Evolution Takes a Road Trip

I’ve seen several articles regarding the evolution of cliff swallows and wanted to follow-up on an article that appeared in The Scientist.

Students are often taught that evolution takes millions of years, but it’s also common to hear claims like “evolution in action” and “evolution happening before our eyes”.

University of Tulsa biologist Charles Brown had noticed over the years that he found fewer dead swallows along the roads, even though the overall population was rising. To see if he could find out why this was happening, he looked at the specimens he had collected over the last 30 years and discovered that there was a difference in wing length. The swallows being hit by cars had significantly longer wings and wingspans than the general population.

The article claims that the results suggest that cliff swallows are adapting to avoid deadly collisions with cars. I agree with part of this conclusion- namely that the results suggest that cliff swallows are adapting, but the article makes several leaps of faith that are not supported by the evidence. To suggest that the reason why the swallows are adapting is to “avoid deadly collisions with cars” is simply not true. A bird doesn’t consciously decide to lay eggs with baby birds that have shorter wings so that they don’t get hit by cars. There was no planned outcome by the birds or the environment. Adaptation, speciation, and natural selection all occur without any thought by the organism. It’s a random, natural process in which birds with longer wings are at a disadvantage and are being hit and killed by cars, preventing them from reproducing. Birds with shorter wings, on the other hand, have an advantage and are able to avoid being hit, which means they’ll survive and reproduce. Since swallows with short wingspans have been selected, there are fewer swallows with long wingspans, thus there are fewer swallows being hit and killed by cars. The birds are forced to adapt by the process of elimination, not because of any conscious decision they’ve made.

Another unsupported conclusion is that this is “the latest growing body of research that suggests evolution can happen on much shorter timescales than previously imagined”, and that selection pressures “can drive the evolution of organisms before our very eyes”.

The definition of “evolution” is very slippery and elastic, and it’s the definition and use of this term that confuses people and causes controversy. What is being described in this article is adaptation and natural selection (maybe even speciation), but not evolution. It’s true that many scientists will call this evolution, but it’s not. That’s why it’s important to understand these definitions and recognize the distinction of these terms because of how they affect our culture and politics.

The cliff swallows always had variation in wing size built into their genes and the population at large, so it’s silly to suggest that these swallows “evolved” shorter wings and wingspans over a period of time, and that this change suggests evolution can happen over short timescales and before our very eyes. It’s also silly to think these changes would take millions of years. In fact it should be easy to predict that such changes could happen over a short period of time because we have many other examples to choose from, such as Darwin’s finches, in which their beak size varied depending on the type of food available from season to season. These are examples of natural selection- the genetic information already present in the swallow’s genome is being selected naturally by environmental factors.

Evolution can be defined a number of ways. It’s the theory that all living organisms are descended from a common ancestor, and that that first ancestor came from inorganic material. Evolution is when an organism develops a new, novel trait in its offspring over a period of time. For example, pigs don’t have wings or feathers, nor do they have the genetic code to express them. But if, after 300,000 years, their descendants developed the genetic code to grow feathers and wings, then this would be evolution, and we probably wouldn’t recognize it as a pig any longer- it would be a new organism in need of a new name. Evolutionists believe that dinosaurs evolved into birds, which means that dinosaurs without feathers, wings, avian lungs and bones, would have had to develop these traits through their offspring over millions of years as a result of random mutations and trial and error. Dinosaurs would have had to go through massive transformations in their genetic code in order to become what we call birds today.

We’re not seeing any of this type of change in the cliff swallows. We’re not seeing any new traits, and we’re not seeing any new organism or species. So there’s no evolution occurring in the population of cliff swallows. The traits were already present in the population, and the shorter wings were selected by eliminating the swallows with longer wings. We didn’t have to wait for the swallows to evolve shorter wings because those genes already existed and only needed to be expressed as a result of selection pressure and observed by someone who could quantify those changes.

Evolutionary biologist Steven Brady at Yale University said, “We now know that evolution doesn’t just affect changes over very long periods of time, but affects changes over timescales we see in our lifetimes.”

Brady is pulling together two different definitions of evolution and equating them. He acknowledges evolutionary changes that require very long periods of time and massive amounts of new genetic information expressed in an organism. But then he talks about a totally different type of change that has been observed and calls that evolution as well. The problem is that evolutionists have a habit of calling any change “evolution”, even if there was no real change or new genetic information. It’s not as if swallows with shorter wings never existed or couldn’t exist. The change he’s referring to is a change in the overall population- a shift in demographics. In other words Brady is offering us (perhaps unknowingly) a bait-and-switch; he first refers to a process that has never been observed (one organism giving rise to a completely new organism, or an organism developing a previously non-existent trait), and then provides an example that can be seen and observed (wing size), and then calls both of these evolution, reinforcing the belief that evolution is real. So if one doesn’t’ believe in evolution, evolutionists can refer to this article about cliff swallows and claim that this is proof of evolution in action, even though it has nothing to do with evolution. They’ve merely failed to make a distinction in their definitions and terms by confusing evolution with natural selection.

I’ve listed a dictionary definition of evolution below. If you look closely, you’ll see that none of these definitions apply to the article about cliff swallows. Since some cliff swallows already had short wings to begin with, there was no gradual process in which the wing size changed into a more complex or better form. There was no process of development. In this case there’s no new species of swallow, and no new group of organisms. It’s simply a shift in population to express an already existent trait, and it’s being used to indoctrinate students and the public into accepting a type of evolution that has never been observed. The cliff swallows are still cliff swallows with wingspans of various lengths, just as they were 30 years ago.

Definition of Evolution:

1. A gradual process in which something changes into a different and usually more complex or better form.


a. The process of developing.

b. Gradual development.

3. Biology

a. Change in the genetic composition of a population during successive generations, as a result of natural selection acting on the genetic variation among individuals, and resulting in the development of new species.

b. The historical development of a related group of organisms; phylogeny.

4. A movement that is part of a set of ordered movements.

5. Mathematics The extraction of a root of a quantity.

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