1.1. General properties of living organisms
In contrast to the inorganic world, living organisms in the process of evolutionary development have embodied a number of qualitatively new properties.
The fit of living beings in the space-time continuum of the surrounding world. The Earth, as a planet, was formed about 4.5 billion years ago. Living organisms in their most primitive form appeared about 0.5-1 billion years ago. Consequently, living organisms fit into the surrounding phenomena of the inorganic world on Earth: the gravitational attraction of the Earth, the gas environment of the atmosphere, the temperature of the air, seas, and oceans, and Earth's electromagnetic field. The properties of the environment surrounding living organisms are reflected in the biological properties of living beings (P.K. Anokhin).
The environment, in which living organisms fit in, is a space-time continuum of events (A. Einstein). This means that all events on Earth are closely connected in time and space. This is not a chaotic series of events, but their material and informational organization. The organization of events in the physical world is primarily determined by the ratio of the planets in the solar system, and first of all by the ratio of the Earth and the Sun. In the space-time continuum of the surrounding world, episodic events, such as atmospheric precipitation, earthquakes, etc., are present. Along with this, there are events that periodically repeat with a regular rhythm. They are the change of the seasons, the tide and flow of the oceans, as well as the change of day and night. Living beings, in their organization, reflect both episodic and repeated events of the world surrounding them. Particularly important for vital activity are the effects that periodically repeat throughout the life of one generation.
Isolation of living beings. Living beings not only fit into the space-time continuum of the external world but also isolate themselves from inanimate nature.
Isolation is performed in a universal way with the help of phospholipid membranes. It is characteristic that the membranes of different cells, the shells of sea urchin eggs and the membranes of nerve cells, are almost identical in structure. The membranes make it possible for living organisms to contrapose themselves to the aquatic environment, in which they primarily evolved, to actively influence their environment, and to make their organization more advanced. Isolation is predisposed for the formation of functional properties of living subjects.
Irritability. The membranes are irritated by various environmental factors called excitants. Excitants are divided into:
- physical (mechanical, temperature, electrical, etc.);
- chemical (acids, alkalis, salts, hormones, mediators, etc.);
- physical-chemical (changes in osmotic pressure, reactions of the internal environment, ionic composition, etc.);
- biological (bacteria, viruses, etc.);
- informational, carrying, along with physical and chemical properties, certain information, resulting from the interaction of living beings and the physiological processes occurring in them. They include various emotional states, signals of calls and dangers in animals, human speech, etc.
Irritability is the ability of living beings to react to the action of excitants by changing their protoplasmic properties, primarily by changing the structure of the components of their cell membranes. The two types of irritability are distinguished: non-specific and selective.
Non-specific (trigger) irritability does not depend on the quality of the excitant. It is the result of internal processes that occur under the influence of external excitants in the living object itself, primarily in its cell membranes. This process resembles the process of pulling the trigger of a gun. The excitant gradually takes the molecular changes in the cell membranes to a critical level and generates a specific reaction in the living object.
Specific (selective) irritability appears predominantly in relation to the action of biologically active substances, in particular, medicinal substances. Certain parts of the cell membrane were shown to have receptor zones - special protein molecules that are most sensitive to the action of certain chemicals, with which they interact in a "key-lock" form. These structures are called molecular receptors. Chemical substances, ligands, specifically interacting with the receptor, cause biochemical reactions in the cell membrane and protoplasm. Selective irritability is also associated with the diameter of the protein ion channels of the membranes, through which molecules of only a certain size can penetrate.
Irritability is the primary manifestation of the reaction of living beings to external environmental factors. During the evolution of living beings, irritability transformed into the excitability of nervous and muscular tissue.
Memory. The universal property of living objects is memory, i.e., the ability to record molecular changes caused by one or another excitant, store signs of these changes, and subsequently reproduce this information.
The property of memory is most clearly manifested in relation to re-acting excitants. However, single strong effects are also remembered, especially those that cause emotional reactions in living beings. It is characteristic that the mechanisms of memory are principally the same in living objects of different levels of organization. They are associated with the functioning of the universal genetic apparatus.
An anticipatory reflection of reality. a general property of living objects described by P.K. Anokhin, is the ability of anticipatory reflection of surrounding events. This property of living beings is closely associated with the signal value of conditional excitations discovered by I.P. Pavlov.