Entropy and life

More recent work has restricted the discussion to Gibbs free energy because biological processes on Earth normally occur at a constant temperature and pressure, such as in the atmosphere or at the bottom of the ocean, but not across both over short periods of time for individual organisms.

In 1863 Rudolf Clausius published his noted memoir On the Concentration of Rays of Heat and Light, and on the Limits of Its Action, wherein he outlined a preliminary relationship, based on his own work and that of William Thomson (Lord Kelvin), between living processes and his newly developed concept of entropy.

Nor should it, therefore, be a matter of surprise that already, in the short space of time, not yet one generation, elapsed since the mechanical theory of heat has been freely adopted, whole branches of physical science have been revolutionized by it.[5]: p.

His first example is physiology, wherein he states that "the body of an animal, not less than a steamer, or a locomotive, is truly a heat engine, and the consumption of food in the one is precisely analogous to the burning of fuel in the other; in both, the chemical process is the same: that called combustion."

To answer this question he turns to the mechanical theory of heat and goes on to loosely outline how the heart is what he calls a "force-pump", which receives blood and sends it to every part of the body, as discovered by William Harvey, and which "acts like the piston of an engine and is dependent upon and consequently due to the cycle of nutrition and excretion which sustains physical or organic life".

[7] In his note to Chapter 6 of What is Life?, however, Schrödinger remarks on his usage of the term negative entropy: Let me say first, that if I had been catering for them [physicists] alone I should have let the discussion turn on free energy instead.

But this highly technical term seemed linguistically too near to energy for making the average reader alive to the contrast between the two things.This, Schrödinger argues, is what differentiates life from other forms of the organization of matter.

[11][12] This is because biological processes on Earth take place at roughly constant temperature and pressure, a situation in which the Gibbs free energy is an especially useful way to express the second law of thermodynamics.

In a popular 1982 textbook, Principles of Biochemistry, noted American biochemist Albert Lehninger argued that the order produced within cells as they grow and divide is more than compensated for by the disorder they create in their surroundings in the course of growth and division.

The (apparent) paradox between the second law of thermodynamics and the high degree of order and complexity produced by living systems, according to Avery, has its resolution "in the information content of the Gibbs free energy that enters the biosphere from outside sources.

In fact the entropy or disorder in a system can spontaneously decrease, such as an aircraft gas turbine engine cooling down after shutdown, or like water in a cup left outside in sub-freezing winter temperatures.

Where ‘exergy’ is the thermal, mechanical, electric or chemical work potential of an energy source or flow, and ‘instruction or intelligence’, is understood in the context of, or characterized by, the set of processes that are within category IV.

The robotic machinery requires electrical work input and instructions, but when completed, the manufactured products have less uniformity with their surroundings, or more complexity (higher order) relative to the raw materials they were made from.

A related line of reasoning is that, even though improbable, over billions of years or trillions of chances, did life come about undirected, from non-living matter in the absence of any intelligence?

Metabolic processes force the sum of the remaining two terms to be less than zero through either a large rate of heat transfer or the export of high entropy waste products.

), at which biomass production would be theoretically maximized but metabolism would proceed at an infinitely slow rate, and the opposite limiting case at which growth is highly favorable (

[37] The Darwinian dynamic was formulated by first considering how microscopic order is generated in relatively simple non-biological systems that are far from thermodynamic equilibrium (e.g. tornadoes, hurricanes).

[38][39][41] The thermodynamic function of the original pigments (fundamental molecules of life) was to increase the entropy production of the incipient biosphere under the solar photon flux and this, in fact, remains as the most important thermodynamic function of the biosphere today, but now mainly in the visible region where photon intensities are higher and biosynthetic pathways are more complex, allowing pigments to be synthesized from lower energy visible light instead of UVC light which no longer reaches Earth's surface.

In 1964 James Lovelock was among a group of scientists requested by NASA to make a theoretical life-detection system to look for life on Mars during the upcoming Viking missions.

Because these ideas conflicted with more traditional approaches that assume biological signatures on other planets would look much like they do on Earth, in discussing this issue with some of his colleagues at the Jet Propulsion Laboratory, he was asked what he would do to look for life on Mars instead.

This idea was perhaps better phrased as a search for sustained chemical disequilibria associated with low entropy states resulting from biological processes, and through further collaboration developed into the hypothesis that biosignatures would be detectable through examining atmospheric compositions.

In fact, there was probably a strong chemical disequilibrium present on early Earth before the origin of life due to a combination of the products of sustained volcanic outgassing and oceanic water vapor.

This imbalance would actually be decreased by the presence of chemotrophic life, which would remove these atmospheric gases and create more thermodynamic equilibrium prior to the advent of photosynthetic ecosystems.

[51] In 2013 Azua-Bustos and Vega argued that, disregarding the types of lifeforms that might be envisioned both on Earth and elsewhere in the Universe, all should share in common the attribute of decreasing their internal entropy at the expense of free energy obtained from their surroundings.

These authors showed that by using fractal mathematics analysis alone, they could readily quantify the degree of structural complexity difference (and thus entropy) of living processes as distinct entities separate from their similar abiotic surroundings.

This approach may allow the future detection of unknown forms of life both in the Solar System and on recently discovered exoplanets based on nothing more than entropy differentials of complementary datasets (morphology, coloration, temperature, pH, isotopic composition, etc.).

[52] The notion of entropy as disorder has been transferred from thermodynamics to psychology by Polish psychiatrist Antoni Kępiński, who admitted being inspired by Erwin Schrödinger.

Information metabolism, which allows living systems to maintain the order, is possible only if a hierarchy of value exists, as the signals coming to the organism must be structured.

[57] In 2011, the notion of "psychological entropy" was reintroduced to psychologists by Hirsh et al.[58] Similarly to Kępiński, these authors noted that uncertainty management is a critical ability for any organism.

The Belgian scientist Ilya Prigogine has, throughout all his research, contributed to this line of study and attempted to solve those conceptual limits, winning the Nobel prize in 1977.