Ecology deals with the interactions between
species and the necessary conditions of existence in the
environment to which they are adapted. At the level of individual
animals, plants and microbes these adaptations comprise webs of
perception and action evolved to ensure resources are available to
maintain growth and reproduction.
Behavioural interactions are at the heart of
ecology where they function to unite individuals into more or less
stable social structures. In particular, the structures determine
and regulate the relations of individuals to one another. They
provide such external adaptation to the physical environment, and
such internal adaptation between the component individuals or
groups to make possible an ordered social life. Each species has
evolved a behaviour structure that is an harmonious whole to
maintain the sum of its parts in a steady state biochemical
equilibrium with its environment. It survives and flourishes
because it successfully maintains external social solidarity among
its members, and chemical integrity amongst its internal organs and
cells.