1.2 Systems and models
Significant ideas:
- A systems approach can help in the study of complex environmental issues.
- The use of systems and models simplifies interactions but may provide a more holistic view without reducing issues to single processes.
International Mindedness
The use of models facilitates international collaboration in science by removing language barriers that may exist.
ToK
Models are simplified constructions of reality—in the construction of a model, how can we know which aspects of the world to include and which to ignore?
Connections
ESS: Introduction to water systems (4.1); introduction to soil systems (5.1); terrestrial food production systems and food choices (5.2); introduction to the atmosphere (6.1)
Diploma Programme: Geography (option G), Biology (topic 4)
synergy
biosphere
system
closed system
transfers
ecosystem
storage
processess
functional
KEY WORDS TO TRANSLATE, DEFINE AND USE
models
flows
inputs
outputs
model
energy transfer
assemblage
matter
ecosystem
transformation
open system
energy efficiency
flows
stock
boundaries
isolated system
equilibria
model
Knowledge and Understanding 1,2,3
- A systems approach is a way of visualizing a complex set of interactions which may be ecological or societal.
- These interactions produce the emergent properties of the system.
- The concept of a system can be applied at a range of scales.
Systems thinking
A system is a collection of parts that interact with each other to function as a whole. We are surrounded by systems e.g. the nervous system, digestive system, solar system, social systems, mechanical systems,etc.
It is:
- made up of parts
- that interrelate with each other
- this interrelationship has some function or purpose
- that depends on how the parts are arranged.
In order to achieve sustainability we have to understand how systems work and how to keep them working indefinitely without breaking down.
In the video below, Paul Andersen explains how matter and energy are conserved within the Earth's system. Matter is a closed system and Energy is open to the surroundings. In natural systems steady state is maintained through feedback loops but can be be affected by human society.
Knowledge and Understanding 4,5,6,7
- A system is comprised of storages and flows.
- The flows provide inputs and outputs of energy and matter.
- The flows are processes that may be either transfers (a change in location) or transformations (a change in the chemical nature, a change in state or a change in energy).
- In system diagrams, storages are usually represented as rectangular boxes and flows as arrows, with the direction of each arrow indicating the direction of each flow. The size of the boxes and the arrows may be representative of the size/magnitude of the storage or flow.
Source: https://www.slideshare.net/geographyalltheway/ib-geography-ecosystems-nutrient-cycling
Knowledge and Understanding 8,9
- An open system exchanges both energy and matter across its boundary while a closed system exchanges only energy across its boundary.
- An isolated system is a hypothetical concept in which neither energy nor matter is exchanged across the boundary.
Is this bottle garden an example of an open, closed or isolated system?
Knowledge and Understanding 10
- Ecosystems are open systems; closed systems only exist experimentally, although the global geochemical cycles approximate to closed systems.
Source: www.geosci.ipfw.edu
What type of system is this? Why?
Systems thinking in 'The Lorax' by Dr Seuss
'Did you chop down this trees?'
The original 'The Lorax' film.
Audio book 'The Lorax' (link below)
Watch/Read The Lorax and answer the following questions:
- Identify the different systems you observed in “The Lorax” (hint: think about open, closed, isolated systems)
- Describe and explain how each of the systems that you have named works. Use a systems diagram if you can.
- Suggest the possibilities of any small systems within bigger systems. (hint: think beyond the story itself)
- Suggest how “The Lorax” represents the concept of systems thinking.
Work through the worksheet ESS 1.2 Systems thinking and 'The Lorax' to ensure you understand systems and feedback loops fully.
(click here for direct link for Google doc or for OneDrive)
Knowledge and Understanding 11,12
- A model is a simplified version of reality and can be used to understand how a system works and to predict how it will respond to change.
- A model inevitably involves some approximation and therefore loss of accuracy.
Typical exam question: Evaluate the strengths and limitations of systems models.
Strengths:
- allow scientist to predict/simplify complex systems
- inputs can be changed and outcomes examined without having to wait for real events.
- results can be shown to scientists and the public
Limitations:
- might not be totally accurate
- environmental factors are very complex
- different models use slightly different data to calculate predictions
- rely on the expertise of people making them
- different people may interpret them in different ways
- vested interests might hijack them politically
- any model is only as good as the data goes in and this may vary over time, as technology and understanding develops or if data contains an inbuild bias for some reason
- different models may show different effects using the same data
Below are 5 different climate model simulations. You should be able to discuss the strengths and weakness of each of these models. Which model do you believe is the best for understanding climate change? Justify your reasoning (Think carefully about your note taking structure, a table is the best way for any 'evaluate' question)
Concord Consortium Climate Model
Window's to the Universe Climate Model
All living organisms rely on systems to sustain them.