7 Environmental Systems and Ecosystem Ecology Part C PowerPoint® Slides prepared by Jay Withgott and Kristy Manning Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

The rock cycle—a key environmental system Rocks change from one form to another over time. Igneous rock = of volcanic origin; cooled magma that may flow across Earth’s surface as lava Sedimentary rock = mineralized sediments (layers of mud, dust, or sand) formed by lithification Metamorphic rock = transformed by extreme heat or pressure

The rock cycle

Plate tectonics The process by which plates of crust move across Earth’s surface, atop its malleable mantle and molten core Over millions of years, continents change position. Movement = only 2–15 cm (1–6 in) per year Plate tectonics underlies earthquakes, volcanoes.

Global map of tectonic plates

Plate boundaries Tectonic plates can meet in several ways. Magma seeps up beneath ocean at divergent boundaries. Earthquakes occur at transform boundaries where plates slip alongside each other. At convergent boundaries where one plate is subducted beneath another, volcanoes occur. Where two plates collide, mountains are formed.

Viewpoints: The dead zone Terry Roberts Paul Templet “Evidence that nitrogen fertilizer is polluting the Gulf of Mexico is not conclusive… Used correctly, fertilizer increases food production and helps protect the environment.” “The Dead Zone is driven by a massive influx of nutrients into a system no longer able to process them. … We need to act now to save these resources.”

Conclusion Physical systems and processes lay the groundwork for how life spreads itself across the planet. They include the hydrologic cycle, rock cycle, and plate tectonics, among others. Life interacts with its abiotic environment in ecosystems, through which energy flows and materials are recycled. Human activities are causing significant changes in the ways those cycles operate.

Conclusion, continued Thinking in terms of systems will help us avoid disrupting its processes and mitigation any disruptions. The systems model applied to the Gulf of Mexico can be adapted to many other environmental issues. The natural systems of our planet may provide lessons for future sustainability.

QUESTION: Review Which is part of the lithosphere? a. Air b. Plants c. Birds d. Rock e. Ice Answer:d

QUESTION: Review Carbon enters the atmosphere as carbon dioxide when… ? a. Animals respire b. Sedimentary rocks are uplifted and eroded c. Humans burn fossil fuels d. All of the above take place Answer: d

QUESTION: Review Water enters the atmosphere through the process of…? a. Precipitation b. Transpiration c. Infiltration d. Runoff Answer: b

QUESTION: Weighing the Issues If farmers’ use of fertilizers affects shrimp fishermen far downstream, who should be responsible for developing policies to address the problem? a. Governments of the farming states upstream b. Governments of the fishing states downstream c. The federal government d. Both state and federal governments Answer: any

QUESTION: Interpreting Graphs and Data Nitrogen inputs from fertilizer…? a. Have decreased since 1950. b. Are less than inputs from animal manure. c. Equal 8 million metric tons/year. d. Became the primary nitrogen source in the 1960s. Answer:d

QUESTION: Interpreting Graphs and Data Answer: b What is the general trend of the size of the hypoxic zone in the Gulf of Mexico? a. Decreasing c. Stable b. Increasing d. Increasing, then decreasing

QUESTION: Viewpoints What should be done about the Gulf of Mexico’s dead zone? a. Mandate that Midwestern farmers reduce use of fertilizers. b. Work with Midwestern farmers to find ways to lessen fertilizer runoff. c. Nothing yet; more research is needed to determine the causes of the hypoxia. Answer: any