Pyramids of Biomass

• What do pyramids of biomass show?

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

  Grass
• What is the role of rabbits in the food chain?

  They are the primary consumers
• What does the term biomass refer to?

  The mass of living organisms
• Why do the bars in a biomass pyramid get smaller as you go up?

  Total mass of organisms decreases at each level
• Why is the total mass of snakes lower than that of rabbits?

  Fewer snakes exist compared to rabbits
• What happens to most of the biomass and energy when one organism is consumed by another?

  It is lost or used by the consumer
• What percentage of biomass is typically transferred to the next trophic level?

  About 10%
• What is one reason why not all biomass is consumed by predators?

  Predators do not eat all parts of prey
• What happens to the parts of the organism that are not absorbed?

  They are excreted as feces
• How do animals primarily use the nutrients they absorb?

  For energy through respiration
• What is the formula to calculate the efficiency of biomass transfer?

  Efficiency = (biomass transferred / biomass available) × 100
• If the biomass transferred to snakes is 15 kg and the biomass available from rabbits is 144 kg, what is the efficiency?

  10.4%
• What is the efficiency between snakes and hawks if the biomass transferred is 1.6 kg and the biomass available is 15 kg?

  10.7%
• What are the main reasons only 10% of biomass is transferred between trophic levels?

  • Not all parts of prey are consumed
  • Some consumed parts are not absorbed
  • Most nutrients are used for energy via respiration
• What are the roles of snakes and hawks in the food chain?

  Snakes are secondary consumers; hawks are tertiary consumers