Systems Theory


The Systems Approach

The term "systems" is derived from the Greek word "synistanai," which means "to bring together or combine." The term has been used for centuries. Components of the organizational concepts referred to as the "systems approach" have been used to manage armies and governments for millennia. However, it was not until the Industrial Revolution of the 19th and 20th centuries that formal recognition of the "systems" approach to management, philosophy, and science emerged (Whitehead 1925, von Bertalanffy 1968). As the level of precision and efficiency demanded of technology, science, and management increased the complexity of industrial processes, it became increasingly necessary to develop a conceptual basis to avoid being overwhelmed by complexity. The systems approach emerged as scientists and philosophers identified common themes in the approach to managing and organizing complex systems. Four major concepts underlie the systems approach:


What is a system?

The systems approach considers two basic components: elements and processes. ELEMENTS are measurable things that can be linked together. They are also called objects, events, patterns, or structures. PROCESSES change elements from one form to another. They may also be called activities, relations, or functions. In a system the elements or processes are grouped in order to reduce the complexity of the system for conceptual or applied purposes. Depending on the system's design, groups and the interfaces between groups can be either elements or processes. Because elements or processes are grouped, there is variation within each group. Understanding the nature of this variation is central to the application of systems theory to problem-solving.


Ecosystems are composed of elements and processes. (These are usually referred to as ecosystem structures and functions or the patterns and processes of an ecosystem.) As an example, the elements of a forest ecosystem might include trees, shrubs, herbs, birds, and insects, while the processes might include growth, mortality, decomposition, and disturbances.


Open vs Closed Systems

Some systems are open with respect to certain elements or processes (e.g., figure to the right). The elements or processes can flow into or out of the system. For example, an automobile engine is "open" with respect to gasoline--gasoline flows in and exhaust (oxidized gasoline) flows out.  


Other systems are closed with respect to certain elements or processes (e.g., figure to the right). The elements or processes do not leave the system. For example, an automobile engine is largely "closed" with respect to lubricating oil--the oil does not leave the engine.


Ecological systems are open systems with respect to most elements and processes. They receive energy and nutrient inputs from their physical environment and, at the same time, cycle nutrients back out of the system. They are also open to outside influences such as disturbances (e.g., hurricanes, ice storms, fires, insect outbreaks).



Most systems contain nested systems; that is, subsystems within the system. Similarly, many systems are subsystems of larger systems.


For example, the nested system above right could represent:

atoms (black dots), molecules (red circles), cells (blue), and organs (green);

leaves (black dots), trees (red circles), stands (blue), and landscapes (green);

planets (black dots), solar systems (red circles), galaxies (blue circle), and universes (green).

Nested systems can be considered as a hierarchy of systems. Hierarchical (nested) systems contain both parallel components (polygons of the same color, above) and sequential components (polygons of different colors, above).

"At the higher levels, you get a more abstract, encompassing view of the whole emerges, without attention to the details of the components or parts. At the lower level, you see a multitude of interacting parts but without understanding how they are organized to form a whole (Principia Cybernetica 1999)."

Attempting to measure, study, or manage a system at a precision greater than the innate variation among its components leads to meaningless measures. At the upper levels of a hierarchical system, the amount of precision which can be measured, studied, or managed declines for two reasons:

  1. The elements or processes in parallel components of a system (e.g., two stands) are slightly different; therefore, combining them at a broader level (e.g., landscape) increases the innate variation of the average component (e.g., stand).
  2. The elements or processes in sequential components of a system are dependent on each other; therefore, variation in components become additive. For example, size variation among trees within a stand means that there is innate variation in the average tree size in a stand, and even greater variation in the average tree size when stands are combined into landscapes.

Moving information between levels of a hierarchy requires time. The variation in time needed to process different steps within a hierarchy can lead to innate temporal lags or bottlenecks. These can be minimized by not trying to consider a system with high precision from a single, central, upper hierarchical level (e.g., centralized planning by governments or regional models of ecosystems). Instead, such centralized levels are useful for generalities which allow local variation, while more precision is achieved through independent, parallel processes at more localized levels.