Mollusca

In terms of gastropod coiling, a shell lays all whorls in a single plane and a shell lays each successive whorl to the side of the preceding whorl.

Blank 1: planospiral Blank 2: conispiral

With over 70,000 living species, the Class is the largest class of molluscs.

Blank 1: Gastropoda

Octopuses, snails, and chitons are all examples of organisms in the phylum

Blank 1: Mollusca

The periostracum is composed of , a quinone-tanned protein.

Blank 1: conchiolin

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

Blank 1: dorsal

The ctenidium are in the primitive condition found in most prosobranchs.

Blank 1: gills

Select all of the following that are molluscs.

Oyster Octopus Chiton

Select all of the organisms that belong to Class Gastropoda.

Slugs Snails Limpets Conchs

The shell of cephalopods provides __________ buoyancy.

neutral

Respiration in most gastropods is performed by a ________.

ctenidium

There are typically ______ layers in the mollusc shell.

3

Gastropoda is the largest class of molluscs with about ______ extant species and 15,000 extinct species described.

70,000

The class is also known as Pelecypoda, meaning "hatchet-footed", bivalved molluscs.

Blank 1: Bivalvia

Fossils attributed to molluscs appear in geological strata that date from the early period

Blank 1: Cambrian

Snails, slugs, and limpets are examples of molluscs in the class

Blank 1: Gastropoda

Squid and cuttlefish are examples of molluscs in the class

Cephalopoda

What molluscs have a closed circulatory system?

Cephalopods

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

Cephalopods

Select all of the following that are members of the mollusc class Bivalvia.

Clams Oysters Scallops Mussels

___________ have a small curved shell that provides buoyancy and is completely enclosed by a mantle.

Cuttlefish

What complex sensory structures are present in cephalopods and have a similar structure to those of vertebrates?

Eyes

Select all of the examples of cephalopods.

Octopus Squid Nautilus

Class ______ is another name for the class Bivalvia.

Pelecypoda

Molluscs called chitons belong to the class

Polyplacophora.

Molluscs first arose during the ______ time period.

Precambrian

In bivalves, what organ contains a rotating crystalline rod that keeps food whirling and releases enzymes?

Stomach

Select all of the characteristics of chitons.

They possess a radula. Their mantle forms a girdle. They are usually small in size.

There are ______ living species in the phylum Mollusca.

about 90,000

Mollusks called ______ are mostly sedentary filter feeders and have two shells, no head, and no radula.

bivalves

The ______ are somewhat flattened and have a convex dorsal surface that bears seven to eight articulating plates.

chitons

The class Polyplacophora contains molluscs called

chitons

Cephalopods have a(n) ______ circulatory system and branchial ______ that increase blood pressure in the gills, which occur at the end of the molluscan circulatory system.

closed; hearts

Most molluscs have a type of kidney in which the inner end opens into the

coelom.

In terms of gastropod shell coiling, ______ shells are more compact.

conispiral

The anterior margin of the cephalopod foot has been modified into a

crown of arms.

Most molluscs are

dioecious

True or false: Gastropods all have similar feeding habits.

false

Most bivalves are __________.

filter feeders

In the cephalopods, the _______ has been modified into a funnel for expelling water for locomotion.

foot

Many molluscs use the ______ for locomotion.

foot

The mollusc ______ may be adapted for locomotion, for attachment to substratum, or for a combination of functions.

foot

Many gastropods that are ______ use their rasping tongue to scape algae from hard surfaces.

herbivores

In general, cephalopods move by forcefully expelling water from the _______ through the siphon.

mantle cavity

In bivalves, respiratory currents bring in both oxygen and organic particles to the gills, where ciliary action and mucous eventually take food to the

mouth.

Although ______ can move by spurting jets of water through their funnel, they are better adapted to crawling over rocks and coral using their arms.

octopuses

Mollusca is ______ animal phyla.

one of the largest

Most molluscs have ______ kidney(s).

pair

_______ is a rasping, protrusible, tongue-like organ that is found in almost all molluscs except bivalves.

radula

The radula is a ______ tongue-like organ with rows of chitinous ______.

rasping; teeth

In molluscs, the mantle creates a space between itself and the visceral mass which houses the ______ organs.

respiratory

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

shells

In cephalopods called ______, the shell has been lost leaving only a thin, proteinaceous strip called a pen.

squids

The outer surface of the mantle secretes

the shell.

In many molluscs, a free-swimming ______ larva emerges from the egg stage.

trochophore