What Is the Origin of Life?
OUR earth teems with life. From the snowy Arctic to the Amazon rain forest, from the Sahara Desert to the Everglades swamp, from the dark ocean floor to bright mountain peaks—life abounds. And it is loaded with the potential to amaze us.
It comes in types, sizes, and quantities that stagger the imagination. A million species of insects hum and wiggle on our planet. In the waters around us swim over 20,000 species of fish—some the size of a grain of rice, others as long as a truck. At least 350,000 plant species—some weird, most wonderful—embellish the land. And over 9,000 species of birds fly overhead. These creatures, including man, form the panorama and symphony that we refer to as life.
But more amazing than the delightful variety around us is the profound unity linking them. Biochemists, who peek beneath the skin of earth’s creatures, explain that all living things—be they amoebas or humans—depend on an awesome interaction: the teamwork between nucleic acids (DNA and RNA) and protein molecules. The intricate processes involving these components occur in virtually all our body cells, as it does in the cells of hummingbirds, lions, and whales. This uniform interaction produces a beautiful mosaic of life. How did this orchestration of life come about? In fact, what is the origin of life?
Likely you accept that at one time the earth had no life on it. Scientific opinion agrees, and so do many religious books. Still, you may realize that those two sources—science and religion—differ in explaining how life began on earth.
Millions of people of all educational levels believe that an intelligent Creator, the original Designer, produced life on earth. In contrast, many scientists say that life arose from nonliving matter, one chemical step after another, merely by chance. Is it one, or is it the other?
We should not think that this issue is rather remote from us and from our finding a more meaningful life. As already noted, one of the very fundamental questions humans have sought to answer is, Where did we as living humans come from?
Most science courses focus on the adaptation and survival of life-forms instead of on the more central question of the very origin of life. You may have noted that attempts to explain where life came from are usually presented in generalizations such as: ‘Over millions of years, molecules in collision somehow produced life.’ Yet, is that really satisfying? It would mean that in the presence of energy from the sun, lightning, or volcanoes, some lifeless matter moved, became organized, and eventually started living—all of this without directed assistance. What a huge leap that would have been! From nonliving matter to living! Could it have occurred that way?
Back in the Middle Ages, accepting such a concept might not have seemed a problem because spontaneous generation—the notion that life could arise spontaneously from nonliving matter—was a prevailing belief. Finally, in the 17th century, Italian physician Francesco Redi proved that maggots appeared in rotten meat only after flies had laid eggs on it. No maggots developed on meat that flies could not reach. If animals as big as flies did not just appear on their own, what about the microbes that kept appearing in food—covered or not? Although later experiments indicated that microbes did not arise spontaneously, the issue remained controversial. Then came the work of Louis Pasteur.
Many people recall Pasteur’s work in solving problems related to fermentation and to infectious disease. He also performed experiments to determine whether tiny life-forms could arise by themselves. As you may have read, Pasteur demonstrated that even minute bacteria did not form in sterilized water protected from contamination. In 1864 he announced: “Never will the doctrine of spontaneous generation recover from the mortal blow struck by this simple experiment.” That statement remains true. No experiment has ever produced life from nonliving matter.
How then could life come to be on earth? Modern efforts to answer that question might be dated to the 1920’s, to the work of Russian biochemist Alexander I. Oparin. He and other scientists since then have offered something like the script of a three-act drama that depicts what is claimed to have occurred on the stage of planet Earth. The first act portrays earth’s elements, or raw materials, being transformed into groups of molecules. Then comes the jump to large molecules. And the last act of this drama presents the leap to the first living cell. But did it really happen that way?
Fundamental to that drama is explaining that earth’s early atmosphere was much different from what it is today. One theory assumes that free oxygen was virtually absent and that the elements nitrogen, hydrogen, and carbon formed ammonia and methane. The concept is that when lightning and ultraviolet light struck an atmosphere of these gases and water vapor, sugars and amino acids developed. Bear in mind, though, that this is theory.
According to this theoretical drama, such molecular forms washed into the oceans or other bodies of water. Over time, sugars, acids, and other compounds concentrated into a broth of “prebiotic soup” where amino acids, for instance, joined to become proteins. Extending this theoretical progression, other compounds called nucleotides formed chains and became a nucleic acid, such as DNA. All of this supposedly set the stage for the final act of the molecular drama.
One might depict this last act, which is undocumented, as a love story. Protein molecules and DNA molecules happen to meet, recognize each other, and embrace. Then, just before the curtain rings down, the first living cell is born. If you were following this drama, you might wonder, ‘Is this real life or fiction? Could life on earth really have originated in this way?’
Genesis in the Laboratory?
In the early 1950’s, scientists set out to test Alexander Oparin’s theory. It was an established fact that life comes only from life, yet scientists theorized that if conditions differed in the past, life might have come slowly from nonlife. Could that be demonstrated? Scientist Stanley L. Miller, working in the laboratory of Harold Urey, took hydrogen, ammonia, methane, and water vapor (assuming that this had been the primitive atmosphere), sealed these in a flask with boiling water at the bottom (to represent an ocean), and zapped electric sparks (like lightning) through the vapors. Within a week, there were traces of reddish goo, which Miller analyzed and found to be rich in amino acids—the essence of proteins. You may well have heard of this experiment because for years it has been cited in science textbooks and school courses as if it explains how life on earth began. But does it?
Actually, the value of Miller’s experiment is seriously questioned today. (See “Classic but Questionable,” pages 36-7.) Nevertheless, its apparent success led to other tests that even produced components found in nucleic acids (DNA or RNA). Specialists in the field (sometimes called origin-of-life scientists) felt optimistic, for they had seemingly replicated the first act of the molecular drama. And it seemed as though laboratory versions of the remaining two acts would follow. One chemistry professor claimed: “The explanation of the origin of a primitive living system by evolutionary mechanisms is well within sight.” And a science writer observed: “Pundits speculated that scientists, like Mary Shelley’s Dr. Frankenstein, would shortly conjure up living organisms in their laboratories and thereby demonstrate in detail how genesis unfolded.” The mystery of the spontaneous origin of life, many thought, was solved.—See “Right Hand, Left Hand,” page 38.
Moods Change—Riddles Remain
In the years since, however, that optimism has evaporated. Decades have passed, and life’s secrets remain elusive. Some 40 years after his experiment, Professor Miller told Scientific American: “The problem of the origin of life has turned out to be much more difficult than I, and most other people, envisioned.” Other scientists share this change of mood. For example, back in 1969, Professor of Biology Dean H. Kenyon coauthored Biochemical Predestination. But more recently he concluded that it is “fundamentally implausible that unassisted matter and energy organized themselves into living systems.”
Indeed, laboratory work bears out Kenyon’s assessment that there is “a fundamental flaw in all current theories of the chemical origins of life.” After Miller and others had synthesized amino acids, scientists set out to make proteins and DNA, both of which are necessary for life on earth. After thousands of experiments with so-called prebiotic conditions, what was the outcome? The Mystery of Life’s Origin: Reassessing Current Theories notes: “There is an impressive contrast between the considerable success in synthesizing amino acids and the consistent failure to synthesize protein and DNA.” The latter efforts are characterized by “uniform failure.”
Realistically, the mystery encompasses more than how the first protein and nucleic acid (DNA or RNA) molecules came into existence. It includes how they work together. “It is only the partnership of the two molecules that makes contemporary life on Earth possible,” says The New Encyclopædia Britannica. Yet the encyclopedia notes that how that partnership could come about remains “a critical and unsolved problem in the origin of life.” True, indeed.
Appendix A, “Teamwork for Life” (pages 45-7), reviews some basic details of the intriguing teamwork between protein and nucleic acids in our cells. Even such a glimpse into the realm of our body cells elicits admiration for the work of scientists in this field. They have shed light on extraordinarily complex processes that few of us even think about but that operate every moment of our lives. From another standpoint, however, the staggering complexity and precision required returns us to the question, How did all of this come about?
You may know that origin-of-life scientists have not ceased trying to formulate a plausible scenario for the drama about the first appearance of life. Nevertheless, their new scripts are not proving to be convincing. (See Appendix B, “From ‘the RNA World’ or Another World?” page 48.) For example, Klaus Dose of the Institute for Biochemistry in Mainz, Germany, observed: “At present all discussions on principal theories and experiments in the field either end in stalemate or in a confession of ignorance.”
Even at the 1996 International Conference on the Origin of Life, no solutions were forthcoming. Instead, the journal Science reported that the nearly 300 scientists who convened had “grappled with the riddle of how [DNA and RNA] molecules first appeared and how they evolved into self-reproducing cells.”
Intelligence and advanced education were required to study and even begin to explain what occurs at the molecular level in our cells. Is it reasonable to believe that complicated steps occurred first in a “prebiotic soup,” undirected, spontaneously, and by chance? Or was more involved?
Why the Riddles?
A person today can look back over nearly half a century of speculation and thousands of attempts to prove that life originated on its own. If one does that, it would be hard to disagree with Nobel laureate Francis Crick. Speaking about origin-of-life theories, Crick observed that there is “too much speculation running after too few facts.” It is thus understandable that some scientists who examine the facts conclude that life is much too complex to pop up even in an organized laboratory, let alone in an uncontrolled environment.
If advanced science cannot prove that life could arise by itself, why do some scientists continue to hold to such theories? A few decades ago, Professor J. D. Bernal offered some insight in the book The Origin of Life: “By applying the strict canons of scientific method to this subject [the spontaneous generation of life], it is possible to demonstrate effectively at several places in the story, how life could not have arisen; the improbabilities are too great, the chances of the emergence of life too small.” He added: “Regrettably from this point of view, life is here on Earth in all its multiplicity of forms and activities and the arguments have to be bent round to support its existence.” And the picture has not improved.
Consider the underlying import of such reasoning. It is as much as saying: ‘Scientifically it is correct to state that life cannot have begun by itself. But spontaneously arising life is the only possibility that we will consider. So it is necessary to bend the arguments to support the hypothesis that life arose spontaneously.’ Are you comfortable with such logic? Does not such reasoning call for a lot of ‘bending’ of the facts?
There are, however, knowledgeable, respected scientists who do not see a need to bend facts to fit a prevailing philosophy on the origin of life. Rather, they permit the facts to point to a reasonable conclusion. What facts and what conclusion?
Information and Intelligence
Interviewed in a documentary film, Professor Maciej Giertych, a noted geneticist from the Institute of Dendrology of the Polish Academy of Sciences, answered:
“We have become aware of the massive information contained in the genes. There is no known way to science how that information can arise spontaneously. It requires an intelligence; it cannot arise from chance events. Just mixing letters does not produce words.” He added: “For example, the very complex DNA, RNA, protein replicating system in the cell must have been perfect from the very start. If not, life systems could not exist. The only logical explanation is that this vast quantity of information came from an intelligence.”
The more you learn about the wonders of life, the more logical it is to agree with that conclusion: The origin of life requires an intelligent source. What source?
As noted earlier, millions of educated individuals conclude that life on earth must have been produced by a higher intelligence, a designer. Yes, after examining the matter fairly, they have accepted that even in our scientific age, it is reasonable to agree with the Biblical poet who long ago said about God: “For with you is the source of life.”—Psalm 36:9.
Whether you have yet reached a firm conclusion about that or not, let us turn our attention to some wonders that involve you personally. Doing so is most satisfying and may shed considerable light on this matter that touches our lives.
[Box on page 30]
How Much Chance for Chance?
“Chance, and chance alone, did it all, from the primeval soup to man,” said Nobel laureate Christian de Duve, speaking about the origin of life. Is chance, though, a rational explanation for the cause of life?
What is chance? Some think in terms of a mathematical probability, such as the chance involved in flipping a coin. However, that is not how many scientists use “chance” regarding the origin of life. The vague word “chance” is used as a substitute for a more precise word such as “cause,” especially when the cause is not known.
“To personify ‘chance’ as if we were talking about a causal agent,” notes biophysicist Donald M. MacKay, “is to make an illegitimate switch from a scientific to a quasi-religious mythological concept.” Similarly, Robert C. Sproul points out: “By calling the unknown cause ‘chance’ for so long, people begin to forget that a substitution was made. . . . The assumption that ‘chance equals an unknown cause’ has come to mean for many that ‘chance equals cause.’”
Nobel laureate Jacques L. Monod, for one, used this chance-equals-cause line of reasoning. “Pure chance, absolutely free but blind, [is] at the very root of the stupendous edifice of evolution,” he wrote. “Man knows at last that he is alone in the universe’s unfeeling immensity, out of which he emerged only by chance.” Note he says: ‘BY chance.’ Monod does what many others do—he elevates chance to a creative principle. Chance is offered as the means by which life came to be on earth.
In fact, dictionaries show that “chance” is “the assumed impersonal purposeless determiner of unaccountable happenings.” Thus, if one speaks about life coming about by chance, he is saying that it came about by a causal power that is not known. Could it be that some are virtually spelling “Chance” with a capital letter—in effect saying, Creator?
[Box on page 35]
“[The smallest bacterium] is so much more like people than Stanley Miller’s mixtures of chemicals, because it already has these system properties. So to go from a bacterium to people is less of a step than to go from a mixture of amino acids to that bacterium.”—Professor of Biology Lynn Margulis
[Box/Picture on page 36, 37]
Classic but Questionable
Stanley Miller’s experiment in 1953 is often cited as evidence that spontaneous generation could have happened in the past. The validity of his explanation, however, rests on the presumption that the earth’s primordial atmosphere was “reducing.” That means it contained only the smallest amount of free (chemically uncombined) oxygen. Why?
The Mystery of Life’s Origin: Reassessing Current Theories points out that if much free oxygen was present, ‘none of the amino acids could even be formed, and if by some chance they were, they would decompose quickly.’* How solid was Miller’s presumption about the so-called primitive atmosphere?
In a classic paper published two years after his experiment, Miller wrote: “These ideas are of course speculation, for we do not know that the Earth had a reducing atmosphere when it was formed. . . . No direct evidence has yet been found.”—Journal of the American Chemical Society, May 12, 1955.
Was evidence ever found? Some 25 years later, science writer Robert C. Cowen reported: “Scientists are having to rethink some of their assumptions. . . . Little evidence has emerged to support the notion of a hydrogen-rich, highly reducing atmosphere, but some evidence speaks against it.”—Technology Review, April 1981.
And since then? In 1991, John Horgan wrote in Scientific American: “Over the past decade or so, doubts have grown about Urey and Miller’s assumptions regarding the atmosphere. Laboratory experiments and computerized reconstructions of the atmosphere . . . suggest that ultraviolet radiation from the sun, which today is blocked by atmospheric ozone, would have destroyed hydrogen-based molecules in the atmosphere. . . . Such an atmosphere [carbon dioxide and nitrogen] would not have been conducive to the synthesis of amino acids and other precursors of life.”
Why, then, do many still hold that earth’s early atmosphere was reducing, containing little oxygen? In Molecular Evolution and the Origin of Life, Sidney W. Fox and Klaus Dose answer: The atmosphere must have lacked oxygen because, for one thing, “laboratory experiments show that chemical evolution . . . would be largely inhibited by oxygen” and because compounds such as amino acids “are not stable over geological times in the presence of oxygen.”
Is this not circular reasoning? The early atmosphere was a reducing one, it is said, because spontaneous generation of life could otherwise not have taken place. But there actually is no assurance that it was reducing.
There is another telling detail: If the gas mixture represents the atmosphere, the electric spark mimics lightning, and boiling water stands in for the sea, what or who does the scientist arranging and carrying out of the experiment represent?
Oxygen is highly reactive. For example, it combines with iron and forms rust or with hydrogen and forms water. If there was much free oxygen in an atmosphere when amino acids were assembling, it would quickly combine with and dismantle the organic molecules as they formed.
[Box on page 38]
Right Hand, Left Hand
We know that there are right-handed and left-handed gloves. This is also true of amino acid molecules. Of some 100 known amino acids, only 20 are used in proteins, and all are left-handed ones. When scientists make amino acids in laboratories, in imitation of what they feel possibly occurred in a prebiotic soup, they find an equal number of right-handed and left-handed molecules. “This kind of 50-50 distribution,” reports The New York Times, is “not characteristic of life, which depends on left-handed amino acids alone.” Why living organisms are made up of only left-handed amino acids is “a great mystery.” Even amino acids found in meteorites “showed excesses of left-handed forms.” Dr. Jeffrey L. Bada, who studies problems involving the origin of life, said that “some influence outside the earth might have played some role in determining the handedness of biological amino acids.”
[Box on page 40]
“These experiments . . . claim abiotic synthesis for what has in fact been produced and designed by highly intelligent and very much biotic man in an attempt to confirm ideas to which he was largely committed.” —Origin and Development of Living Systems.
[Box/Picture on page 41]
“A Deliberate Intellectual Act”
British astronomer Sir Fred Hoyle has spent decades studying the universe and life in it, even espousing that life on earth arrived from outer space. Lecturing at the California Institute of Technology, he discussed the order of amino acids in proteins.
“The big problem in biology,” Hoyle said, “isn’t so much the rather crude fact that a protein consists of a chain of amino acids linked together in a certain way, but that the explicit ordering of the amino acids endows the chain with remarkable properties . . . If amino acids were linked at random, there would be a vast number of arrangements that would be useless in serving the purposes of a living cell. When you consider that a typical enzyme has a chain of perhaps 200 links and that there are 20 possibilities for each link, it’s easy to see that the number of useless arrangements is enormous, more than the number of atoms in all the galaxies visible in the largest telescopes. This is for one enzyme, and there are upwards of 2000 of them, mainly serving very different purposes. So how did the situation get to where we find it to be?”
Hoyle added: “Rather than accept the fantastically small probability of life having arisen through the blind forces of nature, it seemed better to suppose that the origin of life was a deliberate intellectual act.”
[Box on page 44]
Professor Michael J. Behe stated: “To a person who does not feel obliged to restrict his search to unintelligent causes, the straightforward conclusion is that many biochemical systems were designed. They were designed not by the laws of nature, not by chance and necessity; rather, they were planned. . . . Life on earth at its most fundamental level, in its most critical components, is the product of intelligent activity.”
[Diagram/Picture on page 42]
(For fully formatted text, see publication)
Even a glimpse into the complex world and intricate functions in each body cell leads to the question, How did all of this come about?
• Cell membrane
Controls what enters and leaves the cell
The cell’s control center
Contain the DNA, the genetic master plan
Place where proteins are made
Site where ribosomes are assembled
Production center for the molecules that supply energy for the cell
[Picture on page 33]
Many scientists now acknowledge that the complex molecules basic to life could not have been spontaneously generated in some prebiotic soup