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Evolution by Natural Selection in Oldfield Mice


Katherine S. LaCommare
Department of Natural Sciences
University of Michigan—Dearborn
Peter A. Van Zandt
Department of Biology
Birmingham-Southern College


The theory of evolution by natural selection is simple, elegant, and profound. Yet, a large number of undergraduate students including biology majors, medical students, and pre-service science teachers maintain a large set of misconceptions that interfere with a solid understanding of the process of natural selection. It is also well known that lecturing is an insufficient strategy to help students confront and correct these misconceptions. This activity uses the evolution of coat color in oldfield mice (Peromyscus polionotus) as the basis of a case study in which students investigate the role of variation, heritability, and selection in the evolution of a trait. Students examine graphs, data, and excerpts from a series of papers that have been published about this system over the last 100 years. The content is delivered as an interrupted case and encourages peer-to-peer teaching and interaction. The case is appropriate for use in non-major, introductory, or advanced biology courses.


  • Summarize the logic of evolution by natural selection.
  • Explain the role and source of variation, the role of heredity, genetics, survival and reproduction, and the environment in natural selection.
  • Apply this logic to explain how adaptations arise in organisms.
  • Correctly describe natural selection in written work and avoid language that elicits misconceptions. For example, students should be able to articulate that populations evolve, not individuals, that evolution doesn't happen in response to need, and that natural selection is not random.
  • Envision, manipulate, and display data and use information to predict patterns in data.


Oldfield mice; evolution; natural selection; beach mice; Peromyscus;

Topical Areas


Educational Level

High school, Undergraduate lower division, Undergraduate upper division



Type / Methods

Analysis (Issues), Interrupted



Subject Headings

Biology (General)  |   Ecology  |   Environmental Science  |   Evolutionary Biology  |   Zoology  |  

Date Posted


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Answer Key

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The following video(s) are recommended for use in association with this case study.

  • The Making of the Fittest: Natural Selection and Adaptation
    The rock pocket mouse is a living example of Darwin’s process of natural selection; this video explains how random changes in the genome have led to a colored coat that hides these mice from predators. Running time: 10:25 min. Produced by HHMI Biointeractive, 2011.