Specialised organisms (gas exchange)

Specialised organisms (gas exchange)

1. amoeba

   • single-celled organism
   • aquatic
   • oxygen enters and carbon dioxide exits by diffusion
   • gases diffuse through membrane

2. earthworm

   • annelid - segmented worm
   • uses "skin" which is slimy/ a moist surface - if drys out will "suffocate
   • pseudoheart (muscular bag that pumps the blood)
   • o2 diffuses in and co2 diffuses out through moist surface

3. insects

   • have exoskeleton - protective outer coat stops water loss
   • small holes called spiracles
     • open into tubes called tracheoles
       • go direct to muscle
   • ventilate by body contraction

4. frog

   • has lungs
   • moist skin - used over winter with mud
   • has gills - as tadpoles
   • lungs, skin and gills are respiratory surfaces

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