BZ110- Ch 11

Which of the following general statements concerning molluscs are true? Choose all that apply.

Some members of the mollusc taxa are excellent predators Cephalopods have rapid locomotion, complex sensory structures, and tearing mouthparts

In molluscs the space between the mantle and the foot, called the mantle cavity, functions in gas exchange, excretion, elimination of digestive wastes, and what other function?

Release of reproductive products

True or false: Members of Gastropoda may be intermediate hosts for some trematode parasites that impact humans.

True

Some members of the _____ group have larger brains, relative to body size, than any other invertebrates, fish, or amphibians.

cephalopod

The ______ are flattened dorsoventrally and have a dorsal surface that bears eight articulating plates.

chitons

The class Polyplacophora contains molluscs called ______.

chitons

The muscular mantle of ____ extends beyond the margin of the shell and foot.

chitons

Cephalopods that can change color do so with ____, cells in the mantle and body wall that contain pigment granules.

chromatophores

Shell ___ in modern gastropods is asymmetrical, which results in less room for organs on one side of the visceral mass.

coiling

Which are members of the Lophotrochozoa? Choose all that apply

Molluscs Annelids

Which description of the mollusc heart is most accurate?

One ventricle, two auricles

True or false: A gland in the gastropod visceral mass secretes enzymes and acid to the stomach to facilitate digestion.

False

Which of the following descriptions of the radula is correct?

Muscle moves the radula back and forth over the odontophore and scraped food moves posteriorly to the digestive tract

The gastropod ___ is associated with gastropod locomotion.

foot

The nervous system of chitons is ladderlike, with ______ anteroposterior nerve cords.

four

The branchial hearts provide blood circulation to the ______.

gills

The cephalopod circulatory system has multiple contractile components, including branchial hearts that feed the ____ and a heart that has two auricles and one _____.

gills, ventricle

Of the two main body regions found in a mollusc, the ______ contains the sensory structures and the means of locomotion and attachment.

head-foot

Gastropod gas exchange always involves the structure called the ___ ____

mantle cavity

The ______ is located between the mantle and the foot.

mantle cavity

The pulmonates have lost their gills but a vascularized ______ now serves as a lung.

mantle cavity

When snails are ______, having two types of gonad per animal, then internal cross-fertilization is used for reproduction.

monoecious

Chromatophores function when ______ act(s) to expand the chromatophore, changing the color of the animal.

muscles

The ______ is the innermost layer of the shell that is continuously secreted by the mantle.

nacreous layer

Excretory efficiency in the cephalopods is high due to a close association of ______ and blood vessels.

nephridia

____ are more sedentary animals but can move by spurting jets of water through the siphon; they are better adapted to crawling over the substrate using their tentacles.

octopuses

Examples of cephalopods include ______.

octopuses squids nautiluses

Cephalopods other than nautiluses possess ______.

one pair of gills

Gastropods have a(n) ___ circulatory system where blood directly bathes cells.

open

Most molluscs have a(n) ____ circulatory system with a pumping heart, blood vessels, and blood sinuses.

open

The ______ is a proteinaceous or calcareous covering on the dorsal, posterior margin of the foot of some snails that offers additional protection.

operculum

Chitons use sensory structures called _____ as well as chemoreceptors near the mouth, statocysts in the foot, and tactile receptors on the mantle margin.

osphradia

The "lung" in pulmonate gastropods opens to the outside by a small opening called the ______.

pneumostome

The valves, or ____, of bivalves are drawn together by muscles.

shells

Molluscs have three shell layers, a characteristic that is called ___

triploblastic

Following bivalve fertilization, the stages of development are ______ larvae followed by ______ larvae.

trochophore, veliger

Members of the class Bivalvia have ______ valve(s).

two

What are the component parts of the cephalopod circulatory system?

Arteries, veins, capillary beds, heart

Which accurately describes a typical mollusc?

Bilaterally symmetrical, reduced coelom, presence of a radula

Which statements concerning bivalve diversity are accurate? Choose all that apply.

Bivalves that burrow can bore into wood, coral, and limestone Mussels use byssal threads and oysters use adhesive from a byssal gland to attach to their substrates Surface-dwelling bivalves attach to their substrates by byssal threads

Which statements given below accurately represent bivalve gas exchange? Choose all that apply.

Blood and water are in close proximity when water is in water tubes Water exits bivalves through the suprabranchial chamber

Gastropod feeding strategies can be described as which of the following? Choose all that apply.

Can be scavengers Can be carnivores Can be parasites Can be herbivores

Molluscs in the class ______ are comprised of marine predators, with the anterior margin of the foot modified into arms or tentacles.

Cephalopoda

Squid and cuttlefish are examples of molluscs in the class ____.

Cephalopoda

______ have the most elaborate nervous and sensory system of all of the molluscs.

Cephalopods

Which of the following describe the complex nervous systems found in cephalopods? Choose all that apply.

Cephalopods have been trained to move through mazes Cephalopods can distinguish shapes, sizes, and patterns in objects

______ have an internal shell laid down in thin layers, leaving small, gas-filled spaces that provide buoyancy.

Cuttlefish

Gastropoda, the largest class of molluscs, has members that occupy which habitats?

Marine, freshwater, and terrestrial

Which of the following statements accurately describe cephalopod eyes? Choose all that apply.

Nautiloids have the least developed eyesight of cephalopods and rely on olfaction Some squid species may be able to detect specific colors Cephalopod eyes do not have the blind spot found in the vertebrate eye

All cephalopods use sight to locate prey but then use unique strategies for capturing and killing prey. Which statement below is accurate?

Octopuses are nocturnal predators that feed on snails, fishes, and crustaceans

The ancestral form of gastropod shells involved coiling in how many planes?

One

Molluscs called chitons belong to the class ______.

Polyplacophora

Select all of the characteristics of molluscs in the class Cephalopoda.

Predators Tentacles Funnel formed from the foot All marine

Which statements given below accurately describe the function of the siphon found in cephalopods? Choose all that apply.

Radial and circular muscles, found in the mantle of cephalopods, help to control water movements for the siphon Circular muscle contraction decreases mantle cavity volume and closes valves to prevent water escape Water is forced from the siphon, and muscles attached to the siphon allow the animal to control the direction of the siphon

Which sequence correctly describes chiton feeding and digestion?

Radula rasps food from substrate, food passes to esophagus by ciliary action, digestion and absorption happen in the stomach

Which statements concerning gastropod locomotion are accurate? Choose all that apply.

The foot of a gastropod is often ciliated The gastropod foot can be modified in some groups for clinging or swimming Large gastropods use muscular contractions for movement

Which statement concerning the bivalve nervous system is accurate?

The ganglia are associated with the esophagus, foot, and posterior adductor muscle

Which statements below are accurate? Choose all that apply

The head-foot contains the means of attachment and locomotion The head-foot contains the mouth and sensory structures The visceral mass contains the organs of reproduction, digestion, and excretion, among others

True or false: Gills of most bivalves are modified to also allow for filter feeding.

True

Which statement best describes the use of a hydraulic skeleton in the gastropod?

To extend sensory tentacles from the head, a gastropod can squeeze blood into the tentacle from nearby areas

In cephalopods, miniature ___ hatch from the fertilized eggs.

adults

____ live in most aquatic environments because they can burrow into the substrate or attach to submerged wood, coral, or limestone.

bivalves

____ are the second most abundant gastropod group and include clams, oysters, mussels, and scallops.

bivalvia

the shells of cephalopods have gas-filled spaces that increase ____ for the animal.

buoyancy

Bivalves are laterally compressed, with the two shells hinged at the ___ margin.

dorsal

The common exit for products of the digestive, excretory, and reproductive systems is the ______.

exhalant area of the mantle cavity

If marine snails are dioecious then the gametes are released to the water for ___ fertilization.

external

Most bivalves exhibit ___ fertilization, which takes place in the water.

external

In a ____ skeleton, fluid is under pressure that allows it to provide support to the animal.

hydraulic

The closed circulatory system of cephalopods acts to ___ blood pressure, which is needed in highly active predatory animals.

increase

Cephalopods have beaklike structures called ___ for tearing food and a _____ for rasping food and forcing it into the mouth.

jaws, radula

Molluscs and annelids are both animal groups that are classified in the ____ group.

lophotrochozoa

The pneumostome is an external opening of the ______ in pulmonate gastropods.

lung

Digestion in gastropods involves the movement of a mucoid mass called the ____ into the stomach where it is rotated by cilia.

protostyle

The ______ include land and most freshwater snails and slugs.

pulmonates

The _____ is a rasping structure that is found in almost all molluscs.

radula

Cephalopods have ______.

separate sexes

Male cephalopods use a modified ______ called a hectocotylus to deliver the spermatophores into the mantle cavity of the female.

tentacle

Bivalves contain ____ pairs of interconnected ganglia.

three

The mollusc shell is typically composed of ______ layers.

three

In gastropod development, the relative positions of the gills, anus, and openings from excretory and reproductive systems all change in a process called ____

torsion