Pyramids of biomass

• What do pyramids of biomass show?

  The biomass of each trophic level
• In the given food chain, what is the producer?

  Grass
• What role do snakes play in the food chain?

  Secondary consumers
• What is the term 'biomass' defined as?

  The mass of living organisms
• What does the bottom bar of the pyramid represent?

  Total mass of all grass
• What trend is observed in the biomass as you go up the trophic levels?

  The total mass decreases
• Why is the total mass of snakes lower than that of rabbits?

  Fewer snakes than rabbits exist
• What percentage of biomass is typically transferred to the next trophic level?

  About 10%
• What happens to most of the biomass and energy when one organism is consumed by another?

  It is lost or used
• What is one reason why not all biomass is absorbed by the consumer?

  Not every part is eaten
• What is a second reason why biomass might not be absorbed?

  Some parts can't be broken down
• What is the most important reason for biomass loss during consumption?

  Energy is used for respiration
• How do you calculate the efficiency of biomass transfer?

  Efficiency = biomass transferred / biomass available
• What is the efficiency between snakes and rabbits if 15 kg is transferred?

  10.4%
• What is the efficiency between snakes and hawks if 1.6 kg is transferred?

  10.7%
• What are the main reasons for biomass and energy loss in food chains?

  • Not all parts of organisms are eaten
  • Some parts are not absorbed
  • Most nutrients are used for respiration
• How do you calculate the efficiency of biomass transfer in a food chain?

  1. Identify biomass transferred to the next level
  2. Identify biomass available at the previous level
  3. Use the formula:

  • Efficiency = (biomass transferred / biomass available) × 100