What is a Species?

Speciation and the Maggot Fly

Author:	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 Area:	N/A
Educational Level:	High school, Undergraduate lower division
Formats:	PDF, PowerPoint
Type/Method:	Clicker, Interrupted
Language:	English
Subject Headings:	Evolutionary Biology Biology (General) Ecology Botany / Plant Science Zoology
Date Posted:	11/04/09
Date Modified:	N/A
Copyright:	Copyright held by the National Center for Case Study Teaching in Science, University at Buffalo, State University of New York. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.

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