Topic 1 Systems and models
- 1. DP Environmental systems and societies Topic 1 Systems and models
- 3. What is a system? Is an organized collection of interdependent components that perform a function and which are connected through the transfer of energy and/or matter All the parts are linked together and affect each other. Examples: • Ecosystems in which various elements such as air, water, movement, plants and animals work together to survive or perish. • Organizations in which people, structures, and processes work together to do business.
- 5. • What do the blue lines represent?
- 6. Figure 54.20 Review: Generalized scheme for biogeochemical cycles
- 8. Large ecosystem - biome • A biome (or ecosystem) is a climatically and geographically defined area often with similar communities of plants and animals. • Biome movie
- 9. Figure 50.24 The distribution of major terrestrial biomes
- 10. Figure 50.10 A climograph for some major kinds of ecosystems (biomes) in North America
- 11. Figure 50.25a Tropical forests
- 17. Figure 50.25e Temperate grassland
- 18. Figure 20.25f Temperate deciduous forest
- 19. Figure 20.25g Coniferous forests
- 21. Global ecosystem - Gaia The Gaia hypothesis is an ecological hypothesis proposing that the biosphere and the physical components of the Earth (atmosphere, hydrosphere and lithosphere) are closely integrated to form a complex interacting system that maintains the climatic and biogeochemical conditions on Earth in a preferred homeostasis.
- 23. Terminology • Open system - where matter and energy is exchange outside the system. eg. Local ecosystems (biomes) • Closed system – where only energy is exchanged outside the system. eg. Carbon, nitrogen, water, phosphate cycles • Isolated system – neither heat nor energy is exchanged. eg. The cosmos?
- 24. Open systems • Ecosystems animation
- 25. Closed systems • Water cycle • Carbon cycle • Nitrogen cycle • Phosphorus cycle
- 26. Closed systems - The water cycle
- 27. Closed systems - The carbon cycle
- 28. Closed systems - The nitrogen cycle
- 29. Closed systems - The phosphate cycle
- 30. Terminology First law of thermodynamics – energy is neither created nor destroyed Second law of thermodynamics – in any isolated system entropy tends to increase spontaneously Equilibrium – forward and reverse reactions are equal - balance
- 33. Figure 50.14 How mountains affect rainfall
- 34. Flows and storages Two basic processes must occur in an ecosystem: 1. A cycling of chemical elements. 2. Flow of energy. TRANSFERS: normally flow through a system and involve a change in location. TRANSFORMATIONS: lead to an interaction within a system in the formation of a new end product, or involve a change of state.
- 37. Components of a system: 1. Inputs such as energy or matter. Calories Protein
- 38. 2. Flows of matter or energy within the systems at Calori es certain rates. Protei n
- 39. 3.Outputs of certain forms of matter or energy that flow out of Waste the system into Calorie s Heat sinks in the environment. Waste Protei n Matte r
- 40. 4. Storage areas in which energy or matter can accumulate for Calorie various s lengths of time before being Protei released. n
- 42. Positive and Negative Feedback • Positive feedback includes a sequence of events that will cause a change in the same direction as the stimulus and thereby augments the change, moving the state of the system even further from the equilibrium point. • Negative feedback systems include a sequence of events that will cause an effect that is in the opposite direction to the original stimulus and thereby brings the system back to its equilibrium position.
- 45. Negative feedback = equilibrium
- 46. Negative feedback = equilibrium
- 47. • Predator/prey relationships are usually controlled by negative feedback where: • The increase in prey-increase in predator- decrease in prey decrease in predatorincrease in prey---and so on in a cyclical manner. The classic study in Northern Canada between the Lynx and the hare populations is famous for its regular 11 year cycle of rising and falling populations.
- 49. Models What is a model? • A representation or a simulation, could be conceptual, physical, mathematical How to evaluate a model? • Does it explain past observations • Does it agree with other models • Does it predict accurately
- 50. Models • What are the strengths and weakness of these models? • Determining if asteroids affected earth’s past but craters not formed due to ice - see impact crater Permafrost connecting ice layer Brittleness of crust vs sand • What problems might the aquarium model have? Biodiversity, storages…
- 51. SUSTAINABILITY is the extent to which a given interaction with the environment exploits and utilizes the natural income without causing long-term deterioration to the natural capital.