Al Islam

Origin of Life—Different Theories and Propositions

OR AEONS, philosophers have been attempting to solve the riddle of existence and origin of the universe. In the current era, their attention has been particularly focused on the origin of life. The dilemma they face is the question of who preceded whom—was it the chicken which laid the egg, or the egg which hatched the chicken? The most difficult challenge they face is about the creation of organic material. Organic material is a product of life and life itself is a product of organic material. How did inorganic chemicals convert into organic chemicals before the creation of life?

The problem which confronted researchers was evidently of a paradoxical nature. Every problem solved gave birth to many others perhaps more difficult to resolve. Every question that was answered led to a chain of other unanswerable questions, or, so it seemed. As the research proceeded, with a growing number of participating scientists, sometimes it appeared as if some of the researchers had at last struck bonanza. Such discoveries created great excitement among some who were inclined to make tall claims at every breakthrough that favoured their conception of how things might have been. There were others however, who were far more cautious and kept warning their fellow scientists not to be overzealous in drawing conclusions. The search for such clues as could scientifically satisfy their inquiry was set in motion in every direction. To date, none of the proposed solutions have found unanimous acceptance in the scientific community. Different scientists have reacted differently to different theories. Some have rejected them entirely, propounding their own propositions instead, while some have accepted them but only partially. Yet as a whole, the general direction of the overall research has begun to emerge, becoming clearer with the passage of time. Evidence is being discovered which lends new support to some of the propositions which are finding greater favour among the scientific community.

The purpose of this exercise is not to bother the reader with overmuch scientific jargon but some of it is unavoidable, otherwise we shall fail to achieve the object of co-relating the scientific data with the relevant Quranic verses. As much as the subject would allow, care is taken to simplify the language so that even the ordinary reader, unfamiliar with science, could keep up with us provided he makes a special effort to remain alert. A difficult task indeed, but not altogether impossible we hope!

This study will help the reader to realize that none of the Quranic declarations relating to the origin of life and its consequent evolution have ever been proved wrong. On the contrary, the general trend of the research continues to support the scenario of the creation of life as presented by them. We believe this will lead the reader to a world of wonders, far more intriguing than the story of Alice in Wonderland. The wonders of Alice's dreamland were fictional after all, but the journey we propose to undertake into our ancient past is on the wings of Divine revelation supported by scientific evidence. This is no fiction. It is a real land of wonders and mysteries of the creation of God, the Unique, the Peerless.

rigin of Life Theories
Let us visualize with the help of scientific investigation, the image of the environment and the atmosphere around the earth as it existed for three and a half billion years before the origin of life. The atmosphere at that time is believed to be anoxic—lacking free unlocked oxygen. No form of life which depends on metabolism for the release of energy through oxidation could have survived in such an atmosphere. In fact the absence of oxygen was an essential prerequisite for the synthesis of organic material from inorganic chemicals. Hence by design, as we believe, or by accident as the secular scientist will have it, it so happened that during the first three and a half billion years of the age of the earth, the atmosphere remained oxygen-free. There was no protective ozone layer in the stratosphere either. The chemical materials which must have been the precursors to stable forms of organic chemicals had to evolve without oxygen:

'J.B.S. Haldane, the British biochemist, seems to have been the first to appreciate that a reducing atmosphere one with no free oxygen, was a requirement for the evolution of life from nonliving organic matter.' 1

The absence of an ozone layer must have facilitated the high energy radiation blasts from the cosmos to reach the earth and ocean surfaces uninterrupted. The bombardment of this intense cosmic energy became largely instrumental in the creation of pre-biotic organisms which helped the transfer of material from inorganic to organic. The synthesis from inorganic chemicals in the oceans into preliminary organic chemicals such as amino acids was initially triggered off by the cosmic radiation in an anoxic atmosphere. This chemical reaction started from simple inorganic molecules such as water, carbon dioxide and ammonia. As this process advanced, according to Haldane, the primitive oceans reached the consistency of a hot, dilute soup (primordial soup). 2

The outcome of Haldane's research was published in 1929 in the Rationalist Annual but no serious note was taken of it in scientific circles. A few years before Haldane, A.I. Oparin, a Soviet scientist, had also published a small monograph in Russia in 1924, proposing similar ideas concerning the origin of life. This article too was met with no better fate. Both had simultaneously and independently worked on the problem of how organic material could have been synthesized from inorganic material before the beginning of biotic evolution.

New Landmark
After Oparin and Haldane, other scientists rose to fame by taking up the same inquiry all over again. During this period, it was undoubtedly Harold C. Urey of the American University of Chicago, who made the greatest theoretical contribution in this field. He restated the Oparin-Haldane thesis in his book The Planets 3 and resurrected the interest of the scientists in their pioneer research concerning the issue of the origin of life. In practical research however, it was Stanley L. Miller, a pupil of Urey, who stole the limelight in 1953. He, in accordance with Urey's theory recreated the atmospheric semblance of the primitive earth in a sealed glass apparatus. He filled it with a few litres of methane, ammonia and hydrogen gases, representing the atmosphere which scientists thought had then existed. To this mixture he added some water. A spark discharge device simulated lightning while a heated coil kept the water bubbling. Within a few days a reddish precipitate began to stain the glass which on analysis, to the utter delight of Miller, was found rich in amino acids.4 It is amino acids, one should remember, which link up together to form proteins, the building material from which the bricks of life are made.

At that time, the outcome of this experiment was considered the most stunning evidence that the prerequisite organic material for building the bricks of life could originate from natural atmospheric interaction with sea water, producing the 'primordial soup'. Soon, scientific fiction began to take root in this discovery. Many a scientist, in a highly excited state of mind, began to predict that it would not be long before life itself could be conjured up in test tubes. Many years later, however, Miller himself had quite a different gloomy confession to make:

'The problem of the origin of life has turned out to be much more difficult than I, and most other people, envisioned.' 5

His epoch-making experiment was performed in 1953 when he was a mere twenty-three year old undergraduate at the University of Chicago. Coincidentally, it was in the same year that another highly important research was successfully carried out, which was profoundly linked with the same issue. It related to the deciphering for the first time, by Watson and Crick, of the structure of deoxyribonucleic acid (DNA). DNA together with RNA, constitute the fundamental bricks of life. This led to a much bigger challenge of envisioning how life could have resulted from some primitive forms of organic material, accidentally created as scientists believed, into such profoundly complex material.

The problems were manifold. Of the many questions raised, one was how and by what game of chance, inorganic material could convert into the preliminary organic material which is a prerequisite for building the bricks of life. Returning to the early experiments of Urey, the first samples of laboratory test tube experiments were critically re-examined by many scientists. Some of them discovered grave flaws in Miller's experiment, taking some lustre off the hitherto much glorified exercise.

One major objection levelled at his experiment was that it was carried out in a simple flask and test-tube apparatus. The water substituting sea water was kept at boiling temperature while the natural conditions could not have admitted to such a proposition. This should have required the constantly controlled boiling of sea water over billions of years.

Some scientists would much rather have a cold start for the synthesis of life than the wet start proposed by Miller. They were inclined towards favouring the synthesis of organic material based on solid state chemistry rather than on the boiling water scenario.

Some went even further to suggest that the preliminary organic chemicals need not have been created here on earth. To support this view, they referred to the study of meteoritic rocks some of which are known to have contained many amino acids. In fact, the controlled experiment of Miller could produce only thirty-five amino acids as against the fifty-two counted during the analytical study of material from space. But those in favour of a 'wet start', originating in the sea water, raised many counter-objections against this proposition. One such objection relates to the well-known phenomenon of atmospheric friction which must have generated an immense amount of heat as the meteorites entered the earth's atmosphere. Such friction can raise the temperature of the intruding rocks so high as to set them ablaze. Hence all organic material carried by the burning rock should have disintegrated in mid-air before reaching the earth. The evidence of amino acids found in meteoric rock, according to the critics, could have indicated only the contamination it must have received after reaching the earth and cooling down. Those who insisted that it is possible for the organic material to have reached the earth safely from space, without confronting frictional heat, proposed another mode of transport which would be free from this flaw. It was suggested that the organic material might have been carried by small particles enwrapped in protective layers of icy covers such as found in the tails of comets. They could have softly alighted upon the earth like dew.

Returning once again to the epoch-making experiment performed by Miller, and the storm it raised, it did not take very long for its dust to settle down. In the calm that ensued, many a cool-minded reappraisal was conducted by some scientists.

One most eminent scholar R.E. Dickerson, in his excellent article Chemical Evolution and the Origin of Life, has critically examined at length the inferences drawn from Millers' experiment, in a detached, unbiased study. One thing that emerges predominantly from his review is that all the facts and experimental data relating to the Miller experiment were not included in the early reports.

Dickerson deemed it essential to point out:

'Although the simulations yield many of the amino acids found in the proteins of living organisms, they also yield at least as many related molecules that are not present.' 6

Experiments, simulating Miller's pioneer work, carried out by other scientists, revealed that out of three isomeric forms of an amino acid produced during these experiments 'only valine appears in proteins today'. None of the seven amino acid isomers, created during spark-discharge experiments has been 'designated as a protein constituent' by the universal code of life on earth. He further observes:

'...why the present set of 20 amino acids was chosen. Were there false starts, with genetic codes that specified different sets of amino acids, in lines of development that died out without a trace because they could not compete with the lines that survived?' 6

The task of creating the most highly complex and precisely sequenced proteins, the essential material for building the bricks of life—DNA/RNA, out of the simple amino acids synthesized by Miller is a 'mission impossible'. Even if conceded that due to the interplay of limitless chances the molecules of DNA/RNA were finally synthesized, the dilemma remains far from being resolved.

Dickerson quotes the British scientist, J.D. Bernal to emphasize the problem at hand, by suggesting that the scenario of a single molecule of DNA, created by chance,

'... generating the rest of life was put forward with slightly less plausibility than that of Adam and Eve in the Garden.' 7

Dickerson, during his summarization of the attendant problem highlights the difficulties inherent in the proposed solutions and suggests that the theorists actually rely on a wild, fantastic game of chance. But to that we shall return later.

REFERENCES

1. DICKERSON, R.E. (September, 1978) Chemical Evolution and The Origin of Life. Scientific American, p.70
2. DICKERSON, R.E. (September, 1978) Chemical Evolution and The Origin of Life. Scientific American, p.71
3. UREY, H.C. (1952) The Planets. Yale University Press, New Haven.
4. MILLER, S.L. (1955) Production of Some Organic Compounds under Possible Primitive Earth Conditions. Journal of The American Chemical Society: 77:2351–2361
5. HORGAN, J. (February, 1991) In The Beginning. Scientific American, p.117
6. DICKERSON, R.E. (September, 1978) Chemical Evolution and The Origin of Life. Scientific American, pp.75–76
7. DICKERSON, R.E. (September, 1978) Chemical Evolution and The Origin of Life. Scientific American, p.73