Topic 1.2 - Systems

System

A set of interrelated parts working together to make a complex, functional whole

Storages (Stores)

Places within a system where energy or matter is accumulated or kept, represented visually as rectangular boxes in system diagrams

Flows

Movements of energy or matter into, through, or out of a system, represented visually as directional arrows

Transfer

A flow involving a change in location or position of matter or energy without any change in state or chemical composition

Transformation

A flow involving a change of state, energy form, or chemical composition (e.g., photosynthesis or evaporation)

Open System

A system that exchanges both energy and matter across its defined system boundary (e.g., ecosystems)[15]

Closed System

A system that exchanges energy across its boundary, but does not exchange matter (e.g., global geochemical cycles)

Isolated System

A theoretical system that exchanges neither energy nor matter across its boundary (e.g., the Universe)

Model

A simplified representation of reality used to understand how a system works and to predict responses to change

*Advantages - Simplifies complex reality/reveals global patterns/predicts

*Limitations - Approximations/loss of accuracy; incorrect input data/ inaccurate predictions

Positive Feedback Loop

Accelerates / Amplifies a change

-Pushes system further from starting more

EX: Ice/Albedo → more warming / Childbirth

EX: Eutrophication → Nutrient overload, algal bloom covers surface, lack of sunlight = no new nutrients , decomposition = DEAD ZONE

Negative Feedback Loop

Counteracts/slows down a change

-Keeps system stable and balanced

EX: More/more predators ; Less prey/less predators

EX: Sweating to cool down

Earth; 6 Interacting spheres:

Cryosphere

Frozen water

Earth 6; Interacting spheres:

Atmosphere

Gases

Earth; 6 Interacting spheres:

Biosphere

Living Things

Earth; 6 Interacting spheres:

Geosphere

Rock, Soil, Minerals

Earth; 6 Interacting spheres:

Hydryosphere

Liquid water

Earth; 6 Interacting spheres:

Anthroposphere

Human systems

Gaia Hypothesis

"Earth is a self regulating system where living and non living systems interact tightly"

Stable equilibrium

Returns to normal state after disturbance

Steady State equilibrium

Stays constant : Open system (inputs=outputs) so storages

Tipping point

- Small change , Large effect

- Abrupt

- Hard to reverse

EX: Clean lake → turbid lake

EX: Coral reef dying because of ocean warming past 1.5C causes severe bleaching & overfishing removes fish

Resilience

- Bounceback

- Resistance

- Recover from disturbance

EX: Coral reef staying clean thanks to herbivorous fish, even through storms

Emergent properties

- properties for whole system and not individual parts

When individual compoments interact = new behaviours emerge

Ex: Ecosystem stability, Resilience, Disturbance