Students should produce a graph that resembles the one pictured below.  Students may produce the graph manually or with a computer-based spreadsheet software.
 
 

The answers below should be used as a guide for evaluating students’ responses to the questions posed on the student worksheet.

1. The scatterplot indicates a positive relationship between vegetation cover and precipitation.
2. The relationship between vegetation cover and precipitation appears to be relatively strong.  A strong relationship allows me to predict fairly accurately the amount of vegetation cover as a function of precipitation.
3. Other factors include temperature, soil conditions and fertility, topography, length of day (latitude), and altitude, among others.
4. A decrease in precipitation would most likely result in a decrease in the percentage vegetation cover.  An increase in precipitation would most likely increase the percentage vegetation cover.
5. The relationship appears to be linear until about 110 inches/year of precipitation, where the relationship levels off.  This suggests that beyond this point additional precipitation does not produce an increase in vegetation cover.
6. An increase or decrease in precipitation will affect the vegetation cover in many ways.  If an increase in precipitation occurs, only those plants that can withstand the additional moisture will survive.  If a decrease occurs, only those plants that can withstand the drier conditions will survive.  In both cases, the changes will affect various human and natural systems.  For example, precipitation changes will have impacts on virtually every terrestrial ecosystem and may result in a shift to a different land cover.  Precipitation changes will also affect the ways in which humans can use the land.  Farmers may have to alter the types of crops they plant, timber companies may have to migrate, gardeners may have to change their backyard crops, etc.

The answers below should be used as a guide for evaluating students’ responses to the questions posed on the student worksheet.  If you have used your own images rather than those provided, responses will vary.

Part A: Satellite Images (using the images of Amazonia provided in Supporting Material 2.2a)

1. Deforestation is apparent in Image B.
2. The lighter colors and the geometric shapes on Image B indicate a change in land cover.
3. The geometric shapes indicate that the changes were human-induced.

1. The increased portion of light shading in the image of Time B is evidence of a land cover change.
2. The GIS images are more coarse, meaning the image shows less detail.  It also shows only two classifications.  The coarse spatial resolution means that we can’t be as precise in delineating areas of deforestation.

The essays for this exercise will vary based on the film chosen for review.  Use the criteria below to evaluate the essays.  See Notes on Active Pedagogy for additional suggestions on evaluating students’ writing.

• Does the student demonstrate an understanding of land-use/cover change within the filmmaker’s portrayal?
• Does the student address all or most of the eight questions that they were asked to consider while viewing the film?
• Is the essay well-written and in a movie review format?

 

Activity 2.4:  Our Town:  A Historical Reconstruction of Terrestrial Change

 

Option I
The answers to the questions on the student worksheet will depend on the photos that the instructor chooses for the exercise.  The students’ one-page memo should demonstrate an understanding of driving forces and their connections to terrestrial change.

Option II
Evaluation of this long-term project is left to the discretion of the instructor.  The structure and results of the exercise will vary based on the size of the class, the amount of time allotted, and the availability of multiple data sources.