This activity is part of the Detours and Distractions: How Humans Impact Migration Patterns unit
l. Activate and build on students’ prior knowledge about ecosystems.

  • Read aloud and write on the board the following quotes from the Ecosytem encyclopedic entry.
      • “Every factor in an ecosystem depends on every other factor, either directly or indirectly.”
      • “The whole surface of Earth is a series of connected ecosystems.”
  • Invite students to think-pair-share and come up with examples and ideas about what the quotes above mean. Then invite students to share with the class; record student responses to be displayed in the classroom.
  • Use some of the following prompts to elicit students’ prior knowledge about ecosystems:
      • What is an ecosystem?
      • What are some living and nonliving components of an ecosystem?
          • In the discussion, help students identify and distinguish between biotic vs. abiotic factors.
          • Biotic factors are living parts of an ecosystem, such as predators, plants, and bacteria.
          • Abiotic factors are nonliving parts of an ecosystem, such as wind, temperature, and elevation.
      • What are some examples of ecosystems? (deserts, your backyard, rainforest, Arctic tundra, the deep sea)
      • How are things in ecosystems related?
      • What happens when you change one component of an ecosystem? (Possible responses: Other components are impacted. There could be few or many wide-reaching effects causing the ecosystem to be greatly stressed or, in extreme cases, collapse).
  • Distribute the Ecosystem Illustration handout to each student. Allow time for students to complete these individually, and for students to swap handouts with a peer to check and add to their work.

2. Introduce students to the Greater Yellowstone Ecosystem resources.

3. Prepare students to diagram how changes in the ecosystem can have cascading effects.

  • Write the definition of cascading effects where all students can see: a series of secondary changes that are triggered by the primary changes to a key species in an ecosystem.
  • Illustrate the concept of cascading effects in an ecosystem by showing the Wolves of Yellowstone video.
  • After the video, show the Trophic Cascade Scenario as an example of a cascading effects diagram.
  • On Part 2 of the research guide, have students use their knowledge of the elk migration and cascading effects to diagram the following scenario:
      • What would happen if the temperature got too hot for grass to grow where it normally does? (If the temperature gets too hot, then grass may grow at a slow rate. This might mean that elk populations won’t have an adequate supply of food to support their populations. Or grass won’t grow where it normally does, meaning elk migration patterns may change.)
  • Ask students to work with a partner and explain their ecosystem and their cascading effect diagram to each other. Invite volunteers to share their diagrams with the class. Collect the research guides upon completion.

Informal Assessment

Student responses on the Elk Migration: Yellowstone Ecosystem Research Guide, as well as their participation during class discussions, can be used to informally assess their understanding of ecosystem(s), abiotic and biotic factors in ecosystems, the main components of the Yellowstone National Park Ecosystem, and how migrating elk interact with the ecosystems they travel through. Students’ peer explanations can be used to assess their ability to describe how changes in ecosystems can have cascading effects.

Extending the Learning

  • Show students the Who’s in My Backyard? or Floodplains Ecosystem infographics. Students could replicate this activity’s discussion by working in pairs or groups, or as a homework assignment.
  • Visit a local ecosystem and have a similar discussion. This can include the school grounds, a surrounding neighborhood, or a nearby unique ecosystem, such as a forest, desert, mountain, lake, river, or ocean.

Subjects & Disciplines

  • Biology
  • Conservation
  • Geography

Learning Objectives

Students will:

  • Understand how migrating elk interact with the ecosystems they travel through.

Teaching Approach

  • Project-based learning

Teaching Methods

  • Discussions
  • Research
  • Self-directed learning

Skills Summary

This activity targets the following skills:

  • 21st Century Student Outcomes
  • Critical Thinking Skills
    • Analyzing
    • Remembering
    • Understanding
  • Science and Engineering Practices
    • Asking questions (for science) and defining problems (for engineering)
    • Obtaining, evaluating, and communicating information

Connections to National Standards, Principles, and Practices

Common Core State Standards for English Language Arts & Literacy

  • CCSS.ELA-LITERACY.SL.7.1:  Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on Grade 7 topics, texts, and issues, building on others' ideas and expressing their own clearly.
  • CCSS.ELA-LITERACY.SL.7.2:  Analyze the main ideas and supporting details presented in diverse media and formats (e.g., visually, quantitatively, orally) and explain how the ideas clarify a topic, text, or issue under study.

Next Generation Science Standards

What You’ll Need

Materials You Provide

  • Paper
  • Writing utensils

Required Technology

  • Internet Access: Required
  • Tech Setup: 1 computer per classroom, 1 computer per pair, Monitor/screen, Speakers

Physical Space

  • Classroom


  • Large-group learning
  • Small-group learning
  • Small-group work

Background Information

Ecosystems are geographic areas where plants, animals, and other organisms, as well as weather and landscape, work together to form a bubble of life. The whole surface of the Earth is a series of interconnected ecosystems, and whether indirectly or directly, every component in an ecosystem relies on every other factor. From deserts to the Antarctic tundra to tidepools, there are many different kinds of ecosystems. Cascading effects in ecosystems are a series of secondary changes that are triggered by the primary changes to a key species in an ecosystem. Understanding ecosystems, and how the components are interrelated, can aid in understanding how animal migration patterns are shaped by, and help shape, their ecosystems.


The Greater Yellowstone Ecosystem is one of the largest nearly intact temperate zone ecosystems on the planet. Yellowstone National Park is at the heart of this wider ecosystem, and serves as an ideal example of a complex ecosystem with many interacting factors and stakeholders. The ecosystem is diverse with biotic and abiotic factors that influence the ecosystem, such as hydrothermal vents, lakes, rivers, and iconic wildlife, like elk (who have a well-studied annual migration), wolves, bison, foxes, and many more. The human use of Yellowstone National Park for recreation and the surrounding areas for hunting, fishing, and development provide for a great case study of how humans impact animal migration.



characterized by the absence of life or living organisms

animal migration

process where a community of animals leaves a habitat for part of the year or part of their lives, and moves to habitats that are more hospitable.


having to do with living or once-living organisms.

cascading effect

series of secondary changes that are triggered by the primary changes to a key species in an ecosystem.




unplanned or temporary path.


to divert or draw attention away from something.


community and interactions of living and nonliving things in an area.

growth rate

measurement of how fast something increases in size during a particular period of time.


to influence or have an effect on something.

migration pattern

predictable movements, in time and space, of a group of animals or people.


image or impression of an object used to represent the object or system.




total number of people or organisms in a particular area.


animal that hunts other animals for food.


animal that is hunted and eaten by other animals.


substances such as water, air, shelter, and food sources which are valuable in supporting life.


degree of hotness or coldness measured by a thermometer with a numerical scale.

Yellowstone National Park

large national park in the U.S. states of Wyoming, Idaho, and Montana.

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