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These are excerpts and elaborations from my book "The Nature of Consciousness"
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The Primacy Of Energy Flows The US physicist Ronald Fox argued
that the evolution of life is nothing but the evolution of more and more
sophisticated forms of transducing and storing energy. According to Fox, life was born (the transition from non-life to life occurred) thanks
to structures for transducing energy that were made possible by the use of
phosphate compounds; and that life evolved because these structures inevitably
evolved ways to regulate and to store energy via phosphate compounds as a consequence
of having employed phosphate compounds in the first place. Muscles and nervous
systems arose as a consequence of those phosphate-based processes. Muscles and
nervous systems allowed the organism to interact with the environment and with
other organisms in a much more intense way, thus further accelerating
evolution. Fox showed how, from the beginning,
it was energy flows (lightning, volcanic heat) that allowed for the manufacture
of the unlikely molecules (such as aminoacids and other monomers) that are the
foundations of life. Monomers had to combine in order to form the polymers of
life (notably, proteins), a process that requires polymers. Fox showed that the
flow of energy solved this apparent paradox. Energy moved the monomers to a chemical
state in which polymerization occurs spontaneously, and then polymers
themselves helped manufacture even more polymers. The early Earth’s geophysical
energy flows gave rise to oxidation-reduction energy. Iron is an obvious source
of oxidation-reduction energy, particularly during the “iron catastrophe” of
4.5 billion years ago, when the elements of the iron group percolated through
the silicate layer of the Earth’s crust and became the core of the Earth.
Eventually some oxidation-reduction energy got converted into phosphate-bond
energy, which flowed through the primitive organic elements and enabled the
polymerization of monomers (notably, proteins, which are both catalysts for
further polymerization and structural elements of living beings, and polynucleotides,
the building blocks of genetic memory). In other words, energy flows excited
monomers until they started creating polymers spontaneously. Eventually, the
system reached a state in which polymers helped produce (synthesize) more
polymers. Thus an important form of
energy for the evolution of life on Earth was based on phosphorus, which is a
relatively rare element. As the German chemist Fritz
Lipmann first observed, the meeting of
(pervasive) oxidation-reduction energy and (relatively rare) phosphate-bond
energy was a momentous event in the history of life. Organic molecules are based
on carbon, and energy transactions are based on phosphorus. The reason is
probably to be found in the chemical properties of these elements. Carbon
fosters structural stability, phosphorus fosters energy metabolism. Life seems to be,
ultimately, a process about storing, transducing and using energy. Fox went on to speculate that the
very evolution of life (and the diversity of life we observe today on the
Earth) was due to an evolution of the processes of energy metabolism and
storage. Biological evolution was also driven by energy metabolism and storage,
not just Darwinian natural selection. In other words, Fox argued that, in general,
biological events correspond to changes in flows of energy. One key evolution
was the emergence of phosphagens as the main tool for energy storage. This more
efficient way of storing and using energy enabled the evolution of muscles and
motility in general. Phosphagens themselves evolved, and today all higher forms
of life employ creatine phosphate. A key step in the evolution
of life was the development of a nervous system. Fox pointed out that the
interaction between organism and environment as well as the interaction among
organisms are nonlinear in nature. The nervous system is not only capable of
predicting the outcome of linear situations, but also of predicting the much
more important outcome of nonlinear situations that are, by their own nature,
very hard to predict. The reason is that the nervous system allows the organism
to rapidly simulate the outcome of nonlinear events. Rapid simulation is the
only way that the organism can predict what will happen, and is therefore
essential to survival. A fundamental property of
life is the ability to predict the future. Survival depends not so much on
being able to calculate what to do, but on being able to predict what is going
to happen (in particular, the consequence of an action). A cognitive agent
needs to predict situations. Those
situations in the real world are described by non-linear systems. The dynamics
of nonlinear systems is such that it is virtually impossible to predict their
behavior other than by simulating it. Simulation has to be very fast in order
to be useful, sometimes faster than real-time. It turns out that the nervous
system is precisely such a tool to perform fast simulations of nonlinear
systems. Thus the evolutionary advantage of a nervous system is colossal. Once muscles existed, it was
important for the organism to predict the effect of a muscle movement on the
environment. Fox argued that the evolution of
creatine phosphate (the ultimate phosphagens so far) enabled the emergence of
this wonderful invention. Yet again, the evolution of life was due to an
evolution of energy processes. Darwin’s theory of evolution is both too little and too much. Fox showed that the rise and
decline of different species is a natural consequence of a non-linear system
driven by energy flows. Natural selection is not necessary to explain why there
are different forms of life. At the same time natural selection would not be
enough to explain how life evolved the way it did. Fox’s theory is all based on the simple idea that whatever happened to
life was driven by flows of energy, because ultimately life “is” about storing
and using energy. Even culture itself (i.e., human civilization) can be viewed
as a new flow of energy that is creating a new form of life. Fox did more than advance a
hypothesis on the transition from non-life to life: he introduced a new factor
in Darwin’s theory of evolution. The
purely Darwinian picture of natural selection may be too little in order to
explain the diversity and dynamics of life on the Earth. But Fox basically
points out that there is another very powerful force at work: the flow of
energy. Even without natural selection, the flow of energy alone would result
in a diversity of forms of life. Back to the beginning of the chapter "The Physics Of Life" | Back to the index of all chapters |
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