insects and plants control water loss

• what does exchanging gases tend to cause?

  water loss
• What do insects do if they are losing too much water?

  They close their spiracles using muscles.
• what do insects have which reduce evaporation?

  • Waterproof waxy cuticle all over their body
  • Tiny hairs around their spiracles
• When are plants stomata usually kept open>?

  during the day
• why are plants stomata usually kept open during the day?

  to allow gas exchange
• what is the effect of water entering the guard cells?

  makes the guard cells TURGID, which opens the stomatal pore
• what happens if the plant starts to get dehydrated?

  the guard cells lose water and become FLACCID , which closes the pore
• what are xerophytes?


  Plants which are specially adapted for life in warm, dry or windy habitats, where water loss is a problem
• give 3 examples of xerophytic adaptions?

  • a reduced number of stomata = fewer places for water to escape
  • waxy, waterproof cuticles on stems and leaves to reduce evaporation
  • a layer of hairs on the epidermis - to trap moist air round the stomata