molluscs: bivalves

Question 1

what kind of skeleton/protection do bivalves have

Answer 1

shells with two parts

Question 2

what are the clam’s shell made of

Answer 2

protein and calcium carbonate

Question 3

how are pearls formed

Answer 3

when a foreign body (eg. sand) become trapped between mantle and shell

Question 4

what holds the valves of the shell together

Answer 4

adductor muscles

Question 5

in the mantle cavity, what organ is used for gas exchange? where do they hang

Answer 5

gills
- hangs down on either side of the visceral mass

Question 6

what kind of feeder are bivalves

Answer 6

filter feeder

Question 7

where does food enter the mantle cavity

Answer 7

through the incurrent siphon: posterior opening between the two valves

Question 8

mucous secretions do what to feed

Answer 8

cause smaller particles to adhere to the gills, ciliary action sweeps them towards the mouth

Question 9

where is the heart of the clam and where does it pump blood to

Answer 9

• below the hump of the shell, within the pericardial cavity (only remains of the coelom)
• pumps blood into a dorsal (back) aorta that leads to organs

Question 10

what kind of circulatory system?

Answer 10

open: blood flows out of vessels and organs to bathe tissues. lowers blood pressure. usually for inactive animals

Question 11

describe the digestive system of bivalves

Answer 11

mouth with labial palps, esophagus, stomach, intestine which coils in visceral mass, anus

Question 12

describe how clams excrete

Answer 12

2 exerctory kidneys in the clams (lies
below the heart)
- remove waste from the precardinal cavity for excretion into the mantle cavity

Question 13

all clams have a ______ stage

Answer 13

larval

Question 14

are bivalve sexes usually separate

Answer 14

yes

Question 15

where is their gonad located

Answer 15

around coils of intestine