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2.systems and models new

  1. 1. Models and the behavior of systems BY GURU GURU IBESS/GURU/SYSTEMS & MODELS
  2. 2. Syllabus Statements      1.1.1: Outline the concept and characteristics of a system 1.1.2: Apply the systems concept on a range of scales 1.1.3: Define the terms open system, closed system, isolated system 1.1.4: Describe how the first and second laws of thermodynamics are relevant to environmental systems 1.1.5: Explain the nature of equilibria GURU IBESS/GURU/SYSTEMS & MODELS
  3. 3. Syllabus Statements      1.1.6: Define and explain the principles of positive and negative feedback 1.1.7: Describe transfer and transformation processes 1.1.8: Distinguish between flows (inputs and outputs), and storages (stock) in relation to systems. 1.1.9: construct and analyze quantitative models involving flows and storages in a system Evaluate the Strengths and limitations of models GURU IBESS/GURU/SYSTEMS & MODELS
  4. 4. Vocab         Entropy Equilibrium Feedback Negative Feedback Positive Feedback Model Stable Equilibrium Steady State Equilibrium GURU     System Closed System Isolated System Open system IBESS/GURU/SYSTEMS & MODELS
  5. 5. Systems  A system is a set of components that… 1. 2. GURU Function and interact in some regular, predictable manner. Can be isolated for the purposes of observation and study. IBESS/GURU/SYSTEMS & MODELS
  6. 6. Systems on Many Scales    Ecosystem – The everglades in South FL Biome – Tropical Rainforest The entire planet – Gaia hypothesis GURU IBESS/GURU/SYSTEMS & MODELS
  7. 7. Coral Reef Ecosystem Most diverse aquatic ecosystem in the world ------- Open systems exchange matter and energy with the surroundings GURU IBESS/GURU/SYSTEMS & MODELS
  8. 8. Closed systems exchange energy but not matter. – don’t naturally occur on earth Biosphere II Built as self sustaining closed system in 1991 in Tuscon, AZ Experiment failed when nutrient cycling broke down GURU IBESS/GURU/SYSTEMS & MODELS
  9. 9. Nutrient cycles Approximate closed systems as well GURU IBESS/GURU/SYSTEMS & MODELS
  10. 10. Isolated systems exchange neither matter nor energy with the surroundings Only possible though unproven example is the entire cosmos GURU IBESS/GURU/SYSTEMS & MODELS
  11. 11. Components of systems     Inputs = things entering the system  matter, energy, information Flows / throughputs = passage of elements within the system at certain rates (transfers and transformations) Stores / storage areas = within a system, where matter, energy, information can accumulate for a length of time (stocks) Outputs = flowing out of the system into sinks in the environment GURU IBESS/GURU/SYSTEMS & MODELS
  12. 12. Discharge of untreated municipal sewage (nitrates and phosphates) Nitrogen compounds produced by cars and factories Natural runoff (nitrates and phosphates Inorganic fertilizer runoff (nitrates and phosphates) Discharge of detergents ( phosphates) Discharge of treated municipal sewage (primary and secondary treatment: nitrates and phosphates) Lake ecosystem nutrient overload and breakdown of chemical cycling Dissolving of nitrogen oxides (from internal combustion engines and furnaces) Manure runoff from feedlots (nitrates, phosphates, ammonia) Runoff from streets, lawns, and construction lots (nitrates and phosphates) Runoff and erosion (from cultivation, mining, construction, and poor land use) To assess an area you must treat all levels of the system GURU IBESS/GURU/SYSTEMS & MODELS
  13. 13. Individuals work as well Water 0.000002 ppm Phytoplankton 0.0025 ppm Herring gull 124 ppm Herring gull eggs 124 ppm Zooplankton 0.123 ppm GURU Lake trout 4.83 ppm Rainbow smelt IBESS/GURU/SYSTEMS & MODELS 1.04 ppm
  14. 14. Types of Flows: Transfer vs. Transformation   Transfers  flow through the system, involving a change in location Transformation  lead to interactions in the system, changes of state or forming new end products -Example: Water processes Runoff = transfer, Evaporation = transformation Detritus entering lake = transfer, Decomposition of detritus is transformation GURU IBESS/GURU/SYSTEMS & MODELS
  15. 15. Condensation Transpiration from plants Precipitation Precipitation to ocean Rain clouds Transpiration Precipitation Evaporation Surface runoff (rapid) Evaporation From ocean Runoff Infiltration and percolation Surface runoff (rapid) Groundwater movement (slow) Ocean storage Groundwater movement (slow) What type of System is this? Name the inputs, outputs, transfers and transformations IBESS/GURU/SYSTEMS & MODELS GURU
  16. 16. Systems and Energy     We see Energy as an input, output, transfer, or transformation Thermodynamics – study of energy 1st Law: Energy can be transferred and transformed but it can never be created nor destroyed So…   GURU All energy in living systems comes from the sun Into producers through photosynthesis, then consumers up the food web IBESS/GURU/SYSTEMS & MODELS
  17. 17. Energy at one level must come from previous level Sun Producers (rooted plants) Producers (phytoplankton) Primary consumers (zooplankton) Secondary consumers (fish) Dissolved chemicals Tertiary consumers (turtles) Sediment GURU IBESS/GURU/SYSTEMS & MODELS (bacteria and fungi) Decomposers
  18. 18. Using the first law of thermodynamics explain why the energy pyramid is always pyramid shaped (bottom bigger than top) GURU IBESS/GURU/SYSTEMS & MODELS
  19. 19.      2nd Law: With every energy transfer or transformation energy dissipates (heat) so the energy available to do work decreases Or in an isolated system entropy tends to increase spontaneously Energy and materials go from a concentrated to a dispersed form The concentrated high quality energy is the potential energy of the system The system becomes increasingly disordered Order can only be maintained through the use of energy GURU IBESS/GURU/SYSTEMS & MODELS
  20. 20. First Trophic Level Third Trophic Level Fourth Trophic Level Producers (plants) Heat Second Trophic Level Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Heat Solar energy Heat Heat Heat Heat Detritivores (decomposers and detritus feeders) GURU IBESS/GURU/SYSTEMS & MODELS Heat
  21. 21. What results from the second law of Thermodynamics? GURU IBESS/GURU/SYSTEMS & MODELS
  22. 22. Feedback loops      Self regulation of natural systems is achieved by the attainment of equilibrium through feedback systems Change is a result of feedback loops but there is a time lag Feedback occurs when one change leads to another change which eventually reinforces or slows the original change. Or… Outputs of the system are fed back into the input GURU IBESS/GURU/SYSTEMS & MODELS
  23. 23. Positive feedback    A runaway cycle – often called vicious cycles A change in a certain direction provides output that further increases that change Change leads to increasing change – it accelerates deviation Example: Global warming 1. Temperature increases  Ice caps melt 2. Less Ice cap surface area  Less sunlight is reflected away from earth (albedo) 3. More light hits dark ocean and heat is trapped 4. Further temperature increase  Further melting of the ice GURU IBESS/GURU/SYSTEMS & MODELS
  24. 24. Solar radiation Energy in = Energy out Reflected by atmosphere (34%) Radiated by atmosphere as heat (66%) UV radiation Absorbed by ozone Lower stratosphere (ozone layer) Visible Greenhouse light Troposphere effect Heat Absorbed by the earth Heat radiated by the earth Earth GURU IBESS/GURU/SYSTEMS & MODELS
  25. 25. Negative feedback    One change leads to a result that lessens the original change Self regulating method of control leading to the maintenance of a steady state equilibrium Predator Prey is a classic Example      GURU Snowshoe hare population increases More food for Lynx  Lynx population increases Increased predation on hares  hare population declines Less food for Lynx  Lynx population declines Less predation  Increase in hare population IBESS/GURU/SYSTEMS & MODELS
  26. 26. Remember hare’s prey and other predators also have an effect IBESS/GURU/SYSTEMS & MODELS GURU
  27. 27. Most systems change by a combination of positive and negative feedback processes GURU IBESS/GURU/SYSTEMS & MODELS
  28. 28. Which of the populations show positive feedback? Which of the populations show negative feedback? IBESS/GURU/SYSTEMS & MODELS GURU
  29. 29. Positive or Negative?  If a pond ecosystem became polluted with nitrates, washed off agricultural land by surface runoff, algae would rapidly grow in the pond. The amount of dissolved oxygen in the water would decrease, killing the fish. The decomposers that would increase due to the dead fish would further decrease the amount of dissolved oxygen and so on... GURU  A good supply of grass for rabbits to eat will attract more rabbits to the area, which puts pressure on the grass, so it dies back, so the decreased food supply leads to a decrease in population because of death or out migration, which takes away the pressure on the grass, which leads to more growth and a good supply of food which leads to a more rabbits attracted to the area which puts pressure on the grass and so on and on.... IBESS/GURU/SYSTEMS & MODELS
  30. 30. End result? Equilibrium…      A sort of equalization or end point Steady state equilibrium  constant changes in all directions maintain a constant state (no net change) – common to most open systems in nature Static equilibrium  No change at all – condition to which most natural systems can be compared but this does not exist Long term changes in equilibrium point do occur (evolution, succession) Equilibrium is stable (systems tend to return to the original equilibrium after disturbances) GURU IBESS/GURU/SYSTEMS & MODELS
  31. 31. Equilibrium generally maintained by negative feedback – inputs should equal outputs GURU IBESS/GURU/SYSTEMS & MODELS
  33. 33. You should be able to create a system model. Observe the next two society examples and create a model including input, flows, stores and output GURU IBESS/GURU/SYSTEMS & MODELS
  34. 34. High Throughput System Model GURU IBESS/GURU/SYSTEMS & MODELS
  36. 36. Inputs (from environment) System Throughputs Output (intro environment) Low-quality heat energy High-quality energy Unsustainable high-waste economy Waste matter and pollution Matter GURU IBESS/GURU/SYSTEMS & MODELS
  37. 37. Low Throughput System Model GURU IBESS/GURU/SYSTEMS & MODELS
  38. 38. Inputs (from environment) High-quality energy Matter System Throughputs Outputs (from environment) Low-quality energy (heat) Sustainable low-waste economy Pollution prevention by reducing matter throughput Pollution control by cleaning up some pollutants Recycle and reuse Energy Feedback GURU IBESS/GURU/SYSTEMS & MODELS Matter output Matter Feedback Waste matter and pollution
  39. 39. Easter Island What are the statues and where are the trees? A case Study in unsustainable growth practices. GURU IBESS/GURU/SYSTEMS & MODELS
  40. 40. Evaluating Models        Used when we can’t accurately measure the real event Models are hard with the environment because there are so many interacting variables – but nothing else could do better Allows us to predict likelihood of events But… They are approximations They may yield very different results from each other or actual events There are always unanticipated possibilities… GURU IBESS/GURU/SYSTEMS & MODELS
  41. 41. Anticipating Environmental Surprises      Remember any action we take has multiple unforseen consequences Discontinuities = Abrupt shifts occur in previously stable systems once a threshold is crossed Synergistic interactions = 2 factors combine to produce greater effects than they do alone Unpredictable or chaotic events = hurricanes, earthquakes, climate shifts http://www.nhc.noaa.gov/archive/2008/FAY_graphic s.shtml GURU IBESS/GURU/SYSTEMS & MODELS
  42. 42. What can we do?    Develop more complex models for systems Increase research on environmental thresholds for better predictive power Formulate possible scenarios and solutions ahead of time GURU IBESS/GURU/SYSTEMS & MODELS
  43. 43. Define objectives Systems Measurement Data Analysis Identify and inventory variables Obtain baseline data on variables Make statistical analysis of relationships among variables Determine significant interactions © 2004 Brooks/Cole – Thomson Learning System Modeling Construct mathematical model describing interactions among variables System Simulation Run the model on a computer, with values entered for different variables System Optimization Evaluate best ways to achieve objectives GURU IBESS/GURU/SYSTEMS & MODELS
  44. 44. Other systems examples GURU IBESS/GURU/SYSTEMS & MODELS
  45. 45. Uranium mining (95%) Uranium 100% Uranium processing and transportation (57%) 95% Waste heat Power Transmission plant of electricity (31%) (85%) Waste heat 14% 17% 54% Waste heat Resistance heating (100%) Waste heat Electricity from Nuclear Power Plant Sunlight 100% GURU Passive Solar 90% Waste heat IBESS/GURU/SYSTEMS & MODELS Energy Production 14%
  46. 46. sun EARTH Economic Systems Natural Capital Air; water, land, soil, biodiversity, minerals, raw materials, energy resources, and dilution, degradation, and recycling services Production Heat Depletion of nonrenewable resources Degradation and depletion of renewable resources used faster than replenished Consumption Pollution and waste from overloading nature’s waste disposal and recycling systems Recycling and reuse GURU IBESS/GURU/SYSTEMS & MODELS Economics & Earth
  47. 47. Energy Inputs System Outputs 9% 7% 41% 84% U.S. economy and lifestyles 43% 8% 4% 4% Nonrenewable fossil fuels Nonrenewable nuclear Biomass Petrochemicals Unavoidable energy waste Unnecessary energy IBESS/GURU/SYSTEMS & MODELS waste Hydropower, geothermal, wind, solar GURU Useful energy
  48. 48.  Thank you  By  Guru GURU IBESS/GURU/SYSTEMS & MODELS