Mollusca

Question 1

The structure of molluscs that forms the shell and houses the gills is the
 A) 	mantle.
 B) 	epidermis.
 C) 	gastrovascular cavity.
 D) 	odontophore.

Answer 1

A) Mantle

Question 2

The structure that is used for feeding in most molluscs is the
 A) 	buccal cavity.
 B) 	radula.
 C) 	mouth.
 D) 	odontophore.

Answer 2

B) Radula

Question 3

The first larval stage that is typical of molluscans is the
A) 	planula.
B) 	veliger.
C) 	actinotroph.
D) 	trochophore.

Answer 3

D) Trochophore

Question 4

The trochophore larva indicates a common ancestry between Mollusca and ……….

Answer 4

Annelida

Question 5

Which of the following structures do bivalves use in the process of digestion?
A) 	a crystalline style
B) 	a jaw
C) 	peristaltic muscles
D) 	byssal threads

Answer 5

A) A crystalline Style

Question 6

Torsion is a process that rotates the _________ of the body of gastropods.

Answer 6

Viscera

Question 7

In molluscs, the shell is secreted by the
A) 	mantle.
B) 	gills.
C) 	ctenidia.
D) 	odontophore

Answer 7

A) Mantle

Question 8

The type of excretory organs possessed by molluscs is
A) 	pronephridia.
B) 	metanephridia.
C) 	mesonephridia.
D) 	telonephridia.

Answer 8

B) Metanephridia

Question 9

Some gastropods have a horny plate that covers the shell aperture; this structure is called an osphradium. True or False

Answer 9

False

Question 10

What is the function of the osphradium

Answer 10

A sense organ to test the purity of water passing through the gills

Question 11

A mollusc that has a shell of two valves and is usually a filter feeder is a scaphopod. True or False

Answer 11

False

Question 12

a class of molluscs that comprises the tusk shells is a ……..

Answer 12

Scaphopoda

Question 13

A mollusc that is an active predator, has tentacles, and is marine could only be classified in the class……..

Answer 13

Cephalopoda.

Question 14

Unlike the other classes of the molluscs, which have a heart and a hemocoel, the members of class Cephalopoda have a closed circulatory system. True or False

Answer 14

True

Question 15

the primary body cavity of most invertebrates, containing circulatory fluid is called……

Answer 15

Hemocoel

Question 16

Most of the molluscs are dioecious but some of the gastropods are hermaphroditic. True or False

Answer 16

True.

Question 17

What are some of molluscs external characteristics?

Answer 17

Unsegmented/Bilaterally symmetrical. Calcium carbonate shell (Some no shell), 3 body regions.

Question 18

What are the 3 body regions?

Answer 18

Head - Foot - Visceral hump (Contains the digestive/respiratory/reproductive/excretory systems)

Question 19

What are the general CNS characteristics

Answer 19

Brian/Paired ventral nerve cord. Developed sense organs i.e Statocysts (Balance), Photoreceptors, or eyes.
Cephalopods have highly developed brain/sight/touch/memory/shape recognition.

Question 20

What are molluscs general modes of transportation

Answer 20

Foot.

Tentacles/jet propulsion (Water siphons) in Cephalopods

Question 21

What are molluscs general modes of respiration?

Answer 21

Cavity between mantle holds the gills (‘Lung’) Cilia move water across ventral -> dorsal, with a counter current of blood

Question 22

What are molluscs circulation system

Answer 22

Open (Closed in Cephalopods), Heart and haemocoel

Question 23

How do molluscs feed

Answer 23

Mouth, and Radula (Rasping food), Bivalves filter feed. Cephalopods use beak/radula. Complete guy, with intracellular digestion.

Question 24

How do molluscs excrete waste

Answer 24

Large folded paired Metanephirdia (Excretion glands) that have selective re-absorption. Aquatic = Ammonia
Land = urea/uric acid.

Question 25

How do molluscs reproduce

Answer 25

Most are dioecious (many Gastropods are Hermaphrodites). Aquatic=External, Land=internal fertilisation. Trochopore larvae -> Veligar larvae Land forms do this in the egg.

Question 26

What prof is there for Annelids and Molluscs having a common ancestry

Answer 26

Both having a Trochophore Larvae.

Question 27

What are the major morphology features of Bivalves

Answer 27

Mostly marine/sedentary life style - Shell Bi-valved - Laterally compressed, Small head, Absent radula - Light sensitive eyes/statocysts - Gills - Palp

Question 28

What are the major digestion features of bivalves

Answer 28

Crystalline style ->Rotates against gastric shield/acidic enzymes -> Intracellular digestion via Phagocytosing Amoeboid cells

Question 29

What are the 2 major bivalves sub-classes

Answer 29

Protobranchia (Deposit feeder)

Lamellibranchia

Question 30

What are some of protobranchias features

Answer 30

Deep oceans
Mucous coated palps that collect-sort-and ingest food
Gills (can aid in filtration)
Burrows foot into ground

Question 31

What are some of Lamellibranchia features

Answer 31

Life styles (Soft bottom/Attached surface/Unattached surface dwellers/ Borers some Burrow/ Commensals Parasites)
Inhalent/Exhalent siphons (Zooxanthellae Symbiotic aglae)

Question 32

Define and explain Torsion

Answer 32

A 180 rotation of the mantle. Results with Anus near the Head/mouth. Greater forward ventilation.
Loss of right side mantle cavity
Single gill on left
Filamentous = easy to clog

Question 33

What are Pulmonates

Answer 33

Snail

Hermaphroditic and direct development

Question 34

What is Protandry, and give an example

Answer 34

Males that go through an irreversible sex change when no females are available.
Crepidula forhicata (Slipper limpet)