State the first law of thermodynamics and explain how living systems comply with this law. provide one real-life example to support your explanation.

The first law of thermodynamics states that the total energy of a system is constant. Energy can not be destroyed or created, it can only change forms. The energy in an ecosystem is constantly transformed into different forms, according to the needs of the living organisms. For example, plants absorb radiant energy from the sun and (through photosynthesis) they transform it into chemical energy which is kept in organic molecules. 

First law of thermodynamics states that energy can neither be created nor be destroyed but it can be transferred and transformed. Let me explain this with with example of living leafs which are attached to the branches of the trees. They have static energy stored in them but when they fall from the tree it transfers into kinetic energy that makes fall in the ground due to gravity. Another example would be when we take rest or sit, we restore or regain the static energy and when we walk or move that static energy is converted to dynamic energy.