A population is individuals belonging to the same biological species, capable of free crossbreeding and having a common gene pool. The biological species has abundance, mortality, fertility, dynamics, range, and density. The population structure also includes the ratio of females and males, ages, spatial distribution system.
The size of the range is set in accordance with the radius of a single (individual) activity and represents the distance between the death point and the birth point of most individuals. So, for example, this radius is thirty meters for a lizard, about four hundred for a muskrat, and three kilometers for a rabbit and a sparrow. In plants, the size of the range is set in accordance with the distance that the pollen flies. So, for example, a pine has an activity radius of about one hundred and twenty, and corn has about fifteen meters.
The area and shape of the range in each case is set in accordance with the landscape features of the territory. Intrapopulation distinctive features, as well as geographical (territorial) connections of individuals are of no small importance.
Most often, such types of populations are distinguished as geographic, ecological, and local.
Ecological is called such a collection of individuals that lives within the framework of one system. Moreover, the boundaries coincide with the boundaries of the ecosystem itself, determined by vegetation and phytocenosis.
A local population is a local population of populations of a particular species. Individuals live on various ecosystems of a particular area. So, the local population of house sparrow is a collection of populations of individuals from settlements located at a distance of less than three kilometers from each other.
Geographic is the set of individuals occupying an area with geographically homogeneous conditions. From Kamchatka to Brest, for example, twenty-nine aggregates of the common squirrel have been identified. A geographical population is a territorial race, a subspecies. Individuals have phenotypic similarities.
The population (population) is, first of all, the elementary unit of the evolutionary process. Along with this, it is also the main spatial unit of a certain type. Thus, the population can be characterized as a collection of individuals not only occupying a certain territory (space), but also capable of reproduction over a long time. From the point of view of evolution, the integrity of the population is mainly associated with panmixia (free crossbreeding), which is to one degree or another within the same set of species higher than between neighboring peoples. At the same time, despite its integrity, the population is heterogeneous in genetic characteristics. The main characteristics of the species are fixed hereditarily.
There is a classification of the population from a medical point of view.
So, for example, a closed collection of individuals is isolated. In this case, one population is isolated from the other by gender.
There is also an ideal collection of individuals. In this case, a hypothetical panmictic (crossbreeding) population is considered, which has a large number that remains in generations. This set of species is not affected by mutational pressure, external factors, natural selection. The concept of an ideal population is used in modeling the evolutionary process.
Individuals of the same species may be genetically identical. In this case, we are talking about an isogenic population.
The population can be open. In this case, migratory individuals introduce new genes into it.
A microbial population is a collection of cells of a particular strain.