This is not just an analogy: animals
derive their energy from oxygen reacting with hydrogen-rich compounds,
much as a candle flame "lives" as
long as its hydrogen-rich waxes have oxygen fuel. But there are, of course,
major differences. Among these are that organisms "burn" at
a much lower temperature, and that their "burning" includes
not just the maintenance of a specific shape over a relatively short
period of time, but the reproduction of their form and function before they expire—are snuffed out by accident or fatally deteriorate. Like
a flame, life spreads. But unlike a flame, living organisms reproduce.
And because they vary in their reproduction (never a perfect process),
and not all the variants survive, life evolves. Life also exhibits, in
the aggregate, a kind of prudence—burning not like a bright meteorite
for a few minutes in the night, but for over 3.5 billion years. The science
we elaborate upon in this book deals with energy and its transformations
in complex systems.
The science in question is a deep mix at the interface of two important
modern sciences, physics and biology. You may never even have heard of
this science, but if you have, you've probably heard of it in its general
form and in association with its most famous law, the second law of thermodynamics.
Thermodynamics, which studies energy flow and comes
from the Greek terms for heat and movement, began with the study of
steam engines. But the science we focus on here is (at least at first
sight) more specialized. It studies how energy flow works to bring
about complex structures, structures that seem to maintain themselves
apart from their environment, structures that cycle the fluids, gases,
and liquids of which they're made, structures that have a tendency
to change and grow. Since you may recognize such structures—you are
one of them!-as including life, the science in question can be described
as the thermodynamics of life. But actually the science encompasses
more than life. It extends to virtually all naturally occurring complex
structures, from whirlpools to construction workers. Because the flow
systems that seem sometimes to be self-organized or even miraculous
are in fact organized by the flows around them, to which they are open
and connected, another name for this science is open system thermodynamics.
Technically, open system thermodynamics has been known most often by
the imposing name of "nonequilibrium thermodynamics"—because the systems of interest, the centers of flow, growth, and change, are
not static, still, or dead; they are not in equilibrium. To make this
ungainly mouthful of a term less cumbersome—to integrate it into our own systems of narrative flow-we will refer to nonequilibrium thermodynamics
when occasion permits by its more sinuous abbreviation, NET.
In part 1 of Into the Cool, "The Energetic," we trace the
development of gradient-based thermodynamics from its humble origins
in observations of hot objects inevitably becoming cool. We begin our
first chapter with Schrödinger, whose little book What Is Life?
was a major influence on Watson and Crick, the discoverers of DNA's helical
structure. Schrödinger emphasized two themes: the presence in life
of a chemical "code-script"—which was discovered to be nucleic
acids-and life's ability to concentrate upon itself a "stream of
order," thereby resisting the universal tendency for things to fall
into disarray, into thermodynamic randomness and atomic chaos (Schrödinger
1944, 20-21).
Although it was not Schrödinger's main theme, and although he got
an essential aspect of it wrong, his second theme is our focus here.
Life's ability to maintain itself, expand, and reproduce in a world subject
to the second law is a paradox explained by the fact that live beings,
open to and dependent upon energy via light or chemical reactions, release
heat and other thermodynamic wastes into their environment. Organisms
do not maintain their complexity, and become more complex, in a vacuum.
Their high organization and low entropy is made up for by pollution,
heat, and entropic export to their surroundings. Although the proportion
of entropy they add, and which would not be there without their intervention,
is small compared to the vast quantity that would be produced in any
event, and ultimately without them, their ability to behave as natural
entropy-producing machines helps explain their—our—existence.
In part 2, "The Complex," we investigate nonliving complex
systems. These include temperature-driven Bénard cells, wild self-organizing
chemical reactions, and air pressure-organized tornadoes. Although simpler
than life, these systems, like life, exhibit cyclic behaviors and massive
coherence among their parts. For a time they "live"—they show identities distinct from the relative chaos around them. Spontaneously
arising (as life must first have), these complex systems are set up by
a gradient, a measurable difference in pressure, temperature, or chemical
concentration. The gradients lead to energy flow, and if conditions are
friendly, complex systems arise—and sometimes, as in the case of Taylor vortices, which are complex hydrodynamic structures, even "reproduce"—to reduce the ambient gradients (Koschmieder 1993). Do we see, in relatively
simple NET systems, the precursors of the physiology, the ability to
regulate and resist perturbations, that will become fully developed later
in life?
Part 3, "The Living," presents the scientific meat of the
book. If life arose on Earth, which is quite possible given the natural
increases of organization in regions exposed to energy flow, it may
have arisen beneath the ocean along the mineral sides of submarine
vents providing both temperature and sulfur gradients….
After a brief discussion of the history of ecology,
we marshal comparative ecosystem and satellite data to show how ecosystems
behave like other NET systems: they grow, cycle materials, and predictably
develop in response to ambient energy flow. They also predictably regress
when they are deprived of energy or the means to use energy due to
damage. Stressed ecosystems revert to earlier stages in their development
in a way that precisely parallels nonliving, nongenetic NET systems
deprived of energy flow. Thermometers attached to planes and weather
satellites demonstrate that the richest, most complex ecosystems, such
as those of the Amazon River basin, are the best reducers of the thermal
gradient between Earth's surface and the sun. The thermodynamically
proficient ecosystems cool themselves mostly by evapotranspiration,
that is, via water flow up through and evaporating off the leaves of
trees…
Like other NET systems, life's complexity is a
natural outgrowth of the thermodynamic gradient reduction implicit
in the second law: where and when possible, organizations come cycling
into being to dissipate entropy as heat. Gradients, such as that between
the sun and space, may be huge, and draining them may take literally
eons. Nonetheless, the complex systems that come swirling into being
near gradients are natural. Although they may sometimes seem to be
organized by an outside force, no "agent deliberating," as
Aristotle put it over twenty centuries ago, is needed (Physics 2.8
[McKeon 2001, 251]).
In part 4, "The Human," we look at how
NET sheds lights on economics, human health, and our understanding
of our place in an energetic cosmos of great possibility. Although
ours is by no means a traditional religious interpretation, we note
that organisms are purposeful, and that this tendency, connected to
the need to find food and mates and excrete wastes, is best understood
as a reflection of their thermodynamic genesis.
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Introduction
Confessions of a Government Worker
In 1971 one of us, Eric Schneider, was haunted by two simple questions:
Do laws exist that govern the behavior of whole ecosystems? If so,
what are they?
At the time there may have been no one in the world for whom an answer to these
questions would have proved more useful. As the director of the National Marine
Water Quality Laboratory of the Environmental Protection Agency (EPA) in Narragansett,
Rhode Island, Eric's mission was to provide scientific data to protect coastal
water quality and estuaries. U.S. water-quality laws specifically gave the EPA
the responsibility of protecting human health, commercial fisheries, and ecosystems
within these coastal waters. Eric was expected to measure the health of ecosystems
without definitions of ecosystem health and without adequate measuring tools.
It was a difficult job.
It was to lead Eric Schneider and a few others to the bigger question
of why ecosystems behave as they do, a question directly related to
the fascinating question—some would say the question of questions—of
why (from a material and physical perspective) life
exists.
The answer had to do with energy, and it would eventually shed light not only
on ecosystems, but also on organisms and nonliving systems—the entire field
of what has come to be called the sciences of complexity. Indeed, as Eric was
to find out with delight and surprise, he was not alone: a most promising research
program linking biology to the physics of energy was already underway. It
was like finding a buried treasure: gems lingered in past theoretical work,
and the energy-flow characteristics of a handful of ecosystems had already
been enumerated. To his great excitement, Eric found out that there was already
a young but sophisticated science of thermodynamics that specifically studies
energy flow and transformations in natural systems.
Thermodynamics, often considered
boring and irrelevant-a gray mathematical wasteland of steam tables
and arcane verbiage, important perhaps for laboratory measurement of
molecules, for creationists or Victorian historians, but of no concern
to the ordinary scientist or person-turns out to be a most fascinating
field. It bears directly on our deepest understanding of life and its
operations. Among those who have developed, clarified, and tried to
improve upon the foundations of classical thermodynamics are some of
the greatest names in the history of science: Carnot, Clausius, Boltzmann,
Gibbs, Maxwell, Planck, and Einstein. But theirs was a thermodynamics
of equilibrium systems-systems that were boring, because they were
headed toward stasis, an end state where nothing (or at least nothing
of interest) happened. "Heaven
is a place," David Byrne sings, "where
nothing ever happens." Indeed, the initial investigations of thermodynamics
were prematurely extrapolated to the entire universe to predict an end
state more boring than heaven, colder than hell—a nonmystical apocalypse
more meaningless than the most pessimistic fantasy of the most depressed
philosopher. This foregone scientific conclusion was called the "heat
death" of the universe….
Far from predicting cosmic burnout,
modern thermodynamics shows how complex structures, living or not,
often come into being, expand, and increase their complexity in regions
of the universe exposed to energy flow; because the interaction of
the fundamental forces of the universe (gravity, electromagnetism,
the weak and strong nuclear forces) are not completely integrated,
nor the total matter of the universe known, guarantees of a heat death
(or even an end) are not scientifically credible. This book focuses
on how thermodynamics has evolved over the past fifty years to allow
for the study of a new class of thermodynamic systems known as nonequilibrium
or dissipative systems because they exist some distance away from equilibrium.
The structures studied by this science include thunderheads, whirlpools,
intricate chemical cycles, and life….
This idea that nature abhors a gradient, one of the key ideas of this
book, is very simple: A gradient is simply a difference (for example,
in temperature, pressure, or chemical concentration) across a distance.
Nature's abhorrence of gradients means that they will tend spontaneously
to be eliminated-most spectacularly by complex, growing systems. The
simple concept of collapsing gradients encapsulates the difficult science
of thermodynamics, demystifies entropy (as important to the universe
as gravity), and illuminates how all complex structures and processes,
including those of life, come naturally into being.
The classical students of thermodynamics recognized both the power and
limitations of their science. They knew that they lived in a world quite
separate from the highly idealized systems where maximum entropy and
disorder reigned. Nowhere was this apparent conflict so dramatic as when
one compared evolving life to the prediction that random processes would
lead to the heat death of the universe. The second law in its original
formulation foretold things inexorably losing their ability to do work,
burning out and fading away until all states are in or near equilibrium
with no energy left to run organisms or machines. But life demonstrates
an opposite, evolutionary tendency, of complexity increasing with time.
How? This was the heart of the paradox. In this book we call it the Schrödinger
paradox after the quantum physicist who first focused on the need to explain
life's apparent defiance of the second law of thermodynamics. The second law,
in its basic original form, states that entropy (atomic or molecular randomness)
will inevitably increase in any sealed system. Yet living beings preserve and
even elaborate exquisite atomic and molecular patterns over eons.
Eric Schneider had begun a mission, a scientific quest for biological-ecological
bedrock. Acquainting himself with the energy ecologists, he looked for the
ecological equivalent of Newton's laws, the F = ma (force = mass <mult> acceleration)
of physics. Where were the simple equations such as those that describe transport
in fluids (the so-called Navier-Stokes equations) for ecosystems? Did they
even exist? At first it seemed they might not. Yet the search for them, detailed
in Erwin Schrödinger's famous 1944 book, What Is Life? certainly did.
The three lectures upon which Schrödinger's book was based outlined two
future sciences: the molecular biology that has proved to be such a force in
the world, and the thermodynamics of biology that has yet to prove its mettle.
Schrödinger's second subject is the topic of the present book. Into
the Cool should be considered a journey into the heart of an emerging science that
combines life with physics in a mix that may some day be as potent as molecular
biology and as practical as biotechnology. In this book we test our "biothermodynamic" thoughts
against the data and extend them into economics, human health, the sustainability
of ecosystems, and the possibility of life in outer space.
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