Limiting water loss Flashcards
Limiting water loss in insects- adaptations
+Small surface area to volume ratio to minimise the area over which water is lost
+Water proof coverings over their body surfaces. In the case of insects this covering is a rigid outer skeleton of chitin that is covered with a water proof cuticle.
+Spiracles are the openings of the tracheae at the body surface and these can be closed to reduce water loss. Mainly occurs during rest to avoid conflict with the need for O
Limiting water loss in plants
+ Have a waterproof covering over leaves and can close stomate
Xerophytes= plants that have adapted to live in areas where water is in short supply.
Modifications to reduce water loss in plants
A thick cuticle- A thick waxy cuticle lowers the rate of water loss.
rolling up of leaves- The rolling up of leaves to cover the lower epidermis traps a region of air over the stomata. This region becomes saturated with water and increases the water potential to reduce the concentration gradient.
Hairy leaves- The hairs of the leaves trap a layer of air. ∴ the gradient of conc is reduced.
Stoma in pits and grooves- These traps a layer of air and reduce the gradient.
A reduced SA to V ratio of the leaves- Having small and roughly circular leaves like pine needles, the rate of water loss can be reduced.
