POPULATIONS

population consists of the individuals of a given species that occur together at one ice and at one time. This is a flexible definition, which allows us to speak in similar terms of the world's human population, the population of protozoa in the gut of an individual termite or the deer that inhabit a forest.
All populations have characteristic features, such as size, density, dispersion, and emography. Each occupies a particular place and plays a particular role in its ecosystem that role is denned as the niche of that population. Understanding these properties of populations is crucial for understanding the nature of life on earth.