Laws of Thermodynamics

The first law of thermodynamics states that energy cannot be crested or destroyed but may be transformed from one form into another. The second law states that the energy transformations  which occur in doing work are never completely efficient and that some energy must escape as bear energy.

    Living organisms which comprise the biotic component of an ecosystem are energy converters. For example, plants convert solar energy onto chemical energy; and animals convert chemical energy into kinetic energy they move about. In fact, all organisms convert chemical energy into heat and various other forms of energy all the time as they do 'work'. ' Work' here refers not only to physical activities but also to the various metabolic processes necessary to maintain life, and growth and reproduction of the living organism.

   Each time ' Work' is done, some useful energy is converted to heat. This occurs at each trophic level in a food chain. Heat energy cannot be harnessed to d o work by living organisms. It cannot also be transformed into chemical energy by primary producers. Ultimately, all the useful energy that enters the biotic component is lost from the  ecosystem as heat. Thus , the laws of thermodynamics explain

• What happens to the energy that enters an ecosystem, and 

• The linear flow of energy through ecosystem.

       In an ecosystem, every time heat is lost from a food chain, highly complex organized food molecules are broken down, I.e. disorganized. a measure of the degree of disorganization is called entropy. every time chemical energy is Transfered from one trophic level in a food chain to the next higher tropic level, the entropy of the ecosystem increases. In fact, since photosynthesis producers are continuously harnessing the sun energy which is eventually lost as heat, we can say that the entropy of the universe as a whole is constantly increasing.

Important characteristics of living organisms : A living organism is highly organized, I.e. its entropy is low. This is an important characteristic of a living organism. However , to maintain this state it had to take in a constant  supply of energy (food) to replace complex molecules that are continuously broken down SNF the useful energy that is lost as heat.