Energy

• What is the general equation for % efficiency?

  Efficiency = (useful energy / total energy) x 100
• Why does biomass decrease at each trophic level?

  • Energy lost in nitrogenous waste (urine) & faeces
  • Some of the organism is not consumed
  • Energy lost to surroundings as heat
• What are the units for biomass when sampling an area?

  gm⁻²
• What are the units for biomass when sampling a volume?

  gm⁻³
• What is the mathematical relationship between GPP and NPP?

  NPP = GPP - R
• What does R represent in the equation NPP = GPP - R?

  Respiratory losses from plants
• What does NPP account for after respiratory losses?

  Energy transfer to other trophic levels
• Define net primary productivity (NPP).

  
  

  
  

  Total chemical energy available for plant growth, plant reproduction and energy transfer to other trophic levels after respiratory losses.
• Define gross primary production (GPP)

  Total chemical energy in plant biomass within a given volume or area.
• What is biomass?

  
  

  
  

  Total dry mass of tissue or mass of carbon measured over a given time in a specific area.
• Give the mathematical relationship between GPP and NPP.

  
  

  Give the mathematical relationship between GPP and NPP.

  NPP = GPP - R

  
  

  Where R represents respiratory losses from plants.
• Suggest the units for biomass.

  
  

  
  

  When an area is being sampled: gm-2

  When a volume (e.g. a pond) is being sampled: gm-3