adaptation and variation in 4 classes of molluscs

Question 1

what are the key characteristics of molluscs

Answer 1

fott
radula
shell
mantle

Question 2

foot

Answer 2

muscular; usually ventrally located and generally used for locomotion

Question 3

radula

Answer 3

a scraping oral structure which is unique to mollusks

Question 4

shelll

Answer 4

either an external calcium carbonate shell or an internal chiton shell

Question 5

mantle

Answer 5

an organ that secretes the shell

Question 6

Chiton (polyplacophora)

Answer 6

-have a reduced head and flat body protected by segmented plates
-large ventral foot is adapted for clinging tightly to rocks that are expose to waves
-the radula in chiton is used like teeth for scraping algae of rocks
-the muscular foot is very strong and undulates during movement
-there are 8 plates that make up the shell; light-sensitive organs on the shell allow the chiton to move away from sunlight and find a darker, cooler place to feed
-live in rocky intertidal zones

Question 7

Clam

Answer 7

-class: bivalvia
-they have 2 halves
-move by digging their foot. They burrow into the sand or mud to feed at the bottom of the ocean or freshwater area
- they are filter feeders and have
-no radula
-live in the open ocean during larval stage and then as adults move to the floor of oceans or bays
-mantle secretes the shell allowing the shell to grow as the internal organs grow
-muscles keep the shell closed and when the muscles relax the shell can open, allowing the foot to dig up into the sand and siphon to reach up into the water.
the siphon filters food and water through the gills an into the mouth

Question 8

what are clam gills used for

Answer 8

respiration and feeding

Question 9

snail

Answer 9

-class gastropods
-largest class of molluscs
-live in the ocean, in freshwater, and on land
- have a broad foot used to creep; they have a mucus secretion that helps aid locomotion by preventing injury to the foot
-have radulas that allow them to scrape algae from the surface of rocks, aquarium, and other shell in order to feed

Question 10

what does the visceral mass in the shells of snail do

Answer 10

it holds the bulk of the digestive, reproductive , excretory, and respiratory systems

Question 11

benefit of torsion

Answer 11

gives it the ability to retract into the shell if in any danger. Allows for elongation in growth without toppling sideways

Question 12

squid

Answer 12

-class cephaalopoda
-most active group of molluscs
- open-ocean swimmers
-their shell is reduced and internalized
-they do not have radula to aid in feeding
-they have a siphon used for locomotion
-muscular contractions force water through the siphon, propelling the squid through the water,
-the siphon is a modification of the foot

Question 13

which mollusc lives in rockey intertidal zones

Answer 13

chiton; class polyplacophora

Question 14

in this mollusc the ventral foot clings to rocks in area where waves constantly hit the rock surface

Answer 14

chiton; class polyplacophora

Question 15

this mollusc is known to have a radula stronger than a kitchen knife to scrape algae off rock

Answer 15

chiton; class polyplacophora

Question 16

this mollusc is armor plated; 8plates that make up their shell

Answer 16

chiton; class polyplacophora

Question 17

this mollusc has light-sensitive organs on their shell that allow it to move away from the sunlight

Answer 17

chiton; class polyplacophora

Question 18

which mollusc moves by burrowing its foot into the sand mud

Answer 18

clam; class bivalvia

Question 19

this mollusc lives in the open ocean when younger, but as an adult moves toward the floor of the oceans

Answer 19

clam; class bivalvia

Question 20

the mantle of this mollusc secretes the shell allowing the shell to grow as the internal organs grow

Answer 20

clam; class bivalvia

Question 21

in this mollusc when the muscles relaxes the shell opens, which allows the foot to dig into the sand and the siphon to reach up into the water

Answer 21

clam; bivalvia

Question 22

this mollusc has no radula

Answer 22

clam; bivalvia

Question 23

what is the siphon a modification of in clams?

Answer 23

mantles

Question 24

this type of mollusc lives in ocean, freshwater, and land

Answer 24

snail; class gastropoda

Question 25

this mollusc has a broad foot that can be used to creep

Answer 25

snail; class gastropoda

Question 26

this mollusc is able to withdraw into the shell for protection

Answer 26

snail; class gastropoda

Question 27

these types of molluscs use their radula to drill a hole in other mollusc shells in order to obtain food

Answer 27

carnivorous snails

Question 28

this type of mollusc is known to be the most active group of molluscs

Answer 28

squid; class cephalopods

Question 29

these molluscs are known for their fast swimming abilities

Answer 29

squid; class cephalopods

Question 30

these molluscs don’t have an outer shell; instead they have an internalized shell

Answer 30

squid; class cephalopods

Question 31

these molluscs have a siphon for locomotion

Answer 31

squid; class cephalopods

Question 32

these molluscs have muscular contractions to force water through the siphon, propelling it through the water

Answer 32

squid; class cephalopods

Question 33

the siphon of a squid is modification of what?

Answer 33

the foot

Question 34

class of chiton

Answer 34

polyplacophora

Question 35

class of clam

Answer 35

bivalvia

Question 36

class of snails

Answer 36

gastropoda

Question 37

class of squid

Answer 37

cephalopods