Dr. N.L. Kachhara
Some scientists draw a parallel between physical systems and biological systems. As a biological ecosystem evolves by the process of natural selection, it disperses energy, increases entropy, and moves towards a stationary state with respect to its surroundings. According to them whether an object is animate or inanimate, science does not make a distinction. In both cases, energy flows towards a stationary state, or a state of equilibrium, in the absence of a high-energy external source.
Erwin Schrödinger in his 1944 book What is Life? explains that most physical laws on a large scale are due to chaos on a small scale. He calls this principle "order- from disorder". He states that life greatly depends on order and that a naive physicist may assume that the master code of a living organism has to consist of a large number of atoms. He further states "... living matter, while not eluding the "laws of physics" as established up to date, is likely to include "other laws of physics" hitherto unknown, which however, once they have been revealed, will form just as integral a part of science as the former."
Schrödinger concludes the book with philosophical speculations on determinism, free will, and the mystery of human consciousness. He is sympathetic to the view that each individual's consciousness is only a manifestation of a unitary consciousness pervading in the universe. In the final paragraph, however, he emphasizes the uniqueness of each human being's store of memories, thoughts and perceptions.
The argument that life feeds on negative entropy or negentropy by Schrödinger served as a stimulus to further research. In the popular 1982 text book Principles of Biochemistry by American biochemist Albert Lehninger it is 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. Thus, according to Lehninger, "living organisms preserve their internal order by taking from their surroundings free energy, in the form of nutrients or sunlight, and returning to their surroundings an equal amount of energy as heat and entropy.
In a study titled "Natural selection for least action" published in the proceedings of the Royal Society A, Ville Kaila and Arto Annila of the University of Helsinki describe how the second law of thermodynamics can be written as an equation of motions to describe evolution, showing how natural selection and the principle of least action can be connected by expressing natural selection in terms of chemical thermodynamics. In this view, evolution explores possible paths to level differences in energy densities and so increase entropy most rapidly. Thus, an organism serves as an energy transfer mechanism, and beneficial mutations allow successive organisms to transfer more energy within their environment.
Entropy has been associated with disorder and disorder, has been linked to disorganization by some workers; higher entropy means higher disorder and also higher disorganization. But this kind of relationship has been questioned by others, particularly in context with living systems. Living creatures are a very significant sub-class of open systems. An individual cell continuously takes up metabolites through its enclosing membranes and this material undergoes chemical reactions within the cell interior resulting in a variety of low- and high molecular weight products, some of these pass out of the cell: others contribute to the cell's growth and to its eventual division. It is really difficult to make an accurate entropy balance on an organism with its environment. But the experimental evidence available does not reveal any violation of the second law.
K.G. Denbigh has cited an example of a fertile bird's egg inside an incubator. The latter contains a sufficiency of air and was initially raised to a temperature high enough for the hatching of the egg. The incubator was thereafter surrounded by perfect thermal insulation so that its total entropy can only increase or remain constant. However there remain two possibilities concerning a different aspect of the system's temporal development: (1) the egg dies; (2) the egg lives and eventually gives rise to a live chick. Now it is true that in case (1) there is an entropy increase accompanied by a process of disorganization, localized in the egg. But the opposite is the situation in case (2): for although the egg is certainly a highly organized system, the live chick must surely be deemed to be much more so. Entropy again increases but now there is an increase in the degree of organization as well. This example thus provides a clear instance of its being false to suppose that entropy increase is equivalent to a process of disorganization. This does not mean that organisms operate in a manner contrary to the second law. That is not the case at all. The irreversible processes of metabolism, heat conduction etc., occurring within organisms are entropy producing like any others. It is only to say that changes in amount of organization and of entropy can occur quite independently of each other.
A similar conclusion was reached by Denbigh about changes or 'orderliness' and of entropy being mutually independent. He thinks that in addition to entropy there may well exist other 'one way functions' which add to the overall description of the worlds' temporal development.
