There is a natural tendency for populations with unlimited food supplies to grow increasingly rapidly with exponential growth as we showed in Part II-1. As storage grows, the auto-catalytic feedback also grows accelerating growth.
In Figure III-3 two populations are shown, both growing from the same unlimited source. Even though resources are not in short supply, and even though there are no negative interactions, one population may become increasingly dominant. See Figure III-3b.
Some populations have individuals that work cooperatively in their production processes. Their growth is proportional to the interaction of its individuals. Its growth is proportional to the square of the population number. It is said to be "quadratically auto-catalytic”.
Examples of the rapid growth of populations on unlimited food resources are the early stages of growth of microorganisms in food, the growth of new plants when a field is abandoned, and the growth of new industries during human colonization of a new area.
Examples of the quadratic growth are the growth of fishes that school and birds that nest in colonies. The growth of the economy of the United states prior to 1973 was utocatalytically quadratic.
"What if" Experiments
COMPUTER MINIMODELS AND SIMULATION EXERCISES
FOR SCIENCE AND SOCIAL STUDIES
Howard T. Odum* and Elisabeth C. Odum+
* Dept. of Environmental Engineering Sciences, UF
+ Santa Fe Community College, Gainesville
Center for Environmental Policy, 424 Black Hall
University of Florida, Gainesville, FL, 32611
Autorização concedida gentilmente pelos autores para publicação na Internet
Laboratório de Engenharia Ecológica e Informática Aplicada - LEIA - Unicamp
Mileine Furlanetti de Lima Zanghetin
Campinas, SP, 20 de julho de 2007