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Testing for Grazer Adaptation to Toxic Algae

Co Authors:

Michael B. Finiguerra
Department of Ecology and Evolutionary Biology
University of Connecticut: Avery Point Campus

Hans G. Dam
Department of Marine Sciences
University of Connecticut

David E. Avery
Department of Arts and Sciences
Maine Maritime Academy


The intent of this interrupted case study is to present a clear example of both the scientific method and evolutionary adaptation in a model system consisting of marine grazers (copepods) and toxic prey (phytoplankton). Briefly, a certain toxic phytoplankton is found only north of Long Island Sound in the United States; however, populations of their copepod grazers are found more extensively from Maine to Delaware. Students will consider whether exposure to toxic phytoplankton among northern grazer populations has led to greater fitness compared to those populations that have never experienced the toxin (i.e., southern populations), and whether the evidence supports adaptation or plasticity. Students will also discuss the broader impacts of adaptation to toxins in marine food webs. A primary aim is to show students how to go from observation and hypothesis to analysis of data. This activity was originally designed for a second year evolutionary biology or ecology course, but can easily be adapted for the evolution section of a general biology course or an upper-level biological oceanography course.

  • Understand how a set of observations leads to an important and testable scientific question.
  • Generate a testable hypothesis.
  • Develop a detailed experimental methodology to test the hypothesis, with emphasis on controls.
  • Determine if the results presented in the case study support the hypothesis, and why.
  • Identify how answering the question (i.e., testing and supporting the hypothesis) leads to additional related scientific questions.
Keywords: evolution; toxic algae; common garden; food web; copepods; Long Island Sound; paralytic shellfish toxins; PST; harmful algal blooms; HAB; nitrogen; nutrients; phosphorus; red tides
Topical Area: Scientific argumentation
Educational Level: Undergraduate lower division, Undergraduate upper division
Formats: PDF
Type/Method: Interrupted
Language: English
Subject Headings: Biology (General)   Ecology   Evolutionary Biology   Science (General)   Marine Science / Oceanography  
Date Posted: 2/26/2018
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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Supplemental Materials

This optional material from Science Friday provides another nice example of rapid adaptation by a fish.

  How Lake Fish Are Coping With Pollution
This brief (~1200 words) excerpt from The Death and Life of the Great Lakes by Dan Egan sets the stage for the podcast below by relating the story of one of the last Great Lakes fisherman who witnesses the adaptation of a fish to Lake Michigan’s polluted ecosystem.
  Can The Great Lakes Stay Great?
Milwaukee journalist Dan Egan joins ecologists for a conversation about the evolution of the lakes and the challenges they’ve faced in the last four decades. Podcast created by Science Friday. Running time: 34:39 min. Date: June 16, 2017.


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

  The Origin of Species: The Beak of the Finch
This video from HHMI on the Galapagos Finches provides a great example of natural selection and adaptation and can serve as a useful introduction to this case study. Running time: 16:08 min. Produced by HHMI BioInteractive, 2014.

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