Given below are two statements:

Statement I: In ecosystem, there is unidirectional flow of energy of sun from producers to consumers.

Statement II: Ecosystems are exempted from 2nd law of thermodynamics.

In the light of the above statements, choose the most appropriate answer from the options given below:

The correct option is: Statement I is correct but Statement II is incorrect.

Let us analyze the two statements step-by-step to understand the flow of energy and the laws of thermodynamics in an ecosystem:

Analysis of Statement I:

In any ecosystem, energy flows from the sun to autotrophic organisms (producers like green plants) through photosynthesis, and is then transferred to various heterotrophic organisms (consumers like herbivores and carnivores) through food chains and food webs.

This flow of energy is strictly unidirectional. The energy captured by producers from solar radiation does not revert back to the sun, and the energy passed from producers to consumers cannot flow backward to producers. Thus, Statement I is correct.

Analysis of Statement II:

The second law of thermodynamics states that every energy transfer or transformation increases the entropy (disorder) of the universe, and no energy transfer is 100% efficient as some energy is always lost as heat.

Ecosystems are not exempted from the laws of thermodynamics. They require a constant input of energy (from the sun) to maintain their highly organized structure and counteract the natural tendency toward entropy. As energy flows through the trophic levels, a significant portion (roughly 90%) is dissipated as heat, which increases the entropy of the surroundings. Because ecosystems must obey the second law of thermodynamics to function, Statement II is incorrect.

Conclusion:

Since Statement I is correct and Statement II is incorrect, the most appropriate choice is: Statement I is correct but Statement II is incorrect.