Understanding Natural Selection

On the grassy plains of East Africa, a herd of Grant’s gazelles meander slowly in the afternoon sun. Suddenly, the herd dashes off in unison—with a streak of spotted fur in hot pursuit. The healthy gazelles easily escape the hungry cheetah, but a sickly and weak gazelle at the back of the herd pitifully succumbs to the carnivore’s devices. Has “natural selection” struck again? And why does it matter to the creation/evolution debate?

Grant’s Gazelle (Nanger granti), Serengeti, Tanzania. Reproduced from Wikimedia Commons.

The term natural selection has been defined clearly for over 150 years. Charles Darwin put the term in the title to his book On the Origin of Species by Means of Natural Selection, and he articulated what he meant in the text of his seminal work:

But if variations useful to any organic being do occur, assuredly individuals thus characterised will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterised. This principle of preservation, I have called, for the sake of brevity, Natural Selection.1

Evolutionists to this day define it much the same way (but without the Victorian verbosity):

The differential survival of and/or reproduction of classes of entities that differ in one or more characteristics.2

Thus, “survival of the fittest”3 or “survival of the fittest to reproduce” is the standard definition of the process termed natural selection, and it finds no conflict with the text of Scripture.4 Ever since the fall (Genesis 3), living things have been dying and killing each other, and the self-evident fact of natural selection is perfectly consistent with the Bible. Natural selection has happened, and it continues to happen every day. In fact, the concept of natural selection was first articulated, not by an evolutionist, but by a creationist nearly a quarter century before Darwin published his most significant work.5

Furthermore, as biblical creationists, we must affirm that the term natural has been used from the earliest days of formal scientific inquiry to describe God’s upholding of the universe through the laws of nature. For the Christian, nature is simply shorthand for God’s providential operation of the creatures and creation we see around us.6 In our example above, the culling of the sickly gazelle removes its unique genetic contribution from the overall genetic pool of the gazelle population, potentially preventing propagation of its genetic mutations from spreading.

In addition, repetition of this predation cycle over time could alter the ratios of genetic varieties in the gazelle species, potentially leading to the formation of a new species. Thus, natural selection is an observable fact that can participate in the process of variation and speciation within the original kinds of animals that God created.

Unfortunately, evolutionists have taken a straightforward truth and co-opted it for their anti-biblical purposes:

[Natural selection] provided an entirely natural, mechanistic explanation for adaptive design that had been attributed to a divine intelligence.7

In the evolutionary worldview, natural selection and mutations are the primary driving forces resulting in the evolution of all living things from a single-celled common ancestor over billions of years—without any divine intervention. In essence, atheistic evolutionists substitute natural selection for God Himself!

The misuse of this term shouldn’t intimidate biblical creationists. After all, people have been co-opting terms for anti-biblical purposes for millennia. Even today, unbelievers justify gay “marriage,”8 abortion,9 and all sorts of other sins in the name of “Christianity.” Yet no Bible-believer would logically conclude that, because sinners wrap the cloak of “Christianity” around their vices, the entire Christian religion should be thrown out. Instead, we would all agree that the abusers of the term should be exposed, and the correct definition should be restored and emphasized to prevent error from spreading.

The same principle holds true in the realm of natural selection. Just because unbelievers co-opt the term for their anti-Christian purposes doesn’t mean that natural selection isn’t real or that the term should be thrown out. Instead, biblical creationists should point out the ability of natural selection to remove the sickliest individuals from a population and to preserve the least degenerate and most well-adapted organisms,10 and we should also emphasize scientific inability of natural selection to evolve the diversity of life from a common ancestor.11

We should also expose the logical fallacies that evolutionists employ with natural selection in an attempt to buttress their case. For example, when pressed for evidence for molecules-to-man evolution, evolutionists often cite examples of natural selection. This is an equivocation fallacy since natural selection has been deftly substituted for evolution mid-argument. These two terms have very different definitions.

Natural selection is a fact, but Darwinian evolution from a universal common ancestor is not.

Furthermore, natural selection—the survival of the fittest to reproduce—actually works in the opposite direction of molecules-to-man evolution. Natural selection eliminates variety, and goo-to-you evolution requires an ever-increasing growth in variety.12 Thus, natural selection is a fact, but Darwinian evolution from a universal common ancestor is not—despite the evolutionists’ best attempts to use the former to prove the latter.

Nevertheless, some biblical creationists have fallen into the evolutionists’ equivocation trap and have attempted to refute evolution by throwing out the concept of natural selection entirely. On occasion, we are asked what we think about such efforts. In short, while well intended, such attempts end up being logically unsound, scientifically erroneous, and theologically deficient.

At first pass, these arguments have an intrinsic appeal. For example, Randy Guliuzza,13 a medical doctor and engineer by training, has prominently appealed to design analogies to argue against the existence of natural selection and for a process that he terms “programmed filling.”14

According to Guliuzza, in the human design process, it’s the engineers who do all the work in trying to solve a problem, and the problem contributes nothing to the solution. Extrapolating this process to our gazelle example above, Guliuzza would argue that the gazelle represents the engineer, and that the life-and-death attack by the cheetah represents the problem to be solved. Therefore, Guliuzza would argue that the survival of the gazelle depends entirely on the gazelle’s ability to “solve” this “problem” and has nothing to do with the environment.

In fact, Guliuzza takes his analogy so literally that he has denied any role whatsoever for the environment:

Whether creatures live or die depends on their ability to generate information from their DNA to produce specific traits that fit environments . . . diversity depends solely on variables inside the creature.15

He even denies the existence of natural selection:

natural selection—is a phantasm.16

While Guliuzza is well intentioned in his efforts to rebut evolution, his analogy fails on several counts.17 First, creatures are not human engineers—by definition. In our example, the gazelle cannot, by sheer will, change its DNA to improve its metabolism, restructure its physiology, and grow longer legs to outrun the cheetah. Furthermore, creatures reproduce, and engineers rarely have to solve problems with self-replicating devices. In our example, even if the gazelle could change its DNA, grow longer legs, and survive, how would that information be passed to its offspring? For that to happen, changes would also have to occur in the animal’s egg or sperm.

Second, even if we loosen the analogy and make God the ultimate “engineer,” God is not a human engineer (he’s much greater), and his creation and design acts encompass more than animals. He designed the environment as well, and he sovereignly rules it and even summons it on occasion to perform his will (e.g., the flood, the Red Sea crossing, etc.). To say that a creature’s survival has nothing to do whatsoever with the environment is to rob God of his glory. It’s not the fault of Pharaoh’s soldiers that they drowned. Their death is not a failure to adapt, a failure to remember to wear buoyant armor, or a failure to excel in their swimming lessons. Rather, God deliberately killed Pharaoh’s men with the waters of the Red Sea as an act of judgment on them and an act of salvation on Israel.

In our example above, confusing causality also misses explicit Scriptural truths about the acts of God in history. Since the gazelles and the cheetah are modern, post-Flood creatures, they exist in a world judged by God at the fall (Genesis 3). As we all know, death and bloodshed are part of the curse under which we still live, and the purpose of the curse is an ongoing reminder of the realities of sin, of God’s anger against sin, and of the need for salvation. To blame the death of the gazelle on a failure of the gazelle to grow longer legs—rather than on the deliberate design of the cheetah to kill (in a fallen world)—is to miss an important reminder of critical gospel truths.

Third, it is well-documented observational science that certain aspects of animal diversity—e.g., their genetics—depend on environmental variables. Textbook observational science shows how UV light and radiation induces specific types of DNA damage. In fact, tests to measure environmentally induced DNA changes have existed since the 1970s.18 Changes to the DNA sequence effectively result in increased genetic diversity.

Aspects of animal diversity do depend on more than variables inside creatures.

Environmental variables also participate in the expression of more visible traits. For example, in certain bird species, the action of sea water initiates the expression of a salt gland. Though the gland is encoded by the creature and not by the environment, the gland doesn’t become expressed until environmental variables (e.g., salt water) trigger its appearance.19 Clearly, aspects of animal diversity do depend on more than variables inside creatures.

In short, biblically, Guliuzza’s claims deny that God sovereignly uses the environment and the natural order to accomplish his work in the post-fall world in which we live. Scientifically, his claims are demonstrably false by virtue of prior scientific findings that are both testable and repeatable.

Thus, the process of natural selection—the survival of the fittest to reproduce—is a fact that highlights the providential care of God over a fallen creation and brings glory to his power, judgment, and salvation. We embrace the proper use of this term, and we reject Randy Guliuzza’s erroneous claims about the nonexistence of natural selection.