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In the Light of Evolution Volume IV: The Human Condition
mtDNA mutations, plus changes in the expression of bioenergetic genes mediated by the epigenome. Consequently, common nDNA polymorphisms in anatomical genes may represent only a fraction of the genetic variation associated with the common “complex” diseases, and the ascent of man has been the product of 3.5 billion years of information generation by energy flow, accumulated and preserved in DNA and edited by natural selection.
Charles Darwin and Albert Russel Wallace hypothesized that the environment acts on individual variation via natural selection to create new species (Darwin and Wallace, 1858; Darwin, 1859). However, nothing in the concept of natural selection requires that biological systems should evolve toward ever greater complexity. Yet, throughout the more than 3.5 billion years of biological evolution (Simpson, 2003), life has generated ever more complex forms. What, then, drives increasing biological complexity, and what are its implications for the ascent of man?
BIOENERGETICS AND THE ORIGIN OFBIOLOGICAL COMPLEXITY
In a thermodynamically isolated system, complex structures decay toward randomness. However, in nonequilibrium systems, the flow of energy through the system generates and sustains structural complexity, and nonhomogeneous structures embody information (Morowitz, 1968; Rubí, 2008).
On Earth, the flux of energy through the biosphere is relatively constant. If the flow of energy were the only factor generating complexity, complexity would soon achieve a steady state between the production and decay of structure. Biology is not static, because the information embedded in biological structures can be encoded and duplicated by informational molecules, DNA and RNA. Therefore, biological complexity increases because a portion of the information generated by energy flow through each generation is added to the accumulated information stores from previous generations. The increasingly complex information can then be used to recreate the more complex structures, as long as there is sufficient energy flow (Mathematical Formulations).
The flow of energy through biological structures permits them to reproduce, thus duplicating their DNA. In the process of DNA copying, errors occur. The duplicated mutant DNA changes the physiology and structure of the progeny. These progeny must compete for the available energy resources within the environment. Those that are more effective at acquiring and/or expending the available energy will sustain their