Ichneumon sp.

0.580 (0.90 X 0.65)

increases in the course of an ecological development because an ecosystem encompasses an integration of all the modifications that are imposed on the environment.

Thus, it is in the background of genetic information that systems develop which allows interaction of information with the environment. Herein lies the importance in the feedback organism-environment, which means that an organism can only evolve in an evolving environment. The differences between the two stages include entropy and exergy. This latter concept will be discussed later in Chapters 4 and 5.

The conservation laws of energy and matter set limits to the further development of "pure" energy and matter, while information may be amplified (almost) without limit. These limitations lead to the concept of limiting factors that is playing a significant role in ecology, including systems ecology. Patten et al. (1997) have speculated how a world without the conservation principles would look. Things would behave erratically. Something could arise from nothing. Mathematical counting would be meaningless. They conclude that, if there is a scientific law more fundamental than the rest, it is probably the conservation principles of matter, energy, momentum and electrical charge.

A major design principle observed in natural systems is the feedback of energy from storages to stimulate the inflow pathways as a reward from receiver storage to the inflow source (Odum, 1971a,b). By this feature, the flow values developed reinforce the processes

Table 2.5

Differences between initial stage and mature stage are indicated

Properties Early stage Late or mature stage


P/B High

Yield High

Specific entropy High

Entropy production per unit of time Low

Exergy Low

Information Low


Total biomass Small

Inorganic nutrients Extrabiotic

Diversity, ecological Low

Diversity, biological Low

Patterns Poorly organised

Niche specialisation Broad

Size of organisms Small

Life cycles Simple

Mineral cycles Open

Nutrient exchange rate Fast

Life span Short

Selection and homeostatis

Internal symbiosis Undeveloped

Stability (resistance to external perturbations) Poor

Ecological buffer capacity Low

Feedback control Poor

Growth form Fast growth

Types r-strategists

Close to 1




Large Intrabiotic High High

Well organised







Developed Good High Good

Feedback controlled growth K-strategists that are doing useful work. In other words, feedback allows the circuit to learn. A wider use of the cosystem's self-organisation ability in environmental, or rather ecological, management has been proposed by Odum (1988).

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