Impact of male alternative reproductive tactics on female costs of sexual conflict under variation in operational sex ratio and population density.

Sexual conflict over mating rate is both pervasive and evolutionarily costly. For females, the lifetime reproductive fitness costs that arise through interactions with potential mates will be influenced by the frequency of such interactions, and the fitness cost of each interaction. Both of these factors are likely to be influenced by variation in operational sex ratio (OSR) and population density. Variation in OSR- and density-dependent male alternative reproductive tactics (ARTs) may be particularly important if the fitness costs that females experience vary with the reproductive tactics that males express. Using a simple model, we consider several examples of OSR- and/or density-dependent variation in male ARTs and the frequency of male-female interactions, and find that variation in the expression of male ARTs has the potential to augment or diminish the costs of frequent male interactions for females. Accurately documenting variation in the expression of male ARTs and associated female fitness costs will benefit future work in this area.

Development of the Statistical Reasoning in Biology Concept Inventory (SRBCI).

We followed established best practices in concept inventory design and developed a 12-item inventory to assess student ability in statistical reasoning in biology (Statistical Reasoning in Biology Concept Inventory [SRBCI]). It is important to assess student thinking in this conceptual area, because it is a fundamental requirement of being statistically literate and associated skills are needed in almost all walks of life. Despite this, previous work shows that non-expert-like thinking in statistical reasoning is common, even after instruction. As science educators, our goal should be to move students along a novice-to-expert spectrum, which could be achieved with growing experience in statistical reasoning. We used item response theory analyses (the one-parameter Rasch model and associated analyses) to assess responses gathered from biology students in two populations at a large research university in Canada in order to test SRBCI's robustness and sensitivity in capturing useful data relating to the students' conceptual ability in statistical reasoning. Our analyses indicated that SRBCI is a unidimensional construct, with items that vary widely in difficulty and provide useful information about such student ability. SRBCI should be useful as a diagnostic tool in a variety of biology settings and as a means of measuring the success of teaching interventions designed to improve statistical reasoning skills.

Investigating the Role of an Inquiry-Based Biology Lab Course on Student Attitudes and Views toward Science.

Students' academic experiences can influence their conceptualization of science. In contrast experts hold particular beliefs, perceptions, opinions, and attitudes about science that are often absent in first-year undergraduate students. Shifts toward more expert-like attitudes and views have been linked to improved student engagement, critical-thinking ability, conceptual understanding, and academic performance. In this study, we investigate shifts in attitudes and views toward science by students in four biology classes with differences in student enrollment, academic support, and instruction. We observe significant, positive effects of enrollment in a guided-inquiry lab course and academic performance on the percentage of expert-like student attitudes and views at the end of term. We also identify variation in two aspects of student attitudes and views: 1) confidence and interest and 2) understanding and acceptance. In particular, enrollment in the lab course boosts student confidence and interest in scientific inquiry in the short term, even for students with low academic performance or little English-language experience. Our results suggest that low-performing students in particular may require additional opportunities for experiential learning or greater academic support to develop expert-like perceptions of biology as a science.

Development of the Biological Experimental Design Concept Inventory (BEDCI).

Interest in student conception of experimentation inspired the development of a fully validated 14-question inventory on experimental design in biology (BEDCI) by following established best practices in concept inventory (CI) design. This CI can be used to diagnose specific examples of non-expert-like thinking in students and to evaluate the success of teaching strategies that target conceptual changes. We used BEDCI to diagnose non-expert-like student thinking in experimental design at the pre- and posttest stage in five courses (total n = 580 students) at a large research university in western Canada. Calculated difficulty and discrimination metrics indicated that BEDCI questions are able to effectively capture learning changes at the undergraduate level. A high correlation (r = 0.84) between responses by students in similar courses and at the same stage of their academic career, also suggests that the test is reliable. Students showed significant positive learning changes by the posttest stage, but some non-expert-like responses were widespread and persistent. BEDCI is a reliable and valid diagnostic tool that can be used in a variety of life sciences disciplines.