Energy transfer

• Biomass - mass of living material

  • energy transfers = biomass transfers
  • food chain - simple lines of energy transfer
  • food web - lots of food chains and how they overlap
  • only 10% of energy is transferred to the next trophic level
• Simple food chain - with terms

  producer -> primary consumer -> secondary consumer -> tertiary consumer
• Energy transfer as biomass

  • 60% of energy is not taken in
  • 40% of energy available is called the gross productivity
  • 75% of gross productivity is lost
  • 25% of gross productivity becomes biomass - called the net productivity
  • this 25% equates to 10% of total energy that is available to the next trophic level
• Why is 60% of energy available not taken in?


  • plants can't use all the light energy that reaches them - wavelengths
  • light hits areas that can't photosynthesise
  • some parts aren't eaten - they are passed to decomposers
  • some parts are indigestible - passes as waste to decomposers
• What happens with the 40% of energy available that is taken in?


  • 75% of gross productivity is lost to the environment
  • respiratory loss
  • respiration for movement or body heat
• What happens with the 40% of energy available that is taken in?


  • 25% of gross productivity becomes biomass
  • aka. net productivity
  • this is the energy available for the next trophic level