Skip to main content
 

Exaggerated Traits and Breeding Success in Widowbirds

A Case of Sexual Selection and Evolution

By J. Phil Gibson

Exaggerated Traits and Breeding Success in Widowbirds


 

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.

   

Date Posted

06/11/2008

Overview

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

  

Subject Headings

Ecology
Evolutionary Biology
Zoology

EDUCATIONAL LEVEL

High school, Undergraduate lower division, Undergraduate upper division

  

FORMAT

PDF

   

TOPICAL AREAS

Scientific method

   

LANGUAGE

English

   

TYPE/METHODS

Interrupted

 

 

Asset 2