Energy transfer and productivity

• Gross primary production - total quantity of chemical energy store in plant biomass
• Net primary production - the chemical energy store that is left when these losses to respiration have been taken into account
• Primary production = gross primary production - respiratory losses
• The low percentage of energy transferred is a result of:

  • some of the organism is not consumed
  • some parts are lost in excretion
  • some is lost in respiration
• Net production of consumers is calculated as:

  N = I - (F+R)

  net production = chemical energy store of ingested food - (energy lost in faeces and urine + energy lost in respiration)