Phylum Mollusca

Question 1

Phylum mollusca is the ___ largest phylum after phylum arthropoda.

Answer 1

Phylum mollusca is the Second largest phylum after phylum arthropoda.

Question 2

1)NUMBER OF SPECIES:

In molluscs , _____ species are living and the rest ____ are fossils.

Answer 2

1)NUMBER OF SPECIES:

In molluscs , 50,000 species are living and the rest 35,000 are fossils.

Question 3

2) SIZE:
The smallest mollusc is the size of a grain of ____ , while the largest is the “ ____ ____” which is __ metre in length .

Answer 3

2) SIZE:
The smallest mollusc is the size of a grain of sand , while the largest is the “ Giant squid” which is 18 metre in length .

Question 4

3) CELLULAR ORGANIZATION

Molluscs belong to sub-kingdom ____ , which means they have proper ___ organization.

Answer 4

3) CELLULAR ORGANIZATION

Molluscs belong to sub-kingdom Eumetazoa, which means they have proper tissue organization.

Question 5

4) NUMBER OF GERM LAYERS:

Molluscs have ____ germ layers i.e. they are _____blastic.

Answer 5

4) NUMBER OF GERM LAYERS:

Molluscs have three germ layers i.e. they are triploblastic.

Question 6

5) SYMMETRY:

molluscs are _____ symmetrical.

Answer 6

5) SYMMETRY:

molluscs are bilaterally symmetrical.

Question 7

6) SEGMENTATION:

Molluscs have _____ bodies.

Answer 7

6) SEGMENTATION:

Molluscs have unsegmented bodies.

Question 8

7) DIGESTIVE SYSTEM:
The Digestive system of molluscs consists of a gut with two openings ; the ___ and the ____.
The alimentary canal maybe ____ or coiled.

Answer 8

7) DIGESTIVE SYSTEM:
The Digestive system of molluscs consists of a gut with two openings ; the mouth and the anus.
The alimentary canal maybe straight or coiled.

Question 9

8) COELOM:

molluscs have ___ coelom, as it is a cavity filled with ____.

Answer 9

8) COELOM:

molluscs have true coelom, as it is a cavity filled with liquid.

Question 10

9) FATE OF BLASTOPORE:

Molluscs belong to the group ____ as blastopore develops into the ____ of the adult.

Answer 10

9) FATE OF BLASTOPORE:

Molluscs belong to the group Protostomata as blastopore develops into the mouth of the adult.

Question 11

11) CIRCULATORY SYSTEM:

Molluscs have an ______ circulatory system, in which _____ circulates within open body sinuses called haemocoel .

Answer 11

11) CIRCULATORY SYSTEM:

Molluscs have an open-type circulatory system, in which haemolymph circulates within open body sinuses called haemocoel.

Question 12

12)SKELETAL SYSTEM:

The large __ - filled ___ in circulatory system of molluscs acts as a ____ skeleton.

Answer 12

12)SKELETAL SYSTEM:

The large fluid-filled cavities in circulatory system of molluscs acts as a hydrostatic skeleton.

Question 13

13) Excretory system:

Molluscs have ___- developed excretory system.

Answer 13

13) Excretory system:

Molluscs have well-developed excretory system.

Question 14

14) NERVOUS SYSTEM:

nervous system in molluscs is __ developed.

Answer 14

14) NERVOUS SYSTEM:

nervous system in molluscs is well developed.

Question 15

15)HEAD-FOOT REGION:

molluscs have a head-foot region for ___ , feeding and ___.

Answer 15

15)HEAD-FOOT REGION:

molluscs have a head-foot region for sensation, feeding and locomotion.

Question 16

16) MASS:

All molluscs carry their major organs in their __ - __ mass.

Answer 16

16) MASS:
All molluscs carry their major organs in their
dorsal-visceral mass.

Question 17

17)MANTLE:

All molluscs have ___ of delicate ___ that surrounds their body called the mantle.

Answer 17

17)MANTLE:

All molluscs have fold of delicate tissue that surrounds their body called the mantle.

Question 18

18) SEXES:

In molluscs, sexes are _____ .

Answer 18

18) SEXES:

In molluscs, sexes are separate .

Question 19

19) MODE OF FERTILIZATION:

Fertilization in molluscs takes place in ___ .

Answer 19

19) MODE OF FERTILIZATION:

Fertilization in molluscs takes place in water .

Question 20

20) LARVAL STAGE:

The larval stage of molluscs is called ____ stage.

Answer 20

20) LARVAL STAGE:
The larval stage of molluscs is called
trochophore stage.

Question 21

Molluscs are divided into __ classes, three of which are :

i. ____
ii. ____
iii. ____

Answer 21

Molluscs are divided into six classes, 
three of which are :
i. Gastropoda
ii. Bivalvia
iii. Cephalopoda

Question 22

CLASS GASTROPODA:
1. Class Gastropoda is the \_\_\_ class of Phylum mollusca.

Answer 22

CLASS GASTROPODA:
1. Class Gastropoda is the largest class of Phylum mollusca.

Question 23

CLASS GASTROPODA:

2. Its members are mostly ___ , some are aquatic and the rest are ____ .

Answer 23

CLASS GASTROPODA:

2. Its members are mostly marine, some are aquatic and the rest are terrestrial.

Question 24

CLASS GASTROPODA:

3. Some of them become secondarily asymmetrical by twisting visceral mass at __ by ___ .

Answer 24

CLASS GASTROPODA:

3. Some of them become secondarily asymmetrical by twisting visceral mass at 180° by Torsion .

Question 25

CLASS GASTROPODA: | 4. They have prominent ___ and a broad muscular ___ developed on their visceral mass.

Answer 25

CLASS GASTROPODA: | 4. They have prominent head and a broad muscular foot developed on their visceral mass.

Question 26

CLASS GASTROPODA: | 5. External shell maybe ___ or ___ . If present, the shell is usually ____ .

Answer 26

CLASS GASTROPODA: | 5. External shell maybe present or absent. If present, the shell is usually coiled.

Question 27

CLASS GASTROPODA: | 6. They have a ___ and feeding structure in their buccal cavity called ___ .

Answer 27

CLASS GASTROPODA: | 6. They have a rasping, feeding structure in their buccal cavity called radula.

Question 28

CLASS GASTROPODA: 7. Examples are: a. ___ b. ___ c. ___

Answer 28

CLASS GASTROPODA: 7. Examples are: a. snails b. slugs c. Pila

Question 29

``` CLASS BIVALVIA: 1. It is the ___ - ___ class of phylum mollusca. ```

Answer 29

``` CLASS BIVALVIA: 1. It is the second-largest class of phylum mollusca. ```

Question 30

CLASS BIVALVIA: | 2. bodies enclosed in a ___ that has left and right pieces called ___ .

Answer 30

CLASS BIVALVIA: | 2. bodies enclosed in a shell that has left and right pieces called Valves.

Question 31

CLASS BIVALVIA: | Both valves are __able and ___ed together.

Answer 31

CLASS BIVALVIA: | Both valves are movable and hinged together.

Question 32

CLASS BIVALVIA: | 4. Muscular foot is ____ and ___ally compressed.

Answer 32

CLASS BIVALVIA: | 4. Muscular foot is ventral and laterally compressed.

Question 33

CLASS BIVALVIA: | 5. Foot helps to ___ or ___ in the mud or ___ .

Answer 33

CLASS BIVALVIA: | 5. Foot helps to creep or burrow in the mud or sand.

Question 34

CLASS BIVALVIA: | 6. Can be ___ or ___water.

Answer 34

CLASS BIVALVIA: | 6. Can be marine or freshwater.

Question 35

CLASS BIVALVIA: 7. Examples are : a. ___ b. ___ c. ___ ___

Answer 35

CLASS BIVALVIA: 7. Examples are : a. Unio b. Mytilus c. pearl oyester

Question 36

CLASS CEPHALOPODA : | 1. Foot is on their ___ .

Answer 36

CLASS CEPHALOPODA : | 1. Foot is on their heads.

Question 37

CLASS CEPHALOPODA : | 2. Foot is transformed into ___ , which are attached to the ____ and ___.

Answer 37

CLASS CEPHALOPODA : | 2. Foot is transformed into suckers, which are attached to the tentacles and arms.

Question 38

CLASS CEPHALOPODA : | 3. ___ are present in a ring around the ___.

Answer 38

CLASS CEPHALOPODA : | 3. Tentacles are present in a ring around the mouth.

Question 39

CLASS CEPHALOPODA : 4. Examples of cephalopoda with shell type are: a. ___ b. ___ c. ___ d. ___

Answer 39

S. No...............EXAMPLES...............SHELL TYPE 1. ..........................Sepia.......................internal shell 2. .......................Nautilus....................internal shell 3..........................Loligo......................external shell ........................... (squid) 4........................Octopus.......................No shell ........................ (devil fish)