Science Case Network Fellow 2014

Sarah A. Orlofske


New Case Development

As a SCN Fellow I was inspired this year to develop a case study on a topic related to my own original research that would teach undergraduate fundamental principles of biology. In addition, I wanted students to have the opportunity to gain experience in both conceptual and mathematical modeling. I chose the topic of food webs.

This was a more challenging topic than I anticipated because students tend to have the misconception that food webs are complete, static, and illustrative rather than functional. I wanted the students to have the opportunity to discover that in reality food webs are a focus of on going research, lead to crucial new discoveries about the natural world, and fun.

The case study is presented as a research problem faced by a pair of undergraduate researchers who discover that indeed they have “missed” a trophic level in their study. As the students in the class read the story they can also create the food web networks by hand (a simplified, conceptual model) and mathematically using the software program R. They can then compare the two different food webs as illustrated below and answer follow-up questions using articles from the primary scientific literature.



Figure 1 A & B. Two food webs generated with the R programing language one without (A) and with (B) the “missing” trophic level. Students can then compare the properties of the networks and answer questions about what these interactions represent.


This case is still in development. With help from my mentor Pat Marsteller, I hope to submit this case for publication to the National Center for Case Study Teaching in Science. By working with the other instructors who teach additional sections of the Ecology course at Northeastern Illinois University I hope to test the case study later this semester with those students.

Existing Case Implementation

I am currently teaching the lecture portion of a two semester introductory biology sequence. This second semester covers ecology, evolution, animal and plant diversity, anatomy and physiology, and conservation biology. While coordinating the course with my department, I was able to incorporate a problem-based or case study activity in each of the main sections of the course. Some of these activities were short discussions following the students reading the introduction to the case, while others were more extensive.

One example shown below (Figure 2A) included adapting a case from the Ecological Society of America Teaching Issues and Experiments in Ecology using an original research article showing the impacts of invasive species on food web interactions. This activity allowed me to identify the misconceptions students had about the feeding relationships between organisms and the direction of energy flow. This case also dealt with issues related to the inclusion of humans in food webs and our influences on them. The students enjoyed working in groups and with the addition of a box of colored sidewalk chalk enjoyed creating their food webs on the chalkboard. This demonstrated the usefulness of the case study to a variety of audiences as the case was originally intended for an upper level course dealing with ecosystem services.

The next activity was adapted from a published article in the American Biology Teacher on the evolution of Chocolate Bars. This activity allowed the students to focus on the traits important in determining evolutionary relationships and the construction of phylogenies. With limited time in the laboratory portion of the course this activity supported many of our learning goals not only for evolution, but also animal and plant diversity. Other case studies used included one on the fossil Archaeopteryx and the evolution of flight in birds and one on the differences between acclimation and adaption in humans at high elevations that I learned about during the poster session this summer at the University of Delaware during the SCN meeting.








Figure 2 A. Students developing their food web models based on the primary literature and analyzing the effects of invasive species. B. Students identifying taxonomically informative traits and developing phylogenetic hypotheses for their chocolate “specimens”.

In addition to these case study activities students also engaged in authentic inquiry using epidemiological models. Using a series of computer labs and hands-on mathematical problems students gained the skills and confidence to develop their own original mathematical modeling question, write the equations, use the R programing language to implement their models, and finally write a scientific paper style report explaining and interpreting their results in the context of primary scientific literature. This has been an exciting and rewarding process. I look forward to converting the materials into a more general format that could be useful for a wider audience including microbiology, emerging infectious disease, or public health courses.

Quantitative Reasoning

This semester the biggest challenge was developing a new course on Parasites and Human Health. This course was equal parts medical parasitology, public health, and mathematical modeling. The course was designed with a problem based and quantitative reasoning component at its core. One case study was used from the National Center for Case Study Teaching in Science on the ethical and environmental issues regarding using DDT for malaria control. Other cases I developed from scratch including using the CDC – DPDx Monthly Case Study Training Website ( and the Carter Center’s work on eradication of the Guinea Worm.


Figure 3. Students in the Parasites and Human Health course working in teams to develop their mathematical modeling project, collect their data, and interpret their results.

Case Study Outreach

Just days ago I was informed that the proposal I submitted to lead an hour long workshop presentation on case study and problem based teaching strategies was accepted for the annual Learn and Lead Symposium. This event helps develop and share expertise across disciplines at Northeastern Illinois University for the goal of helping our entire faculty become more effective teachers and mentors and our students become better life long learners.

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