Kathryn E. Perez

Biology Undergraduates’ Misconceptions about Genetic Drift

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.

Does Displaying the Class Results Affect Student Discussion during Peer Instruction

The use of personal response systems, or clickers, is increasingly common in college classrooms. Although clickers can increase student engagement and discussion, their benefits also can be overstated. A common practice is to ask the class a question, display the responses, allow the students to discuss the question, and then collect the responses a second time. In an introductory biology course, we asked whether showing students the class responses to a question biased their second response. Some sections of the course displayed a bar graph of the student responses and others served as a control group in which discussion occurred without seeing the most common answer chosen by the class. If students saw the bar graph, they were 30% more likely to switch from a less common to the most common response. This trend was more pronounced in true/false questions (38%) than multiple-choice questions (28%). These results suggest that observing the most common response can bias a students second vote on a question and may be misinterpreted as an increase in performance due to student discussion alone.

Short Lesson Plan Associated with Increased Acceptance of Evolutionary Theory and Potential Change in Three Alternate Conceptions of Macroevolution in Undergraduate Students

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 (Cohens 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.

The Genetic Drift Inventory: A Tool for Measuring What Advanced Undergraduates Have Mastered about Genetic Drift

The Genetic Drift Inventory is a multiple true–false format concept inventory consisting of 22 statements. It tests how well upper-division undergraduate biology students grasp four key concepts, while simultaneously testing for the presence of six misconceptions.

Molecular phylogeny and morphology reveal three new species of Cantharellus within 20 m of one another in western Wisconsin, USA

Three new species, Cantharellus phasmatis, Cantharellus flavus and Cantharellus spectaculus, all previously considered Cantharellus cibarius, are described in this study. The circumscription of these three species from C. cibarius and other Cantharellus species is supported by morphological differences and nuclear DNA sequence data (nLSU, ITS, TEF1). All were found under Quercus spp. in a small plot in Hixon Forest Park in La Crosse, Wisconsin, emphasizing the need for further taxonomic study of even common and conspicuous genera in North America. In addition, a review of the current state of C. cibarius sensu lato systematics is presented, including a review of the recent elevation of C. cibarius var. roseocanus to the species rank. Taxonomic descriptions and photographs are provided for the newly described species.

The EvoDevoCI: a concept inventory for gauging students' understanding of evolutionary developmental biology.

The authors present the development and validation of the EvoDevoCI, a concept inventory for evolutionary developmental biology. This CI measures student understanding of six core evolutionary developmental biology (evo-devo) concepts using four scenarios and 11 multiple-choice items, all inspired by authentic scientific examples. Distracters were designed to represent the common conceptual difficulties students have with each evo-devo concept.

Getting to Evo-Devo: Concepts and Challenges for Students Learning Evolutionary Developmental Biology

In this study we used surveys of evo-devo experts to identify the core concepts of evo-devo and outline an underlying conceptual framework. We also use interviews and surveys of conceptual difficulties with these concepts.

Development and characterization of 17 polymorphic microsatellite loci in the faucet snail, Bithynia tentaculata (Gastropoda: Caenogastropoda: Bithyniidae)

Bithynia tentaculata (Linnaeus, 1758), a snail native to Europe, was introduced into the US Great Lakes in the 1870’s and has spread to rivers throughout the Northeastern US and Upper Mississippi River (UMR). Trematode parasites, for which B. tentaculata is a host, have also been introduced and are causing widespread waterfowl mortality in the UMR. Waterfowl mortality is caused by ingestion of trematode-infected B. tentaculata or insects infected with parasites released from the snails. We isolated and characterized 17 microsatellite loci from the invasive faucet snail, B. tentaculata (Gastropoda: Caenogastropoda: Bithyniidae). Loci were screened in 24 individuals of B. tentaculata. The number of alleles per locus ranged from 2 to 6, observed heterozygosity ranged from 0.050 to 0.783, and the probability of identity values ranged from 0.10 to 0.91. These new loci provide tools for examining the origin and spread of invasive populations in the US and management activities to prevent waterfowl mortality.

Beyond the Adaptationist Legacy: Updating Our Teaching to Include a Diversity of Evolutionary Mechanisms

Abstract A paradigm shift away from viewing evolution primarily in terms of adaptation — the “adaptationist programme” of Gould and Lewontin — began in evolutionary research more than 35 years ago, but that shift has yet to occur within evolutionary education research or within teaching standards. We review three instruments that can help education researchers and educators undertake this paradigm shift. The instruments assess how biology undergraduates understand three evolutionary processes other than natural selection: genetic drift, dominance relationships among allelic pairs, and evolutionary developmental biology (evo-devo). Testing with these instruments reveals that students often explain a diversity of evolutionary mechanisms incorrectly by invoking misconceptions about natural selection. We propose that increasing the emphasis on teaching evolutionary processes other than natural selection could result in a better understanding of natural selection and a better understanding of all evolutionary processes. Finally, we propose two strategies for accomplishing this goal, interleaving natural selection with other evolutionary processes and the development of bridging analogies to describe evolutionary concepts.

Hendersonia occulta (Say, 1831), the Cherrystone Drop Snail (Gastropoda: Helicinidae), extended geographic distribution, Wisconsin, USA

This paper describes a range extension of Hendersonia occulta, the cherrystone drop snail. This species, occurring in heavily wooded areas with carbonate geology, is imperiled in Wisconsin. Prior to our research, H. occulta had been found in 13 counties within Wisconsin, mostly in the southwestern and eastern parts of the state. We have found 13 new populations, both within counties where the snail was known to occur, and within three new counties, representing a ~150 km range extension northward.