1. 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.
Big Questions
What strengths and weaknesses of the systems approach and the use of models have been revealed through this topic?

2. Systems
A system is a set of inter-related parts working together to make a complex whole in order to perform a particular function
Can be living or non-living
Exits on any scale
= cells, you, a bicycle, a car, your home, a pond, and ocean, a smart phone, a farm, the economy, the Earth, the Universe
All systems have inputs and outputs of energy, matter, or information
All systems have storages, flows, processes, and feedback mechanisms
Page

3. Systems This course focuses hugely on SYSTEMS
Material an energy undergo transfers (change in location of matter/energy) and transformations (change in chemical nature, change in state, or change in energy) in flowing from one storage to the next
Transfers: (ex)
The movement of material through living organisms
Movement of material in non-living process
The movement of energy
Transformations
Matter to matter
Energy to energy
Matter to energy
Energy to matter
This course focuses hugely on SYSTEMS
The systems approach is a way of visualizing a complex set of interactions which may be ecological or societal

4. All Systems Have
Represented By:
STORAGES of stores of matter and energy
A box
FLOWS into, through, and out of the system
Arrows
INPUTS
Arrows in
OUTPUTS
Arrows out
Boundaries
Lines
PROCESSES which transfer or transform energy or matter from storage to storage
Ex: respiration, precipitation, diffusion

5. 3 types: opened, closed, isolated
Types of Systems
3 types: opened, closed, isolated
Opened Systems
Exchanges matter and energy with its surroundings
Most natural living systems are open systems
Ex: ecosystems (lakes, forests, etc)…why?

7. 2. Closed Systems https://www.youtube.com/watch?v=cQUkX9S06qw
A system in which energy is exchanged across boundaries of the system, but matter is not
Extremely rare in nature
Ex: the Earth (almost a closed system)
Light energy enters, and some is returned to space as heat
Most closed systems are artificial and for experimental purposes
Ex: the hydrological, carbon, or nitrogen cycles when considered on a global scale

8. Light Energy from the Sun Long-wave (heat) energy returned to space

9. Biosphere 2 https://www.youtube.com/watch?v=oUJGR6qNVzA
P. 22

10. 3. Isolated Systems
A system in which neither energy nor matter is exchanged with its environment
Do not exist naturally
No such system actually exists with the possible exception of the entire universe

15. Day 6

16. Models
A model is a simplified description to show the structure and working of a system
Models can be used to show the flows, storage, and linkages within ecosystems
While they are unable to show much of the complexity of the real system, they help us to understand ecosystem function better
In this class we will…
Model climate and climate change
Model human and species population dynamics
Model groundwater flow
Model different types of energies
Model landfills and pollution clean up
And others

18.  A model inevitably involves some approximation and therefore loss of accuracy.
Strengths: 
Simple to work with
allow scientist to predict changes
See patterns
Used to visualize very small or very large things
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 these may be suspect
different models may show different effects using the same data

19. Gaia Hypothesis – A model of the Earth
the earth is a planet sized organism and the atmosphere is its organ that regulates it and connects all its parts
the temperature and composition of the Earth's surface are actively controlled by life on the planet. It suggests that if changes in the gas composition, temperature or oxidation state of the Earth are caused by extraterrestial, biological, geological, or other disturbances, life responds to these changes by modifying the abiotic environment through growth and metabolism.
In simpler terms, biological responses tend to regulate the state of the Earth's environment in their favor.

20. Application and skills
Construct a system diagram or a model from a given set of information
Draw a systems diagram for a simplified human body system.

21. Application and skills
Evaluate the use of models as a tool in a given situation, for example, climate change predictions
Below are 4 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! ​
Concord Consortium Climate Model
Watch video only
Window's to the Universe Climate Model
Koshland Science Museum Climate Model
UCAR Climate Model

22. Day 7

23. 1.3 Energy and Equilibria Significant Ideas
The laws of thermodynamics govern the flow of energy in a system and the ability to do work
Systems can exist in alternative stable states or as equilibria between which there are tipping points
Destabilizing position feedback mechanisms will drive systems toward these tipping points, whereas stabilizing negative feedback mechanisms will resist such changes
Big questions:
What strengths and weaknesses of the systems approach and the use of models have been revealed through this topic
How are the issues addressed in this topic of relevance to sustainability or sustainable development?
The principle of conservation of energy can be modeled by the energy transformations along food chains and energy production systems: what are the strengths and limitations for such models?
How do the delays involved in feedback loops make it difficult to predict tipping points and add to the complexity of modelling systems?
Do the benefits of the models used to predict tipping points outweigh their limitations?
How does sustainability reduce the change that tipping points will be reached?

24. 1.3 Energy and Equilibria – energy in systems
1st Law of Thermodynamics = energy is neither created nor destroyed (but can be transferred & transformed)
Energy can change from one form to another (light to heat) but no new energy is created.
There has always been, and always will be, exactly the same amount of energy in the universe
Sometimes called conservation of energy.

25. 1st Law of Thermodynamics
Ex: sunlight -What happens to all of the light that reaches Earth?
30% reflected back into space
50% converted to heat
19% powers hydrologic cycle
1% used for photosynthesis
That’s 100%

26. 1st Law of Thermodynamics
In a food chain: Light is changed to chemical energy through photosynthesis and transferred again as chemical energy to an herbivore and then carnivore.
The energy at one level must come from the previous level
Hence, the 1st Law of Thermodynamics explains why the Energy Pyramids is always bigger on the bottom than on the top