Systems

Introduction

In the study of Environmental Systems and Societies (ESS) within the International Baccalaureate (IB) syllabus, one of the foundational topics is "1.2 Systems and Models." This topic introduces the concept of systems thinking and the use of models to understand and analyze environmental systems. This study note will break down these concepts into digestible sections, provide examples, and highlight key points to help you grasp the material effectively.

What is a system?

A system is an assemblage of parts and the relationships between them, which together constitute an entity or whole.

Key Characteristics of Systems

• Components: The individual parts that make up the system.
• Processes: The interactions and relationships between the components.
  • Transfer: Matter and energy moving through a system without changing form or shape.
  • Transformations: When matter or energy changes form or state moving through a system.
• Boundaries: The limits that define the scope of the system.
• Inputs and Outputs: The energy, matter, or information that enters and exits the system.

Types of Systems

• Open Systems: Exchange both energy and matter with their surroundings.
• Closed Systems: Exchange only energy, not matter, with their surroundings.
• Isolated Systems: Do not exchange energy or matter with their surroundings (theoretical and do not exist in reality).

Case study: Gaia hypothesis

The hypothesis states that all living organisms interact with their surroundings on Earth to create a synergistic and self-regulating system that maintains balance. The theory argues that all living organisms along with their inorganic surroundings adapted and evolved as a collective whole in the form of one giant self-regulating system that keeps things in place for life to survive on Earth.

The Gaia hypothesis, proposed by James Lovelock, has a holistic approach because it views Earth and its biological systems as a single, interconnected organism that self-regulates to maintain conditions conducive to life. It caused much criticism around the world because critics argue that the entire theory violates the scientific method since it only provides ideas but offers no real explanation of exactly how organisms could act together to maintain a balance of life on earth.

Tipping Points

A tipping point is the minimum amount of change within a system that will destabilize it, causing it to reach a new equilibrium or stable state. Such changes are caused by human population growth and are associated with factors such as:

• Resource consumption
• Habitat transformation and fragmentation
• Energy production and consumption
• Climate change.

Case Study: Krill Harvesting in the Southern Ocean

Krills are a food source for seals, whales, penguins, and other seabirds. Because of that, krill form the base of the food chain, and so a significant reduction in their population density severely affects other animals. Studies show that animals that feed on krill begin to suffer when the krill population declines below a critical level (approximately one-third of the maximum measured amount of krill available).

Resilience of a system

Resilience of a system is the capacity to resist damage and recover from or adapt to disturbances. Diversity and size of storage within a system contribute to its resilience and affect the speed of response to change.

Anthropogenic activities can affect the resilience of systems through the reduction of storage and diversity.

Models in ESS

Models are simplified representations of reality used to understand and predict the behaviour of systems.

Types of Models

• Physical Models: Tangible, scaled-down versions of real objects (e.g., a globe).
• Mathematical Models: Use mathematical equations to represent relationships within the system (e.g., population growth models).
• Computer Models: Simulations run on computers that can handle complex calculations and large datasets (e.g., climate models).
  • Climate models: Predict how the climate might change in the future.

Benefits and Limitations of Models

Benefits:

• Models are used in science to show concepts on a scale that is accessible to a wider population.
• They allow us to look at different scenarios so that we can look at the impacts of different changes to the system.
• They allow us to simplify complex systems to study them more closely.

Limitations:

• Models can be oversimplified to the point that accuracy is lost.
• Data may not be accurate so models could be used to manipulate for financial or political gain.
• Models and predictions depend on the skills and experience of the people making them.

Systems Diagrams

Systems diagrams are visual representations of the components and processes within a system. They help to illustrate the relationships and flows between different parts of the system.

Types of Systems Diagrams

• Flow Diagrams: Show the flow of energy or matter through a system.
• Feedback Loops: Illustrate how the outputs of a system can influence its inputs.

Feedback Loops

Feedback loops are crucial in regulating systems. They can be:

• Positive Feedback: Amplifies changes and drives the system towards a tipping point.
• Negative Feedback: Dampens changes and helps maintain stability.

Conclusion

Understanding systems and models is essential for analyzing environmental issues and predicting outcomes. By breaking down systems into their components, processes, and boundaries, and using models to simulate and predict behaviours, we can gain valuable insights into the complex interactions within environmental systems. Always remember the limitations of models and use them as tools to aid, not replace, critical thinking and real-world observations.