6.1 - Exchange between organisms and their environment

• If an organism has a high metabolic rate what does it require ?

  A larger surface area to volume ratio
• What SA:V does a larger organism have ?

  Smaller surface area to volume ratio
• What SA:V does a smaller organism have ?

  Higher
• Do smaller organisms have a higher or lower metabolic rate ?

  Higher, higher SA:V so they lose body heat faster than larger organisms
• Things exchanged with an organism and its environment ?

  Respiratory gases, nutrients (AA, glucose, vitamins), waste products (urea and CO2)
• 2 changes to body shape and systems that facilitate exchange as SA:V ratio decreases ?

  Flattened shape so no cell far from surface(flatworms and leaves), specialised exchange surfaces with large SA to increase SA:V(lungs in mammals, gills in fish)
• 5 features of specialised exchange surfaces ?

  Large surface area, thin barrier, good blood supply, moist environment, selective permeability