Sy Garte
 on September 11, 2020

Purpose, Evolution, and Self-Replication

While natural selection is a very powerful mechanism in evolution, paying more attention to the nature of biological self-replication, we can see hints of the origin of purpose in life.

cancer cells

Richard Dawkins famously wrote: “The universe that we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but pitiless indifference.”1

At first glance, it seems to be reasonable to see nothing but indifference “at bottom.” But the statement cannot be true for everything in the universe, for if it were, it would have been impossible to conceive of or express the idea. Purpose and good and evil have to exist somewhere for their absence to be noted elsewhere. What Dawkins is claiming leads to the conclusion that the human ideals of meaning, pity, and compassion are not to be found outside of human minds. But they undeniably exist in the part of the universe that includes human minds.

Let us consider purpose. It certainly is present, not only when it comes to human beings but in all life. I grant that bacteria do not get up in the morning and ask themselves, what should I do today?—but, like all creatures, they act with purpose, with an apparent goal, which is to remain alive and reproduce themselves, much like beavers, pine trees, fungi, and spiders. Of course, such apparent teleological behaviors that increase the chance of survival are quite different from a human’s purpose for, let’s say, writing an essay on teleology. The spider’s purpose, a biologist will insist, stems directly from the blind, purposeless, non-directional processes of evolution. The term “teleonomy” is sometimes applied to such biologically programmed purpose (as articulated by Ernst Mayr) to distinguish it from purposeful action by intentional agents. But regardless of the hard question of where and how human free will emerges, purposeful behavior seems to be a salient characteristic of all life.

We correctly look to evolution for answers about why life is the way it is, but perhaps we are not always looking at evolution the right way. Is there something purposeful about evolution that reaches beyond the simple fact that within a population of similar organisms, those with more beneficial characteristics will tend to leave more offspring? I think that there is, and to see it clearly, we should take a deeper look at the process that has been so successful at producing the enormous variety of life on this planet.

The Role of Inheritance

In many popular descriptions of evolution, only two of the three major required characteristics of living organisms—namely, their variability and their fitness in a particular environment—are presented as the mechanisms for evolution. The third component is no less critical, but it is almost always assumed and therefore not specifically mentioned. That missing piece is the amazing biological feature of high-fidelity inheritance.

two women's eyes next to each other

Alleles are different versions of the same gene, and evolution is often defined as a change in allele frequencies in a population over time. But the production of a new allele (by means of a genetic mutation) cannot possibly lead to evolution unless it is accurately inherited by the next generation and thus able to spread through the population due to improved fitness. A mutation in a gene for a protein related to visual acuity might produce an allele that confers better eyesight in an individual bird, but if the offspring of the bird do not inherit a precise copy of the new allele, no evolution can occur.

Since long before the discovery of genetics, humans have been aware that offspring can inherit the characteristics of their parents. It is one of those facts of nature that are taken for granted. We now have learned almost all there is to know about how inheritance works, and yet it often seems that we don’t fully consider how remarkable the reality of biological replication is.

The complex molecular reactions and interactions that we think of as the defining features of being alive could theoretically exist in the absence of replication. But such living collections of metabolic chemicals could not evolve, and once their homeostasis was interrupted by some chance event, their death would be the end. Accurate replication is the ideal method to preserve the existence of life, if not the longevity of individual creatures. We see this throughout the living world, where evolution has favored widespread reproduction over individual lifespan. At the same time, there must be an upper limit on replication accuracy, since if no errors were ever made, there would be no mutations, no variations, and no evolution. In modern life the accuracy is about 99.999999%. That number might look almost the same as 100%, but in this case it is quite different, which allows for just the right degree of variation.


How did life manage to accomplish this unique ability of accurate self-replication? Think of a house, complete with walls, roof, floor, electrical and plumbing systems, appliances, furniture, books, paintings, etc. You would have a difficult time replicating that house, although after a great deal of work and time, you might come close. But no house in existence can replicate itself. And a single cell is far more complex than a house—it contains more things, and more kinds of things, than the largest apartment complex you’ve seen. A typical cell contains about ten billion protein molecules of five thousand different kinds. When we add sugars, lipids, nucleotides, amino acids, fats, and inorganic ions, the number of molecules in a cell reaches 1012. Even I don’t have that many books in my house!

Chemicals do not self-replicate. Proteins, sugar molecules, phosphate ions, or any other of the ten billion molecules in a cell cannot replicate themselves, no matter how much energy or time is available. So how are cells able to replicate themselves and all their chemical and physical contents?

It’s a complex, basically two-step process. First, the informational content of the cell, stored in the DNA, is replicated by making a very-close-to-exact copy of the particular nucleotide sequence of the cell’s DNA. That’s the genotype; inheriting the right genotype is the first step. But it is only the start.

For evolution to work, the amino acid of each enzyme must be exactly what it was in the original cell (with a tiny degree of error to allow for variation to arise) because if it isn’t, there is a good chance that inheritance will not be good enough to maintain the characteristics of the parent (as we saw with the bird’s eyesight above).

rendering of cell replication

And this is where we see the amazing process that allows life to prosper and evolve. The information for building (or rebuilding) the entire contents of the cell is present in its (accurately copied) DNA sequence. Now all the cell has to do is use that information to build itself properly. But how does it do that?

Mechanics and Specifications

DNA gets treated like a celebrity, but it is only the specifications manual. It only tells us what the proper cell should look like, the sequence of each of its proteins, its various RNA molecules, organelles, and intracellular components. It doesn’t actually make anything or do anything. It just sits there in the nucleus, much like a repair manual just sits on a desk and doesn’t actually fix the car.

Like a garage, cells need mechanics as well as instruction manuals to do the work of translating the information in the DNA from one form of chemistry (nucleotide chemistry) to another (amino acid chemistry). This translation process results in the production of specific enzymes, which in turn are the mechanics that make everything else. In other words, cells contain a process for making mechanics (enzymes), which then make the rest of the cell the way it is.

How do you make a cellular mechanic? We know how cells do it: in a remarkable process called translation. It involves an RNA that serves as a messenger from the DNA to the ribosome where the proteins are made, and several adapter molecules that act as the actual effectors of the genetic code by an elaborate and ingenious set of enzymatic reactions. You can learn more about the details from textbooks or by watching some good videos illustrating the process. You will be stunned and amazed.

So, while natural selection is a very powerful mechanism in evolution, and while genetic mutations are clearly central to the process, I believe we need to pay more attention to the awe-inspiring nature of biological self-replication. By focusing on self-replication, I believe we can see hints of the origin of purpose in life. Built into the very biochemical fabric of evolution is the underlying teleology of all life—the drive to survive. And part of that highly purposeful survival strategy, enthroned by natural selection into the earliest living creatures, is self-replication.

At this time, we don’t have a firm answer as to how self-replication began, but research is ongoing into many of its aspects, including the origin and evolution of the genetic code and of the protein synthesis machinery. I believe that, like so many other modern discoveries in biology, cosmology, and physics, the answer will point us to see the truth about ourselves and all of life, which is neither purposeless, pitiless, nor indifferent.

As Christians, let us gaze at all the wonders of this created world with praise and worship of its Creator. And, as scientists, let us delve deeply into mysteries like the origin of protein synthesis, which leads to the power of evolution, the magic of the diversity of life, and, of course, to that creature who bears God’s image, and who therefore cares about all this—us humans.

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About the author

Sy Garte

Sy Garte

Sy (Seymour) Garte, PhD in biochemistry, is the author of the award-winning book The Works of His Hands: A Scientist’s Journey from Atheism to Faith (Kregel Publications, 2019). He has been a tenured professor at New York University, Rutgers University, and the University of Pittsburgh, division director at the Center for Scientific Review of the National Institutes of Health, and interim vice president for research at the Uniformed Services University of the Health Sciences. He is currently visiting professor of pharmacology and toxicology at Rutgers University. He has published over two hundred peer-reviewed scientific papers and five books, as well as articles on science and Christian faith in periodicals such as Perspectives in Science and Christian Faith, More to Life, and Christianity Today. He has appeared on numerous podcasts and YouTube channels. Currently, Dr. Garte serves as the Editor-in-Chief of the American Scientific Affiliation’s (ASA) online quarterly magazine God and Nature, and also as vice president for the Washington, DC, metro chapter of the ASA. He was a member of the board of advisors of the John Templeton Foundation. Dr. Garte became a Christian later in life and is now a Certified lay Servant of the United Methodist Church in Rockville, MD.