Class X Biology - Chapter: Our Environment - Topic: Ecological Pyramids Numerical Problems

Problem 1: Pyramid of Energy Calculation

In an ecosystem, the producers have 100,000 Joules (J) of energy. If the energy transfer efficiency between trophic levels is 10%, calculate the energy available at the tertiary consumer level.

Solution:

• Producers (Trophic Level 1): 100,000 J
• Primary Consumers (Trophic Level 2): 10% of 100,000 J = 0.10 * 100,000 J = 10,000 J
• Secondary Consumers (Trophic Level 3): 10% of 10,000 J = 0.10 * 10,000 J = 1,000 J
• Tertiary Consumers (Trophic Level 4): 10% of 1,000 J = 0.10 * 1,000 J = 100 J

Therefore, 100 Joules of energy will be available at the tertiary consumer level.

Problem 2: Biomass Transfer (Conceptual)

If 1000 kg of producers are required to support 100 kg of primary consumers, how much biomass of primary consumers would be needed to support 1 kg of secondary consumers, assuming the same transfer efficiency?

Solution:

From the first statement, the transfer efficiency from producers to primary consumers is: Efficiency = (Biomass of Primary Consumers / Biomass of Producers) * 100 Efficiency = (100 kg / 1000 kg) * 100 = 10%

Now, apply this 10% efficiency to the next trophic level:

Let 'X' be the biomass of primary consumers needed. 10% of X = 1 kg (biomass of secondary consumers) 0.10 * X = 1 kg X = 1 kg / 0.10 = 10 kg

Therefore, 10 kg of primary consumers would be needed to support 1 kg of secondary consumers.