In physics and science the term "evolution" simply refers to change over time. The second law of thermodynamics states that, in an isolated system, entropy, a measure of the amount of energy in a system unavailable to do work, must increase as time passes.

Thermodynamics is the study of the transformation of energy (a state function of a body or system) and changes in entropy. In accord with the laws of thermodynamics, physical systems evolve or undergo changes so that the system seeks a state reflecting the lowest possible energy (unless it is totally isolated, in which case the total amount of energy will remain constant), and a state of maximum thermodynamic disorder, that is, maximum entropy. Considering both the system and surroundings, in accord with the second law of thermodynamics dealing with entropy, all real and natural processes are irreversible. In this regard...