BIOLOGICAL ORDER 



Thus, entropy is a measure of atomic disorder. Physicists have 

 found it convenient to have an expression for its reverse, that is, 

 the degree of atomic order or the availability for work. This 

 negative entropy, "negentropy," represents the quality or grade 

 of energy. And we may admit with Schrodinger that if D is a 

 measure of atomic disorder, its reciprocal \/D will be a measure 

 of atomic order. 



If entropy S = k log D, negative entropy or negentropy N = 

 /flogl/D. 



Life and Entropy 



A system is said to be closed when it does not carry on exchanges 

 of matter with its surroundings. A closed system is said to be 

 isolated when it does not interact in any way with its surroundings. 

 An organism separated from its surroundings will soon die, and 

 is therefore an abstraction. A living system cannot be closed, nor 

 a fortiori isolated, like the systems studied by physicists. 



It should be clear that the live system under consideration is 

 the organism plus a reasonable — that is, unlimited — supply of 

 food. 



Let us now consider the equation of reproduction: 



(Organism) 1 + food — > (organism) 2 + waste + heat 



The organism has synthesized its building blocks — its essential 

 metabolites, nucleic bases, and amino acids — and has organized them 

 into specific macromolecules. As a result of the functioning of the 

 living machine, work has been produced and energy has been 

 degraded. As already stated, order has increased. Increase of order 

 corresponds to a decrease of entropy. Thus, as a result of reproduc- 

 tion, entropy has decreased. Has the over-all entropy of the system 

 represented in the equation for metabolism and reproduction in- 

 creased or decreased? To answer the question, we have to measure 

 the decrease of entropy corresponding to the increase of order. How 

 can we measure the atomic order, that is, the negative entropy in a 

 living organism? 



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