6.5 - Limiting water loss

• 4 ways in which insects are adapted to limit water loss ?

  Small SA:V to minimise area that water is lost, waterproof cuticle is impermeable, Chitin exoskeleton, closing of spiracles controlled by valves when at rest
• What are xerophytes ?

  Plants that have a restricted water supply and have adaptations to limit water loss
• 5 adaptations of xerophytic plants that limit water loss ?

  Thick cuticle so less water can escape, rolling up of leaves protects lower epidermis by trapping air that becomes saturated with water so water potential increases so no gradient between inside of leaf and outside, hairy leaves trap moist air lowering water potential gradient less evaporation, stomata in pits/grooves trap moist air reduce water potential gradient, a reduced SA:V less water loss but balanced with area needed for photosynthesis