Component 3.1 - Gas Exchange In Insects

Question 1

How do the adaptations of the insect exoskeleton help reduce water loss?

Answer 1

They have an impermeable cuticle to reduce water loss by evaporation

Question 2

Why do insects risk dehydration?

Answer 2

Because they live in an arid habitat and so water evaporates from their body surface

Question 3

Describe the gas exchange system of an insect

Answer 3

Air flows through paired holes called spiracles, running along the thorax and abdomen. The spiracles lead into a system of branched tracheae, which branch into smaller tubes called tracheoles.

Question 4

Name 2 other ways the gas exchange system of an insect is adapted to reduce water loss

Answer 4

1) The spiracles can open and close so gas exchange can take place but also, water loss can be reduced.
2) The hairs covering the spiracles in some insects contribute to water loss preventation.

Question 5

What limits the size of an insect?

Answer 5

The insects’ tracheal system for gas exchange is very efficient but diffusion is only efficient over small distances.

Question 6

How do insects perform gas exchange while resting?

Answer 6

They rely on diffusion through the spiracles, tracheae and tracheoles to take in oxygen and remove carbon dioxide.

Question 7

How do insects perform gas exchange while active?

Answer 7

Movements of the abdomen speed up the movement of air through the spiracles. The ends of the tracheoles are fluid-filled and are close to muscle fibres. This is where gas exchange takes place.

Question 8

How do gas exchange take place at the interface between the tracheoles and muscle fibre?

Answer 8

Oxygen dissolves in the fluid and diffuses directly into the muscle tissue, so no respiratory pigment or blood circulation is required.