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How Did Life Begin?

How Did Life Begin?

When you were a child, did you ever startle your parents by asking, “Where do babies come from?” If so, how did they respond? Depending on your age and their personality, your parents might have ignored the question or given you a hurried, embarrassed answer. Or perhaps they told you some fanciful tales that you later found to be false. Of course, if a child is to be properly prepared for adulthood and marriage, he or she eventually needs to learn about the wonders of sexual reproduction.

Just as many parents feel awkward about discussing where babies come from, some scientists seem reluctant to discuss an even more fundamental question​—Where did life come from? Receiving a credible answer to that question can have a profound effect on a person’s outlook on life. So how did life begin?

A fertilized human egg cell, shown about 800 times its actual size

What do many scientists claim? Many who believe in evolution would tell you that billions of years ago, life began on the edge of an ancient tidal pool or deep in the ocean. They feel that in some such location, chemicals spontaneously assembled into bubblelike structures, formed complex molecules, and began replicating. They believe that all life on earth originated by accident from one or more of these “simple” original cells.

Other equally respected scientists who also support evolution disagree. They speculate that the first cells or at least their major components arrived on earth from outer space. Why? Because, despite their best efforts, scientists have been unable to prove that life can spring from nonliving molecules. In 2008, Professor of Biology Alexandre Meinesz highlighted the dilemma. He stated that over the last 50 years, “no empirical evidence supports the hypotheses of the spontaneous appearance of life on Earth from nothing but a molecular soup, and no significant advance in scientific knowledge leads in this direction.”1

What does the evidence reveal? The answer to the question, Where do babies come from? is well-documented and uncontroversial. Life always comes from preexisting life. However, if we go back far enough in time, is it really possible that this fundamental law was broken? Could life really spontaneously spring from nonliving chemicals? What are the chances that such an event could happen?

Researchers have learned that for a cell to survive, at least three different types of complex molecules must work together​—DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and proteins. Today, few scientists would assert that a complete living cell suddenly formed by chance from a mix of inanimate chemicals. What, though, is the probability that RNA or proteins could form by chance? *

Stanley Miller, 1953

Many scientists feel that life could arise by chance because of an experiment first conducted in 1953. In that year, Stanley L. Miller was able to produce some amino acids, the chemical building blocks of proteins, by discharging electricity into a mixture of gases that was thought to represent the atmosphere of primitive earth. Since then, amino acids have also been found in a meteorite. Do these findings mean that all the basic building blocks of life could easily be produced by chance?

“Some writers,” says Robert Shapiro, professor emeritus of chemistry at New York University, “have presumed that all life’s building blocks could be formed with ease in Miller-type experiments and were present in meteorites. This is not the case.”2 *

Consider the RNA molecule. It is constructed of smaller molecules called nucleotides. A nucleotide is a different molecule from an amino acid and is only slightly more complex. Shapiro says that “no nucleotides of any kind have been reported as products of spark-discharge experiments or in studies of meteorites.”3 He further states that the probability of a self-replicating RNA molecule randomly assembling from a pool of chemical building blocks “is so vanishingly small that its happening even once anywhere in the visible universe would count as a piece of exceptional good luck.”4

RNA (1) is required to make proteins (2), yet proteins are involved in the production of RNA. How could either one arise by chance, let alone both? Ribosomes (3) will be discussed in section 2.

What about protein molecules? They can be made from as few as 50 or as many as several thousand amino acids bound together in a highly specific order. The average functional protein in a “simple” cell contains 200 amino acids. Even in those cells, there are thousands of different types of proteins. The probability that just one protein containing only 100 amino acids could ever randomly form on earth has been calculated to be about one chance in a million billion.

If the creation of complex molecules in the laboratory requires the skill of a scientist, could the far more complex molecules in a cell really arise by chance?

Researcher Hubert P. Yockey, who supports the teaching of evolution, goes further. He says: “It is impossible that the origin of life was ‘proteins first.’”5 RNA is required to make proteins, yet proteins are involved in the production of RNA. What if, despite the extremely small odds, both proteins and RNA molecules did appear by chance in the same place at the same time? How likely would it be for them to cooperate to form a self-replicating, self-sustaining type of life? “The probability of this happening by chance (given a random mixture of proteins and RNA) seems astronomically low,” says Dr. Carol Cleland *, a member of the National Aeronautics and Space Administration’s Astrobiology Institute. “Yet,” she continues, “most researchers seem to assume that if they can make sense of the independent production of proteins and RNA under natural primordial conditions, the coordination will somehow take care of itself.” Regarding the current theories of how these building blocks of life could have arisen by chance, she says: “None of them have provided us with a very satisfying story about how this happened.”6

If it takes an intelligent entity to create and program a lifeless robot, what would it take to create a living cell, let alone a human?

Why do these facts matter? Think of the challenge facing researchers who feel that life arose by chance. They have found some amino acids that also appear in living cells. In their laboratories, they have, by means of carefully designed and directed experiments, manufactured other more complex molecules. Ultimately, they hope to build all the parts needed to construct a “simple” cell. Their situation could be likened to that of a scientist who takes naturally occurring elements; transforms them into steel, plastic, silicone, and wire; and constructs a robot. He then programs the robot to be able to build copies of itself. By doing so, what will he prove? At best, that an intelligent entity can create an impressive machine.

Similarly, if scientists ever did construct a cell, they would accomplish something truly amazing​—but would they prove that the cell could be made by accident? If anything, they would prove the very opposite, would they not?

What do you think? All scientific evidence to date indicates that life can come only from previously existing life. To believe that even a “simple” living cell arose by chance from nonliving chemicals requires a huge leap of faith.

Given the facts, are you willing to make such a leap? Before answering that question, take a closer look at the way a cell is made. Doing so will help you discern whether the theories some scientists propound about where life came from are sound or are as fanciful as the tales some parents tell about where babies come from.

^ par. 8 The probability of DNA forming by chance will be discussed in section 3, “Where Did the Instructions Come From?

^ par. 10 Professor Shapiro does not believe that life was created. He believes that life arose by chance in some fashion not yet fully understood. In 2009, scientists at the University of Manchester, England, reported making some nucleotides in their lab. However, Shapiro states that their recipe “definitely does not meet my criteria for a plausible pathway to the RNA world.”

^ par. 13 Dr. Cleland is not a creationist. She believes that life arose by chance in some fashion not yet fully understood.