pyramids of biomass

    Cards (9)

    • Pyramids of biomass show the biomass of each trophic level in a food chain
    • Grass is the producer
      • Rabbits are the primary consumer
      • Snakes are the secondary consumer
      • Hawks are the tertiary consumer
    • Biomass refers to the mass of living organisms
    • Bars in the pyramid represent the total mass of organisms at each trophic level
    • Total mass of organisms decreases as you move up the trophic levels
    • Only about 10% of biomass and energy is transferred up to the next trophic level
    • Reasons for only 10% transfer:
      • Organisms don't eat every part of what they consume
      • Not all consumed parts are absorbed and some are excreted as waste
      • Most nutrients absorbed are used for energy through respiration rather than growth
    • Efficiency of biomass transfer calculation:
      • Efficiency = (Biomass transferred to the next level / Biomass available at the previous level) x 100
      • Example: Efficiency between snakes and rabbits = (15 kg / 144 kg) x 100 = 10.4%
    • Efficiency between snakes and hawks = (1.6 kg / 15 kg) x 100 = 10.7%
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