Lecture Notes: IBESS Topic 1.2 - Systems and Models

Introduction

• Main Topic: IBESS Topic 1, Foundations of Environmental Systems and Societies.
• Subtopic: Systems and Models.
• Significant Ideas:
  • A systems approach aids in studying complex environmental issues.
  • Models of systems simplify interactions for a holistic view rather than isolating single processes.

Understanding Systems

• Definition: A system is a set of interrelated parts working together as a complex whole.
• Examples:
  • Tree: Photosynthesis through interconnected parts.
  • Monarch Butterfly: Interconnected parts like wings, antennae.
  • Flower: Another system example.
  • Non-Living Systems: E.g., California ecosystem model.

Types of Systems

• Open Systems: Exchange both matter and energy with surroundings.
• Closed Systems: Exchange energy but not matter with surroundings.
• Isolated Systems: No exchange of matter or energy with surroundings.

System Processes

• Transfers: Movement of energy/matter without changing state.
  • E.g., Rain transferring from cloud to ground.
• Transformations: Energy/matter changes state.
  • E.g., Hot tea freezing in cold air.

Models in Systems

• Photosynthesis Model:
  • Transfers: Solar energy, carbon dioxide, water.
  • Transformations: Light energy to chemical energy (glucose).
• Importance of Models:
  • Aid in understanding and predicting system behaviors.

Components of Systems

• Storages: Represented by boxes (e.g., plant as a carbon sink).
• Flows: Represented by arrows (e.g., energy, matter inputs, and outputs).
• Boundaries: Lines representing system limits.
• Processes: Transformations and transfers within systems.

System Examples

• Ecosystems: All open systems exchanging matter and energy.
• Forest Ecosystem:
  • Flows: Water, heat, energy, nutrients.
  • Closed Systems: Rare; globe cycles (hydrological, carbon) mostly closed.
• Isolated Systems: None naturally exist; hypothetical universe.

Modeling Earth

• Biosphere 2: Attempt to create a sustainable closed system.
  • Challenges in maintaining balance.
• Gaia Hypothesis:
  • Earth as a living organism.
  • Proposes atmosphere as Earth's regulating organ.

Evaluating Models

• Strengths:
  • Simplify complex systems.
  • Predict outcomes and show results to public.
• Limitations:
  • May oversimplify or be inaccurate.
  • Subject to interpretation and political misuse.

Conclusion

• Systems Approach: Essential for comprehending environmental issues.
• Models and Diagrams:
  • Construct and evaluate based on provided information.
• Key Terms: Storages, flows, inputs, outputs, boundaries, processes.

Additional Resources

• Slides by: Dr. Nina Markham.
• Images: Courtesy of Creative Commons.
• Textbook: IB ESS textbook, available in various formats.