This book will
also evaluate another hypothesis put forth in the 19th century. This hypothesis attempts
to explain the origin of life and its basic premise is as follows:
The early earth’s atmosphere was different from today in that
no free oxygen was available. Under these circumstance, energy sources like sunlight and
electrostatic discharges might create the chemicals necessary for life (chemical
evolution). As these chemicals were concentrated in a small pond or puddle (the primordial
soup), they organized themselves in such a way to form the first living organism. Because
life is very complex, the first living thing is usually assumed to be a self replicating
chemical rather than a living cell. Because the first living thing was able to replicate
itself, it evolved into life as it exists today.
This hypothesis or some form of it is found in almost all biology books
where it is put forth as the generally accepted theory. Yet in the scientific journals,
scientists routinely dismiss many aspects of the hypothesis as highly improbable (Shapiro
1995 and 1999; Miller 1995 and 1998; Joyce 1984 and 1989; Nissenbaum 1975; Ferris 1987;
Joyce and Orgel 1999; Thaxton:1984). When it comes to chemical evolution and the origin of
life, science just does not have the answer.
One of the first experiments concerning the origin of life was
conducted in 1953 by Stanley Miller. Miller created several amino acids (the building
blocks that life uses to make proteins) in an electrostatic discharge chamber. The
experiments conducted since Miller have demonstrated how difficult it is to create the
biological precursors required for life. While several amino acids can be created under
plausible conditions, proteins cannot be. Furthermore, DNA is much more problematic
because its building blocks are difficult to create. Many of these building blocks are
unstable and decay rapidly. Science has yet to offer a plausible explanation for how these
hard to make and easy to destroy chemicals accumulated in the primordial soup (see
references 3,4,5, 6, 7, 8 and 13 on page 15, and chapter 9).
The most prevalent myth concerning chemical evolution suggests that a
continuous flow of energy through a complex system of nonliving chemicals will promote the
formation of biologically relevant molecules. The researchers who hold to these views
suggest that life arose spontaneously when these biological precursors combined in a small
pond or puddle several billion years ago. While such energy flows are critical to the
survival of life today, it is not clear how they solve the mystery of life’s
origin. Life knows how to use these energy flows to do work. Such knowledge is completely
lacking from a system that only contains nonliving chemicals. Plentiful energy sources if
anything do more harm than good. Sunlight bombarding a small pond on the earth 4 billions
years ago is much more likely to destroy any useful biological molecules than create one
(see for example Fox, Molecular Evolution and the Origin of Life, p37).
Surprisingly, such difficulties are often overlooked; as a result, many
biologists mistakenly believe that it is quite easy to synthesize all of the required
biological molecules. Nevertheless, a quick review of the relevant literature reveals that
this is not true. For example, to synthesize adenine (one of the most important chemicals
found in DNA and RNA), chemists start with a concentrated solution of hydrogen cyanide and
ammonia. Concentrating ammonia is not an easy task since it is a gas that boils at
sub-freezing temperatures, and it also decays rapidly in the presence of sunlight.
Furthermore, concentrating hydrogen cyanide in the presence of water is impossible since
it reacts with water quite readily to create formic acid. Scientists tend to focus on the
fact that adenine can be synthesized in a laboratory and ignore the fact that the
conditions required for its synthesis did not exist on the primitive earth. 3,4,6
After 50 years of investigation no plausible prebiotic path exists to
synthesize cytosine, ribose or deoxyribose (three critical subunits of DNA and RNA). The
problems with ribose and cytosine synthesis are so severe that Miller and several others
have suggested that the first self replicating molecule probably contained neither.7,
8 Biological molecules may contain thousands of subunits
all linked together by chemical bonds. Coercing the subunits to form a large biological
molecule like DNA or RNA is not easy. These problems are often discussed in scientific
journals like Nature, Science, PNAS, and the Journal of Molecular Biology. For example,
even today, investigators have yet to identify a plausible prebiotic method to link
cytosine, thymine or uracil to ribose (a step necessary for DNA and RNA synthesis).11
Nevertheless, not finding an answer is not news. So only the scientists who read these
journals are aware of the difficulties involved.
Finally, the greatest challenge to the origin of life lies not with
creating the chemical precursors, but instead with creating the required knowledge. The
chemicals that make up life contain useful information, and it is this knowledge that
allows life to propagate. The implication is that even if a few of the biological
precursors required for life existed in the primordial soup, such precursors would not
contain the knowledge necessary to live and evolve.
Joyce and Orgel sum up the situation best “After dreaming of
self-replicating ribozymes emerging from pools of random polynucleotides, and having
nightmares about the difficulties that must have been overcome for RNA replication to
occur in a realistic prebiotic soup, we awaken to the cold light of day . . . It must be
said that the details of this process remain obscure and are not likely to be known in the
near future.” - The RNA World, p72-73.
Next: The Origin of Life
Previous: Evolution of Knowledge
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