The current cultural and political climate make evolution a difficult subject to approach in a manner that encourages critical thinking, even though the National Science Education Standards emphasize inquiry-based learning. Further, while many studies have extolled the substantial benefits of inquiry approaches, few address one of its prominent difficulties: the amount of class time it takes (reviewed in Oliver-Hoyo et al., 2004). In some cases a tradeoff of content quantity for content quality may be justified, but in a survey-level course, where content is already broad and sparse, such a deal may be no bargain. To address this problem, we integrated some existing approaches with several novel ones to compile a unique and fast inquiry-based method for teaching the controversial topic of evolutionary theory in a non-science majors' college laboratory. We feel high school students would also benefit.
Evolution is an ideal topic for the inquiry approach, not only because it is grounded in fundamental and elementary logic, but also because one can apply a "selection" process to the development of that logic. As students critically examine the evidence, they must criticize and reject explanations that don't fit the facts, much as nature eliminates traits that are not adequately adapted to the "facts" of the environment around them. As they recognize that this application of the scientific method is similar to the process of evolution itself, their ownership over the theory increases along with their critical thinking skills.
The current controversy surrounding the teaching of evolution makes it an even better topic for inquiry, because few students enter the classroom without a set of pre-existing assumptions that must be identified and confronted. Many in our state, Ohio, have famously advocated for the teaching of so-called "intelligent design," an idea that is untestable but still masquerades successfully to the public as science. Further, many schools today face political pressures to adopt a "critical approach" to teaching evolution. Rather than dismissing this demand as ignorant (which feeds the popular perception that scientists are dogmatically biased), we decided to tackle the proposition head-on.
It is the natural instinct of many teachers--including ourselves--to avoid direct conflict with students' often sensitive ideas, fearing both religious backlash and poor evaluations (Chuang, 2003; Dean, 2005), or because they may feel it is unethical (McKeachie et al., 2002). However, when we chose to challenge both preconceptions and newly-formed conceptions explicitly but impersonally, we found that students responded well. Moreover, the critical approach was persuasive: before the unit, only 59% of students accepted evolution (though only 6% could correctly explain it), and afterward, 92% of the students both accepted and could explain it.
Others have advocated inquiry, confronting preconceptions or both (Scharmann, 1993; Sinclair & Pendarvis, 1998; Farber, 2003; Scharmann, 2005; Passmore et al., 2005), but none (to our knowledge) show both the preand post-test results of their approach and describe the method they used. We do both here.
Our technique consisted of three steps similar to those laid out by Scharmann (2005) and shown in Figure 1:
1. identification of existing preconceptions
2. brief lecture and laboratory exercises designed to challenge misconceptions
3. interpretation of data with peer instruction to synthesize the principles that ground evolutionary theory.
We chose to use data from fossils, comparative anatomy and comparative biochemistry to develop students' understanding, largely because of the need to encompass a breadth of other material (natural history, anatomy, DNA) in the same short time period. However, we feel that exploring other lines of evidence would be equally appropriate, depending on the needs and resources of the classroom. …