Gas Exchange: Insects

Question 1

How are insects adapted to reduce water loss?

Answer 1

1. Waterproof exoskeleton
2. Small SA:V - minimises area where water can be lost
3. Spiracles can open and close
4. Hairs around spiracles - reduces evaporation

Question 2

Spiracles

Answer 2

Openings on the insects body

Question 3

What are Tracheae

Answer 3

Large tubes extending through all body tissues supported by rings of chitin to avoid collapse

Question 4

Ventilation in Insects

Answer 4

1. Movement of muscles in insects can create mass movements of air in and out of the tracheae
2. This further speeds up exchange
3. This is because an insects circulatory system does not transport oxygen

Question 5

Tracheole walls: properties

Answer 5

thin, permeable walls

Question 6

Limitations of the insect gas exchange system

Answer 6

Relies mostly on diffusion and for diffusion to be effective the pathway has to be short and this limits the size insects can be.

Question 7

Advantage of liquid in tracheoles passing into muscles during flight

Answer 7

larger surface area for diffusion

Question 8

Abdominal pumping increases the efficiency of gas exchange between tracheoles and muscle tissue of the insect. Explain why.

Answer 8

1. More oxygen enters quicker
2. Concentration gradient is maintained