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Squirrels are frequent and beloved residents of college campuses throughout the United States, but oftentimes less welcomed by campus maintenance officials who report squirrels nesting in buildings, interfering with airflow from heating and cooling units, and destroying gutters. In this laboratory case, students act as members of a fictitious "squirrel task force" appointed by their campus administrators to provide recommendations for how to manage their school's squirrel population.  Students work in groups to assess the habitat suitability of their campus for squirrels by identifying and measuring trees that provide seasonal food for squirrels, and by identifying desirable hunting perches for common squirrel predators.  Students conduct squirrel surveys in designated campus zones to calculate the number of squirrels per acre on their campus and compare it with mean squirrel densities reported in forested areas and at a rival institution.  Students then compile and synthesize class data to provide management recommendations for university maintenance officials for either increasing or decreasing campus squirrel populations. Originally developed for an undergraduate wildlife biology course, the case could also be used in a lower-division biology or environmental studies course.

In this case study students are provided with information for piecing together the story of how forest fragmentation and biodiversity loss can affect the risk of Lyme disease transmission to humans. The case introduces the dilution effect, a widely accepted theory-and one of the most important ideas in disease ecology-which suggests that disease risk for humans decreases as the diversity of species in an area increases. It also explains how landscape fragmentation, one of the most common threats to biodiversity, can influence the risk of Lyme disease for humans. Students interpret and discuss various figures to develop a concept map that connects all the individual results of the story. Students gain an appreciation for the complexity of species interactions in an ecosystem, the effects of forest fragmentation on these interactions and the possible consequences for human health. This activity was developed for an undergraduate introduction to environmental sciences course under the topic of biodiversity and conservation, but would also be suitable for interdisciplinary studies interested in examining the connections between conservation and public health.

This case study describes a visit by "Naomi" to her physician, who upon seeing Naomi's bloodwork decides to prescribe her a cholesterol-lowering agent, a statin. The case discusses (1) the prevalence of non-communicable diseases such as atherosclerosis, which can lead to strokes and heart disease; (2) circulating lipoprotein particles including LDL and HDL, differentiating between which is a risk factor for heart disease and which is protective;  (3) the pathway for cholesterol synthesis; (4) the evidence demonstrating that statins inhibit the enzyme HMG-CoA reductase, which is the committed step for cholesterol synthesis; and (5) the kinetic mechanism by which statins inhibit the enzyme. Students examine and interpret data from radioactive tracer and enzyme kinetics studies. The case ends with another visit by Naomi to her physician, who reexamines her bloodwork after she has been taking a statin for six months. Students are asked to determine whether the drug was effective for Naomi and, if not, what changes could be made to her regimen. The case was originally written for use in a survey of biochemistry course for upper level undergraduates.

Although Hardy-Weinberg equilibrium is a fundamental part of introductory biology classes, students often have difficulty understanding its implications. This interrupted case study places students in the role of small teams who are conducting preliminary research into the impact of roads on the population structure of timber rattlesnakes in order to apply for a grant for further research. Research groups consisting of 3-4 students work through a series of questions allowing them to use HWE principles to discover for themselves how deviations from HWE can have implications for conservation biology. Periodic interruptions with help sheets (see Supplemental Materials) allow teachers to maintain an active role in the students' progress, while also demonstrating the collaborative nature of scientific research. Ultimately students formulate formal emails summarizing and interpreting their findings in order to "apply" for the grant. The case is designed for undergraduate students in introductory biology or in lower-level population genetics/conservation courses where connecting basic genetic principles to ecology and sustainability is key.

Human populations have adapted to varying intensities of sunlight with varying tones of skin coloration. The balanced interplay between melanin content and UV absorption allowed populations to successfully migrate from sub-Saharan Africa by influencing levels of two key vitamins: vitamin D and folic acid. This case study explores the evolutionary advantage of different skin tones for the human race; it also emphasizes the absence of scientific evidence for the correlation of abilities, talents, and other complex traits to skin color, and exposes certain social misconceptions linking skin color to specific traits. Although the discussion of race is not always a comfortable fit for science and biology courses, this case study uses the topic as an inherently interesting and important subject for applying basic biological concepts of DNA, the central dogma, and mutations to real world questions of physical difference and skin color. This case has been used in biology courses for non-science majors but would also be appropriate for advanced high school students.

This directed case study follows the story of "Pauline," a 20-year-old college student who has just received results from a personal genetic testing kit she purchased online. The report shows a negative result for variants of the BRCA 1 and 2 genes, which are associated with a greater risk for breast cancer. Although Pauline has a family history of breast cancer, she concludes that she no longer needs to be concerned, or does she? As students work through the questions in this case study, they review the role of genes and how they code for proteins as well as the effects of proteins on health, especially on cellular growth regulation and cancer. They also learn about the process of genetic testing and consider the ramifications of positive and negative tests for diseases or health conditions, especially with respect to breast cancer. The case is designed for non-science majors in a scientific methods course and could also be used in an introductory biology course. The questions in the case could be adapted for an upper level genetics class.

With increasing U.S. government support for biofuel production in the late 2000s came increased pressure to convert more land to cornfields for ethanol. To make way for more corn, millions of acres of prairie grassland were plowed under, destroying an extremely diverse wildlife habitat that also served as a large carbon reservoir. This case study focuses on the reasons for and consequences of large carbon losses when prairie grasslands are converted to agricultural lands. Many students are challenged when faced with linking together energy flows, decomposition, and nutrient cycles.  This case gives students the opportunity to consider different pools in the carbon cycle and the fluxes between them in order to model (on paper) an integrated picture of why carbon is lost when prairie grasslands are plowed and planted to cornfields.  Students also consider ways that carbon loss from land conversion due to ethanol production might be avoided via government incentive programs or mitigated via changes to farming practices. This case study was developed for an introductory ecology, environmental science, soil science, or agriculture course.

This interrupted case is based on a genome wide association study (GWAS) that identified the genetic variation causing some inhabitants of the Solomon Islands to have blond hair. The case illustrates the connection between genotype and phenotype, and an application of Hardy-Weinberg equilibrium. The narrative focusses on John and his new roommate, Peter, from the Solomon Islands who happens to have dark skin and blond hair. Using thought-provoking questions students learn about the genetics and the biochemistry of the hair color trait and how a single genetic variation can influence phenotype. Is migration or mutation involved?  Upon completion of the activity students will know the source of the genetic variation that causes the blond hair phenomenon in the Solomon Islands and if it has any European origins. The case was written for an upper-level genetics course, but could also be adapted for introductory biology or for a genetics course for non-majors. An optional PowerPoint presentation with clicker questions is available for download from within the Answer Key.

This clicker case study follows a dialogue between two college students, Lucy and Dan, as they discover how alternative splicing of mRNA molecules can allow a single gene to code for multiple proteins. Dan is participating in a clinical trial for a drug that may treat his migraines by inhibiting calcitonin gene-related peptide, and Lucy is working in a summer research lab that studies the protein calcitonin. They soon realize that the two proteins are both encoded by the same gene, and through their questioning and dialogue they come to understand the phenomenon of alternative splicing. They also learn about other steps of mRNA processing and about monoclonal antibodies. This case was designed to be taught in a flipped classroom, but could easily be adapted for a more traditional classroom setting if content covered in the pre-class videos is covered during the case study instead. It was designed for an introductory-level molecular biology course, but could be adapted for higher levels by including more information about the physiology and regulatory mechanisms involved.

To what extent should corn be used for the production of ethanol? Are we better off producing corn for food or producing corn for fuel? This case study uses a technique called "intimate debate" (also known as "constructive controversy") in order to examine this issue. Each student participates in a set of mini-debates for which there is no audience. Students are paired with a teammate; these teams then take turns arguing each side of the issue while seated across from their opponents who do the same. The session concludes with opposing teams reaching consensus. Detailed instructions are included in the case handout to prepare students for the experience before debate day. This case was used successfully in a sophomore/junior level, general education, environmental biology course. It would fit appropriately into any college course that discusses environmental issues related to farming practices, land use, alternative fuels, renewable energy, or sustainability.

This 5 lesson unit, which was designed by teachers in conjunction with scientists, ethicists, and curriculum developers, explores the scientific and ethical issues involved in stem cell research. The unit begins with an exploration of planaria as a model organism for stem cell research. Next, students identify stages in the development of human embryos and compare the types and potency of stem cells. Students learn about a variety of techniques used for obtaining stem cells and the scientific and ethical implications of those techniques. While exploring the ethics of stem cell research, students will develop an awareness of the many shades of gray that exist among positions of stakeholders in the debate. Students will be provided an opportunity to become familiar with policies and regulations for stem cell research that are currently in place in the United States, the issues regarding private and public funding, and the implications for treatment of disease and advancement of scientific knowledge. The unit culminates with students developing a position on embryonic stem cell research through the use of a Decision-Making Framework. Two culminating assessments are offered: In the individual assessment, students write a letter to the President or the President's Bioethics Committee describing their position and recommendations; In the group assessment, students develop a proposal for NIH funding to research treatment for a chosen disease using either embryonic or 'adult' stem cells.

When Jordan is diagnosed with brain cancer (glioblastoma multiform), his college plans are unexpectedly put on hold. This scenario is presented in order to teach students about gene regulation, as the efficacy of the drug Jordan receives for post-surgical treatment is dependent upon the activity level of a gene encoding a protein involved in DNA repair. This "flipped" case study requires students to prepare in advance outside of class by watching several short videos that have been selected to teach the basics of how cancer forms as well as the role of epigenetics in gene silencing. Inside of class, the case is delivered using progressive disclosure format in which students gradually receive additional information to answer a series of directed questions. To determine a treatment plan for Jordan, students analyze data from a research study involving patients treated for his specific type of cancer. The case is designed for advanced high school biology classes as well as lower-level undergraduate general biology courses for non-majors and majors.

For at least 10,000 years, humans have been cultivating plants and selectively breeding them for fast growth, pest resistance, long-term survival in storage, and bigger and better fruit. We've been domesticating animals for just as long, selecting for traits that suited our needs, such as size, appearance, or even personality. For a few decades, we've also had genetic engineering methods for getting the characteristics we want in plants, animals, and microorganisms.

This flipped case study explores how the topics of membrane structure, transport, and signaling via membrane-bound receptors are intimately associated with the paralysis of muscle targeted by botulinum neurotoxin. The case scenario revolves around a fictitious socialite that has requested the assistance of her personal concierge physician with a condition that has developed after having participated in a Hamptons Botox party. The physician and a shadowing pre-med undergraduate chat about the molecular mechanisms behind Botox induced muscle paralysis. The case is designed as an engaging capstone exercise for students to gain appreciation for how knowledge of basic cellular and molecular biology mechanisms are essential for pharmaceutical development and medical patient diagnosis and prognosis. Written for an undergraduate general biology course, the case is also suitable for use in courses such as cellular biology, neurobiology, or human physiology.

Every year during the foodless winter months, bears enter their den and lapse into a state of extended dormancy and slumber (called hibernation). For the next 130+ consecutive days they do not drink, eat, defecate, or urinate. Rarely do they die from starvation, dehydration, or poisoning from waste buildup while hibernating. How do bears prepare for this period of starvation coupled with significant weight loss? Bears are not only the champions of winter rest, but are also the undisputed champions of non-stop summer eating. They are constantly on the move during late spring and all summer long into late autumn oftentimes covering great distances over diverse habitats in their incessant search for locally and seasonally available food. In this case study, students learn the basics about bear denning, hibernation energetics, the differences in size of bear home ranges, and the nutritional landscape they must navigate to prepare for the long months of winter inactivity and caloric deprivation. The case is suitable for a wide audience, including majors or non-majors in lower- or upper-level undergraduate courses in environmental science, ecology, biology, or wildlife science.

In this "clicker case," students learn about sex determination, meiosis, and chromosomal "crossing over" through the story of Santhi Soundararajan, an athlete from Kathakkurichi, India, who was stripped of a medal at the 2006 Asian Games after failing to pass a sex test. The case is called a clicker case because it combines the use of student personal response systems (clickers) with case teaching methods and formats. The case itself is a PowerPoint presentation (~2 MB) shown in class that is punctuated by questions students respond to using their clickers. It can be adapted for use without these technologies. Developed for an introductory biology class for both majors and non-majors, the case could also be used in an anatomy and physiology course or an endocrinology course.

In this "clicker case," students learn about sex determination, meiosis, and chromosomal "crossing over" through the story of Santhi Soundararajan, an athlete from Kathakkurichi, India, who was stripped of a medal at the 2006 Asian Games after failing to pass a sex test. The case is called a clicker case because it combines the use of student personal response systems (clickers) with case teaching methods and formats. The case itself is a PowerPoint presentation (~2 MB) shown in class that is punctuated by questions students respond to using their clickers. It can be adapted for use without these technologies. Developed for an introductory biology class for both majors and non-majors, the case could also be used in an anatomy and physiology course or an endocrinology course.

In this interrupted case study, students shadow an endocrinologist as she tries to determine what is wrong with Angela Barber. Angela is a middle-aged woman presenting with symptoms suggestive of a thyroid issue. Students are given background information, patient history, and results from thyroid-specific blood tests. The exercise emphasizes the hypothalamic-pituitary-thyroid axis and particularly highlights the role of negative feedback. Students will use results from serum thyrotropin and thyroid hormone level tests, as well as patient symptoms, to come up with a diagnosis. In preparation for the diagnosis, students are asked to compare the endocrine profiles of patients with Graves' disease, Hashimoto's disease, iodine deficiency (primary hypothyroidism), and various tumors. The case was developed for college-level biology majors in a physiology course, but also has been used successfully for pre-nursing students in a non-majors anatomy and physiology course. Thus, this activity would be suitable for majors in physiology or pre-medical students, as well as allied health majors.

The Aedes aegypti mosquito is the major vector for transmission of numerous viral diseases, including yellow fever, dengue, and now, Zika. Interestingly, different subspecies of A. aegypti are known to exist in close proximity but with considerable genetic divergence between them. One major difference between a "forest" form and a "domestic" form is a strong preference in the latter subspecies for human over non-human blood biting. This difference was explored with genetic and neurophysiological approaches by a research group at Rockefeller University and published in a 2014 paper in Nature. This flipped case study uses parts of the Nature paper to focus on elements of the scientific method as well as evolutionary questions raised by the difference in biting preference between the two subspecies. Students prepare for class by watching a video that provides background information about the published study that forms the basis for the case. In class students then work in groups to develop a hypothesis, predictions and proposed experiments to test the idea of different biting preferences.

Loss of species richness is often due to anthropogenic activity. The global decline of amphibians is one such example. This case study examines the impact of road deicing agents on amphibians living near bridges and roads treated heavily with salt during the winter months. Concepts explored in this case include changes to the aquatic environment as a result of road deicing applications, bioaccumulation, osmoregulation in amphibians living in clean freshwater, and the impact of increased aquatic salinity levels on the ability of amphibians to adequately osmoregulate in an environment for which they are not adapted. Three short videos created by the author can be shown in class or assigned for viewing in advance for a "flipped" classroom approach. Originally developed for a general education/introductory biology course, the case could also be used with introductory level animal anatomy and physiology courses as part of a deeper exploration of the renal system.

Session description: The session will provide an introduction to the ethics of research involving human participants. It will ad-dress the history of research ethics, present a contemporary eth-ical framework, and discuss its application to differing kinds of research studies. The ethical framework consists of four principles: respect for persons, beneficence, justice, and respect for communities. Each principle provides the foundation for ethical rules, including requirements for informed consent and confidentiality of health information. Taken together these ethical principles and rules provide a comprehensive framework for the analysis of ethical challenges in health research.