The Critical Zone



Reading assignment

Before we begin to explore the main topic of ecological processes in the Critical Zone, I want you to first study and consider biodiversity.

To learn more about the measurement, distribution, and control of the biodiversity of life on Earth, please visit and read:

Next, read the following article, located through Library Reserves:

  • Swerdlow, J. L. (1999). Biodiversity: Taking stock of life. National Geographic, 195(2), 6–31.

Enjoy this reading. Learn that the upper reaches of the Critical Zone in an Ecuadoran forest canopy contains ~42,000 insect species per 2.5 acres. View and study the figure entitled "Life's rich tapestry" on pages 21–22. Note that the maintenance of biodiversity is attributed to a wide variety of microhabitats and environments in genetic studies of soil bacterial microdiversity, as the tropical-like variety of plant species in temperate South Africa is similarly maintained, whereas in dry central Australia the type and amount of vegetation dictate animal diversity.


As you reflect on what you just read, complete the following activity.



For this assignment, you will need to record your work on a word processing document. Your work must be submitted in Word (.doc) or PDF (.pdf) format so I can open it. In addition, documents must be double-spaced and typed in 12 point Times Roman font.

L10_ecologicalprocesses_AccessAccountID_LastName.doc (or .pdf). For example, student Elvis Aaron Presley's file would be named "L10_ecologicalprocesses _eap1_presley.doc"—this naming convention is important, as it will help me make sure I match each submission up with the right student!

  1. Consider natural scientists' drive to understand biodiversity in light of the accelerating rate of human-caused extinctions of life. While you do, think specifically about biotic interactions in the Critical Zone at your study site, and, in particular, what role extinction of various life forms may have played or play in the Critical Zone at your site. Can you think of any way to determine the land-use history of your site? A means to assess changes in forest cover?
  2. Record your thoughts as the start of a 3–4-page paper that you will continue working on later in this lesson.
  3. Save your paper as either a Microsoft Word or PDF file in the following format:
  4. Continue with this lesson.