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This "clicker case" gives students an opportunity to apply their understanding of three different types of selection (directional, stabilizing, and disruptive) to a variety of model systems. The case describes each type of selection in detail, presents a paradigm case of each, and then uses clicker questions to test whether students can identify the mode of selection in other systems (answers included in the teaching notes).  Nine different studies are presented so that students gain a broad understanding of selection and how environmental factors can impact species differently. The case concludes with an optional discussion activity (also discussed in the teaching notes) to deepen understanding. Although designed for a high school classroom, it could easily be used in a lower-level college course as an engaging introduction or review of concepts. The case could be used at the beginning of an evolution unit, but it would be helpful if the students were familiar with natural selection before completing the activity.

In their study of the medium ground finches, evolutionary biologists Peter and Rosemary Grant were able to track the evolution of beak size twice in an amazingly short period of time due to two major droughts that occurred in the 1970s and 1980s. This activity simulates the food availability during these droughts and demonstrates how rapidly natural selection can act when the environment changes. Students use two different types of tools to represent different beak types to see which is best adapted to collect and "eat" seeds of different sizes. Students collect and analyze data and draw conclusions about traits that offer a selective advantage under different environmental conditions. They have the option of using an Excel spreadsheet to calculate different descriptive statistics and interpret graphs.

Welcome to the HealthStats Indicator Report Categorized Index. This categorized index provides a selection menu in the form of an explorer type hierarchical folder tree and is organized by topic or subject area. These menu selections are used to navigate to the system's various indicator reports. Listed below are the most general categorized index menu sections. After selecting one of these general category sections, a page will be presented which will allow the folder's sub items to be shown and selected.

This case is an exploration of the process of natural selection using white clover (Trifolium repens) as an example. In general, two forms of white clover can be found around the world in various habitats. One type is able to produce cyanide in its leaves, while the other is not. This variation within the clover species, along with the fact that cyanide production is paired with the production of a white stripe on the leaf, is used to teach the process of evolution through natural selection. 

Select type of data to graph and view changes in data over time for selected cancer type or subpopulations.

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.

A common misconception is that Darwin suggested that something as complex as the eye could not have evolved through natural selection. While the misunderstanding often comes from an incomplete reading of his argument, we have long known that intermediate varieties of eyes (e.g., eyespots, cupped eyes, and complex camera-type eyes) exist in a variety of organisms. Eyes are so common that it was thought that they had evolved independently 40-60 times. More recent molecular work, however, has identified the role of Pax6 genes and their homologs in the formation of eyes during development. The basic information for eye formation appears to have been present in the common ancestor to all bilaterans, and perhaps may be more ancient than that. This interrupted case study examines the history of evidence for eye evolution from Darwin's initial postulates, through evidence of multiple intermediate forms, concluding in an examination of Pax6 homologs. The case is primarily for an introductory biology class but an additional section would be appropriate for upper-level evolution or developmental biology courses.