Earth Systems Evidence and Model Revision

Name:

Date:

Part 1: Source Set and Evidence

Data table: Effects observed after vegetation cover decreased

Vegetation cover: 80% → 40%

Average monthly runoff: 2.0 inches → 3.5 inches

Average soil loss: 1.2 tons per acre → 2.8 tons per acre

Nearby stream temperature: 64°F → 69°F

Interaction diagram

Sun ──energy transfer──> Biosphere (plants)

Atmosphere ──water vapor──> Hydrosphere ──runoff and sediment──> Geosphere

Biosphere ──water vapor and oxygen──> Atmosphere

Less vegetation ──more runoff──> soil loss ──less soil──> less vegetation

Arrows show matter flow, energy transfer, or feedback.

Technical text

When vegetation is removed from a land area, the biosphere changes first. Plant roots no longer hold soil in place, and fewer leaves slow falling rain. As a result, more water moves across the surface as runoff. Runoff can carry soil particles into streams, changing the geosphere and hydrosphere. Cloudy water may absorb more sunlight, and water with fewer shaded banks can become warmer. Warmer stream water holds less dissolved oxygen, which can affect fish and other organisms in the biosphere. The atmosphere may also change because fewer plants remove carbon dioxide through photosynthesis and release oxygen. These connected changes can create feedback. For example, soil loss makes it harder for new plants to grow, which can cause still more runoff and erosion. Energy from sunlight drives photosynthesis and warms land and water, while matter such as water, soil, and gases moves among the four spheres.

1. Which source gives quantitative evidence about runoff, soil loss, and stream temperature?

2. Identify one specific detail from the diagram that shows matter flow and one that shows energy transfer.

3. According to the technical text, why can removing vegetation lead to more soil loss?

Part 2: Revise an Earth Systems Model

Choose one component to change. You may use reduced vegetation, increased rainfall, warmer air, or another teacher-approved change.

4. Changed component and sphere affected first:

5. Predict at least two effects on other Earth spheres. Name the sphere for each effect.

6. Revise your four-sphere model. Include the geosphere, hydrosphere, atmosphere, and biosphere. Add labeled arrows for matter flow, energy transfer, and at least one feedback connection.

Sentence starters: “Because matter moves from ___ to ___, ___ may happen.” “Energy from ___ causes ___.” “This creates feedback because ___.”