Revision 2

Question 1

List 3 main parts of the mollusc body

Answer 1

-a muscular foot used for movement
- a visceral mass containing most of the internal organs
- a mantle that drapes over the visceral mass and secretes a shell if one is present

Question 2

What does torsion mean in phylum mollusc?

Answer 2

As they grow and develop the visceral mass rotates up to 180° so that the anus and mantle cavity are located above the head in the adult

Question 3

What class of phylum mollusc has the torsion feature?

Answer 3

Class Gastropoda

Question 4

What is the tongue like feeding structure unique to molluscs ?

Answer 4

Radula

Question 5

What are chromatophores in the octopus?

Answer 5

Pigment rich cells

Question 6

How do chromatophores contribute to octopus predatory lifestyles?

Answer 6

They expose different amounts of colour to hide to camouflage themselves

Question 7

What is the function of the adductor muscle in bivalves ?

Answer 7

To close the valves

Question 8

Give two functions of the gills in the bivalves.

Answer 8

-gas exchange
-filter feeding

Question 9

What are 4 economic importances of molluscs?

Answer 9

• food source for humans
• pearls have high commercial value
• shells used in jewellery

Question 10

What does metameric segmentation mean?

Answer 10

The division of the body into a series of similar segments arranged linearly from the anterior to the prosterior end

Question 11

In earthworms what is the prostomium?

Answer 11

Fleshy lobe on the anterior end

Question 12

In earthworms what is the setae?

Answer 12

Bristles on each segment of the body that provide traction needed for movement

Question 13

In the earthworm what is the clitellum?

Answer 13

Thickening between segments 32 and 37 that secrete mucus that binds 2 worms together in reproduction

Question 14

What is the function of nephridia in earthworms?

Answer 14

Regulate the volume of body fluids

Question 15

Describe the the circulatory system in earthworms

Answer 15

Closed circulatory system, dorsal and ventral blood vessels run the length of the body connected by capillary network in each segment near the anterior end there is 5 pairs of large side vessels referred to as pseudo hearts

Question 16

Explain how locomotion is achieved in the earthworm

Answer 16

Longitudinal muscles contract and circular ones relax segments shorten and fatten they lengthen when the patterns reverse the alternate contractions and elongations allow the worm to move forward

Question 17

Write a note on the ecological importance of earthworms

Answer 17

Their borrowing activity improves the condition and fertility of soils.

Question 18

List 4 adaptations in Arthropods that have contributed to their huge success

Answer 18

Exoskeleton
Specialisation of segments
Jointed appendages
Specialised sensory organs