is the body's response to the change in the seasons. Actual information

The ancients believed that man and the sky are similar to each other, that the human body is essentially a small universe. Maintaining health, taking into account the time of year, means bringing your body in line with the changes taking place in nature and space.

The treatise “Lingshu” says: “The wise one is engaged in the nurturing of life. He must, depending on the season, adapt to cold and heat, be calm, not showing joy and anger, live in quiet place, maintain the balance of yin and yang, regulate hardness and softness. If this succeeds, then nothing harmful will touch the person, nothing unexpected will happen to him, he will gain longevity. The Nei Ching treatise also speaks of the seasons: “The yin and yang of the four seasons are the root of all things. Therefore, the sage nurtures yang in spring and summer, nurtures yin in autumn and winter, thus not breaking away from the root.”

It is not surprising that Taoism closely links physiological changes in the human body and the change of seasons in nature, rightly believing that these physiological changes are the result of the increase and decrease of yin and yang. To live long, it is necessary to bring changes in the body in line with the decrease and increase of yin and yang in nature. Main principle maintaining health, taking into account the time of year, consists in “cultivating yang” in spring and summer, “nurturing yin” in autumn and winter, that is, “following nature” in everything.

Maintaining health in the spring. The treatise “Suwen” says that in spring nature is completely renewed, everything comes to life and blooms, everything old dies off, and the new sprouts. Therefore, at this time of the year, it is good for health to wake up early from a night's sleep, and then take a walk to stretch the limbs. In the spring it is necessary to encourage, support those who are nearby, but in no case do not lecture, do not punish. In the treatise “Shesheng xiaoxilun” it is said that in spring cold and strong heat abruptly replace each other, in connection with which, especially in older people, there is an exacerbation of old diseases. Intensive addition of spring qi can lead to psychological fatigue. Elderly people at this time should not overeat, as well as undernourish, should refrain from indigestible food that can harm the spleen and stomach.

The main directions of “nurturing life” in the spring period are as follows:

1) Dress appropriately and keep warm. In the spring, it can be quite cold at times, and if not taken care of, this can lead not only to a decrease in the body's resistance, but also to flu, cough and respiratory diseases. It is especially important to avoid hypothermia for the elderly. At the same time, one should not go too far and dress too warmly so as not to sweat, since a large number of “spring” diseases can also result from the cooling of a sweaty person.

2) Keep a healthy diet. In the treatise "Qianjinfang" It is said: "When spring comes, the amount of sour food should be reduced and the amount of sweet should be increased in order to nurture the qi of the spleen." In order not to harm the internal organs, medication should be limited in the spring.

3) Implement disease prevention measures. In this regard, care must be taken to ensure that there are no recurrences of old diseases, as well as to prevent the occurrence of various infectious diseases.

4) Spend more time doing physical exercises (swimming, running, qigong, taijiquan, etc.).

Maintaining health in summer period. Hot weather, typical for this time, can serve as an obstacle to regulating the temperature balance of the body, can disrupt the water-salt metabolism in the body, increase the load on the heart, and adversely affect the function of digestion. Heatstroke is a common occurrence in hot weather, which can be fatal.

The main directions of "nurturing life" in the summer:

1) Avoid physical overwork, give your body time to rest, find time for a short daytime sleep.

2) Maintain an even mood. Gao Lian in his work “Zongypeng zhu-jian” wrote: “In the summertime, one should tune the heart to silence, try to maintain a constant feeling of “ice and snow” in the soul. Due to this, it is possible to reduce the effect of summer heat on the body.” Lack of mood control usually results in heat-induced temper tantrums.

3) Avoid wind when overheated. In summer, the cause of colds is usually hypothermia, which occurs as a result of attempts to get rid of the heat due to the wind. Therefore, you should not, for example, sleep with the fan running.

4) Follow the rules of hygiene. In the summer, intestinal infections are widespread, so we must not forget about hygiene when eating to prevent infection from entering through the oral cavity. In the summer you should not overeat, preference should be given to lean, light food.

5) Avoid overheating and dampness. In summer, as a rule, the weather is hot and damp, therefore, when going outside, you need to hide from the sun, do not walk for a long time in wet or sweaty clothes in order to prevent simultaneous harmful effects heat and dampness, leading to the appearance of abscesses.

Maintaining health in the autumn:

The treatise “Suwen” says that in autumn nature comes to a peaceful and calm state, “heavenly qi” is activated, and “earthly qi” “clears up”. A person must follow changing natural conditions - go to bed earlier and get up earlier, focusing in this, for example, on roosters; keep emotions calm.

According to Qiu Chuji, in the fall, you should reduce the amount of spicy and eat more sour, which contributes to the “nurturing of qi” of the liver. Waking up in the morning, you should close your eyes and perform 21 tapping with your teeth, and then swallow your saliva. You can also rub your palms together until a feeling of strong heat appears, massage your eyes with them, which helps to improve vision. All these ancient folk ways“cherishing life” is quite applicable for maintaining health in the autumn.

Let's look at the problem from the standpoint of modern medicine. In autumn there is a gradual change from hot to cool weather. In early autumn, the weather is still warm enough for the active reproduction of pathogenic bacteria. Therefore, at this time, food quickly deteriorates and there are quite a few cases of dysentery. In late autumn, the weather is dry, causing dry skin, dry mouth, cracked lips, drying of the nasal mucosa, a feeling of discomfort in the throat, etc. In autumn there are periods of prolonged rains, the weather is getting colder, the cold finally replaces the heat. This is the time of colds. Autumn makes special demands on maintaining health, which can be reduced to the following general provisions:

1) Dress for the weather. In autumn, in the mornings and evenings, you need to put on something warm, and in the afternoon, when it gets warmer, undress. You should not immediately dress too warmly so as not to deprive the body of the ability to adapt to the cold.

2) How to prepare for the cold. In other words, in the autumn it is necessary to prepare warm clothes in case of severe frosts, prepare heaters.

3) Monitor the psychological state. The fact is that autumn winds and rains often inspire discouragement, lead a person into a depressed state. Creating a positive psychological attitude in adverse environmental conditions is an important component of measures to preserve health in the autumn.

Maintaining health in winter:

In the treatise "Suwen" it is said that in winter everything that exists in nature passes into a "closed, hidden" state. Therefore, you need to get up in the morning later, and go to bed early. Emotions must be kept in oneself, which corresponds to the needs of maintaining health at this time of the year. According to Qiu Chuji, “in winter, you should avoid cold and take care to stay warm, and, in the latter, you need to know when to stop. You should not constantly warm yourself near a strong fire, as this can also be harmful. Hands and feet are connected to the heart, so do not warm your hands near the fire, so that the “fire” does not enter the heart and cause nervousness. We must live in a warm room, dress well, strive for a balance in eating cold and warm. One should not imprudently be in the cold wind, especially for the elderly, since a cold caused by cold can be complicated by coughing, dizziness and even paralysis.

Modern medicine believes that in the winter cold, a person can easily get insomnia, pain in the lower back and joints, enuresis due to the low temperature in the rooms, due to the neglect of warm clothes, due to hormonal imbalance or anemia. In addition, winter is a period of exacerbation of chronic respiratory diseases, in particular, bronchitis. Cold weather contributes to the emergence of psychological stress in a person, a state of depression, general fatigue, which can lead to the development of a heart attack, emphysema, rheumatism, chronic hepatitis. In winter, hands, feet and ears are most exposed to cold, which is often the cause of abscesses.

Considering all of the above, we can formulate the main content of measures to preserve health in the winter as follows:

1) Keep the room warm.

2) Eat right. After consulting with your doctor, you can take any strengthening medications.

3) Actively engage in physical education. In winter, it is useful to do more physical education or simply improve your health: walk more in the fresh air, practice taijiquan, etc. Physical education allows the human body to more easily adapt to a cold environment, increase its resistance. Besides physical exercise relieve depression, inspire him and fill him with vital energy.

Each species in the process of evolution has developed a characteristic annual cycle of intensive growth and development, reproduction, preparation for winter and wintering. This phenomenon is called biological rhythm. The coincidence of each period of the life cycle with the corresponding season is crucial for the existence of the species.

The connection of all physiological phenomena in the body with the seasonal course of temperature is most noticeable. But although it affects the speed of life processes, it still does not serve as the main regulator of seasonal phenomena in nature. Biological processes of preparation for winter begin in summer, when the temperature is high. Insects at high temperatures still fall into a hibernation state, the birds begin to molt and there is a desire to fly. Consequently, some other conditions, and not temperature, affect the seasonal state of the organism.

The main factor in the regulation of seasonal cycles in most plants and animals is the change in the length of the day. The response of organisms to the length of the day is called photoperiodism . The value of photoperiodism can be seen from the experience shown in Figure 35. With artificial round-the-clock lighting or a day length of more than 15 hours, birch seedlings grow continuously without shedding leaves. But when illuminated for 10 or 12 hours a day, the growth of seedlings stops even in summer, soon the leaves drop and winter dormancy sets in, as under the influence of a short autumn day. Many of our deciduous tree species: willow, white locust, oak, hornbeam, beech - become evergreen with a long day.

Figure 35. Influence of day length on the growth of a birch seedling.

The length of the day determines not only the onset of winter dormancy, but also other seasonal phenomena in plants. Thus, a long day promotes the formation of flowers in most of our wild plants. Such plants are called long-day plants. Of the cultivated ones, they include rye, oats, most varieties of wheat and barley, and flax. However, some plants, mainly of southern origin, such as chrysanthemums, dahlias, need short day. Therefore, they bloom with us only at the end of summer or autumn. Plants of this type are called short-day plants.

The effect of the length of the day on animals also has a strong effect. In insects and mites, the length of the day determines the onset of winter dormancy. So, when the caterpillars of the cabbage butterfly are kept under conditions long day(more than 15 hours), butterflies soon emerge from the pupae and a successive series of generations develops without interruption. But if the caterpillars are kept at a day shorter than 14 hours, then even in spring and summer overwintering pupae are obtained, which do not develop for several months, despite the rather high temperature. Similar type The reaction explains why in nature in summer, while the day is long, insects can develop several generations, and in autumn development always stops at the wintering stage.

In most birds, the lengthening day in spring causes the development of the gonads and the manifestation of nesting instincts. Autumn shortening of the day causes molting, the accumulation of spare fats and the desire to fly.

Day length is a signaling factor that determines the direction of biological processes. Why did the seasonal changes in the length of the day acquire such great importance in living organisms?

The change in the length of the day is always closely related to the annual course of temperature. Therefore, the length of the day serves as an accurate astronomical harbinger. seasonal changes temperature and other conditions. This explains why the most diverse groups of organisms in temperate latitudes, under the influence of the driving forces of evolution, have formed special photoperiodic reactions - adaptations to climatic changes at different times of the year.

photoperiodism- this is a common important adaptation that regulates seasonal phenomena in a variety of organisms.

The biological clock

The study of photoperiodism in plants and animals showed that the reaction of organisms to light is based on the alternation of periods of light and darkness of a certain duration during the day. The reaction of organisms to the length of day and night shows that they are able to measure time, that is, they have some biological clock . All types of living beings have this ability, from unicellular to humans.

The biological clock, in addition to seasonal cycles, governs many others. biological phenomena, the nature of which until recently remained mysterious. They determine the correct daily rhythm of both the activity of whole organisms and the processes that occur even at the level of cells, in particular cell divisions.

Management of seasonal development of animals and plants

Elucidation of the role of day length and the regulation of seasonal phenomena opens up great possibilities for controlling the development of organisms.

Various methods of development control are used in the year-round cultivation of vegetable crops and ornamental plants in artificial light, during winter and early forcing of flowers, to accelerate the production of seedlings. Pre-sowing treatment of seeds with cold achieves earing of winter crops during spring sowing, as well as flowering and fruiting in the first year of many biennial plants. By increasing the length of the day, it is possible to increase the egg production of birds on poultry farms.

» Impact on organisms of some environmental factors

Seasonal Rhythms

is the body's response to the change in the seasons. Actual information buy float valve from us.

So, with the onset of a short autumn day, plants shed their leaves and prepare for winter dormancy.

winter calm

- these are the adaptive properties of perennial plants: cessation of growth, death of above-ground shoots (in grasses) or leaf fall (in trees and shrubs), slowing down or stopping many life processes.

In animals, a significant decrease in activity is also observed in winter. A signal for the mass departure of birds is a change in the length of daylight hours. Many animals fall into hibernation

- adaptation to endure the unfavorable winter season.

In connection with the constant daily and seasonal changes in nature, certain mechanisms of an adaptive nature have been developed in living organisms.

Warmly.

All life processes take place at a certain temperature - mainly from 10 to 40 ° C. Only a few organisms are adapted to life at higher temperatures. For example, some mollusks live in thermal springs at temperatures up to 53 ° C, blue-green (cyanobacteria) and bacteria can live at 70–85 ° C. The optimum temperature for the life of most organisms ranges from 10 to 30 °C. However, the range of temperature fluctuations on land is much wider (from -50 to 40 °C) than in water (from 0 to 40 °C), so the temperature tolerance limit for aquatic organisms is narrower than for terrestrial ones.

Depending on the mechanisms of maintaining a constant body temperature, organisms are divided into poikilothermic and homeothermic.

Poikilothermic,

or cold-blooded,

organisms have unstable body temperature. Temperature increase environment causes them a strong acceleration of all physiological processes, changes the activity behavior. So, lizards prefer a temperature zone of about 37 ° C. As the temperature rises, the development of some animals accelerates. So, for example, at 26 °C in a caterpillar of a cabbage butterfly, the period from leaving the egg to pupation lasts 10–11 days, and at 10 °C it increases to 100 days, i.e. 10 times.

Many cold-blooded animals have anabiosis

- a temporary state of the body, in which vital processes slow down significantly, and there are no visible signs of life. Anabiosis can occur in animals both with a decrease in the temperature of the environment, and with its increase. For example, in snakes, lizards, when the air temperature rises above 45 ° C, numbness occurs, in amphibians, when the water temperature drops below 4 ° C, vital activity is practically absent.

In insects (bumblebees, locusts, butterflies) during the flight, the body temperature reaches 35-40 ° C, but with the termination of the flight it quickly drops to air temperature.

homeothermic,

or warm-blooded,

animals with a constant body temperature have more perfect thermoregulation and are less dependent on the temperature of the environment. The ability to maintain a constant body temperature is important feature animals such as birds and mammals. Most birds have a body temperature of 41-43°C, while mammals have a body temperature of 35-38°C. It remains at a constant level, regardless of fluctuations in air temperature. For example, in a frost of -40 °C, the body temperature of the arctic fox is 38 °C, and that of the ptarmigan is 43 °C. In more primitive groups of mammals (oviparous, small rodents), thermoregulation is imperfect (Fig. 93).

Seasonal changes include profound shifts in the body under the influence of changes in nutrition, environmental temperature, radiant solar regime and under the influence of periodic changes in the endocrine glands, mainly associated with animal reproduction. The question of factors external environment, defining seasonal periodicals, is extremely complex and has not yet received full resolution; in the formation of seasonal cycles, shifts in the functions of the sex glands, the thyroid gland, etc., which are very stable in nature, are of great importance. These changes, well established morphologically, are very stable in their successive development for different species and greatly complicate the analysis of the influence of physical factors causing seasonal periodicity.

Seasonal changes in the body include behavioral responses. They consist either in the phenomena of migration and nomadism (see below), or in the phenomena of winter and summer hibernation, or, finally, in a variety of activities for the construction of burrows and shelters. There is a direct relationship between the depth of the holes of some rodents and the winter temperature drop.

Of great importance for the total daily activity of the animal is the lighting regime. Therefore, seasonal periodicals cannot be considered outside the latitudinal distribution of organisms. Figure 22 shows the breeding seasons for birds in different latitudes northern and southern hemispheres. One can clearly see the timing of reproduction shifted to earlier months when moving from north to south in the Northern Hemisphere and an almost mirror image of these relationships in the Southern Hemisphere. Similar dependences are also known for mammals, for example, for sheep. Here we mainly consider

physiological changes in the body occurring in the temperate climate of the middle latitudes of the Northern Hemisphere. The greatest changes in the body during the seasons of the year relate to the blood system, general metabolism, thermoregulation, and partly digestion. Of exceptional importance for boreal organisms is the accumulation of fat as an energy potential spent on maintaining body temperature and muscle activity.

The most notable changes motor activity in different seasons can be observed in diurnal animals, which is undoubtedly related to the lighting regime. These relationships have been best studied in monkeys (Shcherbakova, 1949). When keeping monkeys for all year round at a constant ambient temperature, the total daily activity depended on the length of daylight hours: an increase in activity took place in May

and June. An increase in the total daily activity was observed in December and January. The latter cannot be attributed in any way to the influence of daylight hours and is probably associated with spring manifestations in nature in Sukhumi conditions (Fig. 23).

These studies also found a significant seasonal variation in body temperature in monkeys. The highest temperature in the rectum was observed in June, the lowest - in January. These shifts cannot be explained by changes in temperature in the external environment, since the room temperature remained constant. It is very likely that the effect of radiative cooling took place here, due to the reduced temperature of the walls of the room.

Under natural conditions (Khrustselevsky and Kopylova, 1957), Brandt's voles in Southeastern Transbaikalia show a striking seasonal dynamics of locomotor activity. They have a sharp decrease in activity - exit from holes in January, March, November and December. The reasons for this pattern of behavior are quite complex. They are associated with the nature of the pregnancy of usually very active females, with the timing of sunrise and sunset, high temperatures in summer and low in winter. Daily activity studied under natural conditions is much more complicated and does not always reflect the picture obtained by the researcher using the actographic technique.

Similar complex relationships were discovered (Leontiev, 1957) for Brandt's vole and Mongolian gerbil in the Amur Region.

In minks (Ternovsky, 1958), significant changes in motor activity are observed depending on the seasons of the year. The greatest activity takes place in spring and summer, which, apparently, is associated with the length of daylight hours. However, as the temperature drops, activity decreases, as does precipitation. In all gregarious ungulates, without exception, seasonal changes in gregariousness are observed, which is pronounced in moose. In the reindeer, herd relations (grouping, following each other) are more noticeable in autumn than in summer or spring (Salgansky, 1952).

Seasonal changes in metabolism (basal metabolism) are best studied. Back in 1930, the Japanese researcher Ishida (Ishida, 1930) found a significant increase in basal metabolism in rats in the spring. These facts have since been confirmed by numerous studies (Kayser, 1939; Sellers, Scott a. Thomas, 1954; Kocarev, 1957; Gelineo a. Heroux, 1962). It has also been established that in winter the basal metabolism in rats is much lower than in summer.

Very striking seasonal changes in basal metabolism are found in fur-bearing animals. Thus, the basal metabolism in arctic foxes in summer compared with winter is increased by 34%, and in silver-black foxes - by 50% (Firstov, 1952). These phenomena are undoubtedly connected not only with the seasonal Cycle, but also with the overheating that takes place in the summer (see Chap. V) and have been noted by various researchers in arctic foxes, raccoon dogs (Slonim, 1961). In the gray rats under the conditions of the Arctic, an increase in metabolism in the spring and a decrease in the autumn were also found.

Study of chemical thermoregulation in polar species (arctic foxes, foxes, hares) wintering in the conditions of the Leningrad Zoological Garden (Isaakyan and Akchurin,

1953) showed, under the same conditions of keeping, sharp seasonal changes in chemical thermoregulation in foxes and raccoon dogs and the absence of seasonal changes in arctic foxes. This is especially pronounced in autumn months when the animals are in summer fur. The authors explain these differences by the responses to changes in lighting that are specific to Arctic foxes. It is Arctic foxes who practically lack chemical thermoregulation in the autumn period, although the insulating layer of wool by this time had not yet become winter. Obviously, these reactions, specific for polar animals, cannot be explained only by the physical properties of the skin: they are the result of complex specific features of the nervous and hormonal mechanisms of thermoregulation. These reactions in polar forms are combined with thermal insulation (Scholander and co-workers, see p. 208).

A large amount of material on seasonal changes in gas exchange in various rodent species (Kalabukhov, Ladygina, Maizelis and Shilova, 1951; Kalabukhov, 1956, 1957; Mikhailov, 1956; Skvortsov, 1956; Chugunov, Kudryashov and Chugunova, 1956, etc.) showed that non-sleeping rodents can observe an increase in metabolism in autumn and a decrease in winter. The spring months are characterized by an increase in metabolism, and the summer months by a relative decrease. The same data on a very large material were obtained for the common vole and bank vole in the Moscow region.

Schematically, the seasonal curve of metabolic changes in non-hibernating mammals can be represented as follows. The highest metabolic rate is observed in spring time during the period of sexual activity, when animals, after a winter food restriction, begin active food-procuring activities. In summer, the level of metabolism again decreases somewhat due to high temperatures, and in autumn it rises slightly or remains at the summer level, gradually decreasing towards winter. In winter, there is a slight decrease in basal metabolism, and by spring it again rises sharply. This general scheme of changes in the level of gas exchange throughout the year for individual species and under individual conditions can vary significantly. This is especially true for farm animals. So, the main metabolism in non-lactating cows (Ritzman a. Benedict, 1938) in the summer months, even on the 4-5th day of fasting, was higher than in winter and autumn. In addition, it is very important to note that the spring increase in metabolism in cows is not associated with pregnancy and lactation, with the conditions in the stall or on the pasture. With stall keeping, gas exchange in spring is higher than with grazing in autumn, although grazing itself increases gas exchange at rest throughout the pasture season (Kalitaev, 1941).

In summer, gas exchange in horses (at rest) increases by almost 40% compared to winter. At the same time, the content of erythrocytes in the blood also increases (Magidov, 1959).

Very large differences (30-50%) in energy metabolism in winter and summer are observed in reindeer (Segal, 1959). In Karakul sheep, despite the course of pregnancy in winter, there is a significant decrease in gas exchange. Cases of a decrease in metabolism in winter in reindeer and Karakul sheep are undoubtedly associated with food restrictions in winter.

Changes in basal metabolism are also accompanied by shifts in chemical and physical thermoregulation. The latter is associated with an increase in thermal insulation (insulation) wool and feather covers in winter time. The decrease in thermal insulation in summer affects both the level critical point(see ch. V), and on the intensity of chemical thermoregulation. So, for example, the values ​​of heat transfer in summer and winter in different animals are: for squirrels, as 1: 1; in a dog 1: 1.5; in a hare 1: 1.7. Depending on the seasons of the year, heat transfer from the surface of the body changes significantly due to the processes of molting and overgrowing with winter wool. In birds, the electrical activity of the skeletal muscles (due to the absence of non-shivering thermogenesis) does not change in winter and summer; in mammals, such as the gray rat, these differences are very significant (Fig. 25).

Seasonal changes in the critical point of metabolism have recently been found in polar animals in Alaska (Irving, Krogh a. Monson, 1955) - in the red fox they are + 8 ° in summer, -13 ° in winter; for squirrels - in summer and winter + 20 ° С; at the porcupine (Erethizoon dorsatum) +7°C in summer and -12°C in winter. The authors also associate these changes with seasonal changes in the thermal insulation of the fur.

The metabolism of polar animals in winter, even at a temperature of -40 ° C, increases relatively slightly: in the fox and polar porcupine - no more than 200% of the metabolic level at the critical point, in squirrels - about 450-500%. Similar data were obtained in the conditions of the Leningrad Zoo on arctic foxes and foxes (Olnyanskaya and Slonim, 1947). A shift in the critical point of metabolism from +30°C to +20°C was observed in the gray rat in winter (Sinichkina, 1959).

Study of seasonal changes in gas exchange in steppe lemmings ( Lagurus lagurus) showed (Bashenina, 1957) that in winter their critical point, unlike other species of voles, is unusually low - about 23 ° C. The critical point of metabolism in midday gerbils shifts in different seasons, while in Grebenshchikov it remains constant (Mokrievich, 1957 ).

The highest values ​​of oxygen consumption at environmental temperatures from 0 to 20°C were observed in yellow-throated mice caught in summer, and the lowest in winter (Kalabukhov, 1953). The data for mice caught in autumn were in the middle position. The same work made it possible to discover very interesting changes in the thermal conductivity of wool (taken from animals and dried skins), which strongly increases in summer and decreases in winter. Some researchers are inclined to attribute to this circumstance a leading role in changes in metabolism and chemical thermoregulation during different seasons of the year. Of course, such dependences cannot be denied, but also in laboratory animals (white rats) there is a pronounced seasonal dynamics even at constant environmental temperatures (Isaakyan and Izbinsky, 1951).

In experiments on monkeys and wild carnivores, it was found (Slonim and Bezuevskaya, 1940) that chemical thermoregulation in spring (April) is more intense than in autumn (October), despite the fact that the ambient temperature was the same in both cases (Fig. 26) . Obviously, this is the result of the previous influence of winter and summer and the corresponding changes.

in the endocrine systems of the body. In summer, there is a decrease in the intensity of chemical thermoregulation, in winter - an increase.

Peculiar seasonal changes in chemical thermoregulation were found in the yellow ground squirrel, which enters winter and summer hibernation, and the non-hibernating fine-clawed ground squirrel (Kalabukhov, Nurgel'dyev and Skvortsov, 1958). In the thin-toed ground squirrel, seasonal changes in thermoregulation are more pronounced than in the yellow ground squirrel (of course, in the waking state). In winter, the exchange of fine-clawed ground squirrel is sharply increased. In summer, the yellow ground squirrel's chemical thermoregulation is disturbed already at + 15-5 ° C. Seasonal changes in thermoregulation are almost absent in it and are replaced by long winter and summer hibernation (see below). Seasonal changes in thermoregulation are equally poorly expressed in the tarbagan, which falls into summer and winter hibernation.

Comparison of seasonal changes in chemical thermoregulation and biological cycle animals (N. I. Kalabukhov et al.) showed that seasonal changes are weakly expressed both in hibernating species and in species that spend the winter in deep burrows and are little exposed to low outdoor temperatures (for example, the great gerbil).

Thus, seasonal changes in thermoregulation are reduced mainly to an increase in thermal insulation in winter, a decrease in the intensity of the metabolic reaction (chemical thermoregulation) and a shift in the critical point to a zone of lower environmental temperatures.

The thermal sensitivity of the body also changes somewhat, which is apparently associated with a change in coat. Such data were established by N. I. Kalabukhov for arctic foxes (1950) and yellow-throated mice (1953).

In gray rats living in the middle lane, the preferred temperature in winter is from 21 to 24 ° C, in summer - 25.9-28.5 ° C, in autumn - 23.1-26.2 ° C and in spring - 24.2 ° C (Sinichkina , 1956).

Under natural conditions in wild animals, seasonal changes in oxygen consumption and heat production can largely depend on feeding conditions. However experimental confirmation so far missing.

The hematopoietic function changes significantly according to the seasons of the year. The most striking shifts in this regard are observed in humans in the Arctic. In spring, one can observe a large increase in the number of erythrocytes and hemoglobin (Hb) blood, which is associated with the transition from the polar night to the polar day, i.e., with changes in insolation. However, even in conditions of sufficient insolation in the Tien Shan mountains, a person has a somewhat reduced amount of hemoglobin in the blood in winter. A sharp increase in Hbobserved in spring. The number of erythrocytes decreases in spring and increases in summer (Avazbakieva, 1959). In many rodents, for example, in gerbils, the content of erythrocytes decreases in summer, and increases in spring and autumn (Kalabukhov et al., 1958). The mechanism of these phenomena is still unclear. There are also changes in nutrition, vitamin metabolism, ultraviolet radiation, etc. The influence of endocrine factors is also not excluded, and especially important role belongs to the thyroid gland, which stimulates erythropoiesis.

Highest value in maintaining the seasonal rhythm have hormonal shifts, representing both independent cycles of endogenous origin, and associated with exposure the most important factor environment - lighting mode. At the same time, a scheme of relationships between the hypothalamus - the pituitary gland - the adrenal cortex is already being outlined.

Seasonal changes in hormonal relations have been revealed in wild animals under natural conditions using the example of changes in the weight of the adrenal glands (which, as is known, play an important role in the adaptation of the body to specific and non-specific conditions of "tension" - stress).

The seasonal dynamics of the weight and activity of the adrenal glands has a very complex origin and depends both on the actual “stress” in connection with living conditions (nutrition, environmental temperature) and on reproduction (Schwartz et al., 1968). In this regard, data on changes in the relative weight of the adrenal glands in non-breeding field mice are of interest (Fig. 27). During the period of enhanced nutrition and optimal temperature conditions, the weight of the adrenal glands increases dramatically. In autumn, with cooling, this weight begins to decrease, but with the establishment of snow cover it stabilizes. In the spring (April), an increase in the weight of the adrenal glands begins in connection with the growth of the organism and puberty (Shvarts, Smirnov, Dobrinsky, 1968).

The morphological picture of the thyroid gland in many species of mammals and birds is subject to significant seasonal changes. In the summer, there is a disappearance of the follicle colloid, a decrease in the epithelium, and a decrease in the weight of the thyroid gland. In winter, the reverse relationship takes place (Riddle, Smith a. Benedict, 1934; Watzka, 1934; Miller, 1939; Hoehn, 1949).

The seasonal variability in the function of the thyroid gland in the reindeer is just as clearly expressed. In May and June, its hyperfunction is observed with increased secretory activity of epithelial cells. In winter, especially in March, the secretory activity of these cells ceases. Hyperfunction is accompanied by a decrease in the volume of the gland. Similar data were obtained in sheep, but the pattern was much less pronounced.

At present, there are numerous data indicating the presence of stable seasonal fluctuations in the content of thyroxine in the blood. The highest level of thyroxin (determined by the content of iodine in the blood) is observed in May and June, the lowest - in November, December and January. Studies have shown (Sturm a. Buchholz, 1928; Curtis, Davis a. Philips, 1933; Stern, 1933) there is a direct parallelism between the intensity of thyroxine production and the level of gas exchange in humans during the seasons of the year.

There are indications for close connection between cooling the body and the production of thyroid hormone and pituitary thyroid-stimulating hormone (Uotila, 1939; Voitkevich, 1951). These relationships are also very important in the formation of seasonal periodicals.

Apparently, a significant role in seasonal periodicals belongs to such a non-specific hormone as adrenaline. A large body of evidence suggests that adrenaline promotes better acclimatization to both heat and cold. Combinations of thyroxine and cortisone preparations are especially effective (Hermanson a. Hartmann, 1945). Animals well acclimatized to cold have a high content of ascorbic acid in the adrenal cortex (Dougal a. Fortier, 1952; Dugal, 1953).

Adaptation to low ambient temperature is accompanied by an increase in the content of ascorbic acid in tissues, an increase in the content of hemoglobin in the blood (Gelineo and Raiewskaya, 1953; Raiewskaya, 1953).

Recently accumulated great material characterizing seasonal fluctuations the content of corticosteroids in the blood and the intensity of their release during incubation of the adrenal cortex in vitro.

The role of the lighting regime in the formation of the seasonal rhythm is recognized by the vast majority of researchers. Lighting, as was established in the middle of the last century (Moleschott, 1855), has a significant effect on the intensity of oxidative processes in the body. Gas exchange in humans and animals under the influence of lighting increases (Moleschott u. Fubini, 1881; Arnautov and Weller, 1931).

However, until recently, the question of the effect of illumination and darkening on gas exchange in animals with in different ways life and only when studying the effect of illumination intensity on gas exchange in monkeys (Ivanov, Makarova and Fufacheva, 1953) did it become clear that it is always higher in the light than in the dark. However, these changes were not the same for all species. In hamadryas, they were most pronounced, followed by rhesus monkeys, and the effect of illumination had the least effect on green monkeys. The differences could only be understood in relation to ecological features the existence of these species of monkeys in nature. So, the hamadryas monkeys are the inhabitants of the treeless highlands of Ethiopia; rhesus macaques are inhabitants of the forest and agricultural cultural areas, and green monkeys are dense tropical forests.

The reaction to illumination appears relatively late in ontogeny. So, for example, in newborn kids, the increase in gas exchange in the light compared to the dark is very small. This reaction increases significantly by the 20-30th day and even more by the 60th (Fig. 28). It can be assumed that in animals with daytime activity the reaction to the intensity of illumination has the character of a natural conditioned reflex.

In the nocturnal loris lemurs, an inverse relationship has been observed. Their gas exchange was increased

in the dark and reduced when illuminated during the determination of gas exchange in the chamber. The decrease in gas exchange in the light reached 28% in lorises.

The facts of the influence of prolonged illumination or darkening on the organism of mammals were established by an experimental study of the light regime (daylight hours) in connection with the seasonal effects of illumination. A large number of studies have been devoted to the experimental study of the effect of daylight hours on seasonal periodicals. Most of the data collected for birds, where the increase in daylight hours is a factor stimulating sexual function (Svetozarov and Shtreich, 1940; Lobashov and Savvateev, 1953),

The facts obtained indicate both the value of the total length of daylight hours and the value of the change in the phases of illumination and dimming.

A good criterion for the influence of the lighting regime and the length of daylight hours for mammals is the course of ovulation. However, it is precisely in mammals that such a direct effect of light on ovulation in all species without exception cannot be established. Numerous data obtained on rabbits (Smelser, Walton a. Whethem, 1934), guinea pigs (Dempsey, Meyers, Young a. Jennison, 1934), mice (Kirchhof, 1937) and ground squirrels (Welsh, 1938) show that keeping animals in complete darkness has no effect on ovulation.

In special studies, “winter conditions” were simulated by cooling (from -5 to +7 ° C) and keeping in complete darkness. These conditions did not affect the intensity of reproduction in the common vole. ( Microtus arvalis) and developmental speed of the young. Consequently, the combination of these main environmental factors, which determine the physical side of seasonal influences, cannot explain the winter suppression of the intensity of reproduction, at least for rodents of this species.

In carnivores, a significant effect of light on the function of reproduction was found (Belyaev, 1950). A decrease in daylight hours leads to an earlier maturation of fur in minks. Changing the temperature regime does not have any effect on this process. In martens, additional lighting causes the onset of the mating period and the birth of cubs 4 months earlier than usual. Changing the lighting regime does not affect the basal metabolism (Belyaev, 1958).

However, seasonal periodicals cannot be imagined only as a result of the influence of environmental factors, as indicated by a large number of experiments. In this regard, the question arises whether there is a seasonal periodicity in animals isolated from exposure to natural factors. In dogs that were kept in a heated room under artificial lighting throughout the year, it was possible to observe the seasonal periodicity characteristic of dogs (Magnonet Guilhon, 1931). Similar facts were found in experiments on laboratory white rats (Izbinsky and Isahakyan, 1954).

Another example of the extreme durability of seasonal periodicals concerns animals brought from the southern hemisphere. So, for example, the Australian ostrich in the Askania Nova reserve lays eggs in our winter, despite the severe frost, right in the snow in the season corresponding to summer in Australia (M. M. Zavadovsky, 1930). The Australian dingo breeds at the end of December. Although these animals, like ostriches, have been bred in the northern hemisphere for many decades, no change in their natural seasonal rhythm is observed.

In humans, the change in metabolism proceeds according to the same pattern as in non-sleeping animals. There are observations obtained in a natural setting with an attempt to pervert the natural seasonal cycle. The simplest way of such a perversion and the most reliable facts are obtained in the study of transfers from one locality to another. So, for example, moving in December - January from the middle zone of the USSR to the south (Sochi, Sukhumi) causes the effect of increasing the reduced "winter" exchange during the first month of stay there due to the new conditions of the south. Upon returning to the north in spring, a secondary spring increase in exchange occurs. Thus, during a winter trip to the south, one can observe two spring rises in the metabolic rate in the same person during the year. Consequently, a perversion of the seasonal rhythm also takes place in humans, but only under conditions of changes in the entire complex of natural environmental factors (Ivanova, 1954).

Of particular interest is the formation of seasonal rhythms in humans in the Far North. Under these conditions, especially during life at small stations, the seasonal periodicals are sharply disturbed. Insufficient muscular activity due to the restriction of walks, often impossible in the conditions of the Arctic, creates an almost complete loss of the seasonal rhythm (Slonim, Ol'nyanskaya, Ruttenburg, 1949). Experience shows that the creation of comfortable settlements and cities in the Arctic restores it. The seasonal rhythm in humans is to some extent a reflection not only of seasonal factors common to the entire living population of our planet, but, like the daily rhythm, is a reflection of social environment that affects a person. Big cities and towns in Far North with artificial lighting, with theaters, cinemas, with all the rhythm of life characteristic of modern man,

create such conditions under which the seasonal rhythm manifests itself normally beyond the Arctic Circle and is revealed in the same way as in our latitudes (Kandror and Rappoport, 1954; Danishevsky, 1955; Kandror, 1968).

In the conditions of the North, where there is a large lack of ultraviolet radiation in winter, there are significant metabolic disorders, mainly phosphorus metabolism, and a lack of vitamin D (Galanin, 1952). These phenomena are especially hard on children. According to German researchers, in winter there is a so-called "dead zone", when the growth of children completely stops (Fig. 29). Interestingly, in southern hemisphere(in Australia) this phenomenon is observed in the months corresponding to summer in the Northern Hemisphere. Now additional ultraviolet irradiation is considered as one of the most important methods of correcting the normal seasonal rhythm in northern latitudes. Under these conditions, we have to talk not so much about the seasonal rhythm, but about the specific lack of this natural necessary factor.

Seasonal periodicals are also of great interest to animal husbandry. Scientists are now inclined to believe that a significant part of the seasonal periods should be changed by the conscious influence of man. It is primarily about the seasonal diet. If for wild animals the lack of nutrition sometimes leads to the death of a significant number of individuals, to a decrease in the number of their representatives in a given area, then in relation to cultivated agricultural animals this is completely unacceptable. The nutrition of farm animals cannot be based on seasonal resources, but must be supplemented on the basis of economic activity person.

Seasonal changes in the body of birds are closely related to their characteristic flight instinct and are based on changes in the energy balance. However, despite the flights, birds show both seasonal changes in chemical thermoregulation and changes in the thermal insulation properties of the feather cover (insulation).

Metabolic changes in the house sparrow are well expressed ( Passer domesticus), whose energy balance at low temperatures supported by greater heat production in winter than in summer. The results obtained from the measurement of food intake and metabolism show a flattened type of chemical thermoregulation curve, usually found when heat production is estimated from food intake over several days, and not from oxygen consumption in a short-term experiment.

Recently, it has been found that the maximum heat production in passerines is higher in winter than in summer. In grosbeaks, pigeons columba livia and starlings Sturnus vulgaris the survival time during cold periods in winter was longer mainly as a result of the increased ability to maintain higher heat production. The duration of the period before death is also affected by the state of plumage - molting and the duration of captivity, but the seasonal effect is always pronounced. Those who are IB bird cage food intake in winter increased by 20-50%. But winter food intake in caged finches ( Fringilla montefringilla) and in wild house sparrows did not increase (Rautenberg, 1957).

Significant nocturnal hypothermia, observed in winter in freshly caught birds, is absent in the grosbeak and black-headed tit. Irving (Irving, 1960) concluded that, on cold nights, northern birds cool below their daytime body temperature by about the same extent as birds in temperate regions.

The increase in plumage weight observed in some birds during winter suggests a thermal insulating adaptation that could partially offset changes in cold metabolism. However, Irving's research on several species of wild birds in winter and summer, as well as Davis (Davis, 1955) and Hart (Hart, 1962) provide little evidence for the assumption that the increase in metabolism with a 1° drop in temperature was different in these seasons. It was found that the heat production in pigeons, measured at 15°C, was lower in winter than in summer. However, the magnitude of these seasonal changes was small and no shifts were observed in the range of critical temperatures. Data on shifts in the critical temperature level were obtained for the cardinal ( Richmonda cardinalis) ( lawson, 1958).

Walgren (Wallgren, 1954) studied energy metabolism in yellow bunting ( Emberiza citrinella) at 32.5° C and at -11° C in different time of the year. Exchange at rest showed no seasonal changes; at -11 0 C in June and July, the exchange was significantly higher than in February and March. This insulative adaptation is partly explained by the greater thickness and "fluffing" of plumage and greater vasoconstriction in winter (since the plumage was most dense in September - after molting, and the maximum metabolic changes - in February).

Theoretically, changes in plumage can explain the decrease in lethal temperature by about 40 ° C.

Studies conducted on the black-headed tit ( Parus atricapillus), also indicate the presence of low heat production as a result of thermal insulation adaptation in winter. The pulse rate and respiration rate had seasonal shifts, and the decrease was greater in winter at 6°C than in summer. The critical temperature at which respiration sharply increased also shifted to a lower level in winter.

The increase in basal metabolism at thermoneutral temperatures, which is pronounced in mammals and birds exposed to cold for several weeks, does not play a significant role during winter adaptation. The only evidence of a significant seasonal variation in basal metabolism has been obtained in house sparrows, but there is no reason to assume that it plays any significant role in birds living in the wild. Most of the studied species do not show any changes at all. King and Farner (King a. Farrier, 1961) indicate that a high intensity of basal metabolism in winter would be unfavorable, since the bird would need to increase the consumption of its energy reserves at night.

The most characteristic seasonal shifts in birds are their ability to change their thermal insulation and the amazing ability to maintain a higher level of heat production in cold conditions. Based on the measurement of food intake and excretion at various temperatures and photoperiods, estimates were made of the energy requirements for the existence and productive processes at different times of the year. For this purpose, the birds were housed in individual cages, where their metabolized energy (maximum energy influx minus excretion energy at different temperatures and photoperiods) was measured. The smallest metabolized energy required for existence at certain temperatures and photoperiods of the test is called "existence energy". Its correlation with temperature is shown on the left side of Figure 30. Potential energy is the maximum metabolized energy measured at a temperature corresponding to the lethal limit, which is the lowest temperature at which a bird can support its body weight. Productivity energy is the difference between potential energy and existence energy.

The right side of Figure 30 shows different energy categories calculated for different seasons from average outdoor temperatures and photoperiods. For these calculations, it is assumed that the maximum metabolized energy is found in cold conditions, as well as for productive processes at higher temperatures. In the house sparrow, potential energy is subject to seasonal changes due to seasonal changes in survival limits. The energy of existence also changes according to average temperature outside the premises. Due to seasonal changes in potential energy and energy of existence, the energy of productivity remains constant throughout the year. Some authors point out that the ability of the house sparrow to live in the far northern latitudes is due to its ability to stretch its maximum energy balance throughout the winter and metabolize as much energy during a short daytime photoperiod in winter as during long photoperiods in summer.

At the white-throated sparrow (Z. albicallis) and the junkoJ. hue- malls) with a 10-hour photoperiod, the amount of metabolized energy is less than with a 15-hour photoperiod, which is a serious disadvantage of winter time (Seibert, 1949). These observations were compared with the fact that both species migrate south in winter.

Unlike the house sparrow, the tropical blue-black finch ( Votatinia jacarina) could maintain energy balance down to about 0°C for a 15-hour photoperiod and up to 4°C for a 10-hour photoperiod. The photoperiod limited energy in more when the temperature drops, what is the difference between these birds and the house sparrow. Due to the influence of the photoperiod, the potential energy was lowest in winter, when the energy of existence is highest. Consequently, the productivity energy was also the lowest at that time of the year. These physiological characteristics do not allow this species to exist in winter in northern latitudes.

Although for thermoregulation energy needs during the cold season are maximum, various types of bird activity are distributed, apparently, evenly throughout the year, and therefore the cumulative effects are negligible. The distribution of established energy demands for various activities throughout the year is best described for three sparrows. S. arborea ( West, 1960). In this species the largest number energy productivity potentially accounted for during daylight saving time. Therefore, activities that require energy expenditure, such as migration, nesting and molting, are evenly distributed between April and October. The additional cost of free existence is an unknown that may or may not increase the theoretical potential. However, it is quite possible that potential energy can be used at any time of the year, at least for short periods - for the duration of the flight.

The response of organisms to seasonal changes in day length is called photoperiodism. Its manifestation does not depend on the intensity of illumination, but only on the rhythm of the alternation of the dark and light periods of the day.

The photoperiodic reaction of living organisms is of great adaptive importance, since in order to prepare for the experience adverse conditions or, on the contrary, the most intensive life activity requires quite a considerable time. The ability to respond to changes in the length of the day ensures early physiological adjustments and the adaptation of the cycle to seasonal changes in conditions. The rhythm of day and night acts as a signal of upcoming changes climatic factors which have a strong direct effect on a living organism (temperature, humidity, etc.). Unlike other environmental factors, the rhythm of lighting affects only those features of the physiology, morphology, and behavior of organisms that are seasonal adaptations in their life cycle. Figuratively speaking, photoperiodism is the body's reaction to the future.

Although photoperiodism occurs in all major taxonomic groups, it is by no means characteristic of all species. There are many species with a neutral photoperiodic response, in which physiological rearrangements in the developmental cycle do not depend on the length of the day. Such species either have developed other ways of regulating the life cycle (for example, wintering in plants), or they do not need precise regulation of it. For example, where there are no pronounced seasonal changes, most species do not exhibit photoperiodism. Flowering, fruiting and death of leaves in many tropical trees are extended in time, and flowers and fruits are found on the tree at the same time. In a temperate climate, species that have time to quickly complete their life cycle and are practically not found in active state in unfavorable seasons of the year, also do not show photoperiodic reactions, for example, many ephemeral plants.

There are two types of photoperiodic reaction: short-day and long-day. It is known that the length of daylight, except for the time of year, depends on the geographical location of the area. Short-day species live and grow mainly in low latitudes, while long-day species live and grow in temperate and high latitudes. In species with extensive ranges, northern individuals may differ in type of photoperiodism from southern ones. Thus, the type of photoperiodism is an ecological rather than a systematic feature of the species.

In long-day plants and animals, the increasing spring and early summer days stimulate growth processes and preparation for reproduction. The shortening days of the second half of summer and autumn cause growth inhibition and preparation for winter. Thus, the frost resistance of clover and alfalfa is much higher when plants are grown on a short day than on a long one. The trees that grow in the cities near street lamps, the autumn day turns out to be elongated, as a result, leaf fall is delayed and they are more likely to experience frostbite.

As studies have shown, short-day plants are especially sensitive to the photoperiod, since the length of the day in their homeland changes little during the year, and seasonal climatic changes can be very significant. Photoperiodic species prepare tropical species for dry and rainy seasons. Some varieties of rice in Sri Lanka, where the total annual change in the length of the day is no more than an hour, capture even the slightest difference in the light rhythm, which determines the time of their flowering.

Photoperiodism of insects can be not only direct, but also indirect. For example, in the cabbage root fly, winter diapause occurs through the influence of food quality, which varies depending on the physiological state of the plant.

The length of the daylight period, which ensures the transition to the next phase of development, is called the critical day length for this phase. As you rise geographical latitude the critical day length increases. For example, the transition to diapause of an apple leafworm at a latitude of 32° occurs when the daylight period is 14 hours, 44°-16 hours, 52°-18 hours. The critical day length often serves as an obstacle to the latitudinal movement of plants and animals, for their introduction .

Photoperiodism of plants and animals is a hereditarily fixed, genetically determined property. However, the photoperiodic reaction manifests itself only under a certain influence of other environmental factors, for example, in a certain temperature range. With some combination environmental conditions the natural dispersal of species to latitudes unusual for them is possible, despite the type of photoperiodism. So, in the high-mountainous tropical regions there are many plants of a long day, natives of temperate climates.

For practical purposes, the length of daylight hours is changed when growing crops in closed ground, controlling the duration of lighting, increasing the egg production of chickens, and regulating the reproduction of fur-bearing animals.

The average long-term periods of development of organisms are determined primarily by the climate of the locality; it is to them that the reactions of photoperiodism are adapted. Deviations from these dates are subject to weather conditions. When weather conditions change, the timing of the passage of individual phases may change within certain limits. This is especially pronounced in plants and poikilothermic animals.’ Thus, plants that have not reached the required sum of effective temperatures cannot bloom even under photoperiod conditions that stimulate the transition to the generative state. For example, in the Moscow region, birch blooms on average on May 8 with the accumulation of the sum of effective temperatures of 75 ° C. However, in annual deviations, the timing of its flowering varies from April 19 to May 28. Homeothermic animals respond to weather patterns by changing behavior, nesting times, and migrations.

The study of the regularities of the seasonal development of nature is carried out by a special applied industry ecology - phenology (literal translation from Greek - the science of phenomena).

According to the Hopkins bioclimatic law, derived by him in relation to the conditions North America, the timing of the onset of various seasonal phenomena (phenodate) differs by an average of 4 days for each degree of latitude, for every 5 degrees of longitude and 120 m above sea level, i.e. the norther, easterly and higher the area, the later the onset of spring and earlier in autumn. In addition, phenological dates depend on local conditions (relief, exposure, distance from the sea, etc.). On the territory of Europe, the timing of the onset of seasonal events changes for each degree of latitude not by 4, but by 3 days. By connecting points on the map with the same phenodates, we get isolines that reflect the front of the advance of spring and the onset of the next seasonal phenomena. This is of great importance for planning many economic activities, in particular agricultural work.