Question

ergy & matter in ecosystems
moray eels
(1,000 kg)
shrimp
(10,000 kg)
zooplankton
(100,000 kg)
phytoplankton
(1,000,000 kg)
how is each trophic level of the biomass pyramid related to the adjacent trophic levels?
a. each trophic level contains ten times as much biomass as the level below it and one - tenth as much biomass as the
level above it.

b. each trophic level contains one - tenth as much biomass as the level below it and ten times as much biomass as the
level above it.

c. as the trophic levels progress from phytoplankton to sharks, there is an increase in both the number of individual
organisms and the biomass.

d. as the trophic levels progress from phytoplankton to sharks, there is a decrease in the amount of biomass but an
increase in the amount of available energy.

Explanation:

1. Analyze the biomass values: Phytoplankton (1,000,000 kg), Zooplankton (100,000 kg), Shrimp (10,000 kg), Moray Eels (1,000 kg).
2. Check the ratio between adjacent levels: \( \frac{100000}{1000000}=\frac{1}{10} \), \( \frac{10000}{100000}=\frac{1}{10} \), \( \frac{1000}{10000}=\frac{1}{10} \). So each level has 1/10 the biomass of the level below it (and 10 times the biomass of the level above it).
3. Evaluate options:

• Option A: Incorrect ratio (says ten times below, should be 1/10).
• Option B: Matches the ratio (1/10 of below, 10 times of above).
• Option C: Biomass decreases with higher trophic levels, so "increase in biomass" is wrong.
• Option D: Available energy decreases with higher trophic levels, so "increase in energy" is wrong.

Answer:

B. Each trophic level contains one - tenth as much biomass as the level below it and ten times as much biomass as the level above it.