Debunking Misconceptions Regarding the Theory of Evolution

Myth 1 - Evolution has never been observed.

Biologists define evolution as a change in the gene pool of a population over time. One example is insects developing a resistance to pesticides over the period of a few years. Most people will not disagree with this fact. Direct observations do show us that species change over time, and DNA itself is changeable. Genes change by mutation and can produce variations among species, like a white tiger or bacteria that are resistant¹ to antibiotics. At this level, most people do not disagree with the theory of evolution because it can be directly observed.

With advances in gene sequences it has become easier to gather data on how a population changes. Biologists can compare one group of frogs to another group of frogs and see that their DNA sequences have differences (and similarites). Even human DNA can be used to trace a family lineage because ethnic groups have different genetic markers. Ancestry.com will provide customers with a kit that will allow you to trace your family history by submitting a sample of your DNA.

Myth 2 - Evolution violates the 2nd law of thermodynamics.

The Second Law of Thermodynamics is commonly known as the Law of Increased Entropy.  As usuable energy in a system is converted to unusable heat energy, entropy increases. Entropy is a measure of disorganization, randomness and chaos. What does this have to do with evolution? Some people interpret the second law to mean that order cannot come from disorder, as it is the natural tendency² within a system to become more disorderly and more chaotic. This shows more a misconception about thermodynamics than about evolution. Life is not a closed system, organisms must constantly take in energy to maintain their homeostasis, a form of internal order. Plants get energy from the sun, animals get energy from eating plants, and so forth. Without this addition of energy, the organism will die. Evolution does not violate this law because there is a source of energy for all life on this planet, the sun.

It is also erroneous³ to think that order can never come from disorder, as many things naturally organize. Water molecules stick together with hydrogren bonds causing surface tension. Snowflakes and crystals form, and even with the right combination of raw materials, DNA will form within a solution, all of these things can be explained with chemistry and do not violate any physical laws.

Myth 3 - There are no transitional fossils. What about the Missing Link?

A transitional fossil is one that looks like an intermediate between two lineages, it may contain features of both groups or a feature shared amongst two groups of seemingly unrelated organisms.

This myth makes the assumption that evolution occurs in a linear⁴ fashion, with each animal moving step by step toward its current form. Unfortunately, many images of evolution tend to reinforce the idea of linear evolution. Darwin described his model as tree, with groups of animals occupying a branch, where some branches are closer than others. Think of the Felis order, where there are many groups of cats such as tigers, lions, and jaguars, they share a common ancester. A lion is not going to turn into a jaguar, but they do share a common ancestor.

There are plenty of transitional fossils in the record. The absence of any one intermediate does not negate the whole theory. Paleontologists must work with fossils they can find, and it is not surprising that we would have some gaps in our record. Think of a jigsaw puzzle that has a couple of missing pieces, you can still get an idea of what the picture is.

There are also some groups that are well represented in the fossil record and provide us a clear picture of how a group has changed over time. Some notable⁵ examples are the transitions from reptile to mammal, from land animal to early whale, and from dinosaur to bird. Ambulocetes is thought to be the ancestory of whales and because it has whale features but has four legs, like a land mammal.

4 - Evolution proceeds by random chance.

There is probably no other statement which is a better indication that the arguer doesn't understand evolution. Chance certainly plays a large part in evolution, but this argument completely ignores the role of natural selection. Chance provides genetic variation, which is the raw material that natural selection has to work with. From there, natural selection sorts out variations that give greater success.

A common analogy⁶ related to this misconception is the one of the monkey and the typewriter. Those who do not understand evolution argue that if you sit a monkey at a typewriter and let it randomly hit keys, it will never produce a novel. This analogy leaves out the essential component⁷ of evolution - SELECTION. The analogy would have to take into account that the monkey at the typewriter would stop occassionally and weed out bad designs, such as combinations of letters that do not make words. Once you have a collection of words, eliminate any words that do not make sense..and so forth. If you continued this way, you may eventually develop a sentence or a paragraph, or even a novel if you continued long enough.

Myth 5 - Evolution is just a theory.

First, we should clarify⁸ what "evolution" means. Like so many other words, it has more than one meaning. Its strict biological definition is change in genes over time which lead to a change in traits, something that is observable. People often associate the word "evolution" with common descent, which suggest that organisms share a common ancestor. To gather evidence for common descent, inferences⁹ must be made about current organisms and their relationship to other organisms, both past and present. Biologists may disagree on these lineages and relationships, but that does not mean they disagree with the theory of evolution.

Calling the theory of evolution "only a theory" is, strictly speaking, true, but the idea it tries to convey ¹⁰ is completely wrong. The argument rests on a confusion between what "theory" means in common language and what it means in science. In science a theory is a model that is used to explain sets of data, and can be used to make predictions. Theories in science can be modified or even proven false if new data is discovered. Theories are supported by a wide variety of evidence from scientists from different fields and can be used to provide scientists a way to understand natural processes.

Biologists use the theory of evolution to explain a wide variety of observations about life on earth. For example, evolution serves as a model to help us understand why an animal is on the verge of extinction. Climate change may place additional pressures on species who do not have traits to survive in warmer climates. In 1995, conservation officers attempted to save the near extinct Florida Panther by introducing cougars from Texas into their habitat. The effort worked, adding much needed diversity to the struggling population of panthers and saving them from extinction. This plan would not have worked if scientists did not understand the relationship between the two cat populations based on the model of evolution.