Control Of Water Loss

Question 1

Insects

Answer 1

• close their spiracles using muscle

- waterproof waxy cuticle all over their body and tiny hairs around spiracles that reduce evaporation

Question 2

Plants stomata

Answer 2

• kept open during day ro allow gas exchange
• water enters guard cells they become turgid to open the stomatal pore
• when dehydrated guard cells lose water to become flaccid so their able to close the pore

Question 3

Xerophytes

Answer 3

-plants specifically adapted to life in warm,dry or windy habitats

Question 4

Xerophytic adaptions

Answer 4

• stomata sunken pits to trap water vapour this reduces concentration gradient of water between leaf and the air so it reduces evaporation of water from the leaf
• a layer of hairs on epidermis to trap water vapour round the stomata
• curled leaves with stomata inside to protect them from the wind (wind increases rate of diffusion and evaporation)
• reduced number of stomata, fewer places for water to escape
• thicker waxy, waterproof cuticles on leaves and stems to reduce evaporation