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Show title


 
Teaching Guide
Growing Prairie
Indentifying Species
Follow Your Nose
Quiz
Image of Bison

Several hundred years ago, the Great Plains supported a stable and bio-diverse prairie ecosystem. Today, that ecosystem teeters on the edge of extinction. In "Prairie Comeback", you saw how the grazing behavior of free-roaming bison, paired with occasional burning of the grasses, is helping to restore a healthy tallgrass prairie to one corner of Oklahoma. By using burning and grazing to cut back ground cover, scientists have created a more successful niche for a diversity of plant life, specifically broadleaf species. In this activity, you'll examine the affect of various levels of ground shade on new seedlings. But, don't worry - you won't have to eat any plants! In fact, you won't even use living organisms to create the cover. You'll build the variable canopy out of a plastic grid.


Note to educators

 

OBJECTIVE
This activity page will offer:

  • an opportunity to germinate seeds and maintain seedlings within a structured and controlled environment
  • an opportunity to observe how a canopy effects seedling growth
  • inquiry experience in which students compare and contrast the effects of canopy coverage on seedling growth

MATERIALS

  • packaged assortment of grass seeds
  • shoebox with cover
  • scissors
  • plastic transparency film (for overhead projectors)
  • tape ruler
  • permanent marker (to mark plastic)
  • small flowerpots
  • soil

Image of  Shoebox

 

PROCEDURE

  1. Work with a partner. Fill three small flowerpots two-thirds full with soil. Plant a similar assortment of seeds in each of these pots. Water appropriately as described on the seed package.
  2. Use scissors to carefully cut three square windows in the top of a shoebox. The windows should be spaced evenly along the length of the cover. Each window should be about 6 centimeters on each side.
  3. Cut out three squares of plastic transparency film. Each square should be about 10 centimeters on each side.
  4. Use a ruler and permanent marker to create a 1 cm by 1 cm grid across the surface of all three squares.
  5. On one of the grids, fill in half the squares with the black marker. These selected squares should be a random assortment spread out over the whole grid. The marker must completely fill each square, so that this small region does not transmit light.
  6. On another grid, fill in 95 boxes with the black marker. Only five random boxes should remain transparent.
  7. Leave one of the grids without any boxes filled in.
  8. Use tape to secure a grid to each of the cut-out windows in the shoebox, placing the grid with half of the boxes filled in in the center window.
  9. Position a seeded flowerpot beneath each of the windows. Close the box.
  10. Water as necessary, but remember to replace the cover as soon as the plants are watered.
  11. Each day, examine the soil for signs of seed germination. Record all of your observations in a laboratory journal. As the seedlings emerge, compare and contrast the success and health of these plants.
  12. Observe the plants for at least a three-week period. Record your observations on each plant community, comparing and contrasting any observed differences between the three pots.
  13. After three weeks, count the number of plants in each environment. Measure the height of each shoots, as well as the length and width dimensions of the leaves (use higher math calculations to obtain leaf area). Record your data.

STUDENT NOTE: If the plants grow too tall for the shoebox enclosure, you'll need to create your own design for maintaining the experiment.

QUESTIONS

  1. How did the environment of the three flowerpots differ?
  2. Which of the three pots had the best growth?
  3. From your observations, how might ground cover affect the successful growth of seedlings?
  4. How can this activity be applied to bison grazing?

 

EXTENSIONS

CRITICAL THINKING

Should minor fires be allowed to burn out by themselves in remote, unpopulated regions? Supporters argue that smaller fires should be allowed to burn since they keep the forest stable. These fires often clear underbrush, giving trees space to repopulate. Opponents argue that continual fires prohibit young trees from growing into mature forests that can be used for commercial purposes. They also argue that such fires prevent continual public access to unblemished natural regions. What do you think? Some other questions to consider: should wildlife be saved at any cost? What constitutes a minor fire?

NUTRIENTS FROM ASH - INQUIRY IN ACTION

How could you determine whether the ash from burned wood contains nutrients essential for plant growth? Design a strategy for inquiry that would test how the introduction of wood ash into sterile soil affects vegetation growth. Share your controlled experimental design with your instructor. With his or her approval, perform your experiment. Upon its conclusion, discuss your results with other class members.

BISON AND NATIVE AMERICAN NATIONS

Research the historical relationship between Native American nations and the bison that roamed the prairie. How did these communities interact? What sort of products, supplies, and food did the animal offer? Was any sort of preservation program established to ensure the continual existence of the bison herds? Why or why not? How did the arrival of the European immigrants affect the bison herds, and the Native Americans?

 

WEB CONNECTION

Smithsonian National Zoo prairie site

American Buffalo: Spirit of a Nation
Detailed site for this PBS program about American Buffalo

Friends of the Prairie Learning Center
Information for educators and students on the natural history of the prairie. Classroom activities and resources are offered.


Answers

The activities in this guide were contributed by Michael DiSpezio, a Massachusetts-based science writer and author of "Critical Thinking Puzzles" and "Awesome Experiments in Light & Sound" (Sterling Publishing Co., NY).

Academic Advisors for this Guide:

Corrine Lowen, Science Department, Wayland Public Schools, Wayland, MA
Suzanne Panico, Science Department, Fenway High School, Boston, MA
Anne E. Jones, Science Department, Wayland Middle School, Wayland, MA

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