People commonly misuse terminology when discussing or writing about evolution. There are two reasons for this: (1) Sometimes their misstatements are done unknowingly due to a lack of understanding or exposure to others' misuse of the terms; and (2) Some religious groups misuse the terms on purpose in an effort to undermine people's understanding of evolution. This article was written to hopefully educate the former and possibly reach those who hear the latter. I know I won't affect the misuse of terminology by religiously-motivated people. They are set on intentionally clouding the understanding of evolution because it conflicts with the mythological beliefs.
"THEORY"
It is often called the "Theory of Evolution", but what is a "theory"? The general public has a very different definition than the scientific community. To the general public (and often news writers), a theory carries much less weight. It's synonymous with a guess, assumption, belief, speculation, conjecture or hypothesis. The Cobb Country School District attempted to attach labels to textbooks stating "Evolution is a theory, not a fact, regarding the origin of living things." This statement is especially misleading because a theory is based on relating similar facts. These definitions differ dramatically from the definition used by a scientists which refers to a logical, tested, well-supported explanation for a great variety of facts.
Let's look at some examples. "My theory is that the hurricane will shift course and hit Miami." If you hear someone say this, it is not a scientific theory. Your neighbor may say this and it would be pure speculation or a "feeling". If a Ph.D in atmospheric studies makes this statement it may be based on past hurricane paths and current weather patterns. But, it still involves an element of predicting the future based on probabilities and therefore doesn't fall into the definition of a theory. At the other end of the spectrum, we still refer to the "Theory of Gravity". But, is anyone still debating this?! Gravity can be readily observed by anyone on Earth. It's been proven many times by the compilation of facts. We've even experienced differences in gravity between sea level, high mountains and low-earth orbits. Gravity is defined by mathematical equation, yet it still a theory. Next, we have the theory that the "Planets Revolve Around the Sun". Again, this is still a theory. But, nobody is debating it. It is accepted as fact today even though it's original proponents were punished by the Church. In fact, religious believers are often the last to accept a scientific theory as truth, especially when the theory conflicts with their religious beliefs. This is currently true with the "Theory of Evolution". Scientists know that "evolution is indeed a theory, yet it's a theory with a lot of evidence on its side, and with more explanatory power than any competing theory in biology". [1]
Evolution, or natural selection, does not simply apply to humans. It is evident throughout biological history. It can even be individually witnessed in present day with plants, viruses, etc. So, the problems with the theory of evolution are more easily described as a misuse of terminology by religious or uneducated groups instead of a problem with the observed facts.
"Evolution is a fact in the respect that we have hard data – an ever-expanding fossil record – proving that species have changed over time; dinosaurs, early mammals, Trilobites, and other forms no longer exist as living species. The exact mechanism by which these changes occurred (e.g. natural selection and environmental pressures) is the realm of evolutionary theory and is based on interpretation of that fossil record and other available data." [2]
"SURVIVAL OF THE FITTEST"
This phrase is very misleading. It is often used to mean that only the physically strongest survive, but this is not true. The "fittest" species are those who can adapt to a changing environment using strength, knowledge, tools, relocation, dietary changes, habits, etc. The dinosaurs did not survive even though they were physically strongest. Mammals survived because they were smaller and could burrow to escape the effects of the asteroid impact and resulting climate changes. Species don't enter a ring to fight where only the strongest survive. This is a very simplistic view. In fact, the "combat arena" often changes many times in a very short period. For example, animals must migrate or die during a drought. Imagine an farmer during a long period of drought. He must either find new fertile ground with adequate irrigation, or he must change his diet. Otherwise, he will die. Ironically humans are very good at survival not because of strength, but because of knowledge and tools. Without these, we are one of the most fragile species on the planet.
Another misconception is that attributes of adaptation are sequential in progression, that somehow we evolve in a ladder of increasing complexity. Again, this is not true. Mutations occur randomly throughout nature's past. It is only by random mutation that new traits allow species to survive. Some misconstrue this adaptation concept to mean that living species somehow pass on genetic material to alter their offspring. This is not true. It is random changes that produce differences and these randomly acquired new traits determine whether the descendants will survive or become extinct.
Herbert Spencer's term "Survival of the Fittest" (referring to competition among individuals) should be abandoned. It is misunderstood and misused by many when discussing evolution. We should instead refer to the concept as biological selective pressures or natural selection.
"THE MISSING LINK"
How many times have you read that "The missing link has been discovered"? This is a centuries old analogy based on a "chain" metaphor. This metaphor should be abandoned because it implies a sequential stepwise progression of evolution. It also implies that there are "certain links" in the chain that are missing and must be found. But, how many missing links are there? Are there any truly missing? Or, is it an intertwined group of chains?
Another problem with the the chain metaphor is that it implies that species are distinct, unique, fixed entities with identical traits. But, species lines are often blurred with adaptation and change occurring within a given species. When considering this, don't limit yourself to human evolution. For example, there are mutations and adaptation that occur within species of plants and viruses. Instead of the link and chain analogy, we should instead use the metaphor of a tree of evolution. It is fact that many competing varieties of species did not survive. Their branch of the tree went extinct. It is not imperative that their branch survived to continue the evolutionary process. Other branches survived through natural selection or we would not be where we are today.
CONCLUSIONS
We need to be careful in our use and interpretation of terminology related to evolution. Terms such as "Theory", "Survival of the Fittest" and "The Missing Link" are especially problematic. There will continue to be those who try to confuse the meanings of these terms, particularly religious groups, due to a conflict with their beliefs. However, this does not make a theory untrue.
With regards to "Survival of the Fittest", the preferred term should be "Natural Selection" based on selective pressures in the environment. The metaphor "Missing Link" should also be abandoned altogether.
It can be debated how many branches of the evolutionary tree are required to prove evolution. But, the theory of evolution is by far the best explanation which exists in biology today. Evolutionists may continue to be punished by religious groups as in the past with an earth-centric universe or planets revolving around the sun. But, again, this doesn't make the theory untrue. Science will again prevail. It's just a matter of time that is uncertain.