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of free energy is enormous. Fissioning 1 kg of U 235 will
release about 8.2 TJ of energy—about 270,000 times
more than the same mass of coal—and diminish the ura-
nium mass by 1 g, or 0.1%.
The last decades of the nineteenth century and the first
half of the twentieth century also brought great gains in
bioenergetics. Numerous calorimetric experiments per-
formed by Max von Pettenkofer, Carl von Voit, Graham
Lusk, and Wilbur Atwater determined fairly accurate
energy balances of living organisms. Consequently, Max
Rubner (1902) was able to offer an excellent systematic
account of human metabolism that included all the
essentials of modern understanding, including determi-
nation of energy values of various foodstuffs; the distinc-
tion between food intake and energy consumption; the
realization that carbohydrates, proteins, and lipids can all
be converted to work and heat; correlations between
environmental conditions, individual circumstances,
and metabolic rates, and between basal metabolism and
body surface area; and appreciation of the dynamic effect
of food digestion.
Max Kleiber (1893-1976) uncovered the fundamental
allometric relation between the basal metabolic rate and
the body mass of heterotrophs (Kleiber 1932), a begin-
ning of fascinating studies of energetic scaling (see chap-
ters 3-5). And Samuel Brody (1890-1956) published
his monumental synthesis of bioenergetics analyzing and
summarizing a century of scientific progress (Brody
1945). An important theoretical advance in bioenergetics
came with Alfred Lotka's (1880-1949) formulation of a
law of maximum energy. For biota it is not the highest
conversion efficiency but the greatest flux of useful en-
ergy, the maximum power output, which is most impor-
tant for growth, reproduction, and maintenance, and
species radiation. Consequently, living organisms and
ecosystems do not convert energy with the highest
supportable efficiencies but rather at rates optimized for
the maximum power output (Lotka 1925). Odum and
Pinkerton (1955) demonstrated that the efficiencies are
always less than the possible maxima: they never surpass
50% of the ideal rate.
During the 1930s came rapid advances in understand-
ing nuclear energy that included not only the epochal
discovery of the neutron (Chadwick 1932) and the first
laboratory demonstration of fission (Hahn and Strassman
1939) but also the first correct explanation of energy
processes in stars by Hans Bethe (1939) (fig. 1.5). At
the same time, an inconspicuous but fundamental wave
of change began to affect the scientific method. After
centuries of progressive reductionism and compartmen-
talization came a gradual formulation of general system
approaches based on recognition of underlying common-
alities, multidimensional complexities, nonlinear feed-
backs, and probabilistic outcomes. Vladimir Ivanovich
Vernadsky (fig. 1.5), with his powerful idea of the bio-
sphere (1926), and Ludwig von Bertalanffy (1901-
1972), with his systematic theoretical look at biology
(1932-1942), were the early pioneers of the approach
in life sciences. And Arthur Tansley's (1935) introduc-
tion of the concept of the ecosystem enriched bioscience
with one of its most important cognitive tools.
Just before the end of World War II, Edwin Schr¨-
dinger (1887-1961) addressed the thermodynamic odd-
ity of living systems that create and maintain exquisite
order by using disordered elements dominated by carbon
(1944). He explained this apparent violation of the sec-
ond law by introducing the idea of ''nonequilibrium
thermodynamics'' of open systems (the nonequilibrium
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