Visiting the Origin of Life AgainOne of the greatest challenges to science over the past hundred years at least, has been the question of how life came into existence on the earth. Skeptics of the existence of God have attempted to find ways of explaining the origin of life by chance processes, thinking that this would eliminate any argument for the existence of God. In reality, discussions of the origin of life begin by assuming that certain materials have already been created, and simply tries to explain how these created materials could have become living. In the last year or so a number of discoveries and understandings have come out of research which makes it useful to discuss this subject, even though we have discussed it previously in this journal.
The history of mechanical explanations of the origin of life began with Charles Darwin who proposed in 1871 that life may have emerged from "some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity, etc. present" (Francis Darwin, The Life and Letters of Charles Darwin, New York, D. Appleton, 1887, page 202). In 1924, Alexander Oparin proposed that complex molecules had formed from simple ones by a series of chemical processes. In 1928, J.B.S. Haldane suggested that ultraviolet radiation caused sugars and amino acids to concentrate in oceans in the ancient earth. In the early 1950s, Harold Urey proposed that the earth's ancient atmosphere made life happen, and he directed his student Stanley Miller to do an experiment using gases that Urey thought might work--ammonia, methane, and hydrogen. Miller did the experiment using electrical discharge as the catalyst and was able to detect amino acids in a trap connected to the apparatus. Amino acids are the building blocks of life, so the media picked up on this and headlines like "Scientist Creates Life" appeared around the world. Miller was hailed as having made a great breakthrough, and certainly the fact that simple materials could be used to produce more complex molecules was proven. Transferring this to the ancient earth was difficult, because the apparatus destroyed amino acids 10,000 times faster than it produced them, and thinking of how something on the earth could serve as the trap that Miller used in his apparatus to protect the amino acids from the electrical discharge was very hard to do.
Since 1956 when Miller did all this, research has continued and Miller's experiment has been shown to be almost totally irrelevant to the origin of life. The big problem is that Urey chose the gases that would be used, and assumed that these gases were present in the atmosphere of the newly created earth. The gases that he chose were very active. We heat our homes and cook our food with methane, and hydrogen is an explosive gas--a point made loud and clear when the Hindenburg exploded. Hydrogen is also so light weight, that the earth's gravity cannot hold it, so hydrogen gas in our atmosphere escapes into outer space and could never have been a factor in the make up of the early earth. Ammonia is also a very active material chemically. Just placing ammonia into water causes rapid dissolving and the production of ammonium hydroxide, and ammonia reacts vigorously with any anion. By choosing gases that were very active chemically, Urey stacked the deck for something to happen when the gases were placed together and a catalyst was applied.
As research has continued and more and more materials from the early earth have been examined, it has become obvious that Urey's choices may have been wise chemically, but they are clearly not what the ancient earth was like. Carbon dioxide seems to have been the primary material in the atmosphere of the ancient earth, with nitrogen and water being the other major components. Recent experiments have shown that very little oxygen was present. The point is that the chemicals that were present in the ancient earth's atmosphere are virtually inert chemically. Our atmosphere today is 78% nitrogen, and getting that nitrogen to react chemically is a challenge for agriculture. Nitrogen fixation (in which nitrogen is turned into compounds that plants can use) is accomplished by lightning bolts and certain bacteria in nature. Carbon dioxide dissolved in water is what we drink in soda pop, and it is exhaled by each of us as we breathe. If you were to put these gases in the Miller apparatus, they would never produce an amino acid.
Another problem with questions related to the origin of life is that much more information is available now on how cells are constructed than was available early in the twentieth century. Many of the assumptions made by those theorizing about how life got started on the earth have turned out to be impossible. There are 80 different possible amino acids, but only a fourth of these are actually found in living cells. Fifty percent of amino acids produced in the laboratory have a left-handed orientation and 50% have a right-handed orientation, but only left-handed amino acids are seen in living cells. Amino acids have to be linked together in very specific sequences to produce protein molecules, but other molecules react with amino acids more readily than amino acids react with each other. We have also learned that peptide bonds have to occur in very specific places in order for the proteins produced to be able to fold up three dimensionally.
To make a protein that is functional in living things, 100 amino acids have to be arranged in the right sequence. We do need to point out that proteins are not living, they are simply the next step in building life. The sequencing of amino acids is critical. Imagine having 100 letters and wanting to write a sentence. You could not just randomly pull the letters one at a time and put them in a row and expect to have a sentence. There has to be a special order of letters for the sequence to make any sense. This is equally true of amino acids.
In a living cell the guidance to do this comes from the DNA which works as a microprocessor working with RNA for sequencing. The synthesis of DNA and RNA by a process like the Miller-Urey experiment has never been attempted and is viewed by most biologists as being beyond the reach of modern science. The point is that when one talks about the origin of life, there is no DNA or RNA to do the sequencing. This is a major complication in any attempt to explain the origin of life. People doing the research recognize this. There have been a number of theories proposed over the past 20 years to find a way around these problems. The discovery of sea vents and a biosphere based on sulfur was thought to be a possibility, but the vents have no way to recycle the biological systems to increase their sequencing complexity. In addition to that, the vents are destructive to the chemicals used in the biological systems, so the range of life forms is very limited. Crick and Orgel's proposal that life was seeded on earth by aliens--a proposal that just pushes the questions to another solar system--is too tabloidish to be considered by most scientists.
The origin of life on earth did not happen by chance. There is simply too much evidence of design and purpose in everything we have learned about life to believe that chance is a viable mechanism for life. Francis Crick said, "The origin of life appears to be almost a miracle, so many are the conditions which would have to be satisfied to get it going (Lee Strobel, The Case for Faith, Grand Rapids, MI, Zondervan, 2000, page 100) He also said, "Every time I write a paper on the origin of life, I swear I will never write another one, because there is too much speculation running after too few facts" (Strobel, page107).
The SETI program (Search for Extra Terrestrial Intelligence) has stated that if they could pick up any radio signal from space with an ordered sequence, they would consider it to have come from an intelligent source. In Contact (the sci-fi book and movie based on Carl Sagan's writing), intelligent life being the source of the signal was identified by a series of prime numbers (numbers divisible only by themselves and one). Every cell in your body contains more information in its DNA than is in an Encyclopaedia Britannica. Attempts by skeptics to explain the origin of life on a chance basis have no support from the evidence, and as new discoveries continue to be made the role of intelligence becomes clearer and clearer. God created life by a plan, and that design radiates from every living thing to verify that fact.
--John N. Clayton
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