IB Environmental systems and societies 1.2A Systems Notes

Systems: The Core Lens of ESS

1. The concept of systems lies at the heart of ESS.
   1. It gives a structured way to study the interconnections between living and non-living components.
   2. It shows how these interactions keep the environment in balance.
2. A system is made of components, living or non-living, that interact as a functioning whole.
   1. These components are linked by flows of energy and matter.

Key Characteristics of Systems

1. Interdependence: every component affects and is affected by others.
2. Organization: components are structured hierarchically, systems within systems.
   1. A pond sits within a watershed within the hydrosphere.
3. Inputs and Outputs: systems take in inputs such as solar energy and produce outputs such as heat and waste.
4. Boundaries: they define what is inside the system and what lies outside.

The Systems Approach

1. A systems approach is a holistic way of viewing complex interactions in ecological or societal contexts.
2. It focuses on the relationships and feedback among components rather than studying each part in isolation.
3. It contrasts with a reductionist approach, which breaks systems into individual parts.
4. Reductionism gives detail on specific processes but cannot explain emergent properties, the characteristics that appear only when parts interact.

Holistic Approach

1. It focuses on interconnections and feedback across the system.
2. It lets scientists predict system-wide effects, such as how deforestation hits climate, biodiversity and soil together.
3. It identifies points of balance and imbalance for sustainable management.

Reductionist Approach

1. It examines each component independently.
2. It is useful for specific processes like photosynthesis or nutrient uptake but misses the full picture.

Organization of Components

1. Inputs are materials or energy entering the system, such as sunlight, rainfall and CO₂.
2. Storages are where energy or matter accumulates, such as soil, biomass and ocean water.
3. Flows are the processes moving matter or energy, such as photosynthesis, evaporation and respiration.
4. Outputs are matter or energy leaving the system, such as heat loss, waste and oxygen.
   1. Together these interactions form a network that determines stability and adaptability.

Benefits of a Systems Approach

1. It shows how a change in one part affects the whole.
2. It gives a comprehensive understanding for better decisions in environmental issues and social policy.

Systems Diagrams

1. Systems diagrams are simplified visual models of the flows of energy and matter and the relationships between components.
2. They show inputs, outputs, storages and interactions, from a single tree to the global carbon cycle.

Key Components

1. Storages are drawn as boxes, the reservoirs of matter or energy.
2. Flows are drawn as arrows moving between storages or in and out, labelled with the process.
3. Direction of arrows shows the movement of matter or energy.
4. Boundaries are a line defining the system's limits.
   1. Magnitude can be shown by the size of a box or arrow.

Uses of System Diagrams

1. They give a conceptual model of ecosystem function and human impact.
2. They allow comparison of natural versus managed systems.
3. They can be qualitative, using arrow and box size, or quantitative, using measured values.
4. They help spot key processes, bottlenecks and energy losses.

Flows: Transfers vs Transformations

1. Flows are the processes that connect storages, moving or changing matter and energy.
2. They split into transfers and transformations.

Transfers (Change in Location)

1. Transfers move energy or matter from one place to another without changing its form.
2. They are usually a physical relocation, common in abiotic and biotic processes.

Transformations (Change in Form)

1. Transformations convert energy or matter from one form, state or chemical nature to another.
2. They are central to the biological and chemical processes that sustain life.

Why Flows Matter

1. Transfers and transformations keep energy and matter cycling, maintaining equilibrium.
2. Understanding them explains how systems stay balanced or become disrupted.
   1. In real systems both often happen together: in the water cycle, precipitation and infiltration are transfers while evaporation is a transformation.

Types of Systems: Open, Closed and Isolated

1. Every system sits within a boundary.
2. Systems are classed by what crosses that boundary.

Open Systems

1. Open systems exchange both energy and matter with their surroundings.
   1. Most natural systems are open.
2. Inputs include solar radiation, rainfall, nutrients and organisms; outputs include heat, waste, water and gases.
3. They are dynamic, responding to change through feedback.

Closed Systems

1. Closed systems exchange energy but not matter.
   1. Matter circulates inside while energy enters and leaves as heat or radiation.
2. They are rare in nature, mostly conceptual or experimental, such as Biosphere 2.

Isolated Systems

1. Isolated systems exchange neither energy nor matter, and are purely theoretical.
   1. None exist naturally on Earth.
2. The universe as a whole is sometimes treated as the only true isolated system.

Earth as a Single Integrated System

1. Earth works as one vast, self-regulating system of interacting spheres.
2. Biosphere: all living organisms.
3. Hydrosphere: all water.
4. Cryosphere: frozen water, including glaciers, ice caps and permafrost.
5. Geosphere: solid Earth, including rocks, soil and tectonics.
6. Atmosphere: the surrounding gases that drive climate and weather.
7. Anthroposphere: human activity and its impacts.

The Gaia Hypothesis

1. Proposed by James Lovelock in the 1970s, it holds that Earth is a self-regulating system that maintains the conditions for life.
2. Living organisms interact with their inorganic surroundings to regulate temperature, atmospheric composition and ocean salinity.
3. Lynn Margulis later showed how microbial processes shape planetary chemistry.

Key Principles

1. Life collectively influences the environment to maintain equilibrium.
2. Life modifies its surroundings to stay habitable, regulating CO₂ and oxygen.
3. Stabilising negative feedbacks dominate, though positive feedbacks can drive change.
4. Lovelock and Watson's Daisyworld model demonstrates this self-regulation: simple life, in the form of daisies, keeps planetary temperature stable through negative feedback.

The full Daisyworld mechanism is covered in 1.2B Negative feedback loops.

Systems at Different Scales

1. Systems exist across spatial and temporal scales, from micro to planetary.
2. Studying multiple scales reveals patterns invisible at one level.
3. Storages, flows, inputs and outputs apply at every scale.

Micro-scale

1. A bromeliad holding water is a tiny aquatic ecosystem, as are soil microbes decomposing litter.
2. Even here you can show inputs such as sunlight and rainfall, storages such as water and biomass, and outputs such as gases and nutrients.
3. These systems are small but vital to larger cycles.

Meso-scale

1. Meso-scale systems include forests, lakes, wetlands and grasslands.
2. They involve complex species, water and nutrient interactions.
3. They are the focus of field research and conservation.

Macro and Global-scale

1. Macro-scale systems include the global climate system, the carbon cycle and atmospheric circulation.
2. They are governed by large-scale feedbacks linking all spheres.

Nested Hierarchies

1. Systems are hierarchical, smaller within larger, such as a tree within a forest within a biome within the Earth system.
2. Small-scale changes can accumulate into large-scale effects, a principle called emergence, covered in 1.2E.

Interconnectedness Across Scales

1. Environmental issues span scales, from local to regional to global.
   1. Local issues include soil erosion on farms, regional issues include deforestation changing rainfall, and global issues include climate change and biodiversity loss.
2. Local actions can have global consequences.