exchange surfaces

• The need for specialised exchange surfaces arises as the size of the organism, and its surface area to volume ratio decreases
• In the case of single celled organisms, the substances can

  easily enter the cell as the distance that needs to be crossed over is short
• multicellular organisms that distance is much larger due to a lower surface area to volume ratio.
• multicellular organisms required specialised exchange surfaces for efficient gas exchange of carbon dioxide and oxygen
• What are features of an efficient exchange surface?

  Large surface area

  Good blood supply

  Small concentration gradient