1Chapter 1Essentials of GeographyRobert W. ChristophersonCharlie Thomsen• The Science of Geography• Earth Systems Concepts• Location and Time on Earth• Maps, Scales, and Projections• Remote Sensing and GISEssentials of Geography• The science that studies the relationships among – natural systems – geographic areas– society – cultural activities – and the interdependence of all of these over spaceGeography Is2• PG: studies the physical elements and processes that make up the natural environment• HG: studies patterns and processes that make up the human environmentNo strict boundaries, human environment have to exist on the Earth surface, and human activities modify the natural environment.Physical/Human Geography Figure 1.2Scientific MethodFigure FS 1.1.13• Systems theory• Open systems• Closed systems• System feedback• System equilibriumEarth Systems Concepts• A System is any ordered, interrelated set of things and their attributes, linked by flows of energy and matter, as distinct from the surrounding environment out side the system:e.g. a car, a house, a pound, a watershed, a hurricane, the ocean, the earth, …Earth Systems Concepts• Reservoir/Stock/the state variable: a repository where matter/energy is stored over time.• Processes (flows of energy/matter): the activities in the system that determines the content of the reservoir over time. • Relationships: connections among the components of system.• Parameters: which regulate the rate of change in the processes.System Components41. Open/Closed Systems2. System FeedbacksPositive Feedback: unstableNegative Feedback: stable3. System Status: Growth/Decline Steady-State System PropertiesFigure 1.3Open SystemsFigure 1.45Systems in Steady StateFigure 1.501_05.JPGSteady-state is not static, but dynamic. A steady-state system can withstand certainly level of disturbance and the system can regain its steady-state. After a threshold (tipping point), the system will be permanently displaced and regain new steady-state. Tipping Point ExampleFigure 1.5Harlequin Frog:Monteverde Cloud Forest Reserve, Costa RicaMoist and porous skin: fungus penetrationGlobal WarmingMore Water in the airMore Clouds over Mountains Increase nighttime minimum TDecrease daytime maximum TChytrid fungus: ideal T: 17~25oCstop grow: 28oCdies: 30oC1986-2006:67% of the 110 known species of Harlequin frog extinct.Systems in GeosystemsFigure 1.76Earth’s Four SpheresFigure 1.8Earth System CharacteristicsFigure 1.81. A dynamic evolving system: energy and matter are constantly being transferred and changing in form.2. An open system with respect to energy. 3. A nearly steady-state system in energy.4. A almost closed system with respect to matterexception: air molecules escape earth gravity to leave the Earth system, and meteorites from outer
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