1. Do Now
Get in your groups from last class and continue working on your Ecological Footprint activity
On the back of your illustration, brainstorm and list 10 things that you (and your group) can do to personally reduce your Ecological Footprint
Complete the questions under #3 on the Watch Where You Step Instruction sheet.
Work together as a group and put your answers on the back of the worksheet or on a separate sheet of paper (so I can read your answers!). Staple the answers to the instruction sheet.
Be prepared to present in roughly 45 minutes (2 minute presentations)

2. Topic 1: Systems and Models
Concepts and Characteristics of Systems

3. What is a System?
A system is an assemblage of parts and the relationships forming a functioning entity or whole.
Interdependent components are connected through the transfer of energy and matter.

4. Systems Consist of…. Storages (of matter and energy)
Flows (inputs into the system, outputs from the system)
Processes (which transfer or transform energy or matter)
Feedback mechanisms that maintain stability and equilibrium.

5. Gaia Hypothesis
In the 1960’s, James Lovelock first suggested the Gaia hypothesis.
He proposed that the Earth can be regarded as a single functioning ecosystem.
In the 1970’s, Lynn Margulis further develop the hypothesis.
These scientists suggested that all living things and their non-living environments are closely integrated to form one system which is self-regulating and maintains the conditions for life.

6. Gaia Hypothesis
The Gaia hypothesis states that 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 extraterrestrial, 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.

7. Gaia Hypothesis

8. Reductionist vs. Systems Approach
A reductionist view of a natural system
looks at a single object that can be clearly recognized and identified by its properties
For example: organisms within a pond are simply classified by characteristics like plant or animal, vertebrate or invertebrate, etc.
Does not try to consider how the pond works as a dynamic system
No consideration of interconnections or interrelationships

9. Reductionist vs. Systems Approach
A systems approach
Considers any system as a set of interrelated objects
Gives a holistic view of the pond working as a dynamic system
For example: interrelationship between plants and animals (food chain, flows of energy, structure, function)

10. Reductionist vs. Systems Approach
What are the advantages/disadvantages of the systems approach compared with a reductionists approach to the study of an ecosystem?
What is the most important difference between the philosophies of the two approaches?
What are the benefits and drawbacks of using the systems approach in other fields like economics and engineering?
“The reductionist view that currently dominates society is rooted in unlimited economic growth, unperceptive to its social and environmental impact. It cannot resolve the converging environmental, social, and economic crisis we now face.”
3. Do you think the above statement has any validity?

11. Inputs, Processes, Outputs

12. Scale of Systems
There are different scales of systems. The range must include a small-scale local ecosystem, a large ecosystem such as a biome, and Gaia as an example of a global ecosystem. Can you think of any other examples of a system?

13. Systems: Small and Large

14. Types of Systems Open System Closed System
Energy comes in but no matter is transferred out
Energy and matter in & out

15. Types of systems Open System Closed Systems
An open system exchanges both matter and energy.
Most living systems and all ecosystems are open.
They exchange energy, new matter, and waste.
Even remote ecosystems in Antarctica and isolated ecosystems are open.
A closed system exchanges energy but NOT matter across its boundaries.
These systems are extremely rare in nature.
Most examples are used in experiments and are artificial.
A bottle system is an example.

16. Examples of Open Systems
Woodland ecosystem:
Inputs: light and CO2 which plants use for photosynthesis, herbivores returning minerals to soil via feces, bacteria in the soil which fix nitrogen from the atmosphere
Outputs: water lost during respiration and transpiration, nutrients lost in waterways, and heat which is exchanged with the surrounding environment and the ecosystem

17. Examples of Closed Systems
A bottle garden
Aquarium

18. Do Now What is a system? What are the various components of a system?
Give an example of a system.
Briefly summarize the Gaia hypothesis.
What is the difference between a reductionist approach and a systems approach?
Contrast an open system versus a closed system.

19. Types of Systems
Isolated System – Neither matter nor energy is exchanged. These systems do not exist naturally. The Universe perhaps…?
Do you think that it is useful to have the concept of an isolated system which does not exchange energy or matter with its surroundings?

20. 1.1.3 Energy in Systems Laws of Thermodynamics
1st Law of Thermodynamics
Energy can only change from one form to another
Energy in neither created or destroyed
In a living system, heat cannot be converted to other forms
Light energy chemical energy chemical energy ?

21. 100% 10% 1% 0.1% tertiary consumer secondary consumer Primary consumer
producer

22. 1.1.3 Energy in Systems Laws of Thermodynamics
2nd Law of Thermodynamics
An isolated system entropy tends to increase.
Entropy is a measure of the evenness of energy distribution in a system.
Energy is used to create order and hold molecules together.
This means that if less energy is available, entropy, or disorder, increases.
The availability of energy becomes reduced and the system becomes less orderly.
Natural/living systems require a constant input of energy from the sun to maintain order

23. 1.1.4 Equilibria Open systems tend to exist in a state of balance.
Two types of equilibrium:
1. Static:
When components of the system remain constant over time.
No inputs or outputs
Systems are not living

24. 1.1.4 Equilibrium 2. Steady- State (Dynamic)
The system is in a steady state because the inputs and the outputs that affect it approximately balance over a long period of time.
Allows a system to return to its steady state (homeostasis, body temp, predator-prey cycles)

25. Stable vs Unstable Equilibrium
1. Stable Equilibrium: The system tends to return to the same equilibrium after a disturbance (pendulum)

26. Stable vs Unstable Equilibrium
2. Unstable Equilibrium: A new equilibrium is formed after a disturbance (ruler balanced on finger

27. 1.1.5 Feedback
Systems are continuously affected by and react to information stimuli.
Information, which may come from inside or outside the system, starts a reaction which affects the processes within the system. Changes in these processes lead to changes in output, which also affect levels of input. This whole cycle is known as a feedback loop.

28. Negative Feedback
Negative Feedback: Tends to neutralize or counteract any deviation from an equilibrium and promotes stability.
Allows self-regulation
In organisms, negative feedback is vital to homeostasis
In ecosystems, negative feedback leads to the control of the relative number of species in food webs.

29. Positive Feedback
Positive Feedback: Amplifies or increases change; it leads to exponential deviation away from an equilibrium.
destabilizes the system
Leads to out of control growth of an organism which can overwhelm an ecosystem
A system affected by positive feedback may reach a tipping point when it is unstable and a new equilibrium may form

30. Negative vs Positive Feedback

31. Practice Questions
How does the first law of thermodynamics explain how energy moves through an ecosystem?
What is meant by ‘entropy’ and how does it relate to a natural system?
Outline the difference between a steady-state equilibrium and a static equilibrium.
Why does positive feedback lead to increasing change in a system?
Currently, the human population is growing at an exponential rate. What are the possible consequences of this example of positive feedback? Could this growth actually be part of a long-term negative feedback loop?

32. Do Now What do the laws of thermodynamics state?
Explain the difference between static and steady-state/dynamic equilibrium.
What is negative feedback? Give an example.
What is positive feedback? Give an example.

33. Predator- Prey (negative feedback)

34. 1.1.6 Transfers and Transformations
Both material and energy move through ecosystems
If matter and energy pass through a system without changing form, the movement is called a transfer.
Transfer can involve:
The movement of material through living organisms
(carnivores eating other animals)
The movement of materials in a nonliving process
(water being carried by a stream)
The movement of energy
(ocean currents transferring energy)

35. 1.1.6 Transfers and Transformations
A transformation occurs when a flow in a system involves a change of form or state.
Transformation can involve:
Matter to matter: glucose converted to starch in plants
Energy to energy : light converted to heat by radiating surfaces
Matter to energy: burning fossil fuels
Energy to energy: photosynthesis

36. 1.1.7 Flows and Storages
Both matter and energy flows (inputs and outputs) through ecosystems but at times it is also stored within the ecosystem.

37. Models
A model is a simplified description designed to show the structure or workings of an object, system or concept. In practice, some models require approximation techniques to be used.
For example, predictive models of climate change may give very different results. (pg 34 & 35)
In contrast, an aquarium may be a relatively simple ecosystem but demonstrates many ecological concepts.

38. Discussion
Why do you think that scientists are keen to use models to communicate their ideas to the general public and
politicians?
What are the merits of
presenting information
this way?

39. Models Pros: 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

40. Models Cons: might not be totally accurate
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

41. Models are simplified constructions of reality.
Theory of Knowledge
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?

42. Story of Stuff

43. Systems & Models Project
With a partner, design a diagram or a model of a complex system. Illustrate the inputs and outputs, feedback (positive and/or negative) as well as storages, flows, processes, transfers, and transformations. Also be sure to include any human activities as well. (pages )
Write a one page paper articulating in detail the various components of your system and how they interact with each other.
This will be for a grade so make sure you include all of the necessary components. Make sure that your work is neat and that it reflects your understanding and application of the content. Sloppiness or inaccuracy will result in points deducted.

44. Must be approved by Ms. Simmons before you begin your work
System Ideas
Physical or abstract systems.
Open or closed systems.
'Man-made' information systems.
Formal information systems.
Informal information systems.
Computer-based information systems.
Real-time system.
Must be approved by Ms. Simmons before you begin your work