Evolutionary change that occurs by random sampling of different alleles from one generation to the next. This causes nonadaptive evolutionary change.
"Why Evolution Is True"There seem to be two important themes in the current pedagogical literature on science education. One of them is about student-centered learning—a concept I think we should all adopt. The other is about student misconceptions and how to deal with them. Much of the literature suggests that misconceptions need to be confronted and corrected. They can't be corrected by simply presenting the "correct" information. You need to actually address the misconception and show why it is wrong. This is a form of "teach the controversy" and that's not going to sit well with many American supporters of evolution.
Here's an interesting paper on "Biology Undergraduates’ Misconceptions about Genetic Drift" (Andrews et al., 2012). The abstract covers all the important points.
This study explores biology undergraduates’ misconceptions about genetic drift. We use qualitative and quantitative methods to describe students’ definitions, identify common misconceptions, and examine differences before and after instruction on genetic drift. We identify and describe five overarching categories that include 16 distinct misconceptions about genetic drift. The accuracy of students’ conceptions ranges considerably, from responses indicating only superficial, if any, knowledge of any aspect of evolution to responses indicating knowledge of genetic drift but confusion about the nuances of genetic drift. After instruction, a significantly greater number of responses indicate some knowledge of genetic drift (p = 0.005), but 74.6% of responses still contain at least one misconception. We conclude by presenting a framework that organizes how students’ conceptions of genetic drift change with instruction. We also articulate three hypotheses regarding undergraduates’ conceptions of evolution in general and genetic drift in particular. We propose that: 1) students begin with undeveloped conceptions of evolution that do not recognize different mechanisms of change; 2) students develop more complex, but still inaccurate, conceptual frameworks that reflect experience with vocabulary but still lack deep understanding; and 3) some new misconceptions about genetic drift emerge as students comprehend more about evolution.We all know that evolution is a key concept in biology and every student should take a course on evolution. That course should cover population genetics and the main mechanisms of evolution—including random genetic drift. Among experts on evolution, there's no disagreement on those points.
The problem, from an educational perspective, is that students aren't prepared to learn about random processes because they enter university with a deep-seated misconception that evolution is all about selection and purpose.
Indeed, the most tenacious misconception in biology may be the idea that all processes serve a purpose (Gregory, 2009; Kelemen and Rosset, 2009; Mead and Scott, 2010). This idea is so deep-seated that students fail to even consider random processes as responsible for biological patterns (Garvin-Doxas and Klymkowsky, 2008). The fact that random processes confound students is particularly worrisome, because random processes occur at every level of the biological world, from gene expression (Cai et al., 2006) to clade diversification and extinction (Raup et al., 1973).The authors asked 356 biology students to define genetic drift and only 12% of them could do so satisfactorily. This was part of an American study on developing effective criteria for teaching evolution to undergraduates.
Despite these obstacles, understanding random processes such as genetic drift is essential for a deep understanding of the theory of evolution. In contrast to natural selection, genetic drift is nonselective and therefore results in nonadaptive changes in populations (Beatty, 1992). Genetic drift occurs in any finite population and therefore occurs in every population all the time (Futuyma, 2005; Barton et al., 2007).
The most common misconceptions involved confusing genetic drift with genetics, thinking that genetic drift was a form of natural selection, mixing up drift and mutation, and believing that genetic drift was about populations moving to new locations.
This was AFTER students had taken a course on evolution! When tested BEFORE taking an evolution course, only 1% of students had some knowledge of genetic drift.
The authors don't propose any easy solutions to the problem but they do mention one goal. They say that part of the problem arises from teleological thinking, or the idea that evolution is driven by a need for change.
If this single (albeit tenacious) misconception is affecting students’ ability to learn concepts throughout biology, instruction specifically designed to help students think critically about this sort of reasoning could have an impressive impact on student learning. Future research can explicitly focus on determining the pervasiveness of the idea that need is a rationale for change in biological systems and on effective strategies for changing this misconception to a scientifically accurate explanation.You can't argue with that! Don't we all want an education system that teaches critical thinking?
My general impression from this paper is that the authors have identified a real problem but they seem to think it can be solved by developing better curricula and guidelines for teaching evolution. What they fail to emphasize is that most teachers of evolution probably wouldn't have done any better on the questions! If we want to improve evolution instruction then the first thing we need to do is teach the teachers—this includes, unfortunately, many professors whose main research focus is evolutionary biology.
[Image Credits: (top) Ask a Geneticist: The Tech Museum of Innovation, (bottom) John Hawks: Some genetic drift graphs with Mathematica]
Andrews, T., et al. (2012) "Biology Undergraduates’ Misconceptions about Genetic Drift." CBE-Life Sciences Education 11:248-259. [doi: 10.1187/cbe.11-12-0107]