Meaning. Population. A group of individuals that belong in the same species and live in the same area; for example, the stray cats of New York City. Population ecology. The ecological study of how biotic (living) and abiotic (non-living) factors influence the density, dispersion, and size of a population.Three basic types of population distribution within a regional range are (from top to bottom) uniform, random, and clumped .The organisms in a population may be distributed in a uniform, random, or clumped pattern. Uniform means that the population is evenly spaced, random indicates random spacing, and clumped means that the population is distributed in clusters