New search

Joan Sharp
Teaching Professor
Department of Biological Sciences
Simon Fraser University
A Deadly Passion: Sexual Cannibalism in the Australian Redback Spider

This "clicker case" teaches students about the distinction between proximate and ultimate causes of behavior using the fascinating courtship and mating rituals of the Australian redback spider. The case is presented in class via a PowerPoint presentation (~3MB) punctuated by multiple-choice questions that the students answer using personal response systems, or "clickers." It could be adapted for use without these technologies. Although developed for a general biology class, the case would also be suitable for use in non-majors introductory biology or behavioral ecology courses.

A Tale of Three Lice: A Case Study on Phylogeny, Speciation, and Hominin Evolution

This “clicker case” explores the questions of when hominins lost their body hair and began wearing clothing by examining the surprising phylogeny of human head, body, and pubic lice. Students are led through the scientific process as they are asked to think about hypotheses, predictions, results, and conclusions, and learn about phylogeny, speciation, and hominin evolution. The case is presented class using a set of PowerPoint slides (~1.5MB) that includes multiple-choice questions students answer using personal response systems (“clickers”). It could be adapted for use without these technologies.  Developed for a general biology class focusing on evolution and ecology, the case is also suitable for use in a non-majors introductory biology course.

Cross-Dressing or Crossing-Over?: Sex Testing of Women Athletes

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.

Selection and the Blond Beach Mouse 

This "clicker" case study explores ultimate and proximate explanations for cryptic coloration in animals through the work of Dr. Hopi Hoekstra of Harvard University, who studies Gulf and Atlantic Coast beach populations of oldfield deer mice that have evolved blond fur coloration. An ultimate question addresses the adaptive value of blond coloration, exploring how cryptic coloration increases the evolutionary fitness of a beach mouse. Proximate questions address the mechanisms that produce blond coloration, such as the genetic and developmental mechanisms that alter mouse coat color. Students work in small groups to plan an experiment to assess the design of a published experiment and analyze the results. They learn about roles of mutant alleles of two pigment genes (Mc1r and Agouti) in producing blond coloration in several subspecies of beach mice, as well as woolly mammoths. Finally, students weigh evidence from genomic analysis to select between two contrasting hypotheses about the origin of the blond Mc1r allele. The case is presented in PowerPoint format and includes both a detailed and simplified slide set, allowing instructors to select the most appropriate version for their class. Several recommended videos make it possible to teach the case in a "flipped classroom" setting.

What is a Species?: Speciation and the Maggot Fly

This "clicker case" is modified from Martin Kelly's case study "As the Worm Turns: Speciation and the Apple Maggot Fly," also in our collection. Classic cases of incipient speciation such as the apple maggot fly and the hawthorn maggot fly are an excellent way to teach students about the mechanisms of speciation. In this case, students learn about the natural history of apple and hawthorn maggot flies, then apply various species concepts to decide if they should be considered separate species and decide what evidence is relevant to each species concept. The case is designed for use in a general biology course for majors. It consists of a PowerPoint presentation (~8MB) punctuated by questions that students respond to using their clickers before moving on to the next slide. It could be adapted for use without these technologies.