The Effectiveness of a Case Study-Based First-Year Biology Class at a Black Women's College

Beginning of article

[ILLUSTRATION OMITTED]

Spelman College is a historically black women's college with a mission to promote academic excellence and leadership potential in its students. The Biology Department at Spelman College is presently in the midst of revising its curriculum to make it more student centric. In the new curriculum, the first of the four core biology courses was developed with the objective of enhancing the reading and quantitative skills of our students. The curriculum development team determined that a case study-based course would meet the above objective by engaging the students in reading and discussing the case study materials. This approach would not only create an environment of active learning because students had to read and process the case studies, but it would potentially improve critical-thinking skills among students who had to apply the concepts learned in lectures to solving problems or questions posed in the case study assignments (Herreid 2007). The case study method is very successful as an active learning method in which students "learn by doing" (Herreid 1994). Specific skills that are promoted by case study technique are students' problem-solving ability, analytical reasoning, and decision-making skills, as well as the ability to work in teams and communicate effectively (Herreid 1994). An additional reason why this method was suitable for Spelman is that case study-based science teaching might be particularly attractive to female and minority students (Lundeberg and Yadav 2006a).

Research questions

Given that this was a new class both in terms of the topic as well as the teaching method, we were interested in asking three main questions about this class: (1) What are students' responses to case study activities? (2) Do students' show a gain in course content knowledge? and (3) How does students' perception of their learning in this class compare with the previous introductory biology class? The answers to the above questions are clearly useful for other instructors using a case study method and particularly those using this method for teaching introductory biology or those teaching female or minority students.

We designed two separate surveys to measure students' response to case study work and students' gain in course content knowledge, respectively. Finally, we compared students' perception of their learning in this class with the previous introductory biology class from the college-administered, end-of-semester course evaluation data. Here, we describe this new course and present the results of the assessment.

Participants

This class was taught for the first time in the fall of 2006 and again in the fall of 2007. Two sections of the course with approximately 55 students in each section were offered each semester. All students enrolled in this class were biology majors and females of African descent.

Materials

Course structure

Biological Communities and Populations (Bio 110) was designed to have a significant case study component in addition to the traditional labs (see Table 1). The class met three times each week for 50 minutes and once each week for a three-hour lab. In a typical week, the first two class periods were lectures in which students learned new concepts from the textbook by Campbell and Reece (2005). The third period was used for case study activities. The semester was divided into three modules: ecology, evolution, and biodiversity.

The case studies

For each module, one case study was used to illustrate the concepts presented in the lectures earlier that week. In the ecology module, the story of global mercury pollution was used to illustrate concepts such as the interrelationships between abiotic and biotic factors in the environment, population ecology, and community dynamics. In the evolution module, the role of malaria in the population genetics of humans (sickle cell gene frequency), the malaria parasite (emergence of drug-resistant parasites), and mosquitoes (emergence of drug-resistant vectors) was used to discuss concepts in evolutionary biology such as natural selection and population genetics. Finally, in the Biodiversity module, we used tropical deforestation (in 2006, 2007) and exploration of biodiversity (2007) as the cases to discuss the value of biodiversity for human life.

Bio 110 modules

Ecology module

The first module, ecology, served to introduce students to basic concepts such as the scope and importance of studying ecology, interactions between abiotic and biotic factors, population ecology, community ecology, and ecosystem ecology (Campbell and Reece 2005, chapters 50-54). The case study for this module was global mercury pollution. Because mercury pollution is a global problem that affects entities at all levels of ecological organization (organisms, populations, communities), as well as impacts community dynamics (e.g., food webs) and other ecosystem processes such as biogeochemical cycles, students would be able to apply all the major concepts from lecture to this case. We designed four case study activities for this module (see Table 1).

Evolution module

The evolution section of this course included an introduction to Darwin and the history of evolutionary theory, natural selection, population genetics, Hardy-Weinberg equilibrium, and genetic drift (Campbell and Reece 2005, chapters 22-26). The case study for this section was the impact of malaria in the evolution of humans, malaria parasite, and their vectors. Specifically, the role of malaria in influencing the frequency of the sickle cell gene among humans and the role of malaria control and treatment in bringing about the evolution of drug-resistant …