Whether Or Not Prebiotic Soup Was
Ever Needed/Existed For Origin of Life
Summary: For most of modern theories of Origin of Life, Prebiotic Soup is the
starting point and much of the research is focused on this point. However till date
not an iota of evidence has been detected in support of existence of Prebiotic Soup
at any time in the history of Earth. It is concluded that Prebiotic Soup was neither
needed nor existed for Origin of Life on Earth.
Darwin suggested that life could have begun in a warm little pond with all sorts of
ammonia and phosphoric salts, light, heat, electricity present that a protein was
formed ready to undergo still more complex changes. At the present day such
matter would be instantly devoured or absorbed which would not have been the
case before living creatures were formed.
This gave rise to Primordial Soup Theory which suggests that life began in a pond
or ocean as a result of the chemicals from the atmosphere and some form of
energy to make amino acids; the building blocks of proteins, which would then
evolve into all the species. This is supposed to happen at least 3.8 billion to 3.55
billion years ago.
This involves kaleidoscopic or random permutation and combination of chemicals
with eventual selection and accumulation of useful permutations and
combinations of chemicals so as to eventually give rise to origin as well as
evolution of life.
Alexander Oparin in 1924 suggested the idea of Prebiotic Soup and today this is
the starting point for most of modern theories of Origin of Life. Around the same
time J.B.S. Haldane suggested that Earth’s Prebiotic oceans are different from
today’s oceans – would have formed a hot dilute soup in which organic
compounds could have formed. The underlying hypothesis held by Oparin and
Haldane was that conditions on the primeval Earth favored chemical reactions
that synthesized organic compounds from inorganic precursors. Arguing along the
same line it has been speculated that once upon a time there existed organic
matter on Earth in sufficient concentration that its spontaneous, kaleidoscopic
random interactions ultimately led to Origin of Life. The principal difficulty with
this line of thinking is lack of specificity of organic chemical reactions. This is quite
unlike chemistry of life i.e. Biochemistry.
Biochemist Robert Shapiro has summarized the "primordial soup" theory of
Oparin and Haldane in its "mature form" as follows
1. The early Earth had a chemically reducing atmosphere.
2. This atmosphere, exposed to energy in various forms, produced simple
organic compounds ("monomers").
3. These compounds accumulated in a "soup", which may have been
concentrated at various locations (shorelines, oceanic vents etc.).
4. By further transformation, more complex organic polymers – and ultimately
life – developed in the soup.
While steps 1-3 have been basically observed experimentally, step 4 has been
criticized as simplistic - a stage of "then magic happens".
However even existence of chemically reducing atmosphere of Early earth has
been doubted by geochemists. To quote:
“But is the “prebiotic soup” theory a reasonable explanation for the emergence of life?
Contemporary geoscientists tend to doubt that the primitive atmosphere had the highly reducing
composition used by Miller in 1953.” http://www.sciencemag.org/content/300/5620/745.full
Even need for step 3 is doubtful since Biological systems show extraordinary
capacity to operate under very-very low concentrations of essential chemicals
coupled with ability to concentrate essential chemicals as per the requirements of
particular Biological Systems.
Since 1924, much work has been done to gather evidence in support of Primordial
Soup Theory but till date not an iota of evidence has been discovered supporting
Prebiotic Soup hypothesis or existence of Prebiotic Soup.
What has generally been overlooked by scientific community till date is the fact
that Biochemistry or Chemistry of life is unique and distinctive to living state. It is
totally devoid of randomness. Rather, Biological Systems in order to keep
existence can’t permit random chemical reactions. Some of the salient features of
(I) Specificity, accuracy and precision of reactions — unlike organic
chemistry in which a large number of side reactions invariably occur
during any organic reaction leading to formation of side products, in
biochemistry reactions are highly specific, precise and accurate without
any side reactions and free from side products. This is essential to avoid
chaos in animate matter.
(II) In biochemistry, all reactions take place under conditions of existence
of given organism or conditions of its internal milieu which are often
quite different from conditions in which similar inorganic and organic
reactions proceed. Rationally speaking biochemical reactions must have
originated under the conditions in which relevant organisms are usually
found. Because of vast variation in habitat of organisms, the same
potentiality is realized through differently structured enzymes effective
under different conditions. Therefore, for evolution of Biochemistry,
environment has never been an absolute constraint.
(III) Biochemistry is deterministic. Deterministic character of chemistry of
life is well exhibited by its properties such as specificity of
intermolecular interactions, chemo selectivity, homochirality, stereo-
specificity of biological molecules. Even the subsequent course of events
has been essentially deterministic with a strong propensity to
stabilization, fixation, preservation and propagation of useful past and
present innovations. Biochemistry may have its roots in stochastic
inanimate interaction of matter and energy but stochastic organic
chemical reactions can’t account for specificity of reactions seen in
biochemistry. Unfolding or evolution of biochemistry requires a
surprising lack of side reactions (Smith and Morowitz). How this
extraordinary specificity of chemical reactions is achieved in the absence
of genes giving rise to catalytic polymers with three dimensional
substrate pockets is still a matter of conjecture and contemplation.
So the key questions which we must address ourselves keeping in view
homochirality of biological molecules are:
(i) Why homochirality is so essential that it is a deterministic trait in
entire biosphere or operates as a matter of law. Does it imply some
constraints of molecular intelligence?
(ii) How this deterministic homochirality was obtained and sustained,
may be from a stochastic beginning and in a stochastic world? The
answer to this might be simulation and induction, directed by utility.
All the experimental evidence gathered so far to bridge the gap between
inanimate matter and animate matter belong to the realm of stochastic chemistry
and the reaction products are devoid of life like intelligent molecular activity. This
statement is applicable to both, abiotic monomer synthesis as well as abiotic
Time line of origin of life shows that it must have taken at least 200 Ma after
formation of earth crust and oceans for life to appear. Life might have begun in the
form of fossilized Cyanobacteria in Stomatolites which are known to occur as early as
3.85 Ga. Any theory of origin of life should be able to explain time involved in its
origin. Therefore various experiments demonstrating synthesis of monomers over a
very short period of time fail to explain as to why the time involved in origin of life
was of the ~ 200 Ma. Hence, by whatever mechanisms life originated, it must have
been very slow and cumulative over a period of time. Therefore the vast amount of
experimental evidence only lends credibility to our belief in abiogenesis and that one
day it shall be possible to provide detailed explanation of origin of life from
inanimate matter but the accumulated evidence is otherwise not sufficient to
explain phenomenon of origin of life. Considering the enormous time involved,
processes leading to origin of life must be time dependent, extremely lengthy,
cumulative, complex and intricate which at the same time are relatively stable,
capable of fixation, preservation and propagation so that advances made are
cumulative ultimately leading to origin of life. The process of origin of life should
have proceeded through accumulation of a series of small discrete steps giving
semblance of gradualism and continuity. Easy switching between inanimate behavior
and life like activity should have been widely rampant in very-very early stages of
origin of life. Vast distribution of life on earth shows that constraints like U.V.
Radiation, Toxic effects of atmospheric oxygen against origin of life are just
scientific fictions, since a large number of forms that could exist have evolved only
after successfully meeting those constraints. Hence, these constraints, even
though may be valid are not absolute or non-negotiable. Origin of life must
involve origin of ways and means to circumvent and negotiate these constraints
or to tolerate these constraints.
Therefore, life like activity began on earth at any point of time in its history when
earth was capable of supporting or inducing life like activity due to some
unknown cause-effect sequences. All kinds of life like activity began independent
of each other wherever a source of energy, little moisture and relevant chemical
elements were available even if in very-very minute amounts. Considering
ubiquity of life on earth, environmental conditions could not have been a major
deterrent. Rather they influenced type of life and life like activity to which every
other type of life and life like activity has a relationship of adaptation and
adaptability or harmony. Therefore, all life forms originated in such a way that
they were ab initio adapted to conditions of their existence. Time and place has
played a more significant role in determining type of life like activity and type of
life through yet unknown cause-effect sequences. This is in conformity with time
dependent increase in complexity of life on earth as per fossil records and place
dependent biodiversity. Even Darwin observed that biodiversity on Galapagos
Islands varied according to some geographical rule.
Summarizing all above, for Origin of Life neither Prebiotic Soup was ever needed
nor could have ever existed. This is in conformity with all the experimental
evidence gathered till date.
Author: Dr Mahesh C. Jain is a practicing medical doctor and has written the
book “Encounter of Science with Philosophy – A synthetic view”. The book begins
with first chapter devoted to scientifically valid concept of God and then explains
cosmic phenomena right from origin of nature and universe up to origin of life
and evolution of man. The book includes several chapters devoted to auxiliary
concepts and social sciences as corollaries to the concept of God. This is the only
book which deals with origin of nature and universe from null. Twenty-ninth
chapter of the book deals with the subject matter of ‘Origin of Life’.