Exercises in biological science

v+293hlm.;27c

The integrative approach to evolution education

Evolution is a broad theory that is difficult for many students to understand. Part of the reason for this may be the tendency of instructors to teach evolution in the context of ecological systems, isolated from genetic and cellular mechanisms. To address this, we developed a set of integrative cases that address evolutionary processes from their origination in DNA mutations, to the production of different proteins, to the fixation of alternate macroscopic phenotypes in reproductively isolated populations. These integrative cases represent a comprehensive approach to teaching evolution across biological sub-disciplines. To date, we have implemented these cases in several introductory biology courses and our preliminary data show that students who more successfully learn evolution in a case context are also more able to (i) explain the molecular basis of mutation, (ii) describe how mutations lead to phenotypic change and (iii) make mechanistic links between genotypes and phenotypes. Our findings support the hypothesis that students who acquire an understanding of genetic, molecular and cellular evolutionary mechanisms will have a better overall understanding of evolution. We have three goals for this workshop: (i) to model the case-approach to evolution education, (ii) to provide participants with “instruction ready” web-based evolution education materials, and (iii) to disseminate our preliminary investigation that analyzes the impact of the integrative case-approach on the learning of evolution. The education materials we have developed, including PowerPoint slides and web-based simulations (games), are freely available at http://www.evo-ed.com

Assessing Students' Ability to Trace Matter in Dynamic Systems in Cell Biology

College-level biology courses contain many complex processes that are often taught and learned as detailed narratives. These processes can be better understood by perceiving them as dynamic systems that are governed by common fundamental principles. Conservation of matter is such a principle, and thus tracing matter is an essential step in learning to reason about biological processes. We present here multiple-choice questions that measure students' ability and inclination to trace matter through photosynthesis and cellular respiration. Data associated with each question come from students in a large undergraduate biology course that was undergoing a shift in instructional strategy toward making fundamental principles (such as tracing matter) a central theme. We also present findings from interviews with students in the course. Our data indicate that 1) many students are not using tracing matter as a tool to reason about biological processes, 2) students have particular difficulties tracing matter between systems and have a persistent tendency to interconvert matter and energy, and 3) instructional changes seem to be effective in promoting application of the tracing matter principle. Using these items as diagnostic tools allows instructors to be proactive in addressing students' misconceptions and ineffective reasoning