While working on an assignment for a biology class, I stumbled upon a book in the library entitled "Into The Cool: Energy Flow, Thermodynamics, and Life" by Eric D. Schneider and Dorion Sagan. While the book didn't contribute to my specific homework assignment, it had an incredibly intriguing preface, and I ended up checking the book out and taking it home with me.
Before even diving into Part One, Chapter One, the authors made some profound observations in the introduction about life and its continuous battle against entropy. Entropy is disorder. Specifically, entropy is atomic or molecular randomness. Living things defy entropy because living things are complex, patterned, and organized. The entire universe tends toward randomness and disorder, and life moves against it. As an example, compare the complex structure and pattern of a living tree with the disarray of fallen leaves and decomposing branches. As scientist Evelyn Hutchinson said, "Disorder spreads through the universe, and life alone battles against it."
Just as nature prefers entropy, so "nature abhors a gradient" (Schneider and Kay 1989). A gradient is defined as a difference between properties (such as temperature, pressure, etc) between two regions of space. Unless maintained with an influx of energy, gradients will break down. For example, the heater in your room creates a temperature gradient of hot air against cold air. If you turn your heater off, your room will eventually become cold as the gradient collapses and the air mixes.
If the universe tends towards entropy and chaos, than how can life exist at all? What is its function? Schneider and Sagan make an interesting statement regarding a function of life, that life reduces, "over billions of years, the huge solar gradient between hot sun and cold space." Life can battle entropy because it receives a constant input of energy from the sun. And, as specified by the second law of thermodynamics, energy becomes less useful as it moves through the system. Living things bring energy and heat from the sun, process and churn and convert it, and then spit it back out as heat to dissolve in space. By this logic, we as living things are catalysts in the elimination of a gradient. Our low-entropy systems actually contribute to the overall increase of entropy in the universe.
I find the mixture of physics and biology in the book intriguing, and the implications of the idea astounding... And, I'm looking forward to reading the rest of the book.