Concept “population”

Population ecology is a sub-field of ecology that deals with the dynamics of species populations and how these populations interact with the environment.

Term “population” comes from Latin word populous (people) and in translation means “population”.

Population - this is the group of one species individuals inhabiting certain territory and characterizing by this or other level of genetic information exchange (panmixture), morphobiological type and system of sustainable functional ties.

Ecologists study populations for many reasons. Population studies hold the key to saving endangered species, controlling pest populations, and managing fish and game populations. They also offer clues to understanding and controlling disease epidemics.

Populations, as groups, have a number of specific features that are not inherent in a single species.

Main characteristics of the population:

Abundance: Absolute number of individuals in population. The abundance of an organism, often considered as total population size or the number of organisms in a particular area (density), is one of the basic measures in ecology. Organisms generally are more abundant where conditions are favorable, such as locations with sufficient quantity and quality of food or nutrients, fewer herbivores or predators, fewer competitors, and optimal physical features. The physical features that affect abundance could be substrate type, moisture, light, temperature, pH, salinity, oxygen or CO2, wind, or currents.

Density of population is the number of individuals per unit area or volume. It is expressed when the size of individuals in the population is relatively uniform.

Fertility (natality) refers to the rate of reproduction or birth per unit time. It is an expression of the production of new individuals in the population by birth, hatching, germination or fission.

Mortality: the number of deaths in a population per unit time. The loss of individuals due to death in a population under given environmental conditions is called mortality. Mortality as well as fertility especially of higher organisms varies widely with age.

Population growth - the difference between fertility and mortality. Population growth can be either positive or negative.

Growth rate - is the amount or speed of increase in size of population (per unit time).

The population has a certain organization. The distribution of species in the territory, correlation of groups according to sex, age, morphological, physiological, behavioral and genetic characteristics represent the structure of the population. It is formed, on the one hand, on the basis of the general biological features of the species, and on the other hand - under the influence of abiotic factors of the environment and populations of other species.