The Critical Zone

Lesson Overview


In this final lesson of the semester, you will be introduced to some of the basic concepts of system modeling. We will accomplish this through a series of readings and an activity. The readings will introduce you to the basics of system modeling and some of the specifics (including quantification) of human impacts to the biosphere, atmosphere, hydrosphere, lithosphere, and soil (i.e., the Critical Zone). Your final task for the semester will be to create a qualitative Critical Zone system model.

What will we learn about in Lesson 12?

  • What is a system? What is the difference between quantitative and qualitative system modeling?
  • How (and when) have humans altered global erosion rates?
  • What are the consequences of human domination of ecosystems?
  • How is human-induced climate change expected to alter the hydrologic cycle?
  • What global-scale, human-induced changes can be observed in soils? What is the role of agriculture in these changes?
  • What are some of the consequences of changes to our soils?
  • Are there adaptive actions humanity can take to lessen negative impacts on the Critical Zone and soils?

What is due for Lesson 12?

Lesson 12 will take us one week to complete. As you work your way through these online materials for Lesson 12, you will encounter additional reading assignments and hands-on activities. The chart below provides an overview of the requirements for Lesson 12. For assignment details, refer to the lesson page noted.

Please refer to the Calendar in Canvas for specific time frames and due dates.

Lesson 12 assignments
Create qualitative Critical Zone system model page 3 Submit to the "Lesson 12 - CZ System Model" dropbox in Canvas


If you have any questions, please post them to our Questions? discussion forum (not e-mail), located under the Discussions tab in Canvas. I will check that discussion forum daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate.