Control Systems in the Living World - Building the Most Complex Structure on Earth - page 12

increase in this chamber but will fall in the other. The demon, thus, ideally, would
violate the second law by displacing the system from the initial state of equilibrium
to a state of nonequilibrium, with different temperatures of gas in both chambers.
This is not done free of charge; the price the demon has to pay is to invest work and
information into the system (for now, we ignore the fact that the information used
and work done also increase the entropy of the system!). Thus, Maxwell's thought
experiment suggests that the second law can locally be avoided by a demon willing
to spend information and energy to do the work.
Living systems' ability to maintain their structure, in apparent defiance of the sec-
ond law of thermodynamics, has long amazed and perplexed scientists. What makes
living systems so extraordinary and unique? How do they succeed in maintaining
their improbable structures for considerable periods of time? Where in the living sys-
tem does Maxwell's demon reside?
In What Is Life? the Austrian physicist Erwin R.J.A. Schrödinger (1887-1961)
( Schrödinger, 1944 ) dealt with this issue and popularized the concept of entropy in
living systems. Echoing the idea of his compatriot Boltzmann, he introduced the
concept of negative entropy , shorterend to negentropy by Louis Brillouin (1854-
1948), which is the opposite of the entropy in the system. He attempted to resolve
the enigma of the existence and maintenance of the thermodynamically improbable
structure of living organisms by assuming that they “suck” order or negentropy from
the environment. In other words, they use external sources of order to compensate
for the order they inescapably lose, thus avoiding structural degradation. Living sys-
tems solved life's dilemma of “to be or not to be” by acquiring order from sources in
their environment. Plants, both unicellular and multicellular, succeeded in evolving
a mechanism of photosynthesis for generating their order by using sun radiation and
CO 2 to synthesize polysaccharides, whereas animals choose to use amino acids, car-
bohydrates, lipids, vitamins, and other elements of the plant kingdom. Accordingly,
the ultimate source of information and order in the biosphere is the difference of
temperature between the sun and Earth (it is no wonder that most people in antiquity
worshipped the sun as their most important deity).
With the benefit of hindsight, we know that Schrödinger's pioneering idea is
incongruous with some basic physiological knowledge. Most nutrients contain no
utilizable order of the specific type of metazoan needed to build their structures.
What an animal utilizes from the ingested food for generating its species-specific
molecular and cytological building blocks is the raw material and the free energy
it contains. The organism is a generator of its own order rather than a consumer of
external order. The first step that an animal takes after eating food is to break most of
the ingested organic compounds down to simpler, low-molecular organic compounds
(amino acids, monosaccharides, fatty acids, glycerol, nitrogen bases, pentoses,
etc.). Destroying the original order, it creates its own order by synthesizing de novo
species-specific proteins, carbohydrates, lipids, and other compounds resulting from
the activity of its proteins. Living systems are not stores of extrinsic order and infor-
mation; they transform the order they get from environmental sources into their own
species-specific order. As mentioned earlier, this is done at the price of spending