Question

partial biomass pyramid for a particular marine ecosystem
shrimp
? kg
zooplankton
20,000 kg
phytoplankton
2,000,000 kg
if the proportion of energy transferred between trophic levels remains relatively const prediction of the total biomass in the trophic level containing shrimp is most likely cor
a. 2,020,000 kg
b. 1,980,000 kg
c. 200 kg
d. 20 kg

Explanation:

Step1: Determine Energy Transfer Ratio

In a biomass pyramid, energy (and biomass) transfer between trophic levels is typically about 10% (1/10) of the lower level's biomass. From Phytoplankton (2,000,000 kg) to Zooplankton: \( \frac{20,000}{2,000,000} = \frac{1}{100} \)? Wait, no, 2,000,000 0.01 = 20,000? Wait, 2,000,000 0.01 is 20,000? Wait, 2,000,000 0.01 = 20,000? Yes, 2,000,000 0.01 = 20,000. So the transfer ratio here is 1%? Wait, no, maybe I miscalculated. Wait, 2,000,000 0.01 = 20,000? Yes. So from Zooplankton (20,000 kg) to Shrimp, we apply the same ratio. So 20,000 0.01 = 200 kg? Wait, no, wait: Phytoplankton is 2,000,000, Zooplankton is 20,000. So 20,000 / 2,000,000 = 0.01 (1%). So the transfer efficiency is 1% (since 2,000,000 0.01 = 20,000). Then, for Shrimp, we take Zooplankton's biomass (20,000 kg) and multiply by 0.01: 20,000 0.01 = 200 kg. Wait, but let's check the options. Option C is 200 kg. Wait, maybe the transfer is 10%? Wait, no, 2,000,000 0.1 = 200,000, but Zooplankton is 20,000. So that's 1%? Wait, maybe the problem has a 1% transfer? Wait, let's recalculate. Phytoplankton: 2,000,000 kg. Zooplankton: 20,000 kg. So 20,000 / 2,000,000 = 0.01 (1% transfer). Then Zooplankton to Shrimp: 20,000 0.01 = 200 kg. So the shrimp's biomass should be 200 kg. Let's check the options. Option C is 200 kg. So that's the answer.

Step2: Apply the Ratio to Zooplankton

Using the same transfer ratio (1%) from Zooplankton to Shrimp: \( 20,000 \times 0.01 = 200 \) kg.

Answer:

C. 200 kg