Editor’s note: This paper is by one of the students in our ARS Apologetics Certificate Program, Drew Tacher. The paper is good enough we have decided to post it. If you are interested in enrolling in our Apologetics Certificate Program, contact us at firstname.lastname@example.org
Why Christians Should Believe in the Theory of Evolution
At some point in their lives, most humans will reject a thought, opinion, or theory despite the overwhelming evidence and rhetoric supporting said assertion. Similarly, many Christians around the world continue to blindly reject the theory of evolution. Despite an overwhelming amount of convergent empirical evidence across a number of scientific disciplines, many people still refuse to accept the theory of evolution. This is not a new concept, as people have been rejecting new, sometimes threatening or scary, ideas for millennia. As Peter Enns points out in his book The Sin of Certainty, humans want to be certain of as much as they can, and even more importantly about matters regarding life and the universe. Thus, when someone or something challenges that certainty one has developed through tradition, education, or another mode, they tend to resist it. Christians should not be so quick to rule out evolution on the account that “the Bible teaches differently.” Many Christians discount scientific evidence because it goes against their preconceived, and wrong, notions of creation. Inversely, many scientists declare that evolution is a fact even when they know science cannot discover truth, but instead can only create consistent models.
Many Christians are conflicted because the theory of evolution asserts that life has been around much longer than 6,000 years. Since many Christians still hold to the incorrect and archaic belief that the Earth and life were created 6,000 years ago, they reject evolution entirely. However, anyone who seeks truth must dig deeper into this incorrect belief that most likely blinds them. Christians must come to welcome – rather than fear – the ideas of evolution. In the 17th century, Galileo used the metaphor of the “two books” to help Christians of his generation understand the sacred truth that the Earth moves about the sun. “The Bible,” he liked to say, “tells us how to go to heaven, not how the heavens go.” Most evolutionists do not contradict the Bible unless you force an unreasonable interpretation on Genesis 1. Science is not a sinister conglomerate aimed at destroying faith; it’s an honest exploration of the wonderful world that God created.
Charles Darwin’s originally proposed theory of evolution in On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life is much different from the present-day theory. The theory of evolution by natural selection is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits. Changes that allow an organism to better adapt to its environment will help it survive and have more offspring. Darwin didn’t understand genetics like we do today. He observed the pattern of evolution, but he didn’t really know about the mechanism. Later in the 1860’s, a man named Gregor Mendel helped answer this with his phenomenological theory of genetics. Then, in 1953, DNA was discovered, and this led into the discovery of the understanding of genetic code. So, what is the modern theory of evolution that we will use? This theory came later with the discovery of how genes encode different biological or behavioral traits, and how genes are passed down from parents to offspring. The incorporation of genetics and Darwin’s theory is known as “modern evolutionary synthesis.”
The physical and behavioral changes that make natural selection possible happen at the level of DNA and genes. Such changes are called mutations. Mutations are basically the raw material on which evolution acts. Mutations can be caused by random errors in DNA replication or repair, or by chemical or radiation damage. Most times, mutations are either harmful or neutral, but in rare instances, a mutation might prove beneficial to the organism. If so, it will become more prevalent in the next generation and spread throughout the population.
Evolution explains how existing species have changed over time, not how life came to be. The origin of existence of life is not explained by evolution; it is a miracle. As Darwin said in his book Origin of Species, “It is mere rubbish thinking at present of the origin of life. One might as well think of the origin of matter.” As another scholar puts it, “…evolution is not a theory of origins, rather it is a theory of change.” Evolution can help explain how much life has changed through existence by studying fossil and genetic evidence. Life was created by God, and evolution provides a model to explain how life forms have changed since their creation. So, a Christian’s belief of God creating life doesn’t need to contradict what evolution can explain, and vice-versa. The scientific model of evolution does not replace God as creator any more than the law of gravity replaces God as ruler of the planets.
Contrary to the belief of many uninformed people, evolution is not a fact – it is a theory. In the most basic sense, a scientific fact is an objective and verifiable observation. In everyday usage, “theory” often refers to a hunch or a speculation. When people say, “I have a theory about why that happened,” they are often concluding something based on inconclusive and anecdotal evidence. The scientific definition of theory is different from the platitudinal, everyday meaning of the word. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence.
Let’s describe the modern-day theory of evolution. Evolution simply describes the changes over time that occur in organisms through mutation and genetic variation. There are two categories of evolution – macroevolution and microevolution. Macroevolution is evolutionary change on a grand scale that occurs over long period of time. Microevolution, however, is evolution within existing species. In a larger sense, macroevolution occurs when a lot of microevolutionary changes occur. The foundation of how both these types of evolution occurs is in natural selection. Natural selection is the passing from generation to generation characteristics that have allowed parent generations to survive, while weaker traits are cast aside. These gene pools become influenced by mutation, migration, and a few other factors that lead to changes. This process as a whole comprises the modern-day theory of evolution.
Many scientific theories are so well-established that no new evidence is likely to alter them substantially. Most likely, no new evidence will disprove the Earth revolving around the sun, or the cell theory, or molecular theory, or the theory of gravity. Like these others, the theory of evolution is supported by a broad range of evidence and experiments, providing scientists with confidence that the basic components of the theory will not be overturned by new evidence. However, like all scientific theories, the theory of evolution is subject to continuing refinement as new areas of science emerge or as new technologies enable observations and experiments that were not previously possible. So, what is the evidence supporting the theory of evolution?
Evidence for Evolution
There is a wide variety of data to support evolution. The main categories of evidence for evolution are:
- Direct Observation
Fossils are the preserved remains of previously living organisms or their traces dating from the distant past. Generally, the fossil records do support change over time, and there is evidence for rapid, sudden change followed by periods of near stasis. Fossils cannot prove that one species evolved from one another, but the evidence gives strongly points to evolution. In addition, the fossil record isn’t total or unbroken. Most organisms never fossilize, and even the creatures that do fossilize are rarely found by people. Still, the fossils that have been discovered over time offer unique insights into advancement over long periods of time. There are apparent gaps in the fossil records that continue to be filled as more excavation occurs and we find new fossils. Bipedal dinosaurs and birds was one of the earliest gaps filled. Just a few years after Darwin published On the Origin of Species a 150-million-year-old fossil of Archaeopteryx was found in Germany. It had jaws with teeth and a long bony tail like dinosaurs, broad wings and feathers like birds, and skeletal features of both. This confirmed that birds had reptilian ancestors. Despite the gaps that continue to be filled, the fossil evidence suggests that there has been a tremendous variety of living things, and that some extinct species had traits that were transitional between major groups of organisms that are still alive today. These species’ existence confirms that species are not fixed but can evolve into other species over time.
When an organism dies, it is usually destroyed by other forms of life and by weathering processes, and thus disintegrates without a trace. Rarely, some body parts, such as shells, teeth, or bones, are preserved by being buried in sediment of some kind. Eventually they become petrified and preserved in the rock they were buried in, and this creates a fossil. Fossils can be dated in two main ways. First, fossils are usually found in rocks that are in layers called strata. These layers act as a timeline and allow us to discover the ages of fossils even across separate locations. Secondly, we can date fossils using radiometric dating, which is a process that measures the amounts of natural radioactive atoms that remain in certain minerals. Radiometric dating indicates that Earth was formed about 4.5 billion years ago. The earliest fossils resemble microorganisms such as bacteria and cyanobacteria; the oldest of these fossils appear in rocks that are 3.5 billion years old. The oldest known animal fossils are about 700 million years old, and they are small, wormlike creatures with soft bodies.
These dating techniques help paleontologists to assemble near complete family trees for many different species. The fossil record for whales has been preserved well, and we have an outstanding succession of fossils. The oldest fossil record for whales, near 50 million years ago, looked like land mammals with ears of modern whales, which suggest hearing under water was necessary. 5 million years later we see another fossil record where feet for swimming were adapted. Then, we see spines were also adapted for swimming too. By 40 million years ago, we had fully aquatic animals that could no longer live on land. For a long time, many opponents of evolution and Darwin focused on the absence of any transitional species between apes and humans, and this was known as the missing link. However, many intermediate species have since been discovered that date hominins (primates belonging to the human lineage after it separated from lineages going to the apes) to 6 or 7 million years ago in Africa. All in all, the fossil evidence is consistent with evolution.
Microbiology arguably presents the most convincing evidence for evolution. Through insights into genetic code, we can see patterns and similarities that tell us where species come from and how they relate to each other. Similarities between biological molecules can tell us if species share common ancestry. At the most basic level, all living organisms share:
- Same DNA
- Same or similar genetic codes
- Same transcription or translation processes
- Same molecular building blocks
These shared features suggest that all living things are descended from a common ancestor, and that this ancestor had DNA as its genetic material, used the genetic code, and expressed its genes by transcription and translation. There is no other rational way to account for this molecular uniformity than common ancestry of all organisms. Also, there are a number of other structures that are as equally likely to comprise organisms. In all bacteria in plants, animals, and humans, the DNA is composed of a different sequence of the same four component nucleotides (cytosine (C), thymine (T), adenine (A), guanine (G)). Although several hundred other amino acids do exist, all the various proteins are synthesized from different combinations and sequences of the same 20 amino acids. As Francisco Jose Ayala, Professor of Biological Sciences at UCI, puts it, “this is no more necessary than it is for a language to use a particular combination of letters to represent a particular object. If it is found that certain sequences of letters—planet, tree, woman—are used with identical meanings in a number of different books, one can be sure that the languages used in those books are of common origin.”
However, how can we tell how related two organisms are? To do this, biologists compare the sequences of related genes (homologous) between species. Basically, if two species have the same gene it can suggest that there is common descent.
The genetic evidence is supportive of Common Descent. Common Descent describes how, in evolutionary biology, a group of organisms share a most recent common ancestor. For example, humans and apes share a common ancestor. Chromosome 2, which is unique to our human lineage, emerged as a result of the head-to-head fusion of two ancestral chromosomes that remain separate in other primates. We know this because the dye pattern in chromosome 2 is similar to that of two chromosomes found in apes, there are remnants of an inactive centromere (central point at which a chromosome’s two identical strands are joined), and chromosome 2 has an additional telomere sequence in the middle of it whereas normal chromosomes only have one at each end of it. In addition, there are some pseudogenes (genes that have lost their function) left over in apes and humans that suggest we have common decent. For example, there is a vitamin C pseudogene in great apes and humans, but neither of us create vitamin C anymore. By comparing the genetic codes of humans and other animals, scientists discovered that this gene is dormant in humans and prevents the production of one of the enzymes needed for synthesizing vitamin C. They have also discovered that various primates cannot make their own vitamin C either. So both species still have chunks of the gene that does create vitamin C, but we cannot create it ourselves. There are other species in our family tree, such as guinea pigs and fruit bats, which have remnants of the gene but cannot create vitamin C, too. Other elements such as retroposons, SINEs (Short interspersed elements), Virus insertions, and more suggest we evolved from apes. Like it or not, the evidence suggests common descent.
In many cases, microevolution has been directly observed. Evolution has been seen and documented, and these specific observed instances support the idea of natural selection.
One example of microevolution being observed is the adaptation of mosquitos in the 1950s. In the 50’s malaria was widespread, and we tried to eradicate the carriers of the disease – mosquitos. The pesticide DDT was used to kill off mosquitos, and at first it was extremely effective. However, over time the mosquitos evolved and became resistant to DDT. This is an example of natural selection. At first, a small fraction of the mosquito population had the naturally occurring gene versions called alleles that made them resistant to DDT. Over time, the mosquitos that didn’t have this allele died off, and the mosquitos with the allele survived. These mosquitos survive eventually reproduce, and thus the future mosquitos contain this resistant allele. Nowadays, DDT cannot be used to control mosquito populations because of this adaptation (beside the fact that the US has banned its use). Similarly, bacteria and viruses can evolve resistance to drugs very rapidly. These examples have even larger population sizes and shorter lifecycles than insects. Examples of this would be antibiotic-resistant bacteria and drug-resistant HIV.
Another example that can be more personal to us is Lactose intolerance. Lactose Intolerance is the inability to metabolize lactose because of a lack of a certain enzyme. Normally for mammals, at a young age the species experiences reduced lactase production at the end of the weaning period. For humans in non-dairy consuming societies, lactase production usually declines about 90% during the first few years, although there is variety in the exact decline. However, many human populations have a mutation of chromosome 2 that eliminates the decline in lactase production. This makes it possible for these people to continue consumption of raw milk and other dairy products throughout their lives without ill-effect. This appears to be a recent evolutionarily adaptation to dairy consumption.
There are remarkable similarities between the bodies of today’s animals. If species share physical features because of a common ancestor, they are homologous. For example, Tetrapods (four-legged animals) have essentially the same body plan with some slight variations including elongated limbs, fusions, hair, etc. In addition, there are examples of vestigial traits in many different animals. Vestigial traits are features that are similar to what other animals have, but don’t have a function anymore. Examples of these traits include the human tailbone, the appendix, wisdom teeth, goosebumps, and more.
To make things more interesting, some physical similarities aren’t homologous, but instead analogous. This means two different organisms evolved similarly, but independently. They evolved similarly either because the organisms lived in similar environments or experienced similar threats. For example, humans, horses, birds, turtles, and bats are strikingly similar despite the different ways of life of these animals and the diversity of their environments.
In conjunction with plate tectonics, the geographic distribution of different species can best be explained by evolution. Species that had already evolved before the breakup of Pangea roughly 200 million years ago are widely distributed around the Earth. However, species that evolved thereafter tend to be concentrated to smaller areas of the Earth. For example, most of the mammal species in Australia carry their young in the pouch (marsupials), while most mammal species elsewhere in the world nourish their offspring through a placenta and don’t carry them in a pouch. These species were able to evolve without competition from, or exchange with, mammals elsewhere in the world because Australia was isolated by water for millions of years. In addition, many species on islands around the world are unique to their island. A couple more fun facts: For example, there are about 1,500 known species of Drosophila vinegar flies in the world and nearly one-third of them live in Hawaii and nowhere else. This is true even though the total land area of the Hawaii is less than 1/20th the area of California. Also, Hawaii has more than 1,000 species of snails and other land mollusks that exist nowhere else.
Some opponents say that this is due to the climate and conditions of certain areas; therefore, these animals simply migrated to these areas when they had the change. There is no evidence to support this, and the inverse actually is supported. The fossil and biological evidence suggests that they adapted to their environments, instead. Also, there is no substantiated reason to believe that animals from different areas in the world couldn’t suitably live in another part of the world.
To summarize, there is a plethora of evidence that supports the theory of evolution:
- The fossil records indicate change over time and provide information on when certain species lived and changed throughout history.
- Different species’ similarities can be observed through microbiology to show how they relate to each other.
- Microbiology and natural selection have been directly observed.
- The similar anatomies of different species demonstrate evidence for common ancestry and adaptation across species.
- Plate tectonics and biogeography give insights into why similar species have different features from one another due to location.
Many Christians are afraid to delve into the evidence and arguments for evolution because it poses a threat to their certainty of thinking about life. However, the theory of evolution should not be a threat to any Christian. Interestingly, in a study conducted some years ago, “researchers were able to get people who had thought about death to favor evolution if these people were exposed to information suggesting that an evolutionary approach to studying the natural world can provide a sense of personal meaning.” This research suggests that people that do not perceive evolution as a threat to the meaning of life, but instead see it as understanding the world around us, might be less resistant to evolution. Christians should follow suit and think of scientific evidence as a way to explain how God has set up our world to work, and not as an attack on faith.
Despite what preconceived notion of evolution a person might have, it is important to understand why almost all biologists support the theory of evolution. As Christians, we can see God crafting and governing the evolutionary process to bring it to the state we have now. As Psalms 19:1 reads, “The heavens declare the glory of God; the skies proclaim the work of his hands.”. In the same way, the scientific evidence supporting the theory of evolution testifies to the unfolding plan God has for the Earth. I invite Christians everywhere to consider the same strategy.
 Peter Enns, The Sin of Certainty
 John Oakes, Is there a God?
 Charles Darwin, Origin of Species
 John Oakes, Is there a God?
 Clay Routledge, More than Mortal