Living organisms: their properties, levels of organization and classification

Scientists have long noticed the extreme diversity of our world and therefore they began to study the manifestations, origin and spread of all life forms on Earth. Science, which studies all living organisms, their functions, structure, and their classification, is called biology. In addition, she explores the relationship between the animate world and the inanimate one.

The distinctive properties that only living organisms possess are as follows: the high degree and complexity of their organization; Each part has its own meaning and definite functions; The ability to use, extract and transform the energy of the environment for their life; The ability to respond to external stimuli and changes in the environment. They are also well adapted to their habitat (adaptive properties are developed); Can reproduce themselves (multiply), have a heredity and a propensity to change. In addition, they are characterized by evolutionary processes, as a result of which arose such a variety of living beings.

There are several levels of organization of life, which are among themselves in a complex subordination. The lowest level is the boundary that separates living organisms from inanimate ones and represents a molecular structure. Next comes the cellular level, in which the cells and the main features of the structure are the same for all. More complex organ-tissue level refers only to multicellular, in which the parts of the body formed from the cells have already developed sufficiently. The next step is a complete organism, here, no matter how different the beings, they have one common property - they all consist of cells.
Further all the diversity of life is classified according to a different principle. In biology, even a whole section is called, which is called systematics, which deals with the description and grouping of all beings. Thus, the systematics of living organisms divides them according to the form of life into noncellular (viruses) and cellular ones. The latter are further subdivided into: simple and complex bacteria, plants, animals and fungi. To systematize all these objects, they need to be identified, and for this a number of characteristics are used, which include: morphological, biochemical, physiological and other features.
Great attention is paid in biology to the study of the structure of living beings. They contain a lot of chemical components that form organic and inorganic compounds. The chemical elements in the cells of living organisms contain carbon atoms, which are the hallmark of life. In general, of all organic compounds, only a few classes are important for development. These include nucleic acids, proteins, lipids and carbohydrates. Living organisms can contain up to 70 components of Mendeleev's periodic system in their cells , but only 24 constantly enter into their composition (phosphorus, potassium, sulfur, calcium, iron, magnesium, zinc, aluminum, iodine, etc.)