1.2 Systems (DP IB Environmental Systems & Societies (ESS): SL): Flashcards
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- FrontThe Systems Approach
Define systems approach.
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Cards in this collection (59)
Define systems approach.
A systems approach is a holistic way of visualising and understanding a complex set of interactions.
How are storages usually represented in a systems diagram?
Storages are usually represented as rectangular boxes in a systems diagram.
How are flows usually represented in a systems diagram?
Flows are usually represented as arrows in a systems diagram.
True or False?
In a systems diagram, the size of the boxes and arrows must always be drawn in proportion to the real size of the storage or flow.
False.
The size of shapes and arrows can represent the size of a storage or flow, but they are often not drawn this way.
Define transfer (as a type of flow).
A transfer is the movement of matter or energy from one part of a system to another without any change in form or quality.
When sunlight is absorbed by plants, it is transformed into energy through photosynthesis.
When sunlight is absorbed by plants, it is transformed into chemical energy through photosynthesis.
Define transformation (as a type of flow).
A transformation is a change in the form or quality of matter or energy as it moves through a system.
Which approach to studying systems involves breaking it down into its parts and studying each one individually?
The reductionist approach breaks a system down into its parts and studies each one individually.
Sustainability depends on a complex set of interactions between environmental, social and factors, which a systems approach is needed to understand.
Sustainability depends on a complex set of interactions between environmental, social and economic factors, which a systems approach is needed to understand.
Define emergent properties.
Emergent properties are properties of a system that appear as its components interact, and that the individual components do not have on their own.
Which ecological phenomenon is commonly given as an example of an emergent property in an ecosystem?
Predator-prey cycles are commonly given as an example of an emergent property in an ecosystem.
What is a key limitation of the reductionist approach to studying systems?
The reductionist approach can study specific interactions in detail, but it does not show what is happening in the system as a whole.
Define open system.
An open system exchanges both energy and matter with its surroundings.
Which everyday example is commonly used to illustrate an open system?
The human body is commonly used as an example of an open system.
True or False?
Isolated systems are commonly found occurring naturally on Earth.
False.
Isolated systems do not exist naturally; they are more of a theoretical concept, although the entire Universe could be considered one.
A bromeliad can represent a small-scale local ecological system, while an entire represents a large-scale ecosystem.
A bromeliad can represent a small-scale local ecological system, while an entire rainforest represents a large-scale ecosystem.
Define closed system.
A closed system exchanges energy, but not matter, with its surroundings.
Which large-scale research facility was built in the late 1980s as an artificial closed system to simulate Earth's ecosystems?
Biosphere 2 was built in the late 1980s as an artificial closed system to simulate Earth's ecosystems.
Earth's integrated system includes the biosphere, hydrosphere, cryosphere, geosphere, atmosphere and .
Earth's integrated system includes the biosphere, hydrosphere, cryosphere, geosphere, atmosphere and anthroposphere.
Define isolated system.
An isolated system exchanges neither energy nor matter with its surroundings.
Which large-scale natural cycles are approximated as closed systems, due to the continuous recycling of elements within Earth's reservoirs?
Global geochemical cycles are approximated as closed systems, due to the continuous recycling of elements within Earth's reservoirs.
Define Gaia hypothesis.
The Gaia hypothesis proposes that Earth's biota and environment are closely linked and act together as a single, self-regulating system.
Who proposed the Gaia hypothesis in the 1970s?
James Lovelock proposed the Gaia hypothesis in the 1970s.
Define equilibrium (in the context of a system).
An equilibrium is a state of balance occurring between the separate components of a system.
Which classic ecological example relies on negative feedback loops to keep populations relatively stable over time?
Predator-prey cycles rely on negative feedback loops to keep populations relatively stable over time.
True or False?
No natural systems exist in a state of static equilibrium.
True.
All natural systems, such as ecosystems, have inputs and outputs of energy and matter, so static equilibrium only applies to inanimate objects.
The Daisyworld model was created by James Lovelock and as a computer simulation in the 1980s.
The Daisyworld model was created by James Lovelock and Andrew Watson as a computer simulation in the 1980s.
Define steady-state equilibrium.
A steady-state equilibrium occurs when a system shows no major change over a long time period, despite small oscillations that keep returning it to its average state.
What allows a system in a stable equilibrium to return to its original state after a disturbance?
Stabilising negative feedback loops allow a system in a stable equilibrium to return to its original state after a disturbance.
Define static equilibrium.
A static equilibrium occurs when a system has no inputs or outputs of energy or matter, and so shows no change over time.
What can happen to a system in an unstable equilibrium after even a small disturbance?
A system in an unstable equilibrium can shift suddenly to a new equilibrium after even a small disturbance.
Define negative feedback.
Negative feedback is a mechanism that counteracts a system's deviation from equilibrium, bringing it back towards its average state.
How does positive feedback affect a declining population?
Positive feedback amplifies a population decline, since a smaller population further reduces reproductive potential.
Define positive feedback.
Positive feedback is a mechanism that amplifies a system's deviation away from equilibrium, potentially driving it towards a tipping point.
What does the Daisyworld model demonstrate about the regulation of a planet's temperature?
The Daisyworld model demonstrates how a negative feedback loop involving black and white daisies can regulate a planet's temperature.
Define tipping point.
A tipping point is a critical threshold within a system, beyond which a small further change causes significant, often irreversible, shifts away from equilibrium.
Which type of feedback loop pushes an ecological system towards and past its tipping point?
Positive feedback loops push an ecological system towards and past its tipping point.
True or False?
It is usually easy to identify a tipping point before it has been passed.
False.
It may be impossible to identify a tipping point until after it has already been passed.
The resilience of a system is strongly influenced by its diversity and the size of its .
The resilience of a system is strongly influenced by its diversity and the size of its storages.
Define resilience (of a system).
Resilience is a system's tendency to avoid tipping points and maintain stability.
Why do rainforest ecosystems typically have high resilience?
Rainforest ecosystems have high resilience due to their complex food webs and large storages of long-lived trees and dormant seeds.
True or False?
A small storage system, such as a pond, is typically more stable than a larger storage system, such as a lake.
False.
Larger storage systems, such as a lake, are more stable, since changes in input or output have less immediate impact than in a smaller system.
Humans can reduce a rainforest's resilience through hunting species to extinction or by destroying habitat through .
Humans can reduce a rainforest's resilience through hunting species to extinction or by destroying habitat through deforestation.
Which process is a classic example of an ecological system reaching a tipping point?
Eutrophication is a classic example of an ecological system reaching a tipping point.
Why do agricultural monocultures typically have low resilience?
Agricultural monocultures have low resilience because their low diversity means they cannot counteract a disturbance, such as a new pest or disease.
The burning of fossil fuels by industrialised countries is pushing the basin towards a tipping point of desertification.
The burning of fossil fuels by industrialised countries is pushing the Amazon basin towards a tipping point of desertification.
Which coastal ecosystem is used as an example of high ecological resilience, partly due to its ability to self-regenerate via propagules?
Mangrove forests are used as an example of high ecological resilience, partly due to their ability to self-regenerate via propagules.
Which marine ecosystem is used as an example of low ecological resilience, due to its slow recovery rate and vulnerability to rising sea temperatures?
Coral reefs are used as an example of low ecological resilience, due to their slow recovery rate and vulnerability to rising sea temperatures.
Define model (in the context of environmental systems).
A model is a simplified representation of reality that is often used to represent a system.
What are weather models commonly used to create?
Weather models are used to predict how weather systems change over time, allowing forecasts to be created.
True or False?
Highly complex, supercomputer-powered models are completely free from approximation and loss of accuracy.
False.
All models, however powerful, involve some level of approximation or simplification, and therefore some loss of accuracy.
Some models are very simple, such as a child's model car, while others are highly complex, such as the computer models used to predict how our will change in the future.
Some models are very simple, such as a child's model car, while others are highly complex, such as the computer models used to predict how our climate will change in the future.
What is one advantage of changing a model's inputs, compared to waiting for a real-life event to occur?
Changing a model's inputs allows the effects on outputs to be observed without needing to wait for the real-life event to happen.
One strength of a model is that it is easier to than the real system it represents.
One strength of a model is that it is easier to understand than the real system it represents.
How can the results from environmental models help prevent future problems?
Results from models can warn us about future environmental issues, helping us to avoid or minimise their impact.
True or False?
Model predictions become more certain the further into the future they predict.
False.
Results from models become more uncertain the further into the future they predict.
What do the results produced by a model heavily depend on?
The results from a model depend heavily on the quality of the data inputs used.
What can happen if two different models are given exactly the same data inputs?
Two different models can produce vastly different outputs, even when given exactly the same data inputs.
What can a model be used for, once it has been analysed or tested?
A model can be used to learn how a system works and to predict how it will respond to change.
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