Molluscs

Question 1

locomotion in mollusca

Answer 1

sessile, sluggish-swift

Question 2

diet of mollusca (4)

Answer 2

herbivores, detritivores, filter feeders and predatory carnivores

Question 3

head-foot region (3 organs)

Answer 3

contains feeding, cephalic sensory and locomotor organs

Question 4

visceral mass (4 organs)

Answer 4

contains digestive, circulatory, respirator and reproductive organs

Question 5

mantle/ pallium

Answer 5

two folds of protective skin

Question 6

mantle cavity

Answer 6

space between mantle and body wall

Question 7

where are the gills (ctenidia) housed?

Answer 7

mantle cavity

Question 8

the chief locomotor organ

Answer 8

the foot

Question 9

radula

Answer 9

tongue like organ

Question 10

odontophore

Answer 10

cartilage-like supportive structure

Question 11

function of the foot

Answer 11

• attachment to substratum
• locomotion
• or both

Question 12

• attachment of disc of limpets
• hatchet food of bivalves
• siphon jet of cephalopods
• cephalopod arms

Answer 12

modifications of the foot

Question 13

function of the mantle

Answer 13

gas exchange

Question 14

where do products of digestive, excretory and reproductive systems empty?

Answer 14

mantle cavity

Question 15

ctenidia

Answer 15

gills housed in the mantle cavity

Question 16

ciliary function

Answer 16

provides continuous water current

• respiratory
• waste elimination
• sensory detection
• gamete dispersal

Question 17

butter horny layer of a shell

Answer 17

periostracum

Question 18

thickest layer of the shell

Answer 18

middle prismatic layer

Question 19

open circulatory system

Answer 19

pumping heart, blood vessels and blood sinuses

Question 20

closed circulatory system

Answer 20

(most cephalopods), heart, vessels and capillaries

Question 21

organs for excretory system

Answer 21

kidneys or metanephridia

Question 22

secondary kidney function

Answer 22

discharge sperm and eggs

Question 23

nervous system

Answer 23

inputs sensory information for locomotion

Question 24

highly specialized organs

Answer 24

sense organs

Question 25

internal fertilization

Answer 25

- copulation occurs | - gametes exchange genital ducts

Question 26

external fertilization

Answer 26

- gametes released into water | - free-swimming larval stages

Question 27

can feed themselves

Answer 27

planktoptophic

Question 28

yolk-feeding, cannot feed themselves

Answer 28

lecithotrophic

Question 29

veliger

Answer 29

symmetrical, enclosed two valved shell

Question 30

function of velum

Answer 30

- locomotion - food collection - gas exchange

Question 31

glochidium larva

Answer 31

microscopic non-swimming shelled larva

Question 32

chitons

Answer 32

- no veliger stage | - directly to juvenile

Question 33

lack head, radula or other aspects of cephalization

Answer 33

class bivalves

Question 34

bivalvia

Answer 34

sedentary filter feeders

Question 35

gastropoda

Answer 35

sluggish, toxic secretions | ex: snails

Question 36

one-piece univalve

Answer 36

coiled or uncoiled

Question 37

apex

Answer 37

smallest and oldest whorl

Question 38

cephalopoda (squids)

Answer 38

- separate sexes | - closed circulatory system

Question 39

chromatophores

Answer 39

pigment granules in skin

Question 40

what causes colour change in squids?

Answer 40

contraction of muscle fibres attached to the cell boundary