All the living organisms that inhabit our planet,are characterized by certain criteria. First of all, it is the activity and the course of various physiological processes. Otherwise, their manifestation can be defined by such a concept as life activity. This is the totality of all the processes that occur in living beings, regardless of the level of their organization. In this article we will dwell in detail on some of them.
Mechanisms of physiological processes and their levelare determined by the features of the structure of different organisms. For example, human life is very complex and subject to nervous and humoral regulation. And in viruses, it comes down to a primitive process of reproduction by self-assembly. Photosynthesis of plants, digestion of animals, the division of bacterial cells - is nothing more than life. This is a combination of processes that provide for the exchange of substances and homeostasis.
Living organisms are characterized by such processes asnutrition, breathing, movement, reproduction, growth, development, heredity, variability and adaptation. Life activity is a combination of all of the above. Each systematic group has its own characteristics. Let's look at some of them in more detail.
Depending on the type of food, all organismsare divided into auto- and heterotrophs. The first group includes plants and some types of bacteria. They are able to produce organic substances independently. For this, plants use solar energy, due to which glucose monosaccharide is synthesized in chloroplasts. Therefore, they are also called phototrophs. Bacteria are the source of nutrition energy of chemical bonds of organic compounds. Such unicellular organisms are also called hemotrophs.
Animals and mushrooms assimilate only readyorganic matter. They are heterotrophs. Among them, several groups are distinguished, which differ in the nature of the food source. For example, predators attack their prey and kill it, and saprotrophs consume organic matter. The special group includes mixotrophs. In the presence of favorable conditions, they synthesize carbohydrates independently, and if necessary switch to heterotrophic nutrition. Examples of mixotrophs are euglena green, mistletoe, rogolist, wolvox.
The concept of breathing includes not only absorptionoxygen and the release of carbon dioxide. During this process, oxidation of organic substances takes place with the release of a certain amount of energy. It is "stored" in ATP molecules. As a result, organisms are provided with a reserve, which, if necessary, can be used. In plants, respiration occurs in the mitochondria of cells, and gas exchange provides such elements of the integumentary tissue as stomata and lenticles. In animals, the organs that provide this process are gills or lungs.
Many prokaryotic organisms are capable ofanaerobic respiration. This means that the oxidation of organic substances in them occurs without the participation of oxygen. These include nitrogen-fixing, iron and sulfur bacteria.
Another manifestation of life -reproduction of organisms. This process ensures the continuity of generations. Important properties of all living things are the ability to transmit characteristics by inheritance and acquire new ones, which guarantees their adaptation to the constantly changing environmental conditions.
There are two main ways of reproduction:sexual and asexual. The first occurs with gametes. Female and male sex cells merge, giving rise to a new organism. In-vaginal reproduction can occur by dividing the cells in two, sporulation, budding, or vegetatively.
The conditions of life of any organismsare also in the quantitative and qualitative transformations that occur during their ontogeny. Due to cell division and regeneration processes, growth is ensured. In plants and mushrooms it is unlimited. This means that they increase in size throughout life. Animals, however, grow only a certain period. After this, this process is terminated. Growth is accompanied by development. This concept is a qualitative change that manifests itself in the form of complication of life processes. Growth and development accompany each other and are inextricably linked.
So, the life activity of organisms isa set of physiological processes aimed at ensuring metabolism and homeostasis - maintaining the consistency of the internal environment. The main ones are nutrition, breathing, reproduction, movement, growth and development.
