Question

? Explain why entropy in an isolated system must reach its maximum. Biological system use energy (ultimately from the sun) in organizing highly ordered organisms, such as humans. Does this mean that biological system violate the second law of thermodynamics? Explain your answer. (5%)

Answer 1

The Second Law of Thermodynamics is not violated by highly ordered organisms which perform mutation or natural selection . If an overall process of evolution is split into many small steps involving mutation followed by selection, each step is permitted by the Second Law and the overall process.entropy cannot decrease in a closed system. When you are considered life on Earth, it is not a closed system. Energy comes into the earth from the sun and radiates away from the earth as heat. Every cell in our body has its own internal organization; the cells are organized into tissues, and the tissues into organs; and your entire body maintains a careful system of transport, exchange that keeps you alive. Thus, it may not be clear how you can represent an increase in the entropy of the universe.

Now as we contract the muscles of your legs to move your body forward, you are using chemical energy from complex molecules such as glucose and converting it into kinetic energy. However, you’re doing this with pretty low efficiency: a large fraction of the energy from your fuel sources is transformed into heat. Some of the heat keeps your body warm, but much of it dissipates into the surrounding environment. which increases the entropy of surroundings.