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  • Subject:
  • |
  • Grade(s): 6-8
  • |
  • Duration: Three class periods

Lesson Plan Sections


Students will understand the following:
1. Even a small area of land can offer wide biodiversity in plant life; that is, an ecosystem is composed of many different organisms.
2. Each species of plant has its own name.
3. Each ecosystem will contain evidence of diversity within each species.


For this lesson, you will need:
Access to an unmanaged part of the school grounds or of a local park
Plastic bags for carrying leaf specimens
Field guide to leaves


1. Challenge your students to assess the biodiversity of their own community. Take them to a relatively unmanaged area of your property (or, for urban schools, to a local city park). Determine beforehand that the area does not contain any poisonous plants.
2. When you've arrived at the site, ask students to collect as many different leaf types (representing distinct species) as they can. (You may want to set some ground rules to ensure that plants are not damaged unnecessarily.)
3. Back in the classroom, make a list of the different leaves that were collected. (Naming the species is of secondary importance for assessing biodiversity, but it will be interesting to give your students the time and material to determine names of each plant.)
4. Students will be amazed at how many different plants they found, even in tiny urban patches of ground. This discovery should help them understand the first level of biodiversity—that an ecosystem is composed of many different organisms.
5. Next, choose one of the most commonly occurring species in the area the students explored, and tell your students to return to the same area. Each student is to bring back a single leaf of that species.
6. When students' second collection is complete, let students notice and speak about the fact that even though their leaves all come from the same species of plant, the leaves all look somewhat different. This step should help students understand the second level of biodiversity—that each ecosystem will contain evidence of diversity within each species.
7. Finally, ask students to assess the biodiversity of an area near home (or in a different city park or in a different area of the park already explored) by using the same sampling methods.
8. When students bring in their samples, lead a discussion about their findings in an attempt to assess the plant biodiversity of your community or city as a whole.

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In addition to picking the leaves, older students should bring drawing pads and pencils with them so that they can sketch insects in this ecosystem. As with the leaves, they should identify as many of the species they've drawn as possible.

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Discussion Questions

1. Valleys such as Yosemite are homes to a wide range of plants and animals. Discuss how abrupt changes in elevation make vastly different habitats possible.
2. The common wisdom says that Native American culture as it existed before Europeans arrived here was much more "in tune" with nature's rhythms than modern American culture. Debate whether cultural "progress" has to include the loss of this empathy for nature.
3. Ansel Adams made his fame almost entirely through his photographs of the Yosemite Valley. Discuss why so many artists find inspiration in using natural scenes in their artwork. What creative, artistic, or inspiring qualities does nature possess?
4. Yosemite National Park attracts around five million visitors per year, making it one of the most visited places on Earth. Such a large number of visitors cannot help but cause damage to this wilderness area. For the sake of preservation, should human travel in wilderness areas be restricted by law? Why or why not?
5. John Muir, the founder of the Sierra Club, said, "Any fool can destroy a tree. It cannot run away." He was referring to loggers, who he believed would rather make a profit from the wilderness than preserve and enjoy it. Create a list of businesses that could use the wilderness areas of America without destroying them—while still making a profit. Explain your ideas in each case.
6. Grey wolves were once common in most states, but they became endangered. Recently, grey wolves have been reintroduced into a few very remote wilderness areas. Do you think they could be reintroduced into Yosemite National Park? What problems might occur? Who would support such a program and who would resist it?

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Establish before you leave the classroom a minimum number of specimens for each student to collect, and note who does not meet the criterion, who meets it, and who exceeds it.

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New National Park
National parks in any part of the United States are created by an act of Congress. Behind every national park is a story about how it was founded. Have your students visit the Web site of the U.S. National Park Service atnpsto locate information about the history, habitats, and natural features of a nearby national park. When their research is complete, divide your students into planning groups, and challenge each group to develop a proposal for establishing a new national park in your state or county.
You may ask students to begin this project by examining a state population map and finding areas where population is low. Then ask your students to determine what unique features the new park will offer. They can create a map of the natural features of their park, name it, and establish wildlife habitats for various species within its borders. Finally, ask your students to write up a rationale for creating a new national park in a specific location and adding it to the existing parks system.

Traveling Lightly
Ecotourism has become a large industry in the United States and around the world. The premises of this kind of vacationing are that people should visit locations that are environmentally and educationally significant (e.g., the Galapagos Islands) and they should treat any location they visit in an environmentally sustainable manner, making sure that the local features and wildlife remain unchanged by the visitors' presence.
Have your students choose an unfamiliar biome (rain forest, desert, tundra, etc.) and locate an interesting example of this biome somewhere in the world. They should then develop a two-week ecotour of this spot, producing a trifold travel brochure that includes the itinerary, information about accommodations, and side excursions for the trip.
This activity may serve as an introduction for a school trip to a state or national park.

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Suggested Readings

Ansel Adams and Andrea G. Stillman, eds. Little, Brown and Company, 1995.
In this beautiful book, Adams shares his writing and photography of the Yosemite Valley. Adams wrote that he knew his destiny when he first saw Yosemite at age 14. He returned every year until his death to photograph the lakes, streams, waterfalls, and craggy peaks.

Yosemite: An American Treasure
Kenneth Brower. National Geographic Society, 1997.
This book contains 100 full-color photographs as well as detailed maps and firsthand information about Yosemite. The beauty and history of the park is captured in a detailed narrative explaining Yosemite's importance to America and its people.

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Yosemite National Park Photos
Excellent collection of pictures of Yosemite that would be good fo rstudent research

Yosemite Roadside Geology
Lots of pictures and roadside information from Yosemite

Yosemite Association
Descriptive information about Yosemite

John Muir Flashbacks
Journal entries of John Muir are available here

Yosemite Web Index
Lots of information on John Muir's Life, trails, literature, and favorite quotations

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Click on any of the vocabulary words below to hear them pronounced and used in a sentence.

speaker    biodiversity
Definition: The biological diversity in an environment as indicated by numbers of different species of plants and animals.
Context: An example of Yosemite's extraordinary biodiversity is the fact that the park contains one-third of all of the bird species represented in North America.

speaker    ecosystem
Definition: The complex of a community of organisms and its environment functioning as an ecological unit.
Context: Most ecosystems are extremely complex, containing many different kinds of biological relationships.

speaker    erosion
Definition: The action or process of wearing away by the action of water, wind, or glacial ice.
Context: Wind, water, and ice caused the erosion of the sedimentary rock, exposing the underlying granite.

speaker    glaciate
Definition: To subject to glacial action; to cover with a glacier.
Context: We know that glaciation is responsible for shaping the majority of the Yosemite Valley.

speaker    habitat
Definition: The place or environment where a plant or animal naturally or normally lives and grows.
Context: Trees are an important part of all the habitats in Yosemite, from the foothill woodlands to the mountain alpine areas.

speaker    sediment
Definition: The matter that settles to the bottom of a liquid.
Context: Sediment deposits usually occur on stream bottoms after heavy rainfalls.

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This lesson plan may be used to address the academic standards listed below. These standards are drawn from Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education: 2nd Edition and have been provided courtesy of theMid-continent Research for Education and Learningin Aurora, Colorado.
Grade level: 6-8
Subject area: science
Understands basic Earth processes.
Knows processes involved in the rock cycle (e.g., old rocks at the surface gradually weather and form sediments that are buried, then compacted, heated, and often recrystallized into new rock; this new rock is eventually brought to the surface by the forces that drive plate motions, and the rock cycle continues).

Knows how landforms are created through a combination of constructive and destructive forces (e.g., constructive forces such as crustal deformation, volcanic eruptions, and deposition of sediment; destructive forces such as weathering and erosion).

Grade level: 6-8
Subject area: science
Understands how species depend on one another and on the environment for survival.
Knows factors that affect the number and types of organisms an ecosystem can support (e.g., available resources; abiotic factors such as quantity of light and water, range of temperatures, and soil composition; disease; competition from other organisms within the ecosystem; predation).

Knows that all individuals of a species that occur together at a given place and time make up a population, and all populations living together and the physical factors with which they interact compose an ecosystem.

Knows relationships that exist among organisms in food chains and food webs.

Grade level: 6-8
Subject area: science
Understands the cycling of matter and flow of energy through the living environment.
Knows how energy is transferred through food webs in an ecosystem (e.g., energy enters ecosystems as sunlight, and green plants transfer this energy into chemical energy through photosynthesis; this chemical energy is passed from organism to organism; animals get energy from oxidizing their food, releasing some of this energy as heat).

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R. Mark Herzog, assistant supervisor of science education, Harford County Public Schools, Maryland.

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