Phylum Mollusca Flashcards
What is the primary method of excretion in Phylum Mollusca?
Nephridia
Metabolic waste leaves through a pore into the mantle cavity and gets washed away.
What type of fertilization occurs in terrestrial mollusks and cephalopods?
Internal fertilization
Most mollusks have separate sexes, except for some hermaphroditic species like snails and slugs.
What is the larval stage of mollusks called?
Trochophore larva
What type of circulatory system do most fast-moving mollusks, such as cephalopods, have?
Closed circulatory system
In a closed circulatory system, blood is contained in vessels at all times.
What is the main function of gills in mollusks?
Gas exchange
Most gas exchange occurs with gills located within the mantle.
What structure do all mollusks, except bivalves, possess for feeding?
Radula
The radula is a rasping tongue with tiny teeth used for scraping food into the mouth.
Which class of mollusks is characterized by having ‘2 valves (shells)’?
Class Bivalvia
Examples include clams, oysters, scallops, and mussels.
What is the main role of mollusks in the environment?
Important source of food for organisms including humans
They also serve as hosts for many parasites and environmental monitors of ocean water.
What type of nervous system do most mollusks have?
Mainly simple nervous system
This includes ganglia and nerve cords, with most having simple eyes.
What are the five main parts of the general body plan of mollusks?
- Head
- Foot
- Mantle
- Visceral mass
- Shell
What is the meaning of the name ‘mollusca’?
Soft-bodied animals
Fill in the blank: The shell of a mollusk can be _______ or reduced.
absent
What type of symmetry do mollusks exhibit?
Bilateral symmetry
What are the three main layers of cells in coelomate mollusks?
- Ectoderm
- Mesoderm
- Endoderm
What is a notable feature of the nervous system in cephalopods?
Well-developed brain
Cephalopods have a complex nervous system with advanced sensory capabilities.
What do bivalves primarily use for feeding?
Filter feeding using their gills
True or False: All mollusks have an external shell.
False
The shell can be absent or reduced in some species.
Which class of mollusks includes squids and octopuses?
Class Cephalopoda
This class is characterized as ‘head foot’.
What is the primary habitat of most mollusks?
Mainly aquatic, some terrestrial
What adaptation do terrestrial mollusks like snails and slugs require?
Moist environments
The thin membrane around their mantle cavity acts as a primitive lung.
What the habitat of phylum mollusca?
Mainly aquatic, some terrestial
What are examples of Phylum mollusca?
clams, oysters, snails, slugs, squid, octopus
How many cell layers?
Coelomate 3 cell layers
What does trochophore larvae mean (which all of them have)
free swimming larvae with lots of cilia
What does trochophore larvae mean (which all of them have)
free swimming larvae with lots of cilia
facts about the head
- absent in some bivalves
- Where the mouth and sensory organs are located
facts about the foot
- muscular, mainly for locomotion
- In squid/octopus, their foot is modified into tentacles
facts about the mantle
- thin tissue layer that surrounds the body.
- The mantle also helps create their shell
facts about the visceral mass
soft portion, contains internal organs
facts about the shell
- absent or reduced in some
- The shell can be internal or external
ーThe shell is used for protection
Made from glands that secrete CaCO3
Three facts about cephalopods nervous system
- Have a well-developed brain
- Complex nervous system
- Eyes for sight
Three facts about cephalopods nervous system
- Have a well-developed brain
- Complex nervous system
- Eyes for sight
four ways these creatures fit into this world
- Important source of food for organisms including humans
- Serve as hosts for many parasites
- Environmental monitors of ocean water
- Snails and slugs may cause crop damage
Class Bivalvia definition and examples
2 valves (shells)” ex. Clams, oysters, scallops, mussels
Class gastropoda definition and examples
Stomach foot” ex. Slugs, snails, nudibranchs, abalone
Class Cephalopoda definition and examples
Head foot” ex. Squid, octopus, cuttlefish, nautilus
All mollusc except bivalves have a …
radula
whats a radula
a rasping tongue with tiny teeth for scraping food into mouth (like sandpaper)
Bivalves filter feed using what
their gills
Cephalopods use what for feeding and digestion
a beak and radula
Complete digestive tract goes from what to what
mouth to anus
How is gas exchanged by in respiration
with gills within the mantle
Terrestrial mollusc such as snails and slugs require what environments
moist environments
in resporation The thin membrane around their mantle cavity acts as what
a primitive lung
Open circulatory systems are common in who
Common in slow moving, sessile mollusc: bivalves and gastropods
Closed circulatory systems are common in who
Common in fast moving mollusc: cephalopods
Most have what kind of heart in internal transportation?
a chambered heart
what happens in an open circulatory system?
Blood bathes the tissues rather than directly delivered by blood vessels and it’s not contained in the vessels at all times
How does waste leave
Leaves through a pore into the mantle cavity and gets washed away
What creature changes genders
oysters
internal fertilization happens in who
terrestial molluscs and cephalopods
Which two are hermaphodites
snails and slugs
what kinda fertilization
external fertilization
In reproduction the sexes are mostly
seperate sexes
In reproduction the sexes are mostly
seperate sexes
