Entropy in a biological system does not increase because:

According to the second law of thermodynamics, when energy is conveed from one form to another, some usable energy is conveed into heat that disperses into the surroundings. The entropy of a closed system will tend to increase to a maximum value. Whereas entropy in a biologic system does not increase as it is an open system. Entropy is a measure of the amount of molecular disorder within a closed system. A system that has a high degree of molecular disorder (such as high temperature gas) has a very high entropy value, whereas those with a very low degree of molecular disorder (such as crystalline solid) has a very low entropy value. An entropy value of zero is found in a system which has all its atoms arranged in a perfectly ordered manner. Ref: Biology By Eldra Pearl Solomon, Page 154 ; Modern Engineering Thermodynamics By Robe T. Balmer, Page 206