This investigative case module was prepared as part of a BioQUEST faculty development workshop entitled NSF Chautauqua Short Course: Investigative Cases at Christian Brothers University in July 2004. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

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Investigative Cases
The Case: When Harry met Sally

   When Harry met Sally at the tanning salon, she asked, “How did your doctor’s appointment go?”

   “Oh, pretty good, Sheila. But, he added, "she removed two moles from my face because they had grown bigger and became darker. She told me she was going to analyze them, and to call back in a week to see if they were cancerous.”

   Sally became alarmed because she had a friend who had just died from skin cancer. She said, “I didn’t know that you go out in the sun very often.”

   “I don’t usually,” Harry replied, “I heard that the ozone layer is thinning and that can cause skin cancer. So, when I do go out, I always use sunscreen and wear long sleeves and my Crocodile Dundee hat. I just don’t know where I could have been exposed to ultraviolet radiation. Everyone knows that these salons use safe light to tan with.”

   “But didn’t you grow up in Australia?” asked Sally.

   “That’s right," Harry agreed. "I was born in Sidney, and lived out near Alics Springs until I came here to go to college.”

   “Maybe that’s when you were exposed. After all, the ozone layer’s been thin for many years, and it is worse in the southern hemisphere.”

   “Then maybe I’ve got you Yanks to blame for my cancer,” offered Harry.

   "That may be so..." said Sally, "but I heard the ozone layer is getting thicker again since we outlawed freon. And you definitely have us to thank for that."

Case Author:
Albert Burchsted College of Staten Island

Case Analysis

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?

Learning Goals


Key questions include:

1.Is there a relationship between sunlight and skin cancer?

2. What is cancer?

3. What physiological processes may cause cancer?

4. What does the ozone layer have to do with skin cancer?

5. How do environmental factors affect gene expression?

6. How does ozone filter ultraviolet light?

7. Do tanning salons use safe light?

8. What component of sunlight may cause cancer?

9. What caused the thinning of the ozone layer?

10. Why is cancer still increasing even though the ozone layer is beginning to be restored?



Investigations and Activities

1. Examine data on the incidence of skin cancer both in the US and Australia and compare these data with the amount of ultraviolet radiation reaching earth in these two regions.

2. Examine data on the incidence of skin cancer in persons who frequent tanning salons.

3. Investigate genetic changes that result in cancers.

4. Describe the progression of skin cancer and determine how dangerous it is at each stage of development.

5. Examine the causes of the ozone layer thinning and its reestablishment.

6. Perhaps plot the lag time between release of CFCs and ozone thinning, and development of cancer.

7. Student groups will select one or two topics to investigate.



Textbooks on ecology, environmental science, and biochemistry.

Journal, Internet, and newspaper articles on ozone layer thinning and its reestablishment.

Maps of the world.

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items

1. Charts showing the incidence of skin cancers in the US and Australia over the past fifty years.

2. Charts showing the thickness of the ozone layer over the US and Australia over the past fifty years.

3. Links to medical journal articles on the relationship between tanning salons and skin cancer.

1. RFCatalog2003.jpg
2. Skin_Cancer_Austr_82-94.gif
3. 79_ozone_hole.gif
4. amp_p3.jpg
5. LAtan1.gif
6. 90_ozone_hole.gif


Student Products

1. Group poster presentation to the class describing the segment of the problem the group selected.

2. FAQ question and answer web page on their project.

Assessment and Evaluation Plan

1. Participation during the process:

• Involvement in the development process
• Suggestions to group members
• Collaboration with other groups
• Questions of the instructor

2. Group presentation to the class:

• Materials prepared by each member
• Oral presentation by each member

3. FAQ site – group grade



This will be presented in a General Biology course for science majors. It can be used either at the end of cell division or as an introduction to environmental pollution.
I expect it would encompass three or four hours of class time – about one week.

Course name:
General Biology for Science majors
Likely sequence in syllabus:
end of cell division or as an introduction to environmental pollution
Time during term:
3-4 hours
Students in course:
science majors
Collaborative elements:
Group work, presentation
Additional notes:



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