Question

According to the second law of thermodynamics, the quality of energy changes over time. What sort of significance does this hold for living organisms?

Answer 1

• According to the second law of thermodynamics, during the conversion of enrgy from one form to another form, some energy is wasted. So, at the end, less energy is available to transfer than at the beginning of the process due to entropy.
• Thus, in living systems, second law of thermodynamics signifies that the organisms can not utilize all the energy available in the system as it gets wasted due to different types of metabolic activities.
• The examples of digestion and respiration in living beings and photosynthesis in plants can prove this significance.
• Example 1: The energy produced by eating food is utilized by living being for their physical work and homeostatic activities. Therefore, during working stage, living body excrete energy in the form of sweat whereas during resting stage, living body excretes energy due to the processes of digestion of food and respiration.
• Thus, lesser energy is available for physical work than consumed.
• Example 2: In photosynthesis process, the light energy present in the environment is not completely utilized for the plants because most of the light energy is lost due to the transpiration (loss of heat) as well as reflection processes.
• Thus, the loss of energy from the living system to the environment leads to the increase in entropy which is a measure of the disorder.