Question

Identify incorrect statements with reference to the functioning of ecosystems:
A. Plants are primary consumers.
B. Herbivorous animals are secondary consumers.
C. Energy flow is always unidirectional.
D. Ecological pyramid of biomass is always upright.
Choose the correct answer from the options given below:

• A. A, B and C only
• B. B, C and D only
• C. A, B and D only
• D. C and D only

Hint:

Only the Pyramid of Energy is *always* upright. Biomass and Numbers pyramids can be inverted or spindle-shaped.

Answer 1

The Correct Option is C

Concept: Ecosystems function through the flow of energy and the cycling of nutrients among different "trophic levels." Understanding the correct terminology for these levels is essential.

Step 1: Evaluating Statements A and B (Terminology).

• A. Plants: Plants are Producers (autotrophs), not consumers. They produce energy from sunlight.
• B. Herbivores: Herbivores eat plants directly, making them Primary Consumers. Secondary Consumers are carnivores that eat herbivores. Both (A) and (B) use incorrect terminology.

Step 2: Evaluating Statement C (Energy Flow).
Energy flow in an ecosystem is always unidirectional (from the Sun to producers to consumers). It is never cycled back to the previous level. This statement is correct.

Step 3: Evaluating Statement D (Biomass Pyramids).
While pyramids of energy are always upright, the pyramid of biomass can be inverted in certain ecosystems, most notably in marine environments where a small biomass of phytoplankton supports a much larger biomass of zooplankton and fish. This statement is incorrect because of the word "always."

Step 4: Final Tally.
The question asks for incorrect statements. A, B, and D are incorrect.