree twisting of the visceral mass.
Feeding strategy used by bivalves.
Feeding strategy used by bivalves.
Color-changing pigment cells that provide camouflage to cephalopods.
Color-changing pigment cells that provide camouflage to cephalopods.
What is the only cephalopod to retain its external shell?
What is the only cephalopod to retain its external shell?
What class contains snails, slugs, and nudibranchs?
What class contains snails, slugs, and nudibranchs?
Members of this class have a body plan consisting of a head, foot, and visceral mass.
Members of this class have a body plan consisting of a head, foot, and visceral mass.
The members of this class are free swimming predators.
The members of this class are free swimming predators.
Members of this class have a radula.
Members of this class have a radula.
This class has the most advanced nervous system.
This class has the most advanced nervous system.
Members of this class have a trochophore larva.
Members of this class have a trochophore larva.
This class contains animals whose foot is divided into arms and tentacles.
This class contains animals whose foot is divided into arms and tentacles.
Members of this class undergo torsion.
Members of this class undergo torsion.
Members of this class have bilateral symmetry.
Members of this class have bilateral symmetry.
Members of this class have most species having only one shell but some have none.
Members of this class have most species having only one shell but some have none.
All species in this class have two shells.
All species in this class have two shells.
Members of this class are filter feeders.
Members of this class are filter feeders.
Animals in this class have a closed circulatory system.
Animals in this class have a closed circulatory system.
Members of this class have an open circulatory system.
Members of this class have an open circulatory system.
Most members of this class have no shell.
Most members of this class have no shell.
This muscular structure is used for burrowing into the sand.
This muscular structure is used for burrowing into the sand.
These powerful muscles are used to open and close the valves.
These powerful muscles are used to open and close the valves.
The opening into the digestive system.
The opening into the digestive system.
This structure connects the two valves.
This structure connects the two valves.
Thin layer of epidermal tissue that covers the visceral mass.
Thin layer of epidermal tissue that covers the visceral mass.
These structures help direct food into the mouth.
These structures help direct food into the mouth.
Name given to sex organs.
Name given to sex organs.
Area where digested food is absorbed into the blood.
Area where digested food is absorbed into the blood.
Structure through which water, food, and oxygen enter the clam.
Structure through which water, food, and oxygen enter the clam.
Site of digestion.
Site of digestion.
Shells are known by this name.
Shells are known by this name.
This pumps blood through the open circulatory system.
This pumps blood through the open circulatory system.
Opening leading out of the digestive system.
Opening leading out of the digestive system.
Structures that are responsible for absorbing oxygen from the water.
Structures that are responsible for absorbing oxygen from the water.
Structure through which water and wastes leave the clam.
Structure through which water and wastes leave the clam.
Secretes enzymes responsible for the speedy digestion of food.
Secretes enzymes responsible for the speedy digestion of food.
Made of calcium carbonate and provides protection to the clam.
Made of calcium carbonate and provides protection to the clam.
Label the structure.
Label the structure.
Label the structures.
Label the structures.
What is the composition of a mollusc shell? What are the different layers of a mollusc shell? How is the shell made? What structure(s) help to make the shell?
What is the composition of a mollusc shell? What are the different layers of a mollusc shell? How is the shell made? What structure(s) help to make the shell?
Describe the difference in feeding methods among gastropods, cephalopods, and bivalves.
Describe the difference in feeding methods among gastropods, cephalopods, and bivalves.
Relate the type of movement with the structure of the foot in the snail, clam, and squid.
Relate the type of movement with the structure of the foot in the snail, clam, and squid.
What adaptations allow cephalopods to be excellent predators?
What adaptations allow cephalopods to be excellent predators?
In what ways are cephalopods more advanced than the other classes of molluscs?
In what ways are cephalopods more advanced than the other classes of molluscs?
What roles do molluscs play in the ecosystem? State three examples.
What roles do molluscs play in the ecosystem? State three examples.
List and describe the three main parts of the molluscan body plan.
List and describe the three main parts of the molluscan body plan.
How and why do cephalopods change color?
How and why do cephalopods change color?
List three or more ways the nautilus is different from other cephalopods.
List three or more ways the nautilus is different from other cephalopods.
What is the outer layer of the shell?
What is the outer layer of the shell?
What is the second layer of the shell?
What is the second layer of the shell?
What is the innermost layer of the shell?
What is the innermost layer of the shell?
Flashcards
Bilateral symmetry in Mollusca
Bilateral symmetry in Mollusca
Phylum Mollusca exhibits bilateral symmetry, meaning their body can be divided into two identical halves.
What is the mantle?
What is the mantle?
The mantle is a tissue fold encasing the visceral mass (body organs) in mollusks.
What is a radula?
What is a radula?
A radula is a tongue-like organ found in many mollusks used for scraping food.
What are gastropods?
What are gastropods?
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What is torsion in gastropods?
What is torsion in gastropods?
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What are cephalopods?
What are cephalopods?
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What are bivalves?
What are bivalves?
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What are chitons?
What are chitons?
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What are tusk shells?
What are tusk shells?
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What is the function of the mollusk foot?
What is the function of the mollusk foot?
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What is the periostracum?
What is the periostracum?
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What is the prismatic layer?
What is the prismatic layer?
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What is the nacreous layer?
What is the nacreous layer?
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How do gastropods feed?
How do gastropods feed?
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How do bivalves feed?
How do bivalves feed?
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How do cephalopods feed?
How do cephalopods feed?
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Reproduction in clams
Reproduction in clams
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Reproductive organs in mollusks
Reproductive organs in mollusks
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Ecological role of mollusks
Ecological role of mollusks
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What are chromatophores in cephalopods?
What are chromatophores in cephalopods?
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How do squids move?
How do squids move?
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How do snails move?
How do snails move?
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How do clams move?
How do clams move?
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Intelligence of cephalopods
Intelligence of cephalopods
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Diversity of gastropods
Diversity of gastropods
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What is special about the nautilus?
What is special about the nautilus?
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Nervous system of cephalopods
Nervous system of cephalopods
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Tentacles in cephalopods
Tentacles in cephalopods
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Study Notes
Phylum Mollusca Overview
- Members exhibit bilateral symmetry, not radial symmetry.
- Distinctive structures include the radula (a tongue-like organ for feeding) and the mantle (tissue covering the visceral mass).
Classes of Mollusca
- Gastropoda: Includes slugs, snails, and nudibranchs; exhibit torsion during larval development; utilize a radula for feeding.
- Cephalopoda: Includes squids, octopuses, and cuttlefish; possess a closed circulatory system; highly developed nervous system; capable of jet propulsion.
- Bivalvia: Comprises clams, oysters, and mussels; have shells divided into two halves; use gills for filter feeding.
- Polyplacophora: Chitons characterized by eight overlapping plates on the back.
- Scaphopoda: Known as tusk shells.
Anatomical Features
- Foot: Serves various purposes—burrowing in bivalves, movement in gastropods, and modified into arms in cephalopods.
- Shell Structure: Composed of three layers:
- Periostracum: Outer protein layer protecting from erosion.
- Prismatic Layer: Main structure made of calcium carbonate.
- Nacreous Layer: Inner layer known as mother of pearl.
Feeding and Respiration
- Feeding Strategies:
- Gastropods utilize radula to scrape surfaces for algae; some are scavengers.
- Bivalves filter feed using gills for both respiration and food collection.
- Cephalopods are carnivorous, using tentacles and beaks for capturing prey.
Reproductive Features
- Most clams have separate sexes; fertilization involves development through trocophore larvae.
- All mollusks possess gonads, responsible for reproduction.
Ecological Roles
- Mollusks play vital roles in ecosystems as food sources for various organisms, including birds and mammals; contribute to nutrient recycling and soil regeneration.
Adaptations
- Cephalopods exhibit advanced adaptations, including chromatophores for color changes, enhancing their ability to camouflage and communicate.
Movement
- Squids utilize jet propulsion for swift movement, snails crawl using muscular contractions, and clams burrow into the substrate with their foot.
Unique Class Characteristics
- Cephalopoda: Characterized by intelligence and complex behavior; possess varied tentacle structures adapted for predation.
- Gastropoda: Display a wide range of forms and can be found in marine, freshwater, and terrestrial environments; most species feature a spiral shell.
Special Features
- Nautilus has a distinctive coiled shell; differs from other cephalopods by having a chambered structure and nocturnal behavior.
- Advanced nervous systems in cephalopods facilitate learning and memory, distinguishing them from other mollusks.
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Description
Test your knowledge of the phylum Mollusca with these flashcards. Each card presents a statement regarding mollusks, where you'll determine its accuracy. Perfect for students and enthusiasts looking to deepen their understanding of these fascinating creatures.
