Pyramids of Biomass

• What does each bar in a pyramid of biomass show?

  The biomass of all organisms in that trophic level
• Roughly what proportion of energy biomass is transferred between trophic levels?

  10%
• Which of these is NOT true when drawing pyramids of biomass?

  The primary consumer is at the bottom

  • The producers are at the bottom, the primary consumers are one level above them. 
• Where are apex predators on a pyramid of biomass?

  At the top of the pyramid 
• What does the biomass of an organism refer to?

  The mass of an organism

  • Biomass refers to the organic material that comes from living organisms, such as plants and animals.
• The image above shows a pyramid of biomass. Which trophic level does the highlighted bar represent?

  Apex predators

  
• The image above shows a pyramid of biomass. Which trophic level does the highlighted bar represent?

  Producers

  
• The image above shows a pyramid of biomass. Which trophic level does the highlighted bar represent?

  Primary consumers

  
• Which of the groups below is NOT shown on a pyramid of biomass?

  Decomposers
• Give three reasons why only ~10% of the energy & biomass is passed on at each stage in a food chain? 

  • Organisms don't normally eat every part of their food (e.g. rabbits may not eat the roots of the grass they eat)
  • Some of the material they eat may not be absorbed (e.g. rabbits may not be able to digest all the cellulose in grass)
  • Most of the biomass/energy that is absorbed is used to release energy (via respiration) for movement etc.
• Calculate the efficiency of biomass transfer between trophic level 2, and trophic level 3. Round your answer to 1 decimal place.

  • The formula for efficiency of biomass transfer is: efficiency= BIOMASS TRANSFERRED TO THE NEXT LEVEL/BIOMASS THAT WAS AVAILABLE AT THE PREVIOUS LEVEL

  11.1%

  • (38/342)* 100

  
• Calculate the efficiency of biomass transfer between trophic level 3, and trophic level 4. Round your answer to 1 decimal place.

  12.4%

  (34/350)*100

  
• Calculate the efficiency of biomass transfer between trophic level 1, and trophic level 2. Round your answer to 1 decimal place.

  9.6% (48/490)*100