Question

Study the following statements and select the incorrect ones.
(i) Pyramids of energy and yearly biomass production can never be inverted, since this would violate the laws of thermodynamics.
(ii) Pyramids of standing crop and numbers can be inverted, since the number of organisms at a time does not indicate the amount of energy flowing through the system.
(iii) There are certain limitations of ecological pyramids such as they do not take into account the same species belonging to two or more trophic levels.
(iv) Saprophytes are not given any place in ecological pyramids even though they play a vital role in the ecosystem.

• A. (i) and (ii)
• B. (iii) and (iv)
• C. (ii) and (iii)
• D. None of these

Answer 1

The correct option is D None of these

The second law of thermodynamics states that whenever energy is transformed, there is a loss energy through the release of heat. This occurs when energy is transferred between trophic levels as illustrated in a food web. When one animal feeds off another, there is a loss of heat (energy) in the process. Additional loss of energy occurs during respiration and movement. Hence, more and more energy is lost as one moves up through trophic levels. If this pyramid is inverterved, it would violate the law of thermodynamics. Hence the pyramid can never be inverted.

The pyramid of numbers depicts the relationship in terms of the number of producers, herbivores and the carnivores at their successive trophic levels. There is a decrease in the number of individuals from the lower to the higher trophic levels. The number pyramid varies from ecosystem to ecosystem. Since the amount if energy flowing through the system is not indicated, the pyramid can be inverted.

These are the diagrammatic illustrations of connection between different trophic levels in terms of energy, biomass and number of an organism. The base of each pyramid represents the producers or the first trophic level. Apex represents tertiary or top level consumers. If any species belongs to two or more trophic level, it can causes differences and issues in energy flow and numbers.

Saprophytes are organisms which feed on dead and decaying matter and these pyramid exhibit interaction between the living components and decomposers interact with dead organisms at all level. This makes it difficult to place it in the ecological pyramid. Hence, they are not given any place in ecological pyramids even though they play a vital role in the ecosystem.

So the correct option is 'none of these'.