Specialised Exchange surfaces

• Why do large organisms need specialist gas exchange surfaces?

  • They have a small surface area to volume ratio
  • higher metabolic rate - demands efficient gas exchange
  • specialised organs e.g. lungs / gills designed for exchange
• What adaptions will all exchange surfaces have (to increase the rate of diffusion)?

  • Increase surface area
  • reduce diffusion distance
  • maintain the concentration gradient