Development and Validation of the Conceptual Assessment of Natural Selection (CANS).

We developed and validated the Conceptual Assessment of Natural Selection (CANS), a multiple-choice test designed to assess how well college students understand the central principles of natural selection. The expert panel that reviewed the CANS concluded its questions were relevant to natural selection and generally did a good job sampling the specific concepts they were intended to assess. Student interviews confirmed questions on the CANS provided accurate reflections of how students think about natural selection. And, finally, statistical analysis of student responses using item response theory showed that the CANS did a very good job of estimating how well students understood natural selection. The empirical reliability of the CANS was substantially higher than the Force Concept Inventory, a highly regarded test in physics that has a similar purpose.

Misconceptions Yesterday, Today, and Tomorrow.

A recent essay in CBE-Life Sciences Education criticized biology education researchers' use of the term misconceptions and recommended that, in order to be up-to-date with education research, biology education researchers should use alternative terms for students' incorrect ideas in science. We counter that criticism by reviewing the continued use and the meaning of misconceptions in education research today, and describe two key debates that account for the controversy surrounding the term. We then identify and describe two areas of research that have real implications for tomorrow's biology education research and biology instruction: 1) hypotheses about the structure of student knowledge (coherent vs. fragmented) that gives rise to misconceptions; and 2) the "warming trend" that considers the effects of students' motivation, beliefs about the nature of knowledge and learning (their epistemic beliefs), and learning strategies (their cognitive and metacognitive skills) on their ability to change their misconceptions in science. We conclude with a description of proposed future work in biology education research related to misconceptions.

Six classroom exercises to teach natural selection to undergraduate biology students.

Students in introductory biology courses frequently have misconceptions regarding natural selection. In this paper, we describe six activities that biology instructors can use to teach undergraduate students in introductory biology courses how natural selection causes evolution. These activities begin with a lesson introducing students to natural selection and also include discussions on sexual selection, molecular evolution, evolution of complex traits, and the evolution of behavior. The set of six topics gives students the opportunity to see how natural selection operates in a variety of contexts. Pre- and postinstruction testing showed students' understanding of natural selection increased substantially after completing this series of learning activities. Testing throughout this unit showed steadily increasing student understanding, and surveys indicated students enjoyed the activities.

Are Africans, Europeans, and Asians different "races"? A guided-inquiry lab for introducing undergraduate students to genetic diversity and preparing them to study natural selection.

Many students do not recognize that individual organisms within populations vary, and this may make it difficult for them to recognize the essential role variation plays in natural selection. Also, many students have weak scientific reasoning skills, and this makes it difficult for them to recognize misconceptions they might have. This paper describes a 2-h laboratory for college students that introduces them to genetic diversity and gives them practice using hypothetico-deductive reasoning. In brief, the lab presents students with DNA sequences from Africans, Europeans, and Asians, and asks students to determine whether people from each continent qualify as distinct "races." Comparison of the DNA sequences shows that people on each continent are not more similar to one another than to people on other continents, and therefore do not qualify as distinct races. Ninety-four percent of our students reported that the laboratory was interesting, and 79% reported that it was a valuable learning experience. We developed and used a survey to measure the extent to which students recognized variation and its significance within populations and showed that the lab increased student awareness of variation. We also showed that the lab improved the ability of students to construct hypothetico-deductive arguments.

Nothing in evolution makes sense except in the light of DNA.

Natural selection is one of the most important concepts for biology students to understand, but students frequently have misconceptions regarding how natural selection operates. Many of these misconceptions, such as a belief in "Lamarckian" evolution, are based on a misunderstanding of inheritance. In this essay, we argue that evolution instructors should clarify the genetic basis of natural selection by discussing examples of DNA sequences that affect fitness. Such examples are useful for showing how natural selection works, for establishing connections between genetics and evolution, and for creating cognitive conflict within students having misconceptions. We describe several examples of genes that instructors might use during lectures, and present preliminary evidence from our classroom that an evolution curriculum rich in DNA sequences is effective at reducing student misconceptions of natural selection.