1. Systems and Models

2. What is the common thread?

3. System is… individual components working together.
Look at this bicycle:

4. …when apart no longer a system
You will never get anywhere if you just have the seat or the wheels!

5. Synergy
This is the concept of synergy where the whole is greater than the sum of its parts.

6. Even if you know all the parts of a system, you can’t predict what will happen when they work together
A good example of this is Table salt or Sodium Chloride:
Sodium is highly reactive and has massive reactions with water.
Chlorine as a gas can kill you.
Put the two together and it forms something essential for our body and very important for life in general!

7. The Synergetic Effect
Environmental systems, ecosystems, ecological systems all follow the laws of synergy.
That the whole, the entire process, is far more important than the individual parts of it.

8. Environmental Systems and Societies
Interrelationships among climate, geology, soil, vegetation, water and animals, including humans.

9. System A collection of interdependent components
Each perform a function
Connected through transfer of energy and matter.

10. Characteristics of systems
Components
Reservoirs, storages, stocks, accumulation
Processes
Flows, transformations, transfers, reactions, photosynthesis, respiration
Feedback mechanisms
Equilibrium and stability

11. Systems terminology and symbols
Flows – Inputs and outputs - ARROWS
energy or matter

12. Systems terminology and symbols
Storages - represented by boxes
Areas in which energy or matter can accumulate for various lengths of time before being released.
Remember there is always a fixed time line!

13. The Tree as a System light O2 H2O Heat CO2
Tissue to other trophic levels
Tree Biomass
Litter to soil
Nutrients
H2O

14. Apply the systems concept on range of scales
Scales range from small to large:
You ESS Class CIS Bangkok Thailand SE Asia
Local ecosystem Biome Gaia

15. Scales
Biological ecosystems include levels of complexity beginning with atoms and molecules and broadens up to the biosphere.

16. Gaia James Lovelock 1960’s Earth is an organism
Atmosphere as regulation and connection
Gaia video
The Gaia hypothesis compares Earth to a living organism in which feedback mechanisms maintain equilibrium. It describes how the living and non-living components of the global biosphere regulate the conditions for life on Earth. Daisyworld can be used to illustrate this hypothesis…..

17. Lets study this through Daisyworld
Daisyworld is a very simple planet that has only two species of life on its surface -- white and black daisies. The planet is assumed to be well-watered, with all rain falling at night so that the days are cloudless. The atmospheric water vapour and CO2 are assumed to remain constant, so that the greenhouse of the planet does not change. The key aspect of Daisyworld is that the two types of daisies have different colours and thus different albedos. In this way, the daisies can alter the temperature of the surface where they are growing.
Lets study this through Daisyworld

18. Types of Systems Open Closed Isolated
Differences depend on how matter and energy move in and out of the system

19. Open System
Open Systems: exchange matter and energy with its surroundings.
In forest ecosystems plants fix energy from light entering the system during photosynthesis.
Nitrogen is fixed by soil bacteria. Herbivores that live within the forest canopy may graze in adjacent ecosystems such as a grassland, but when they return they enrich the soil with faeces.
After a forest fire top soil may be removed by wind and rain. Mineral nutrients are dissolved out of the soil and transported in ground water to streams and rivers.
Open system exchange both matte and energy with their surroundings e.g ecosystem

20. Closed Systems Closed Systems: exchange energy but not matter.
Rare in nature.
Biosphere 2 was a human attempt at creating a habitable closed system on Earth.
Video
Closed systems exchange only energy with their surroundings e.g. the Earth

21. No natural closed systems exist on Earth but the planet itself can be thought of as an “almost” closed system.
Light energy in large amounts enters the Earth’s system and some is eventually returned to space a long wave radiation (heat).

22. Isolated Systems
Neither matter or energy is exchanged across the system
No such systems exist (with the exception of the entire cosmos).

23. How are the 1st and 2nd laws of thermodynamics related to ESS
First law – Conservation of Energy Energy is neither created nor destroyed
In the food chain above the energy enters the system as light energy, during photosynthesis it gets converted to stored chemical energy (glucose).
It is the stored chemical energy that is passed along as food.
No new energy is created it is just passed along.

24. Energy Flow Energy absorbed from the previous trophic level 100
Energy lost as heat
Energy lost to detritus 10 65 25
Energy passed on to the next trophic level
So energy is conserved!!!

25. Second Law - Entropy
Entropy is a measure of the amount of disorder, chaos or randomness in a system; the greater the disorder the higher the level of entropy.
The energy in systems is gradually transformed into heat energy due to inefficient transfer, thereby increasing disorder (entropy).
In any isolated system entropy trends to increase spontaneously – so ultimately……..
Energy is needed to create order. Less energy available then disorder increases. So universe is seen as an isolated system and our entropy is steadily increasing so eventually in billions of years there will be no more energy present.

26. What’s the relevance to environmental systems?
Energy flows through ecosystems. Energy enters as sunlight and is converted to new biomass and heat.
The energy entering the system equals the energy leaving it (1st Law)
Energy is inefficiently moved through food chains in the process of respiration and production of heat energy (2nd Law).

27. Continued….
Initial absorption and transfer of energy by producers is also inefficient due to reflection, transmission light of the wrong wavelength and inefficient transfer of energy in photosynthesis (2nd Law)
Light energy starts the food chain but is then transferred from producer to consumer as chemical energy.
As a result of the inefficient transfer of energy, food chains tend to be short.

28. Equilibrium A system needs to be in equilibrium
If not, entropy will increase so much the system will destroy itself by becoming too disordered
There a 4 kinds of equilibrium:
Static
Steady State
Stable
unstable

29. Static Equilibrium State of the system time
Note: this is not realistic – it could only occur in an isolated system

30. Steady State Equilibrium
State of the system
time

31. Stable Equilibrium State of the system time
Weebles wobble but they don’t fall down!
State of the system
disturbance
time

32. Unstable Equilibrium State of the system time He’s going down!
disturbance
time

33. Equilibrium in action

34. Feedback Mechanisms
This is a way that the INPUT is affected by the OUTPUT
In a stable equilibrium, feedback returns the equilibrium to its original state
In an unstable equilibrium, feedback returns the equilibrium to a different state
Feedback can be
POSITIVE – input changes to bring the system to a new equilibrium
NEGATIVE – input changes in order to bring the system back to its original equilibrium

35. Negative Feedback Your (stable) equilibrium body temperature is 37oC
Sensors in the skin detect your skin temperature is rising (you are in Phuket on the beach)
Show what happens in a system diagram

36. Positive Feedback Your (stable) equilibrium body temperature is 37oC
Sensors in the skin detect your skin temperature is decreasing (you are locked in a freezer)
Your body is unable to maintain its stable equibilibrium and therefore you enter a state of hypothermia
Show what happens in a system diagram

37. Living systems 3 characteristics
Functionality: ability to perform a task or serve a purpose.
Sustainability: capacity to endure; how systems remain intact, productive and diverse over time.
Evolution: change over time

38. Transfer and transformation processes
Matter (material and energy move or flow through ecosystems
Transfer
Transformations

39. Transfers
Flow through systems
Change in location

40. Transformations
Interaction within a system in the formation of a new product or change of state.
Matter to matter (Glucose to starch)
Energy to energy (light to heat by
radiating surfaces)
Matter to energy (burning fossil fuels)
Energy to matter (photosynthesis)

41. Transfers and transformations can occur at the same time
Water runoff (transfer) and evaporation (transformation)
Decaying dead organic matter entering a lake (transfer) but the decomposition process is transformation

42. Flows and Storages
Energy and matter flow as inputs and outputs through the system
Can be storages or stocks

43. Energy flows …….. Energy flows from one compartment to another
Energy that moves is stored as chemical energy
Black arrows flow of energy
Red arrows flow of matter

44. Matter cycles…….. Matter cycles around the system as minerals
Black arrows flow of energy
Red arrows flow of matter

47. Case Studies predator-prey equilibria