Question 1

Among living molluscs,the ancestral condition is most nearly approached by the class _____________.

Accepted Answer

Caudofoveata

Question 2

A pair of _______________ serve as sense organs for sampling water and are found in the mantle grooves near the anus of many chitons.

Accepted Answer

osphradia

Question 3

The _________ is the oldest part of the shell and growth occurs in concentric rings around it.

Accepted Answer

umbo

Question 4

The radula

Accepted Answer

A) not only rasps off fine food particles but also serves as a conveyor belt to carry food toward the digestive tract. 
B) replaces worn teeth by secreting new teeth at the posterior end. 
C) varies in number,pattern,and form of teeth,allowing species to be classified by this trait. 
D) may be modified to bore through hard materials. 
E) All of the choices are correct 
A) not only rasps off fine food particles but also serves as a conveyor belt to carry food toward the digestive tract. 
B) replaces worn teeth by secreting new teeth at the posterior end. 
C) varies in number,pattern,and form of teeth,allowing species to be classified by this trait. 
D) may be modified to bore through hard materials. 
E) All of the choices are correct

Question 5

The internal organs in coelomates are covered with a mesodermal epithelium called the _______________.

Accepted Answer

The answer of The internal organs in coelomates are covered...

Question 6

The shell of Polyplacophora is divided into _______ _______ valves.

Accepted Answer

The answer of The shell of Polyplacophora is divided into...

Question 7

Where would you locate the coelomic cavity when dissecting a mollusk such as a clam?

Accepted Answer

A) The coelom is between the mantle and the shell 
B) The coelom is all of the area enclosed by the two shells and exposed when you open the shell 
C) The cavity around the heart,the kidneys,and the lumen of the gonads forms the limited coelom 
D) The cavities inside the siphon are the coelom 
E) The coelom is the space inside small tubules that form the gills 
A) The coelom is between the mantle and the shell 
B) The coelom is all of the area enclosed by the two shells and exposed when you open the shell 
C) The cavity around the heart,the kidneys,and the lumen of the gonads forms the limited coelom 
D) The cavities inside the siphon are the coelom 
E) The coelom is the space inside small tubules that form the gills

Question 8

Scaphopods have a captacula or head with long tentacles;how do they differ from the tentacles of cephalopods? Are these two types of tentacles homologous?

Accepted Answer

Scaphopods, commonly known as tusk shell

Question 9

The central axis around which the shell of a snail coils is called the

Accepted Answer

A) aperture. 
B) columella. 
C) sinistral. 
D) dextral. 
E) torsion. 
A) aperture. 
B) columella. 
C) sinistral. 
D) dextral. 
E) torsion.

Question 10

The caudofoveates

Accepted Answer

A) are mostly worm-like,burrowing,marine organisms. 
B) possess an oral shield associated with food selection and intake. 
C) possess a radula (reduced in some species). 
D) may have more features in common with the common ancestor of all molluscs than any other living group. 
E) All of the choices are correct 
A) are mostly worm-like,burrowing,marine organisms. 
B) possess an oral shield associated with food selection and intake. 
C) possess a radula (reduced in some species). 
D) may have more features in common with the common ancestor of all molluscs than any other living group. 
E) All of the choices are correct

Question 11

Torsion

Accepted Answer

A) involves movement of the shell independent of visceral movements. 
B) rotates the shell between 90 and 180 degrees. 
C) begins with the contraction of an asymmetrical foot retractor muscle. 
D) shifts the anus from posterior to the right side of the body. 
E) All of the choices are correct 
A) involves movement of the shell independent of visceral movements. 
B) rotates the shell between 90 and 180 degrees. 
C) begins with the contraction of an asymmetrical foot retractor muscle. 
D) shifts the anus from posterior to the right side of the body. 
E) All of the choices are correct

Question 12

How do you account for the enormous radiation of the molluscs? Give factual support for your answer.

Accepted Answer

The enormous radiation of molluscs can b

Question 13

The tongue-like,rasping organ in the head of many molluscs is the _____________.

Accepted Answer

The answer of The tongue-like,rasping organ in the head of...

Question 14

Snails that lack gills are called "pulmonate" and their mantle cavity functions

Accepted Answer

A) for propulsion. 
B) to produce pearls. 
C) as a lung. 
D) to store wastes. 
E) All of the choices are correct functions 
A) for propulsion. 
B) to produce pearls. 
C) as a lung. 
D) to store wastes. 
E) All of the choices are correct functions

Question 15

What surface (e.g. ,dorsal,ventral,anterior,posterior)of the squid faces forward as the animal moves by jet propulsion? What surface faces forward in a swimming cuttlefish? Explain your answers.

Accepted Answer

In squid, when moving by jet propulsion,

Question 16

Some prosobranchs have only one _____________ in their mantle cavity.

Accepted Answer

A) Shell 
B) Foot 
C) Gill 
D) Radula 
E) Tentacle 
A) Shell 
B) Foot 
C) Gill 
D) Radula 
E) Tentacle

Question 17

How has the problem of "fouling" been resolved by the various groups of molluscs?

Accepted Answer

The problem of "fouling" has been resolv

Question 18

The scaphopods have a shell that resembles a straightened gastropod shell.Why are they not classified with the gastropods?

Accepted Answer

Scaphopods, commonly known as tusk shell

Question 19

Early gastropods had a coiled shell that did not twist to the right or left;this bilaterally symmetrical shell is called

Accepted Answer

A) sinistral. 
B) planospiral. 
C) conispiral. 
D) dextral. 
E) scaphopodal. 
A) sinistral. 
B) planospiral. 
C) conispiral. 
D) dextral. 
E) scaphopodal.

Question 20

The cephalopod nervous system is best described as

Accepted Answer

A) absent. 
B) primitive and very little advanced from that of a cnidarian. 
C) the most advanced among molluscs. 
D) more complex than ours. 
E) None of the choices is correct 
A) absent. 
B) primitive and very little advanced from that of a cnidarian. 
C) the most advanced among molluscs. 
D) more complex than ours. 
E) None of the choices is correct

Exam 16: Molluscs

Among living molluscs,the ancestral condition is most nearly approached by the class _____________.

A pair of _______________ serve as sense organs for sampling water and are found in the mantle grooves near the anus of many chitons.

The _________ is the oldest part of the shell and growth occurs in concentric rings around it.

The radula

The internal organs in coelomates are covered with a mesodermal epithelium called the _______________.

The shell of Polyplacophora is divided into _______ _______ valves.

Where would you locate the coelomic cavity when dissecting a mollusk such as a clam?

Scaphopods have a captacula or head with long tentacles;how do they differ from the tentacles of cephalopods? Are these two types of tentacles homologous?

The central axis around which the shell of a snail coils is called the

The caudofoveates

Torsion

How do you account for the enormous radiation of the molluscs? Give factual support for your answer.

The tongue-like,rasping organ in the head of many molluscs is the _____________.

Snails that lack gills are called "pulmonate" and their mantle cavity functions

What surface (e.g. ,dorsal,ventral,anterior,posterior)of the squid faces forward as the animal moves by jet propulsion? What surface faces forward in a swimming cuttlefish? Explain your answers.

Some prosobranchs have only one _____________ in their mantle cavity.

How has the problem of "fouling" been resolved by the various groups of molluscs?

The scaphopods have a shell that resembles a straightened gastropod shell.Why are they not classified with the gastropods?

Early gastropods had a coiled shell that did not twist to the right or left;this bilaterally symmetrical shell is called

The cephalopod nervous system is best described as

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The shell of Polyplacophora is divided into _ _ valves.