ABSTRACT
For many ecologists, however, the popula tion is the central focus of study. A population comprises the interbreeding members of a species found in a given habitat, and these individuals collectively express genetic, mor phological, physiological, and behavioral vari ations. For this reason, populations are the functional ecological and evolutionary units. In the definition of populations, there should be separation or discontinuity (also called dis junction) from other populations in one of the following three characteristics: (a) spatial loca tion, (b) gene flow, or (c) demographic structure (Wells and Richmond 1995). In other words, population A is considered distinct when it is disjunct from population B by at least one of these features.
