Rhythm in biology is a very interesting phenomenon. Many scientists today are studying this phenomenon. Rhythm in biology is a universal process that applies to all living organisms. You will be convinced of this by reading this article.
The principle of the unity of the environment and the body is one of the principles of modern science. All living organisms, as well as supraorganismal systems, forming unity with the environment in which they live, have the rhythm of all their processes. Their vital activity is subject to periodic rhythms, which reflect reactions to the rhythms of the whole Universe as a whole (geophysical, astronomical), as well as nature.
P.Ya. Sokolov, a Russian sociologist, notes that the whole animal and plant world, and with it man, is constantly and eternally experiencing the effects of the physical world and responds with rhythmic pulsating reactions to the beating of the world pulse.
What are biological rhythms?
Let us consider in more detail the concept that interests us. Biological rhythms are periodically repeated changes in the nature and intensity of biological phenomena and processes. These batch processes have a wide range of frequencies. They are found at each of the levels of organization of living systems. The more complex the biosystem, the more biorhythms it has. They are fixed at the genetic level. Rhythm in biology is a phenomenon that is very important for adaptation and natural selection of organisms.
Its presence is due to the synchronization of biochemical processes. Since a living organism is a hierarchical system, it needs to balance its functioning with the synchronization of various subsystems and levels, not only in time, but also in biological space.
In this article, you will learn in detail about what rhythm in biology is. Manifestations, properties, examples will also be discussed below.
Chronobiology: emergence and development
The science that studies biorhythms is called chronobiology. It is well known since ancient times that the petals and leaves of plants, depending on the time of day, make certain movements. In 1745, Karl Linney invented the "flower clock" (pictured below), which allows you to determine the time by opening and closing flowers.
In the first half of the 19th century, the first studies of circadian rhythms were already carried out in humans, such as body temperature, frequency of urination and heart rate. In the physiology textbooks of this period, there are indications of the existence of rhythmic functions that are endogenous, that is, arise in the body itself. In 1936, the endogenous nature of the circadian rhythms of plants and flowers was finally established. For this, any external influences on them were excluded.
Other milestones in the development of the science of chronobiology are the discovery of the orientation of birds and bees in flight in the sun, the confirmation of the presence of endogenous circadian rhythms in the human body. A new impetus to this science was given as a result of space exploration. As before, the main interest of scientists in the study of biological rhythms is the study of annual, lunar and diurnal rhythms.
Physiological and adaptive rhythms
The following classifications are distinguished from the point of view of the interaction of the environment and the body.
- Adaptive rhythms (biorhythms) are oscillations that occur with periods close to the most important geophysical cycles. Their role is to adapt various organisms to environmental changes that occur periodically. Their frequency is stable.
- Physiological rhythms (working) - vibrations that reflect the activity of the physiological systems of an organism. Their frequency varies significantly and depends on the state of the given organism.
Exogenous and endogenous rhythms
Rhythms by nature of occurrence are divided into exogenous and endogenous. Exogenous - the reaction of the body to environmental changes. Endogenous arise as a result of the action of self-regulating processes, characterized by delayed feedback. In this case, they are exposed to environmental influences, which can affect their amplitude, as well as shift the phase of biorhythms.
Rhythms by levels of organization of the biosystem and frequency
Rhythms are also divided by the levels of organization of a particular biosystem. They are divided into biospheric, population, organismic, organ and cellular.
In their frequency they are:
- high-frequency rhythms (from one split second to 30 minutes);
- medium (from 30 minutes to 28 hours);
- mesorhythms (from 28 hours to 7 days);
- macro rhythms (from 20 days to a year);
- megarithms (periodicity - tens of years).
The nature of biorhythms
A living organism, according to the most common hypothesis, is an independent oscillatory system, characterized by a set of rhythms that are internally related. Metabolic cycles (catabolism and metabolism) occur in cells continuously. These are complexes of various biochemical reactions - synthesis and breakdown of substances. As a result of this, in accordance with metabolic cycles, changes in the concentrations of various substances (metabolic products, enzymes, messenger and transport RNA, etc.) involved in biochemical reactions continuously occur in cells. The parameters of the internal environment of biosystems as a result of these reactions make continuous oscillations, departing from the average values.
In living organisms, the sensors that determine the nature and speed of metabolic processes are allosteric hormones and modulators that maintain rhythm in biology. It is they who continuously monitor the state of the body. And he seeks to maintain the constancy (homeostasis) of the internal environment - pH, temperature, osmotic pressure, concentration of substances, etc. Many mechanisms are involved in maintaining homeostasis. They are built mainly on the principle of feedback. For example, an excess of glucose in the blood triggers the storage mechanism of this substance (in the form of glycogen). On the contrary, its deficiency leads to increased glycogen breakdown.
The conclusion from this can be drawn as follows. In living organisms, no process occurs continuously. It must certainly alternate with the direction opposite: work with rest, inhaling with exhalation, synthesis with splitting, wakefulness with sleep, etc. The state of a living organism, therefore, cannot be static. It is characterized by such a thing as rhythm. The determination of the presence of this property of a living organism can be made even by simple observation. You may notice that some (but actually all) of its energy and physiological parameters are always in a state of oscillation both in amplitude and frequency relative to average values.
Such oscillations are biorhythms. With their help, living organisms ensure the stability of their thermodynamic state. It allows rhythmicity to successfully adapt to the environment, its cyclical changes. We defined this phenomenon at the beginning of the article.
Internal clock
An external time sensor is not necessary for synchronizing the system with a high degree of conjugation of all its subsystems. During the development of the organism, the innate program of ordering functions over time is modified, allowing it to adapt to the temporal profile of the environment. Such an organism is able to "predict" the time of day. This allows him to connect different effectors in advance, which are not immediately included in the response. For example, body temperature, as well as plasma corticosteroids in normal sleep begin to rise long before it ends. Therefore, awakening sometimes happens before the light turns on.
We give other examples of rhythm. Only those organisms survived the process of natural selection, which possessed the ability not only to catch various changes in natural conditions, but also to adjust their rhythmic apparatus to the beat of external vibrations. For example, animals alternate the rhythms of wakefulness and sleep so that it helps to ensure favorable conditions for food production. In nature, reproductive systems (periods of infertility and fertility) are also adapted to environmental conditions, which are the most optimal in order to grow offspring. Many birds fly south in the fall. This is one example of how rhythm is manifested. Biology knows many other examples. So, some animals hibernate. This helps them survive, despite the fact that external environmental conditions are extreme.
Daily biorhythms
Circadian rhythm in biology - what is it? Let's figure it out. The daily (circadian) biorhythms include such phenomena and changes in the nature and intensity of biological processes, the repetition frequency of which is 24 ± 4 hours. Most physiological and biochemical processes of metabolism, movement, development, growth are subject to these rhythms, which are caused by the circadian (daily) rhythm of the environment. It, in turn, is associated with the rotation around its axis of our planet. Examples of such processes: metabolic rate, fluctuations in body temperature, cell division rate. All of them are characterized by daily rhythm.
Biology is a science that studies not only animals, but also plants. In the latter, in particular, rhythmic cycles of lowering of leaves and closing of flowers are observed at night. In the daytime, they open. Rhythms are preserved even when there is no sunlight. This was confirmed by S.E. Schnol, Russian biophysicist. He cited Maran’s beans as an example. Its leaves rose and fell in the morning and evening, even if the plant was in a dark room. It seemed to feel the time and determined it by an internal physiological clock.
Plants usually determine the length of the day by the transition from one form to another of the pigment of phytochrome when changing the characteristics of sunlight (its spectral composition). For example, the sun at sunset is red because red light has the longest wavelength and is shorter than blue. In twilight or sunset light there is a lot of infrared and red radiation. This is what plants perceive, showing daily rhythm.
Biology is a science in which a large experience of observing various animals has been accumulated to date. It was found, in particular, that the alternation of periods of rest and activity of animals (night and day) also applies to circadian rhythms. For them, the definition of time is not absolute, but relative. They need to know when the sun rises and sets, as daytime creatures use the bright part of the day to search for food, and night creatures use the dark.
Let us give an example - consider the daily rhythm of the alluring crab living on the Atlantic coast. He changes his color, showing daily rhythm. Biology is a science that, like others, reveals patterns. Why does the crab change its color? Let's figure it out.
The crab is lighter in the morning, but when the sun rises higher and higher above the horizon, it becomes darker. Playing a protective role, the pigment protects the alluring crab from the scorching rays of the sun. If there is an ebb at the same time, then a darker color helps him to remain unnoticed on the coastal sand. Namely, a crab goes there in search of food.
Daily rhythms in humans
About 300 physiological functions that have circadian rhythms are observed in the human body. The body weight, based on the human circadian system, is maximum at 18-19 hours, the respiratory rate at 13-16 hours, heart rate at 15-16 hours, the level of red blood cells at 11-12 hours, white blood cells at 21 -23 hours, etc.
Mental processes accelerate in the evening and slow down in the morning. The rhythms of mental and physiological functions, in turn, are affected by changes in wakefulness and sleep, rest and activity. The parameters of the working capacity curve depend on a lot of factors during wakefulness: on the level of motivation, eating, the general situation, the type of person, etc.
The term "desynchronosis" means a violation in the biological system of the temporal ordering of rhythms. The study of its mechanisms is of great importance in the organization of work and rest of staff during various preventive measures aimed at protecting health. Desynchrosis, in particular, is observed in individuals who have flown a long distance (after 4-5 time zones), when changing the mode of operation from day to night, and also to astronauts during space flights.
Lunar biorhythms
Circular (lunar) biorhythms are rhythms, the period of which averages 29.53 days. These rhythms in biology correspond to the lunar-monthly cycle, that is, the phase cycle of the moon.
Many geophysical processes are affected by the periodicity of the rotation of the moon around our planet. For example, the illumination at night, temperature, air pressure, Earth's magnetic fields, and wind direction change . All these phenomena for circalunar rhythms are temporary indications.
The marine organisms show the most impressive examples of how these rhythms affect life processes. For example, the Palolo sea worm, which lives on coral reefs, in October and November, in the final decade of the lunar cycle and at the same time at a certain time of the day, separates its back, which is filled with the products of the reproductive system, in water. This is necessary for procreation.
The lunar cycles of the periods of fertility and fertilization can be not only synodic (as in the previous example). Syzygous met with an interval of 14.7 days. So, one species of fish that lives on the shores of the Gulf of California, in the full moon and new moon (at high tide) lays eggs on the beach. It develops within 14 days on the shore and falls into the water with the next tide.
The moonlight, as we have already mentioned, causes differences in illumination at night. This contributes to the fact that the activity of animals that lead an evening or night lifestyle changes. Even if we exclude the effect of moonlight in the laboratory, the frequency of circular processes is maintained. It may be due to other factors associated with the lunar cycle. For example, these are fluctuations in the magnetic field of our planet.
The lunar cycle also affects plant growth. This can be shown by the example of fluctuations in the yield of radishes, potatoes and legumes. For a long time, lunar calendars have been used to help determine the optimal time for agricultural activities and planting.
Annual biorhythms
Circular (annual) biorhythms in biology have a period of oscillation of 1 year ± 2 months. They are associated with the rotation around the sun of our planet.
These rhythms are observed in all organisms, from the tropical to the polar zone. Their severity grows as the geographical latitude increases. The analysis of rhythm allowed scientists to conclude that in organisms inhabiting the polar and temperate zones, in which seasonal differences are most noticeable, it manifests itself clearly. The basis of annual biorhythms is, firstly, adaptive reactions that occur in response to changes in the most important environmental parameters (water regime, quantitative and qualitative composition of food, temperature).
Secondly, it is the reaction of the body to signaling environmental factors (for example, changes in the geomagnetic field, photoperiod, the appearance of certain chemical components). One-year biorhythms are manifested, for example, in the phenomena of migrations, migrations, summer and winter hibernation, reproductive processes, etc.
Winter hibernation helps many animals survive an unfavorable period. Surprisingly accurately, the animals determine the time for her. A bear, for example, always lays in its den on the eve of snowfall. And he sleeps after that until April, until the temperature is 12 ° C (i.e. 5.5 months). At this time, it exists due to the fat accumulated since the fall. Its stock is almost a third of the animal’s body weight. The bear’s body temperature during hibernation decreases by about 10 ° , its breathing rate decreases by 3 times. This helps to save the vital resources accumulated in the warm time. So the rhythm of the bear’s body is manifested. If the rhythm is broken, and the beast did not lie in the den for some reason, or suddenly wakes up in the middle of winter, it is almost doomed to death. A connecting rod will be overcome by many parasites, which rapidly develop in a weakening body suffering from hunger.
So, numerous examples of rhythm were presented in this article. They confirm that this is a universal phenomenon in the animal kingdom. Biorhythms, moreover, are a determining factor in the existence of living organisms. The principle of rhythm is found at all levels of the organization of biosystems. It serves to adapt the body to better function in the environment.
Coefficient
So, we examined the rhythm in biology, what it is, you now know. However, the concept of interest to us is found not only in this science. In particular, economists have concluded that it is observed in the manufacturing sector. Having made this discovery, they introduced the concept of "rhythm coefficient". He always strives for unity. As a rule, the rhythm coefficient is determined per day, decade, month, etc. Using it, you can characterize, in particular, the degree of use in the production process of working time. The higher the rhythm index, the denser the production cycle, and economic resources (mainly working time) are spent more rationally.