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Exaggerated Traits and Breeding Success in Widowbirds

A Case of Sexual Selection and Evolution


Author(s)

J. Phil Gibson
Department of Biology and Department of Microbiology & Plant Biology
University of Oklahoma
jpgibson@ou.edu

Abstract

Sexual selection has led to the evolution of interesting traits and behaviors in many animal species. In widowbirds, males undergo a dramatic change in plumage coloration and produce exceptionally long tail feathers during the breeding season. This change in appearance has facets of both intrasexual and intersexual selection. As students work through this interrupted case, they develop hypotheses and propose corresponding experiments. They are then presented with data from actual experiments on sexual selection in widowbirds that they must analyze and interpret. Developed for introductory-level biology students, the case could be adapted for upper-division ecology and evolution courses.


Objectives

  • Explain the fundamental features of natural selection.
  • Explain the process of natural selection in terms of sexual selection.
  • Develop hypotheses for experiments testing intrasexual and intersexual selection.
  • Gain experience interpreting data from different experiments and then use those data to evaluate hypotheses and develop ideas for further experiments.
  • Gain an understanding of trait variation among individuals.
  • Develop ideas regarding statistical testing (undergraduate upper-division majors).

Keywords

Widowbirds; bird; natural selection; evolution; sexual selection; intrasexual selection; intersexual selection; sexual dimorphism; handicap hypothesis; experimental design

Topical Areas

Scientific method

Educational Level

High school, Undergraduate lower division, Undergraduate upper division

Format

PDF

Type / Methods

Interrupted

Language

English

Subject Headings

Evolutionary Biology  |   Ecology  |   Zoology  |  


Date Posted

0611/08

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Videos

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

  • "Hot" for Turkey “Science
    The research of Richard Buchholz of the University of Mississippi is shedding light on how female wild turkeys parse the courtship performances of males to determine their genetic potential. Video created by: Science Friday. Produced by: Luke Groskin. Running Time: 5:28 min. Date: November 20, 2014.

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