I'm Looking Over a White-Striped Clover

By Susan Evarts, Alison Krufka, Chester Wilson

Abstract

This case is an exploration of the process of natural selection using white clover (Trifolium repens) as an example. In general, two forms of white clover can be found around the world in various habitats. One type is able to produce cyanide in its leaves, while the other is not. This variation within the clover species, along with the fact that cyanide production is paired with the production of a white stripe on the leaf, is used to teach the process of evolution through natural selection. Students use the scientific method to explore these concepts. As an introduction to evolutionary concepts in biology, the case would be appropriate for both high school and college biology courses.

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Date Posted

11/28/2006

Overview

Objectives

Understand the process of natural selection and the importance of environment-specific adaptations.
Acquire an understanding of the concepts of variation, natural selection, fitness, selection pressure, evolution, and adaptation.
Using these concepts, describe the frequency of the two types of white clover.
Be able to predict the distribution of cyanogenic clover in given microhabitats.
Gain experience with the scientific method and be able to propose hypotheses and justifications to explain the frequency of the two types of white clover.
Design experiments to test hypotheses and describe data that would support these hypotheses.
Understand and synthesize information from figures and tables.

Keywords

Natural selection; variation; adaptation; evolution; white clover; trifolium repens; cyanide; cyanogenesis; experimental design

Subject Headings

Biology (General)

Botany / Plant Science

Evolutionary Biology

EDUCATIONAL LEVEL

High school, Undergraduate lower division

FORMAT

PDF

TOPICAL AREAS

Scientific method

LANGUAGE

English

TYPE/METHODS

Interrupted

Teaching Notes & Answer Key

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Answer Key

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