ABSTRACT
Population system, or life system, is a population with its effective environment.66
Major components of a population system are as follows: (1) The Population: organisms in the population can be subdivided into groups
according to their age, stage, sex, and other characteristics. (2) Resources: food, shelters, nesting places, space, etc. (3) Enemies: predators, parasites, pathogens, etc. (4) Environment: air, water, soil, temperature, composition, variability of these
characteristics in time and space.67
