All living nature is a combination of biological systems of different levels of organization and different subordination.
The level of organization of living matter is understood as the functional place that a given biological structure occupies in the general system of organization of nature.
The level of organization of living matter is a set of quantitative and qualitative parameters of a certain biological system (cell, organism, population, etc.), which determine the conditions and boundaries of its existence.
There are several levels of organization of living systems, which reflect the subordination, hierarchy of the structural organization of life.
The molecular (molecular genetic) level is represented by individual biopolymers (DNA, RNA, proteins, lipids, carbohydrates and other compounds); at this level of life, phenomena associated with changes (mutations) and reproduction of genetic material, metabolism are studied. This is what science is doing – molecular biology.
The cellular level – the level at which life exists in the form of a cell – the structural and functional unit of life – is studied by cytology. At this level, processes such as metabolism and energy, information exchange, reproduction, photosynthesis, transmission of nerve impulses, and many others are studied.
A cell is a structural unit of all living things.
The tissue level is studied by histology.
Tissue is a collection of intercellular substance and cells that are similar in structure, origin and functions.
Organ level. An organ includes several tissues.
The organismic level – the independent existence of an individual – a unicellular or multicellular organism – is studied, for example, by physiology and autecology (the ecology of individuals). An individual as an integral organism is an elementary unit of life. In another form, life in nature does not exist.
An organism is a real bearer of life, characterized by all its properties.
Population-specific level – the level that is represented by a group of individuals of the same species – a population; it is in the population that elementary evolutionary processes take place (accumulation, manifestation and selection of mutations). This level of organization is studied by such sciences as demecology (or population ecology), evolutionary doctrine.
A population is a collection of individuals of one species, existing for a long time in a certain territory, freely interbreeding and relatively isolated from other individuals of the same species.
Biogeocenotic level – represented by communities (ecosystems), consisting of different populations and their habitats. This level of organization is studied by biocenology, or synecology (community ecology).
Biogeocenosis is a combination of all species with varying complexity of organization and all factors of their habitat.
Biosphere level – a level representing the totality of all biogeocenoses. In the biosphere, there is a circulation of substances and the transformation of energy with the participation of organisms.