General Systems Theory

Transcription

1 General Systems Theory

2 Land tenure Zoning Floodplains Wetlands Vegetative cover Soils Georeferencing Composite GIS Overlay

3 General Systems Theory....presumes that there are universal principles of organization, which hold for all systems, be they physical, chemical, biological, mental, social, etc.

4 Electrical analog models

5 widely applied to human resources management in natural resources management, widely regarded as key to workings of interdisciplinary project/research teams, understanding ecological systems, etc.

6 Systems Thinking the ability to perceive some degree of order or inter-connectedness in complex systems

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8 Systems Concepts (Properties) used to characterize and/or delineate relevant systems

9 Property Characteristic type open, closed hierarchy high to low levels of abstraction boundaries permeable, impermeable environment everything outside system boundaries entropy positive, negative equilibrium stable, steady state feedback mechanisms... positive, negative equifinality multiple pathways

10 Properties of Systems Example: Systems Concepts Applied to Soil Development

11 FILM Life in the Balance

12 ENVIRONMENT inputs SYSTEM outputs (throughput) permeable boundary

13 Boundaries a line or point where a system can be differentiated from it s environment and from other systems 1. Permeable (free flow of energy and/or matter)

14 System Type 1. Open - matter, energy transformation (throughput) - permeable boundaries ENVIRONMENT inputs SYSTEM outputs (throughput) permeable boundary

15 human skills - extraction of commodities energy primary resources aesthetic needs natural - manufacturing employment resources - consumers pollution, noise INPUTS TRANSFORMATIONAL OUTPUTS SYSTEM

16 The Soil System Boundary ( pedon )

17 System Type 2. Closed - no exchange of energy and/or matter with the surrounding environment

18 Boundaries a line or point where a system can be differentiated from it s environment and from other systems 1. Permeable (free flow of energy and/or matter) 2. Impermeable (no flow of energy or matter)

19 Hierarchy all systems are composed of subsystems of a lower order and also form part of a larger supersystem embeddedness, nestedness

20 Hierarchy Supersystem Systems Subsystems

21 BIOSPHERE The sum of all the planet s ecosystems

22 Biomes Large scale communities classified by predominant vegetation type and distinctive combination of plant and animals

23 Ecosystem An energy processing system of community interactions that include abiotic and environmental factors such as soil and water

24 High Sierra, California Community Populations of species living in the same area

25 Giant Sequoia grove Population Localized group of organisms belonging to the same species

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27 more information on specific systems functions deeper understanding of coherence and interconnectedness of a system

28 Supersystem Hierarchy (e.g. landscape evolution) Systems (e.g. pedons) Subsystems (e.g. horizon differentiation)

29 Supersystem Hierarchy (e.g. landscape evolution) Systems (e.g. pedons) Subsystems (e.g. horizon differentiation)

30 Supersystem Hierarchy (e.g. landscape evolution) Systems (e.g. pedons) Subsystems (e.g. horizon differentiation)

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32 Entropy a measure of randomness or disorder in a system 2 nd Law of Thermodynamics the irreversible increase in the amount of degraded energy (i.e., heat) in the universe translates into a (+)ve change in entropy

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34 Entropy and soil development Acidic Brunisol Podzol Regosol Ultisol, Oxisol ( laterite ) Basic Brunisol Luvisol

35 Equilibrium lack of change in a system over time ENVIRONMENT 1. Steady state Open System ( dynamic ) inflow = outflow ENVIRONMENT 2. Stable Closed System ( static ) - minimum energy - maximum entropy

36 Feedback Mechanisms mechanism whereby a system continually receives information from its environment, inducing a re-adjustment to the prevailing conditions feedback is information about the results of a process (transformation, action) which is used to change the process itself

37 Feedback loop

38 Feedback Mechanisms 1. Positive feedback divergent behaviour (reinforces external changes) either explosion or collapse of activity increasing entropy leads to total modification or destruction of system

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40 Tacoma Narrows Bridge Collapse Tacoma, Washington Nov. 7, 1940

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42 Snowball Earth

43 Soil Erosion ( Soil erodibility factor [K])

44 Feedback Mechanisms 1. Positive feedback divergent behaviour (reinforces external changes) either explosion or collapse of activity increasing entropy leads to total modification or destruction of system 2. Negative feedback adaptive behaviour ( self-regulation ) reduces and stabilizes external changes

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47 Predator-prey population dynamics

48 Homeostasis ( biofeedback ) characteristic property of highly complex open systems (e.g., ecological, biological, social systems) open system maintains it s structure and functions by means of a multiplicity of dynamic equilibria rigorously controlled by interdependent regulation mechanisms

49 Equifinality (Multicausality) the same final state or condition of a system (or system output) may be reached from different initial conditions (inputs) and in different ways (transformations)

50 Soil Forming Factors (Terrestrial Ecosystem) climate biota (vegetation) parent material relief (topography) time

51 Arctic landscape

52 Glaciated landscape

53 Fluvial landscape

54 Dune landscape