Self-regulation in biology is one of the most important properties of a living system, which consists in the automatic installation and support of a certain level of parameters necessary for normal functioning. The essence of the process is that no external influences become governing. Factors leading changes are formed within the self-regulating system and contribute to the creation of dynamic equilibrium. The processes that arise in this case can be cyclical in nature, decaying and resuming as certain conditions unfold or disappear.
Self-regulation: the meaning of the biological term
Any living system, from the cell to the biogeocenosis, is constantly exposed to various factors from the outside. Temperature conditions, humidity change, food runs out or interspecific competition intensifies - there are many examples. Moreover, the viability of any system depends on its ability to maintain a constant internal environment (homeostasis). It is for this purpose that self-regulation exists. The definition of the concept implies that changes in the environment are not direct impact factors. They are converted into signals that cause one or another imbalance and lead to the launch of self-regulation mechanisms designed to return the system to a stable state. At each level, this interaction of factors looks different, therefore, to understand what self-regulation is, we will dwell on them in more detail.
Levels of organization of living matter
Modern science adheres to the concept that all natural and social objects are systems. They consist of individual elements that constantly interact according to certain laws. Living objects are not an exception to this rule, they are also systems with their own internal hierarchy and multi-level structure. Moreover, this structure has one interesting feature. Each system can simultaneously be an element of a higher level and be a combination (that is, the same system) of levels of a lower order. For example, a tree is an element of the forest and at the same time a multicellular system.
In order to avoid confusion, it is customary in biology to consider four basic levels of organization of living things:
- molecular genetic;
- ontogenetic (organismic - from a cell to a person);
- population-specific;
- biogeocenotic (ecosystem level).
Self-regulation methods
The processes taking place at each of these levels are externally distinguished by the scale, energy sources used and their results, but they are essentially similar. They are based on the same methods of self-regulation of systems. First of all, it is a feedback mechanism. It is possible in two versions: positive and negative. Recall that direct communication involves the transfer of information from one element of the system to another, the reverse flows in the opposite direction, from the second to the first. In this case, both changes the state of the receiving component.
Positive feedback leads to the fact that the processes that the first element reported to the second are fixed and continue to be carried out. A similar process underlies any growth and development. The second element constantly signals the first to continue the same processes. This violates the stability of the system.
Main mechanism
Otherwise, negative feedback works . It leads to the appearance of new changes opposite to those about which the first element informed the second. As a result, processes that upset the balance are eliminated and completed, and the system becomes stable again. A simple analogy is the operation of the iron: a certain temperature is a signal to turn off the heating element. Negative feedback underlies all the processes associated with maintaining homeostasis.
Comprehensiveness
Self-regulation in biology is a process that permeates all these levels. Its purpose is to maintain dynamic equilibrium, the constancy of the internal environment. Due to the all-encompassing process, self-regulation lies at the center of so many branches of natural science. In biology, this is cytology, physiology of animals and plants, ecology. Each of the disciplines is engaged in a separate level. Consider what self-regulation is at the main stages of the organization of the living.
Intracellular level
In each cell, chemical mechanisms are mainly used to maintain stable equilibrium of the internal environment. Among them, the main role in regulation is played by the control of genes, on which the production of proteins depends.
The cyclic nature of the processes can be easily traced by the example of enzymatic chains suppressed by the final products. The purpose of the activities of such entities in the processing of complex substances into simpler ones. Moreover, the final product is similar in structure to the first enzyme in the chain. This property plays a key role in maintaining homeostasis. The product binds to the enzyme and inhibits its activity as a result of a strong structural change. This happens only after the concentration of the final substance exceeds the permissible level. As a result, the fermentation process stops, and the finished product is used by the cell for its own needs. After some time, the level of the substance falls below the permissible value. This is a signal to start fermentation: the protein is disconnected from the enzyme, the suppression of the process stops and everything starts all over again.
Increasing difficulty
Self-regulation in nature is always based on the principle of feedback and generally proceeds according to a similar scenario. However, at each next level, factors complicate the process. For the cell, the constancy of the internal environment is important, maintaining a certain concentration of various substances. At the next level, the process of self-regulation is designed to solve much more problems. Therefore, whole systems supporting homeostasis appear in multicellular organisms. These are respiratory, excretory, circulatory and the like. Studying the evolution of the animal and plant world makes it easy to understand how, as the structure and external conditions become more complex, self-regulation mechanisms are improved.
Body level
Best of all, the constancy of the internal environment is maintained in mammals. The basis for the development of self-regulation and its implementation is the nervous and humoral system. Constantly interacting, they control the processes occurring in the body, contribute to the creation and maintenance of dynamic equilibrium. The brain receives signals from nerve fibers present in every part of the body. Information from the endocrine glands also flows here. The relationship of nervous and hormonal regulation often contributes to almost instantaneous restructuring of the processes.
Feedback
The operation of the system can be traced on the example of maintaining blood pressure. All changes in this indicator are captured by special receptors located on the vessels. An increase or decrease in pressure affects the expansion of the walls of the capillaries, veins and arteries. It is to these changes that receptors respond. The signal is transmitted to the vascular centers, and “instructions” come from them on how to correct vascular tone and cardiac activity. The neurohumoral regulation system is also connected. As a result, the pressure returns to normal. It is easy to notice that the basis of the coordinated work of the regulatory system is still the same feedback mechanism.
At the head of everything
Self-regulation, the definition of certain corrections in the activity of the body, is the basis of all changes in the body, its reactions to external stimuli. Stress and constant stress can lead to hypertrophy of individual organs. An example of this is the developed muscles of athletes and the enlarged lungs of freediving enthusiasts. The stressful effect is often a disease. Heart hypertrophy is a common occurrence in people diagnosed with obesity. This is the body's response to the need to increase the load on pumping blood.
The mechanisms of self-regulation are also the basis of physiological reactions that occur with fear. A large amount of the adrenaline hormone is released into the bloodstream, which causes a number of changes: an increase in oxygen consumption, an increase in glucose, an increase in heart rate, and mobilization of the muscle system. At the same time, the overall balance is maintained by extinguishing the activity of other components: digestion slows down, sexual reflexes disappear.
Dynamic balance
It should be noted that homeostasis, at whatever level it is maintained, is not absolute. All parameters of the internal environment are maintained within a certain range of values and constantly fluctuate. Therefore, they talk about the dynamic equilibrium of the system. It is important at the same time that the value of a particular parameter does not go beyond the so-called oscillation corridor, otherwise the process may become pathological.
Ecosystem sustainability and self-regulation
Biogeocenosis (ecosystem) consists of two interconnected structures: biocenosis and biotope. The first is the totality of living creatures in this area. A biotope is a factor of an inanimate environment where a biocenosis lives. Environmental conditions that constantly affect organisms are divided into three groups:
- abiotic environmental factors: temperature, light, humidity and other elements of inanimate nature;
- biotic environmental factors: the influence of one organism on another, divided into competition, symbiosis, parasitism and predation;
- anthropogenic environmental factors - human exposure.
Preservation of homeostasis means the well-being of organisms in the face of constant exposure to the external environment and changing internal factors. Self-regulation supporting biogeocenosis is primarily based on a system of trophic connections. They are a relatively closed chain along which energy flows. The producers (plants and chemobacteria) receive it from the Sun or as a result of chemical reactions, create with its help organic matter, which feeds consumers (herbivores, predators, omnivores) of several orders of magnitude. At the last stage of the cycle, there are reducers (bacteria, some types of worms) that decompose organic matter into its constituent elements. They are again introduced into the system as food for producers.
The constancy of the cycle is ensured by the fact that at each level there are several types of living creatures. When one of them drops out of the chain, it is replaced with a similar function.
External influence
Maintaining homeostasis is accompanied by constant exposure from the outside. Conditions changing around the ecosystem make it necessary to adjust internal processes. Several stability criteria are distinguished:
- high and balanced reproductive potential of individuals;
- adaptation of individual organisms to changing environmental conditions;
- species diversity and branched food chains.
These three conditions contribute to maintaining the ecosystem in a state of dynamic equilibrium. Thus, at the level of biogeocenosis, self-regulation in biology is the reproduction of individuals, the preservation of numbers and resistance to environmental factors. Moreover, as in the case of an individual organism, the equilibrium of the system cannot be absolute.
The concept of self-regulation of living systems extends the described patterns to human communities and social institutions. Its principles are widely used in psychology. In fact, this is one of the fundamental theories of modern science.