The molecular level is represented by molecules of organic substances – proteins, nucleic acids, carbohydrates, lipids that are in the cells and are called biological molecules. At the molecular level, the role of these most important biological compounds in the growth and development of organisms, the storage and transmission of hereditary information, metabolism and the conversion of energy in living cells and other phenomena is investigated.
The cellular level is represented by cells. This is the first, initial level of organization of the living, which has all the properties of the living. At this level, science studies the morphological organization of cells, the specialization of cells during development, the functions of the cell membrane, the mechanisms of cell division. These problems are very important, including practical, especially for medicine.
The body level can be represented by both unicellular and multicellular organisms. At this level, the organism as a whole is studied, with its characteristic mechanisms of the coordinated functioning of its organs in the process of life, its adaptation and behavior in various environmental conditions.
The population-species level is represented by populations of species and is fundamentally different from the body level. The life expectancy of any organism is determined genetically, while a population under optimal environmental conditions can exist indefinitely. At this level, factors affecting the dynamics of the number of individuals and the age composition of populations, the problems of conservation of endangered species, the effects of microevolution factors, etc. are studied. These issues are of great economic importance, since they allow you to give scientifically sound recommendations to maintain the optimal number of individuals of different populations in exploited ecosystems.
The ecosystem level is represented by a system of populations of different species in their relationship with each other and the environment. At this level, the relationships between organisms and the environment, the conditions that determine the productivity of ecosystems, their sustainability, and the impact of human activities on them are studied.
The biosphere level is the highest form of organization of living matter, uniting all the ecosystems of the planet. Global biogeochemical cycles (cycles of matter and energy flows) occur in the biosphere. The study of the mechanisms of their course, as well as the impact on them of human activity, is currently of paramount importance to prevent the global environmental crisis.