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Biodiversity: The Worms Crawl, In The Worms Crawl Out

 
Lesson Description:  
Students work in cooperative groups of  2 - 4, read background information, and design an experiment to test for the effects of precipitation, and migration of earthworms as a result of global warming. 

 
 
 
 
 
Background:  
Certain atmospheric gases, such as carbon dioxide and methane are called greenhouse gases. Such gases allow sunlight to reach Earth. However, they prevent most the infrared radiation that is then produced from returning directly to space. This natural trapping of infrared rays is called the greenhouse effect. The greenhouse effect helps warm the Earth and its atmosphere. 

Some greenhouse gases, such as carbon dioxide, have been building up quickly in the Earth's atmosphere over the past several decades. A number of direct studies on the atmosphere have shown this. Other studies have shown that the concentration of carbon dioxide has been building up in sea water as well. The sea water absorbs some of the excess carbon dioxide from the atmosphere. 

Extra heat is being trapped by these gases in the atmosphere. This human caused increase in temperature is called global warming. There is evidence that climates around the world may be changing as a result of global warming. To better understand the global effects of air pollution and the loss of biodiversity, review the articles linked to this investigation before beginning. You should also understand the following terms before you perform this investigation: 

        Migration        Habitat        Extinction        Biodiversity        Abiotic factors 
 
 
 
Teacher Notes: Explain to students that this is a simple modeling activity. 
Students should do the additional readings prior to the activity. Look into the availability of the materials that are recommended for part B. If students do not have internet access, you may need to make copies of the readings for them. 
Students are responsible for gathering necessary materials for part B. 
 
Time needed:
Approximately 3-5 class periods. Sufficient time should be given for completion of the pre lab, discussion of the student  lab design, approval by the teacher, time to gather materials and run the lab, and time to present the results to the class.

Grade Level:
Appropriate for grades 7 - 12. Adaptable for younger students.

Hazards/precautions:
Care should be taken when working with live organisms.
Caution is recommended when working with heat or electricity.
Red worms can be substituted for earthworms.
Students may want to look for their own worms instead of purchasing them from any local bait shop.

Materials:
        Long tray or box
        Heat source (lamp)
        Soil
        Water (tap)
        Paper cup
        Pin (to poke holes in cup)
        Foil (to line cardboard box)
        String (optional)
        Thermometers (optional)
        Earthworms
 
 

The Student Lab:

    Introduction:

Different kinds of organisms occupy specific ecological niches. Certain climatic conditions exist in these niches. Because of temperature increases associated with global warming, the habitats may no longer support organisms that once lived in them. Certain other abiotic factors, such as the quantity of rainfall, may also change as a result of global warming. As these factors change, some of the organisms not adapted to the new conditions will migrate. Others will perish. The result can be a widespread habitat destruction and loss of biodiversity.

    Purpose:

      In the pre lab of this investigation you will infer what will happen to an organism
      as conditions in its habitat change.
     You will then design and conduct an experiment to test one of the conditions
      found in the pre lab as a result of global warming.

    Pre lab:

  1. Imagine an extended valley made up of two climate zones. The northern half of the valley has an average yearly temperature of 15oC and an average yearly precipitation of 50 cm. The climate values for the southern half are 20o C and 40 cm. The valley is bordered by high mountains on either side, making it impossible for worms to migrate out of the valley.
  2. To survive, the worms require that the average yearly  temperature remains below 22oC and that the level of precipitation remains above 35 cm. The worms have a maximum migration rate of 10 km/yr.
  3. Now imagine that global warming is taking place at a rapid rate. Scientists determine that over the next ten years, the average temperature throughout the valley will rise by  0.5oC per year. Average rainfall will decrease by 1 cm per year. Calculate the new values for both climate zones within the valley as a result of global warming. Now answer questions 1 & 2 of the evaluation & assessment page.
  4. The worms are now permitted to respond to the environmental change (assume that food is not an issue). Now answer questions  3 - 5 of the evaluation & assessment page.
    Student lab:
        1. Formulate an hypothesis based on one factor concerning global warming and changes in ecological niches.
        2. Design an experiment to test your hypothesis.
        3. Be sure to include the following in your experimental design;
                    a. Purpose
                    b. Equipment
                    c. Procedure
                    d. Observations
                    e. Conclusion
        4. Be sure to get teacher permission before attempting the lab and set
            parameters so as to not harm any organisms.
 

Evaluation :

    Pre lab:

        1. Calculate the new values for the North and South climate zones.
                    North                                South
                    temp:                                    temp:
                    precipitation:                         precipitation:
 

        2. How do the new values for the North climate compare with the
            original values of the valley?
 
        3. Where would you expect to find the greatest concentration of worms
            in the original climate?
 
        4. What would you predict after global warming? (refer to ques. 3)
 
        5. What could you infer about the population of worms originally
            found in the southern most regions of the valley?
 

    Student lab:

       . 6. Given what you have learned from this investigation, why are changes that
            might result from global warming dangerous to individual species and to
            life as a whole on Earth?

Extensions:

  1. Conduct research on the internet to find out more about global warming and evidence that global warming may be taking place.
  2. Investigate changes that may have already been caused by such warming and changes that may occur. Write a report on your findings.
  3. Design and test for other factors that would be affected by global warming such as precipitation and its effects on earthworms.
  4. Test for the effect of temperature on other such organisms such as pill bugs, brine shrimp, or meal worms.

Assessment:
Use the following links to help you develop innovative alternative forms of assessment.

          Concept mapping links:
           1) Lesson in teaching concept maps to students-visual included
           2) More in depth example of a concept map - detailed visual included
           3) Teacher instructions and tips

            Rubrics:
             1) Teacher Links On Rubrics
             2) Rubric Information - Advanced Secondary
 

Bibliography and Additional Sources:

      Global Warming and Biodiversity: Laboratory Investigation, Addison Wesley
      (biodiversity lab was adapted from this material)

      Sierra Club
      This site includes additional information on biodiversity and environmental issues

      Atmospheric Research and Information Center
      General information dealing with greenhouse gases, atmosphere composition, and global warming

       Los Angeles Times
       This article describes the effect of global warming on Edith's Checkerspot Butterfly
 
       Sea World-Diversity of Life
       Teacher guide to hands-on activities teaching students about seals, sea lions, and walruses, and the ecology of the ocean.
 

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