Abstract
Life is considered something different from non-living things, but no single driving force can account for all the different aspects of life, which consists of different levels of hierarchy, such as metabolism, cell physiology, multi-cellular development and organization, population dynamics, ecosystem, and evolution. Although free energy is evidently the driving force in biochemical reactions, there is no established relationship between metabolic energy and spatiotemporal organization of living organisms, or between metabolic energy and genetic information. Since Schrödinger pointed out the importance of exporting entropy in maintaining life, misunderstandings of entropy notion have been obstacles in constructing a unified view on the driving forces of life. Here I present a simplified conceptual framework for unifying driving forces of life at various different levels of hierarchy. The key concept is “entropy deficit”, or simply, ‘inhomogeneity’, which is defined as the difference of maximal possible entropy and actual entropy. This is equivalent to information content in genetic information and protein structure, and is also defined similarly for non-homogeneous structures in ecosystems and evolution. Entropy deficit or inhomogeneoity is a unified measure of all driving forces of life, which could be considered a scientific equivalent to ‘élan vital’ of Bergson.
Highlights
It may be generally accepted that all life on the Earth, except some chemolithotrophs in deep ocean, depends on photosynthesis, but it is not easy to envisage the importance and necessity of photosynthesis for the maintenance and development of all living beings
The third law of thermodynamics, which is derived from statistical mechanics, states that S = 0 at T = 0
The definition of information entropy is identical to the statistical entropy except the Boltzmann constant if natural logarithm is used in both cases, but information entropy is normally expressed using a logarithm of base 2, and its unit is called “bit”
Summary
It may be generally accepted that all life on the Earth, except some chemolithotrophs in deep ocean, depends on photosynthesis, but it is not easy to envisage the importance and necessity of photosynthesis for the maintenance and development of all living beings. The correct meaning of ‘negative entropy’ should be ‘decrease in entropy’ in a dynamic system [2] Another confusion was that light had negative value of entropy, which was not correct at all. There is no consensus regarding what is really fixed or introduced by photosynthesis into the biological world There is no single notion that can be used to describe driving forces in various biological processes at various different levels, such as metabolism, cellular processes, multicellular organization, individual dynamics of ecosystems, and evolution. We attempt in the present paper to clarify the meaning of entropy in the biosphere, which includes dynamically developing systems at various different levels of hierarchy. A preliminary note of the present paper was published in Japanese [12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
