H00102--00A, Front mat Genesis
Page 34
p. xvi
James Trefil: Hazen and Trefil (1991), Trefil and Hazen (1992).
p. xvii
“the unfolding of life . . . ”: Morowitz (2002, p. 84).
p. xvii
conference in Modena, Italy: The “Workshop on Life” was held
September 3–8, 2000, as one of the satellite meetings before the Millennial
World Meeting of University Professors in Rome, September 8–10. The con-
ference proceedings are collected in Pályi et al. (2002).
PROLOGUE
p. 1
This idea had received a boost: Corliss et al. (1979, 1981). See
Chapter 7 for more details on Jack Corliss’s controversial claims.
p. 2
Morowitz’s dense tabulation: The table of water’s dielectric con-
stant as a function of temperature and pressure came from Tödheide (1972,
Table XI, p. 492). See also Uematsu and Franck (1981), Franck (1987), Shaw
et al. (1991), and Franck and Weingartner (1999) for subsequent measure-
ments by the same group at the Institute for Physical Chemistry and Elec-
trochemistry, University of Karlsruhe. In spite of our surprise at seeing these
results, experts in petroleum chemistry had long known about water’s dis-
tinctive changes in properties at elevated temperature and pressure (e.g.,
Simoneit 1995). Theorist Everett Shock had incorporated these effects into
his calculations of hydrothermal reactions relevant to prebiotic chemistry
247
248
GENESIS
(Shock 1990a, 1990b, 1992a, 1993; Shock et al. 1995). Nevertheless, few re-
searchers in the origin-of-life community had made this connection, and no
relevant experiments had been performed at high temperature and pressure.
p. 2
detailed chemical scenario: Wächtershäuser (1988a, 1990a,
1992). His work is reviewed in Chapters 8 and 15.
p. 3
His name provided: A perspective on Harold Morowitz’s contri-
butions to the founding of astrobiology is provided by Dick and Strick (2004,
pp. 61-65).
p. 4
Hat’s pressure lab: The apparatus and its operation is described
in Yoder (1950).
p. 8
“Humpane”: Jack Szostak writes, “It’s the normal result to obtain
a mess of hundreds of compounds. The central problem of prebiotic chem-
istry is how to avoid the universal tar of organic chemistry, and channel the
chemistry into the products needed for the origin of life.” [Jack Szostak to
RMH, 21 August 2004]
1
THE MISSING LAW
p. 11
“It is unlikely . . . ”: J. H. Holland (1998, p. 3).
p. 11
Two great laws: Von Baeyer (1998) provides a history of the laws
of thermodynamics.
p. 12
The discovery of a dozen: For a review of the principal laws of
nature and their discovery, see Hazen and Trefil (1991).
p. 12
scholars of the late nineteenth century: The history of the idea
that science has learned everything of significance appears in Horgan (1996),
who defends and amplifies the idiotic claim.
p. 12
Ilya Prigogine: Prigogine’s influential analyses of emergent sys-
tems, which he called “dissipative systems,” appears in his books Order Out
of Chaos: Man’s New Dialogue with Nature (Prigogine 1984) and Exploring Complexity: An Introduction (Nicolis and Prigogine 1989). Of special interest to Prigogine were patterns that arise spontaneously in a shallow pan of
boiling water (Bénard cells) and in certain types of slowly reacting chemicals
(Belousov–Zhabotinski, or B–Z, systems). These systems, which could be
analyzed with mathematical rigor, are representative of a larger class of phe-
nomena in which energy flows through a collection of interacting particles.
In the words of Wicken (1987, p. 5), “dissipation through structuring is an
evolutionary first principle.”
p. 13
complex, turbulent convection: The peculiar behavior of boil-
ing water is addressed, for example, in Nicolis and Prigogine (1989, pp.
8-15).
NOTES
249
p. 14
patterns in water and sand: An extensive technical literature
analyzes the formation of sand patterning. Of special note are the classic
works of Ralph Bagnold (1941, 1988).
p. 14
understanding such simple systems: Several reviewers question
the idea that studies of patterning in simple mechanical systems such as
sand can elucidate the behavior of much more complex biological systems.
Graham Cairns-Smith writes: “I think that your discussion of emergent sys-
tems could do with a more explicit reference to the two main ways in which
interestingly complex systems arise in biology—development and evolution.
Development is modeled by, say, the Mandelbrot set: an amazing infinitely
complex product with a childishly simple specification. And incidentally I
don’t see any new physical law here, just mathematics.” (G. Cairns-Smith to
RMH, 31 August 2004).
Jack Szostak echoes this opinion: “Part of the problem is the lack of a
clear definition or understanding of what we mean by emergent phenom-
ena, which leads to people referring to distinct things with the same term.
So, in one sense, phenomena such as vortices or sand ripples are ‘emergent’
since they are collective phenomena not exhibited by the individual compo-
nents of the system. On the other hand, there seem to be different kinds of
phenomena one could also call ‘emergent’. . . . Darwinian evolution emerges
from the combination of replicating informational polymers and compart-
mentalization.” [Jack Szostak to RMH, 21 August 2004] In other words, some
scientists argue that emergent systems that become complex through a com-
petitive selection process are fundamentally different from those that obey
simple rules of interaction.
I’m more inclined to think that all emergent systems, whether shifting
sand dunes or biological evolution, may ultimately be modeled based on a
small set of “selection rules” reducible to mathematical statements. Ulti-
mately, evolution through competitive selection represents simply another
(though admittedly more elaborate) way that systems tend toward the most
efficient way to dissipate energy.
p. 15
A small band of scientists: The Santa Fe Institute and its studies
in emergence are discussed in Waldrop (1992) and Regis (2003).
p. 15
John Holland: Holland’s influential works include Hidden Or-
der (J. H. Holland 1995) and Emergence: From Chaos to Order (J. H. Holland 1998).
p. 15
BOIDS: This program is available at www.red3d.com/cwr/boids.
The program tracks the flocking behavior of a hundred or so “BOIDS,” each
of which moves according to three rules: separation to avoid crowding
flockmates, alignment to follow the flock’s average direction, and cohesion
to steer toward the average position of flockmates.
250
GENESIS
p. 15
Physicist Stephen Wolfram: Wolfram (2002).
p. 16
Danish physicist Per Bak: Bak’s most ac
cessible writings are
found in his popular book, How Nature Works: The Science of Self-Organized
Criticality (Bak 1996).
p. 16
Santa Fe theorist Stuart Kauffman: Kauffman (1993).
p. 16
Nobel Laureate Murray Gell-Mann: Gell-Mann and Tsallis
(2004). Ideas of non-extensive entropy and related definitions of complexity
are provided by Lopez-Ruiz et al. (1995), Shiner et al. (1999), Gell-Mann and Lloyd (2004), Latora and Marchiori (2004), Plastino et al. (2004). See
also Gell-Mann (1994, 1995).
p. 17
fossil-rich hundred-foot-tall cliffs: The Miocene formations of
Calvert County, Maryland, have been a Mecca for fossil collectors for two
centuries. Details of the geology and paleontology are recorded in W. B. Clark
(1904).
p. 17
Factor 1: The relationship between concentration of agents and
complexity has the qualitative form of the so-called error function. This
function begins at zero complexity for low concentrations of agents. As the
p. 17
The relationship between the concentration of interacting agents in a system
( N) and the complexity of the system ( C) has the qualitative form of the error function. At low N, no emergent structures arise, but as N increases, so does C, to an upper limit.
NOTES
251
concentration rises, it reaches some critical value, and complexity begins to
rise. Eventually, at a higher concentration of agents, the system’s complexity
achieves a maximum value.
p. 19
One ant species: Camazine et al. (2001, pp. 256-283). [Also E. O.
Wilson to RMH, 9 April 2004; B. Fisher to RMH, 5 May 2004; C. W.
Rettenmeyer to RMH, 12 May 2004]
p. 19
Studies of termite colonies: Solé and Goodwin (2000, p. 151).
p. 19
spiral arm structure: The formation of spiral arms requires “a
central mass and a velocity large enough to produce a significant shear. . . .
You also need time for the patterns to be established. The low mass objects
don’t survive long enough.” [Vera Rubin to RMH, 7 April 2004]
p. 19
Factor 2: I suspect that one of the principal difficulties in quan-
tifying emergent complexity is related to the varied ways that agents may be
interconnected. The shifting interactions by immediate contacts of adjacent
sand grains are not easily equated to the persistent chemical markers of mov-
ing ants or the elaborate networks of variable impulses that connect neu-
rons. Nor are any of these examples exactly analogous to the interactions of
molecules necessary for the origin of life.
p. 19
A rounded grain: Bagnold (1941, p. 85).
p. 20
The conscious brain: See, for example, Johnson (2001).
p. 20
Factor 3: The relationship between energy flow and complexity
bears a qualitative similarity to a bell-shaped curve. At low energy flux, no
patterning occurs and the complexity is zero. At some minimum energy flux,
pattern formation begins and complexity quickly achieves a maximum value.
Above a critical value, however, the energy flux is too great and the emergent
patterns begin to disperse.
p. 20
no pattern can emerge: Physicist Paul C. W. Davies examines
this issue from the standpoint of gravity, which is the initial and ultimate
source of ordering in the universe (Davies 1999, p. 64).
p. 21
Factor 4: Cycling may be important in origin-of-life scenarios,
but the imposition of any kind of cycle adds at least two new variables to an
experiment. In the case of a temperature cycle, for example, one must select
the duration of the cycle (typically on the order of minutes to days) and the
two end-point temperatures. It may also be desirable to control the rate of
temperature change (gradual versus abrupt), which adds additional vari-
ables. Needless to say, such added variables complicate an experiment and
its interpretation.
p. 22
amazing stone circles: Kessler and Werner (2003).
p. 22
∇ E( t): This expression indicates both the flow of energy through the system, ∇ E, and the cycling of that energy, which is a function of time, t.
252
GENESIS
At intermediate ∇E, the
maximum complexity
emerges
C
At high ∇E,
all patterns
are destroyed
At low ∇E, no
patterns arise
∇E
p. 20
The relationship between the energy flowing through a system of interacting
agents (∇ E) and the complexity of the system ( C) has the form of a critical curve. At low ∇ E, no emergent structures arise, but as ∇ E increases above a critical value, structure rapidly appears and C increases. At high ∇ E, however, patterns are destroyed.
2
WHAT IS LIFE?
p. 25
“I know it when I see it.”: Associate Justice Potter Stewart of the
U. S. Supreme Court made this statement as part of his concurring opinion in the 6-3 ruling that overturned the ban on pornographic films, June 22,
1964: “I shall not today attempt further to define the kinds of material . . .
but I know it when I see it.”
p. 25
A recent origin-of-life text: Lahav (1999, pp. 117-121).
p. 25
“What is life?”: Pályi et al. (2002).
p. 26
“top-down” approach: Jack Szostak states “I don’t think the ear-
liest fossils tell us anything about life’s earliest chemistry. These fossils are all quite sophisticated organisms.” [Jack Szostak to RMH, 21 August 2004]
Gustaf Arrhenius echoes this view: “The most ‘primitive’ organisms that we
can lay our hands on are already hopelessly sophisticated biochemically; they
are more like us than anything original.” [Gustaf Arrhenius to RMH, 23 De-
cember 2004]
NOTES
253
Indeed, a principal discovery of Precambrian paleontology is that mod-
ern-type cells have populated Earth for at least 80 percent of its history. The
window for life’s emergence is correspondingly brief.
p. 27
“working definition”: See Joyce (1994).
p. 28
thin molecular coating: The idea of “flat life” has been explored
by Wächtershäuser (1988a, 1992) among others. For more details see Chap-
ter 15.
p. 28
Claude Lévi-Strauss: Lévi-Strauss, the founder of structural an-
thropology, argued that all humans share similar patterns of thought. His
analysis of myths from various cultures, for example, stresses the common
reliance on dichotomies in dealing with our role in the cosmos. See Lévi-
Strauss (1969, 1978).
p. 28
neptunists, . . . plutonists: This debate, as well as that between
catastrophists and uniformitarianists, was fueled by a conflict between sci-
entific and religious interpretation of natural history. See, for example,
Rudwick (1976) and Laudan (1987).
p. 29
“The unfolding of life . . . ”: Morowitz (2002, p. 84). Several
other authors, notably Christian de Duve (1995a), have adopted a similar
Maynard-Smith and Szathmáry (1999), and Bada (2004).
p. 30
semantic question: For a fuller explanation of these ideas, see
Hazen (2002). Jack Szostak writes: “I used to think of the transition from
non-life to life as a discontinuous event marked by the sudden start-up of
Darwinian evolution. But as I’ve started to work on more aspects of the
problem and look at it in more detail, what I see is more of a series of smaller
steps.” [Jack Szostak to RMH, 7 September 2004]
p. 30
philosopher Carol Cleland: Cleland and Chyba (2002).
p. 31
Saturn’s recently visited moon: Evidence for volatiles at Titan’s
surface are presented by Lunine et al. (1999), Campbell et al. (2003), Griffith
et al. (2003), and Lorenz et al. (2003). For the latest results from the Huygen’s
probe, see: http://saturn.jpl.nasa.gov/home/index.cfm.
3
LOOKING FOR LIFE
p. 33
“Scientists turn reckless . . . ”: Lightman (1993, p. 41).
p. 33
meteorite from Mars: For an overview of Martian meteorites
and their identification see McSween (1994). Goldsmith (1997) provides a
popular account of the Allan Hills controversy.
p. 33
Theorists maintained: Calculations by Jay Melosh and co-workers
of Caltech (Melosh 1988, 1993; Head et al. 2002) reveal that, although a lot
of material is vaporized in large planetary impacts, rocks at the periphery of
254
GENESIS
the impact site may be hurled unscathed off the surface into space. Such a
process is thought to have transferred material from Mars to Earth. Similar
impacts on Earth have certainly blasted terrestrial rocks into space, though
the transfer of Earth rocks to Mars is much more difficult because of two
gravitational impediments: Mars is much farther from the Sun, and it has a
smaller gravitational field.
An alternative intriguing hypothesis is that cellular life may have arisen
very early in Earth’s history, and that some of these microbes may have been
blasted into space by large asteroid impacts. Even if a subsequent globe-
sterilizing giant impact occurred, life could have been reseeded by an Earth
meteorite.
p. 33
Allan Hills region of Antarctica: The ice deserts of Antarctica
are ideal hunting grounds for meteorites. These clean, dry regions persist for
thousands of years, and dark-colored meteorites stand out starkly against