Both lfloorwalker and corather are correct.

Thermodynamics rests on two main laws. Both are first principles: The first law commands the conservation of energy, and the second law commands irreversibility: the tendency of all currents to flow from high (temperature, pressure) to low. These two laws are about systems in the most general sense, viewed as black boxes, without shape and structure.

The two laws of thermodynamics do not account for nature completely. Nature is not made of black boxes. Nature’s boxes are filled with evolving, freely morphing configurations—even the fact that they have names (rivers, blood vessels) is due to their appearance, organization, or design. Where the second law commands that things should flow from high to low, the constructal law commands that they evolve in configurations that flow more and more easily over time.

Life is flow. The second law defines "what" flows and the constructal law defines "how" things flow. Evolving networks facilitate easier flow over time.