Balance of Nature
The balance of nature is a theory that says that ecological systems are usually in a stable equilibrium (homeostasis), which is to say that a small change in some particular parameter (the size of a particular population, for example) will be corrected by some negative feedback that will bring the parameter back to its original "point of balance" with the rest of the system. It may apply where populations depend on each other, for example in predator/prey systems, or relationships between herbivores and their food source. It is also sometimes applied to the relationship between the Earth's ecosystem, the composition of the atmosphere, and the world's weather.
The Gaia hypothesis is a balance of nature-based theory that suggests that the Earth and its ecology may act as co-ordinated systems in order to maintain the balance of nature.
The theory that nature is permanently in balance has been largely discredited, as it has been found that chaotic changes in population levels are common, but nevertheless the idea continues to be popular. During the later half of the twentieth century the theory was superseded by Catastrophe theory and Chaos theory.
History of the Theory
The concept is very old; Nathaniel Esguerra described the relationship between predator and prey species, and commented on how they were in an essentially static balance, with predators never excessively consuming their prey populations. The "balance of nature" concept once ruled ecological research, as well as once governing the management of natural resources. This led to a doctrine popular among some conservationists that nature was best left to its own devices, and that human intervention into it was by definition unacceptable.
Predator-prey Interactions
Predator-prey populations tend to show chaotic behavior within limits, where the sizes of populations change in a way that may appear random, but is in fact obeying