1.2 Systems (DP IB Environmental Systems & Societies (ESS): HL): Flashcards

An open system is a system in which both energy and matter are exchanged with the surroundings.

A closed system is a system in which only energy is exchanged with the surroundings, but matter is not.

An isolated system is a system in which neither energy nor matter is exchanged with the surroundings.

Earth is generally considered to be a closed system, because energy can enter or leave but matter is recycled within the system.

An example of an artificially constructed closed system is Biosphere 2, a self-contained research facility designed to simulate Earth’s ecosystems with minimal exchange of matter with the surroundings.

Your body is an example of an open system, exchanging energy and matter with your environment in the form of food, water, movement and waste.

Although technically some matter (e.g. meteorites) enters and leaves the Earth system, these amounts are considered negligible.

False.

Isolated systems do not exist naturally and are considered theoretical concepts; the universe as a whole is the closest example.

An environmental system is a network of interconnected components and processes within the environment, including living organisms and physical elements, that interact at different scales.

The Gaia hypothesis proposes that Earth is a single, self-regulating system in which living organisms and their environment interact to maintain global stability.

The biosphere includes all living organisms on Earth and their interactions with the environment.

The hydrosphere consists of all water bodies on Earth, including oceans, rivers, lakes, and groundwater.

Three major spheres that make up Earth's integrated system are the biosphere, hydrosphere, and atmosphere.

A stable equilibrium is a state of balance in which the components of a system remain in the same state over time and the system can return to its original state after a disturbance.

Negative feedback loops counteract changes away from equilibrium and help the system return to its average state, stabilising open systems.

A system in stable equilibrium returns to its original state after a disturbance.

A steady-state equilibrium is a type of stable equilibrium where a system shows no major changes over a long time, but small oscillating changes occur within closely defined limits, always returning to its average state.

Static equilibrium occurs when there are no inputs or outputs of energy or matter and the system does not change over time, whereas steady-state equilibrium allows for inputs and outputs but maintains an average state.

Most open systems in nature are in steady-state equilibrium, while inanimate objects like a chair are in static equilibrium.

False.

No natural systems are in static equilibrium. All natural systems have inputs and outputs of energy and matter.

A feedback loop is a process in which the output of a system influences or feeds back into the system, causing it to self-regulate in response to disturbances.

Negative feedback stabilises systems by counteracting changes away from equilibrium, while positive feedback destabilises systems by amplifying changes away from equilibrium.

In the Daisyworld model, black daisies decrease albedo, causing the planet's temperature to increase.

In ecological systems, resilience is the ability of a system to maintain stability and avoid tipping points when faced with disturbances or changes.

Greater diversity and larger storages increase the resilience of a system, making it less likely to reach tipping points and better able to maintain stability after disturbances.

Highly complex ecosystems like rainforests have high diversity due to the complexity of their food webs.

Artificial monocultures have low diversity and often small storages, making them less able to recover from disturbances like new diseases or pests.

A lake is more stable than a pond because its larger storage buffers against rapid changes.

Humans reduce resilience by decreasing biodiversity (e.g., through hunting and deforestation) and reducing the size of storages (e.g., by converting grasslands to crops), making ecosystems more vulnerable to disturbances.

A tipping point is a critical threshold in a system, beyond which small changes can cause large, often irreversible shifts away from the original equilibrium.

A regime shift is when a system passes a tipping point and moves to a new equilibrium or alternative stable state, often irreversibly.

Positive feedback loops can push an ecological system towards and past its tipping point.

Tipping points are difficult to predict because feedback loops often have delays, not all components change at the same time, and sometimes a tipping point isn't identified until after it has been passed.

Consequences include rising sea levels, changes in ocean currents, loss of biodiversity, and release of greenhouse gases from melting permafrost.

Eutrophication is a classic example of a system reaching a tipping point and accelerating towards a new state.

A model is a simplified version of reality. It is often used to represent a system.

The main purpose of using a model in science is to represent a system so it can be analysed or tested to learn how it works and predict how it might respond to changes.

Weather models are used to predict how weather systems change over time.

False.

All models involve some level of approximation or simplification, resulting in some loss of accuracy.

One strength of models is that they simplify complex systems, making them easier to understand.

One strength is that models allow predictions to be made about how systems will react to change. One limitation is that models can be oversimplified and inaccurate.