Short lesson plan associated with increased acceptance of evolutionary theory and potential change in three alternate conceptions of macroevolution in undergraduate students

Abstract

Undergraduates commonly harbor alternate conceptions about evolutionary biology; these alternate conceptions often persist, even after intensive instruction, and may influence acceptance of evolution. We interviewed undergraduates to explore their alternate conceptions about macroevolutionary patterns and designed a 2-h lesson plan to present evidence that life has evolved. We identified three alternate conceptions during our interviews: that newly derived traits would be more widespread in extant species than would be ancestral traits, that evolution proceeds solely by anagenesis, and that lineages must become more complex over time. We also attempted to measure changes in the alternate conceptions and levels of acceptance of evolutionary theory in biology majors and nonmajors after exposure to the lesson plan. The instrument used to assess understanding had flaws, but our results are suggestive of mixed effects: we found a reduction in the first alternate conception, no change in the second, and reinforcement of the third. We found a small, but significant, increase in undergraduate acceptance of evolutionary theory in two trials of the lesson plan (Cohen's d effect sizes of 0.51 and 0.19). These mixed results offer guidance on how to improve the lesson and show the potential of instructional approaches for influencing acceptance of evolution.

Figure 1.

A screenshot from the third exercise of the computer-based implementation of the lesson plan. This exercise is intended to demonstrate that organisms that evolve via common descent form nested sets similar to those of living organisms. In this exercise, students cause evolution and migration of populations of lizards. The simulation allows generations to pass and traits to fix in populations. Students then arrange sample lizards from each population based on the shared morphological traits among lizards. They then circle the groups sharing similar morphological traits and label each trait. Students compare the pattern they observe in this exercise (nested sets of traits) with the patterns they observed in a previous exercise that simulated special creation.

Figure 2.

Student performance on pre- and postinstructional content tests. Students exhibited significantly more instances of the LC alternate conception. There was no difference in student usage of the EC alternate conception. Students exhibited significantly fewer instances of the NTW alternate conception. Error bars represent ±1 SE. * = p < 0.05, *** = p < 0.0005.

Figure 3.

Pre- and postinstruction MATE scores for all students who took both tests in (A) phase II (n = 41) and (B) phase III (n = 622). Student MATE scores increased significantly in both phases II and III after completion of the lesson plan. MATE categories from Rutledge and Sadler (2007).