Communicating about evolution: the danger of shortcuts
When we talk about evolution and education, our first thoughts usually race to evangelical churches, school boards, and states like Kansas and Tennessee. While cultural battles over “belief” in evolution and its place in public schools are certainly important, a lesser-known issue is that acceptance and understanding are not the same thing, and many people who enthusiastically “believe” in evolution don’t actually understand the basics of how it works. This may not be a problem if our only concern is that the public votes to keep non-science out of the public science classroom. But an understanding of evolution impacts more than just one hot-button issue at a time. It is necessary to understand issues surrounding antibiotic and pesticide resistance, overfishing, potential effects of climate change, the relevance of animal models in medical research, and it is the conceptual framework through which all other biological fields can be best understood.
A wide variety of evolution misconceptions have been documented in the science education research literature at all levels from elementary students through college students, museum visitors, and the general public. The recently open-access 1 journal Evolution: Education and Outreach is an excellent resource for those looking for insights into communicating with non-experts about evolution. Evolutionary biologist T. Ryan Gregory contributed a review article (pdf) in 2009 that nicely summarizes the most prevalent misconceptions about natural selection. Others have documented learning difficulties associated with macroevolution, the relatedness of species, and interpreting tree diagrams. U.C. Berkeley’s Understanding Evolution website has a good starting list of common misconceptions related to all aspects of evolution.
Experts who do understand evolution by natural selection often use shortcuts and metaphors that are mostly harmless among those in the know. However, these same shortcuts can reinforce and even cause many misconceptions among students and members of the public without strong evolution backgrounds. Increased awareness of the science education research on evolution among teachers, informal educators, exhibit designers, documentary filmmakers, and journalists could go a long way toward preventing further entrenchment of these misconceptions.
I’ll attempt to outline some of the major misconceptions and learning difficulties related to the mechanism of natural selection and discuss some common ways of talking about evolutionary processes that can reinforce these misconceptions.
Fitness and “survival of the fittest”
To evolutionary biologists, fitness has a very specific meaning: the number of offspring left by individuals of a species having a certain genetic makeup compared to other individuals with different genetic makeups. A recent “daily explainer” on i09, “Why ‘survival of the fittest’ is wrong,” tackled some of the issues wrapped up in this word. The colloquial usage of “fit” as “big, strong and healthy” 2 makes the phrase misleading. And evolution isn’t really about survival at all. It’s entirely about reproduction. Often living longer can mean more chances to mate, but survival only contributes to evolutionary fitness inasmuch as it enables an increase in successful reproduction events. An organism that lives to the upper limit of its lifespan—but never successfully reproduces—contributes exactly nothing to the next generation.
Populations and generations
The mechanism of natural selection is based in population thinking. To an expert, a population is a group of organisms of the same species that interbreed and that live in the same geographic area. Importantly, it is not an equivalent term to species. However, most non-experts do not think in terms of populations. They think in terms of individuals, species, or ecosystems. This translates to mistaken assumptions about what natural selection acts on. Many people think that evolution happens to one individual during its lifetime, or that entire species (including all the individuals) gradually change into new species. Again, shortcuts such as “over time, the finches gained bigger beaks” can reinforce the idea that all members of the species grew bigger beaks. A better statement would have been “over many generations, finches with large beaks had more offspring than finches with smaller beaks, until nearly the whole population had large beaks.”
Adaptation is nearly ubiquitous as a “vocab” word for elementary-age students, before they understand anything about genetics. Students are expected to learn that an adaptation is something along the lines of “a trait of an organism that helps it survive in its environment.” This often devolves into “just-so story” explanations about how beavers have big teeth because they chew on trees all the time, or giraffes have long necks because they are always reaching high into the trees for food. It doesn’t help that journalists, teachers, and lecturers often use colorful metaphorical shortcuts to talk about adaptation. While their intention may be to create a lively article or talk, an expert’s metaphor is often a non-expert’s reality.
In his review article, Gregory highlights some of the problematic language used to describe adaptation:
Thus, adaptations in any taxon may be described as “innovations,” “inventions,” or “solutions” (sometimes “ingenious” ones, no less). Even the evolution of antibiotic resistance is characterized as a process whereby bacteria “learn” to “outsmart” antibiotics with frustrating regularity.
Human tendency to anthropomorphize everything from animals to inanimate objects and natural processes is well known, and tough to combat. (See Heider and Simmel’s 1944 experiment in which people assign intentions, emotions and even genders to moving geometric shapes.) In the context of evolution, anthropomorphic descriptions can lead to the misconception that individual organisms try to modify themselves to better fit the environment and then pass down those acquired traits to their offspring. A shaky understanding of genetics also underpins this idea, but sloppy communications can reinforce it.
A focus on adaptation from the early grades forward can also lead to the idea that each organism is perfectly adapted for its particular environment and niche, and that every feature of an organism has an adaptive purpose. Evolutionary biologists know this simply isn’t the case. Most traits that we call adaptations are simply “good enough.” They were a little more useful in a given circumstance than other traits—they weren’t designed from the ground up for the current situation. Learning about adaptation—and developing misconceptions about it—before grasping the genetic, generational mechanism of natural selection can put students at a disadvantage when they get to middle and high school biology classes.
Unity and diversity: a two-step process
As Gregory emphasized in his review article, evolution by natural selection is a two-step process: (1) new variation arises by random mutation and recombination, and (2) individuals with certain variants have more offspring than other individuals with different variants. Focusing on either mutation alone or selection alone can lead to the following misconceptions, respectively: that evolution is completely random, and that evolution results in perfectly optimized organisms. When communicating about evolution with non-experts, it is important never to refer to one without referencing the importance of the other.
Evolution is tricky. For those of us who understand it, its power to make everything else in biology crystal clear is deceptive. Most of us had naive ideas about evolution as children or students. As we progressed in our studies of science these were replaced with more accurate mental models. But we are the exceptions—most people don’t go on to major in science or think about it for a living. Yet as citizens they are often called upon to make decisions that require an understanding of evolution. And as humans, an understanding of evolution can contribute to a deeper appreciation of nature. Shortcuts are catchy, and droning on about populations and generations can get tedious and wordy. It takes talent to communicate about evolution both accurately and compellingly, but experts and science writers and educators have a responsibility to get it right.
Evolution: Education and Outreach used to be open-access, then it was toll-access, and now everything from January 2013 onward is open-access, but you’ll still have trouble getting the older issues. ↩
Amusingly, the British meaning of “attractive” for “fit” is actually a little more accurate in cases of sexual selection—though we’d still have to change it to “Reproduction of the Fittest.” ↩