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What is a Species?

Speciation and the Maggot Fly


Author(s)

Joan Sharp
Department of Biological Sciences
Simon Fraser University
jsharp@sfu.ca

Abstract

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.


Objectives

  • Define several species concepts, including the biological species concept, ecological species concept, morphological species concept, and phylogenetic species concept.
  • Use several species concepts to determine if two groups of organisms represent separate species.
  • Distinguish between sympatric and allopatric speciation.
  • Understand the significance of reproductive isolating mechanisms in reducing gene flow between two populations.
  • Distinguish between prezygotic and postzygotic barriers to reproduction.

Keywords

Rhagoletis pomonella; apple maggot fly; hawthorn maggot fly; speciation; sympatric; allopatric; genetic divergence; gene flow; reproductive barriers; evolution

Topical Areas

N/A

Educational Level

High school, Undergraduate lower division

Format

PDF, PowerPoint

Type / Methods

Clicker, Interrupted

Language

English

Subject Headings

Evolutionary Biology  |   Biology (General)  |   Ecology  |   Botany / Plant Science  |   Zoology  |  


Date Posted

11/04/09

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Answer Key

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