GEO 125

Physical Geography

The Study of Physical Geography: A Systems Approach

Definition of a System: A SET OF LIKE OF SIMILAR OBJECTS THAT ARE RELATED

Types of systems:

• Isolated
• Closed (also called material systems)
• Open (also called energy systems)

Characteristics of an isolated system:

• Energy is confined to the system
• Matter is confined to the system
• Exists only theoretically

Characteristics of a closed system:

• Energy may enter and exit the system
• Matter is confined to the system
• Examle: the movement of water through the hydrologic cycle

Characteristics of an open system:

• Energy may enter and exit the system
• Matter may enter and exit the system
• Example: Mississippi River Basin

Spheres of study in physical geography:

• Lithosphere
• Atmosphere
• Hydrosphere
• Biosphere

Subsystems or physical geographic regions at different scales of geographic reference

Ecosystems:

• Role of limiting factors
• Environmental niches

Dynamic equilibrium and self regulation.

Feedback:

• Positive
• Negative

Global model of the earth using the systems approach.

• The earth as a closed system (related to the concept of the "spaceship earth")
• At the global level the earth has four major subsystems, including the atmosphere, lithosphere, hydrosphere and biosphere.
• Each of theses major subsystems can be considered to be an open system.
• The concept of interlocking relationships can be demonstrated for the earth's major subsystems when together they are assumed to form a cascading system. A cascading system is made up of a chain of open systems where the output from one open system forms the input into another.

• Interlocking relationships among the atmosphere, lithosphere, hydrosphere, and biosphere as related to the greenhouse effect.

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