energy transfer and biomass

• • chemical energy stores in producer biomass is passed to primary consumer when ingested
  • PC uses digested plant tissue for respiration or to build up biomass, stored chemical energy transferred to tissue of primary consumer and passed to secondary when ingested
• energy loss in a food chain

  1.not all suns energy available to producers form building biomass

  • light passes through leaves/reflected
  • light hits non photosynthetic area of plant eg flower
  • light is a mix of wavelengths and only certain waves lengths absorbed

  2.not every part of organism is eaten
• energy losses in food chain

  3. energy lost as heat via respiration(exothermic reaction)

  4.energy lost when organism excretes waste products of metabolism eg urea

  5. consumers not able to digest all food, some egested as faeces- chemical energy in ingested food
• after losses

  • energy left is converted into biomass during growth and used to fuel their life functions
• energy efficiency= net productivity/energy recieved x 100

  • net productivity calculated by energy recieved-energy losses
  • given as a %
• energy efficiency of biomass transfer

  • dry biomass used
  • done by drying sample of an organism in oven and weighing sample at regular intervals until constant

  efficiency of biomass transfer=biomass transferred/biomass intake x 100