Energy and ecosystems

• What is biomass defined as?

  Dry mass of carbon per area at time
• Where are chemical energy stores located?

  Bonds of chemical compounds
• What process forms chemical energy stores?

  Photosynthesis
• What is calorimetry used to estimate?

  Chemical energy store
• What does calorimetry measure?

  Heat energy released per unit of mass
• In calorimetry, what is the weight sample of dry biomass burnt in?

  Excess oxygen
• What happens to the chemical energy stores during calorimetry?

  They are released as heat energy
• How is heat energy released per gram of biomass calculated?

  SHC x volume x temp change / mass
• Why is only a small percentage of light converted into a chemical energy store?

  Some light may be the wrong wavelength
• Why is only a small percentage of light converted into a chemical energy store?

  Some light might not hit chloroplasts
• Why is only a small percentage of light converted into a chemical energy store?

  Another factor may limit photosynthesis rate
• What does GPP stand for?

  Gross Primary Production
• What is Gross Primary Production (GPP)?

  Chemical energy store in plant biomass
• What is the equation relating NPP, GPP and R?

  NPP = GPP - R
• What is NPP?

  Overall chemical energy after respiration
• How do consumers obtain energy?

  By ingesting other organisms
• Approximately what percentage of a producer's energy is passed on to consumers?

  Ten percent
• Why is only a small percentage of energy passed from producers to consumers?

  Not all of the organism is eaten
• Why is only a small percentage of energy passed from producers to consumers?

  Some energy is lost in faeces and urine
• Why is only a small percentage of energy passed from producers to consumers?

  Some energy is lost in respiration
• What is net secondary production (N)?

  Energy after loses from consumers
• What is the equation for net secondary production (N)?

  N = I - (F+R)
• What is primary and secondary productivity measured as?

  Biomass in an area in time
• How do you calculate the percentage efficiency of energy transfer between trophic levels?

  (Energy after transfer/energy before transfer) x100
• How can percentage efficiency from one trophic level to another be increased?

  Simplifying food webs
• How can percentage efficiency from one trophic level to another be increased?

  Reducing respiratory loses
• How can percentage efficiency from one trophic level to another be increased?

  Removing competitors
• How can respiratory losses be reduced?

  Keeping organisms warmer