Chain Reaction
Lesson Overview

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TIME ALLOTMENT: Three 45-minute periods

OVERVIEW: This inquiry-based lesson plan will challenge students to design and conduct scientifically valid experiments to evaluate hypotheses regarding an animal’s expected behavior in response to changes in its environment.

Students will first view and analyze video segments from the NATURE film “Earth Navigators” as they begin to think about animal behavior as a response to stimulus in the environment. The video clips feature many different animal species reacting to changes in the environment by migrating from one part of the earth to another. Students will predict the reasons for these migrations and will determine the stimuli that actually trigger the animals to migrate.

Following the video exploration, students will conduct reading and research to learn about isopods (commonly known as pill bugs or roly polies). The students will use the information they gather to formulate research questions having to do with the isopods’ expected response to environmental stimulus. The students will design experiments that can be conducted in the classroom to test their hypotheses. They will conduct the student-designed experiments, collecting data and reporting their findings and conclusions. They will also make suggestions for future improvements in the experimental protocol.

SUBJECT MATTER: Living Environment/Biology


Students will be able to:

  • Draw connections between the migratory behavior of different animals and seasonal changes on Earth;
  • Describe migration as an instance of behavioral response to stimulus;
  • Using anatomical and environmental information, create a research question about an isopod’s behavior in response to environmental stimulus;
  • Create a hypothesis that addresses the research question;
  • Design and conduct an experiment to evaluate the hypothesis;
  • Collect data from the experiment, describe results, and evaluate conclusions.


CONTENT STANDARD A: As a result of activities in grades 9-12, all students should develop:

  • Abilities necessary to do scientific inquiry
  • Understandings about scientific inquiry

CONTENT STANDARD C: Life Science. As a result of activities in grades 9-12, all students should develop understandings of:

  • Behavior of Organisms.

New York State Regents Core Curriculum Alignments
Living Environment Core Curriculum
STANDARD 1: Students will use mathematical analysis, scientific inquiry, and engineering designs, as appropriate, to pose questions, seek answers, and develop solutions

Key Idea 2: Beyond the use of reasoning and consensus, scientific inquiry involves the testing of proposed explanations involving the use of conventional techniques and procedures and usually requiring considerable ingenuity.

Performance Indicator 2.1: Devise ways of making observations to test proposed explanations.

Performance Indicator 2.3: Develop and present proposals including formal hypotheses to test explanations; i.e., predict what should be observed under specific conditions if the explanation is true.

Performance Indicator 2.4: Carry out a research plan for testing explanations, including selecting and developing techniques, acquiring and building apparatus, and recording observations as necessary.

Key Idea 3: The observations made while testing proposed explanations, when analyzed using conventional and invented methods, provide new insights into natural phenomena.

Performance Indicator 3.1: Use various methods of representing and organizing observations (e.g., diagrams, tables, charts, graphs, equations, matrices) and insightfully interpret the organized data.

STANDARD 4: Students will understand and apply scientific principles and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.

Key Idea 5: Organisms maintain a dynamic equilibrium that sustains life.

Performance Indicator 5.3: Relate processes at the system level to the cellular level in order to explain dynamic equilibrium in multicelled organisms.

5.3a Dynamic equilibrium results from detection of and response to stimuli. Organisms detect and respond to change in a variety of ways both at the cellular level and at the organismal level.

Key Idea 6: Plants and animals depend on each other and their physical environment.

Performance Indicator 6.1: Explain factors that limit growth of individuals and populations.

6.1f Living organisms have the capacity to produce populations of unlimited size, but environments and resources are finite. This has profound effects on the interactions between organisms.



NATURE: Earth Navigators, selected clips

Clip 1: “Planetary Moves”

Introduction to four species’ migratory patterns.

Clip 2: “Monarch Migration”

The start of the monarch butterfly’s northward trek.

Clip 3: “Hungry Beasts”

Wildebeest and locusts on the move.

Clip 4: “Arctic Summer”

Many birds summer in the arctic.

Access the streaming and downloadable video segments for this lesson at the Video Segments Page.

Web Sites

FOSSWEB: Isopods
Includes general information on isopods and useful tips on how to find and keep pill bugs for the classroom

Isopod, Pillbug, Sow bug information
Includes general information on isopods

NCES Graphing Tutorial
This tutorial from the National Center for Education Statistics explains the various kinds of graphs and demonstrates how to build them.


For the classroom:

  • Computer and projection system for showing video clips
  • Several computers for student use
    Chalkboard or whiteboard
  • Isopods (pill bugs) in a terrarium or other classroom habitat (enough specimens for at least 15-20 per student group)
  • Isopod Research Organizer Answer Key (PDF) (RTF)

Materials to be used in pill bug experiments (several of each):

  • Paper towels or filter paper
  • Eye droppers
  • Portable Lamps
  • Heat Packs
  • Cold Packs
  • Card stock or construction paper
  • Substrate materials, e.g. sand, gravel, dirt, shredded paper, bark, etc.
  • Thermometers

Per group of 3-4 students:

  • Stopwatch
  • Materials to make “test chambers”: Petri dishes or small disposable bowls or plates – enough for approx. 5 or 6 per group
  • Roll of masking tape
  • Scissors or art knife
  • Paper cup
  • Data Collection Chart
  • Graph paper

Per student:

  • Isopod Research Organizer (PDF) (RTF)
  • Isopod Experiment Organizer (PDF) (RTF)
  • Isopod Experiment Assessment Rubric (PDF) (RTF)
  • Paper and pen


Prior to teaching this lesson, you will need to:

Preview all of the video clips and Web sites used in the lesson.

Download the video clips used in the lesson to your classroom computer, or prepare to watch them using your classroom’s Internet connection.

Bookmark the Web sites used in the lesson on each computer in your classroom. Using a social bookmarking tool such as or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.

Procure live isopods (pill bugs) for the students to observe and use. Isopods are very easy to care for in the classroom, and can either be collected in the wild or ordered from a biological supply company. For more information on collecting, rearing, and keeping isopods in the classroom, see the two Isopod references mentioned in the “web sites” section.

Familiarize yourself with accepted guidelines for the safe and responsible handling of live animals in a classroom setting. The NSTA’s Responsible Use of Live Animals and Dissection in the Science Classroom and the Institute for Laboratory Animal Research’s Principles and Guidelines for the Use of Animals in Precollege Education are good general resources. Also check to see if your state or district has special animal handling guidelines or requirements.

Make copies of the Isopod Research Organizer and the Isopod Experiment Organizer for each student.

Next: Proceed to Activities

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