Friday, April 17, 2015

Biology, Evolution, and Excellent College Teaching

Biology professor James J. Krupa, University of Kentucky
 
Orion
"TO TEACH EVOLUTION at the University of Kentucky is to teach at an institution steeped in the history of defending evolution education. The first effort to pass an anti-evolution law (led by William Jennings Bryan) happened in Kentucky in 1921. It proposed making the teaching of evolution illegal. The university’s president at that time, Frank McVey, saw this bill as a threat to academic freedom. Three faculty members—William Funkhouser, a zoologist; Arthur Miller, a geologist who taught evolution; and Glanville Terrell, a philosopher—joined McVey in the battle to prevent the bill from becoming law. They put their jobs on the line. Through their efforts, the anti-evolution bill was defeated by a forty-two to forty-one vote in the state legislature. Consequently, the movement turned its attention toward Tennessee.
John Thomas Scopes was a student at the University of Kentucky then and watched the efforts of his three favorite teachers and President McVey. The reason the “Scopes Monkey Trial” occurred several years later in Dayton, Tennessee—where Scopes was a substitute teacher and volunteered to be prosecuted—was in good part due to the influence of his mentors, particularly Funkhouser. As Scopes writes in his memoir, Center of the Storm: “Teachers rather than subject matter rekindled my interest in science. Dr. Funkhouser . . . was a man without airs [who] taught zoology so flawlessly that there was no need to cram for the final examination; at the end of the term there was a thorough, fundamental grasp of the subject in bold relief in the student’s mind, where Funkhouser had left it.”
I was originally reluctant to take my job at the university when offered it twenty years ago. It required teaching three sections of non-majors biology classes, with three hundred students per section, and as many as eighteen hundred students each year. I wasn’t particularly keen on lecturing to an auditorium of students whose interest in biology was questionable given that the class was a freshman requirement.
Then I heard an interview with the renowned evolutionary biologist E. O. Wilson in which he addressed why, as a senior professor—and one of the most famous biologists in the world—he continued to teach non-majors biology at Harvard. Wilson explained that non-majors biology is the most important science class that one could teach. He felt many of the future leaders of this nation would take the class, and that this was the last chance to convey to them an appreciation for biology and science. Moved by Wilson’s words, and with the knowledge that William Funkhouser once held the job I was now contemplating, I accepted the position. The need to do well was unnerving, however, considering that if I failed as a teacher, a future Scopes might leave my class uninspired.
I realized early on that many instructors teach introductory biology classes incorrectly. Too often evolution is the last section to be taught, an autonomous unit at the end of the semester. I quickly came to the conclusion that, since evolution is the foundation upon which all biology rests, it should be taught at the beginning of a course, and as a recurring theme throughout the semester. As the renowned geneticist Theodosius Dobzhansky said: “Nothing in biology makes sense except in the light of evolution.” In other words, how else can we explain why the DNA of chimps and humans is nearly 99 percent identical, and that the blood and muscle proteins of chimps and humans are nearly identical as well? Why are these same proteins slightly less similar to gorillas and orangu­tans, while much less similar to goldfish? Only evolution can shed light on these questions: we humans are great apes; we and the other great apes (gibbons, chimps, gorillas, bonobos, and orangutans) all evolved from a common ancestor.
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To truly understand evolution, you must first understand science. Unfortunately, one of the most misused words today is also one of the most important to science: theory. Many incorrectly see theory as the opposite of fact. The National Academy of Sciences provides concise definitions of these critical words: A fact is a scientific explanation that has been tested and confirmed so many times that there is no longer a compelling reason to keep testing it; a theory is a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence generating testable and falsifiable predictions.
In science, something can be both theory and fact. We know the existence of pathogens is a fact; germ theory provides testable explanations concerning the nature of disease. We know the existence of cells is a fact, and that cell theory provides testable explanations of how cells function. Similarly, we know evolution is a fact, and that evolutionary theories explain biological patterns and mechanisms. The late Stephen Jay Gould said it best: “Evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world’s data. Theories are structures of ideas that explain and interpret facts.”
Theory is the most powerful and important tool science has, but nonscientists have perverted and diluted the word to mean a hunch, notion, or idea. Thus, all too many people interpret the phrase “evolutionary theory” to mean “evolutionary hunch.”
Not surprisingly, I spend the first week of class differentiating theory from fact, as well as defining other critical terms. But I’m appalled by some of my colleagues who, despite being scientists, do not understand the meaning of theory. As I was preparing to teach a sophomore evolution class a few years ago, a biology colleague asked how I was going to approach teaching evolution. Specifically, he asked if I would be teaching evolution as a theory or a fact. “I will teach evolution as both theory and fact,” I said, trying hard to conceal my frustration. No matter. My colleague simply walked away, likely questioning my competence to teach the class.
ONCE I LAY DOWN the basics of science, I introduce the Darwinian theories of evolution. Charles Darwin was by no means the first or only to put forth evolution; others came before him including his grandfather, Erasmus Darwin, who wrote about descent with modification. Later, while Charles was amassing evidence in England for natural selection, one of the most eloquent scientific theories ever, Alfred Russel Wallace was also developing the same theory during his travels in Indonesia. But it was Charles Darwin alone who advanced the theory of descent with modification, with his bold idea that all species belong to the same tree of life and thus share a common ancestor. He also gave us sexual selection theory, which explains how evolution is shaped by competition for mates as well as choice of mates. Too often only natural selection and descent with modification are emphasized in introductory biology classes. I also cover Darwin’s theories of gradualism (including the nuance of punctuated equilibrium); descent from a common ancestor; multiplication of species; and sexual selection. I emphasize that five of the theories explain the patterns of evolution, while natural and sexual selection are the mechanisms that drive evolution."

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