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Environmental conditions. Adaptation (adaptation) of organisms to environmental conditions What helps animals to survive adverse environmental conditions

Sections: Biology

Goals: to increase the area of knowledge of students; learn to analyze the phenomenon of temporary cessation of vital activity in living organisms, using it as a means to adapt and survive in adverse conditions.

Equipment: tables of molluscs, crustaceans, insects, fish, amphibians, reptiles, birds, mammals.

The winter season is unfavorable for many representatives of the animal and plant world, both due to low temperatures and a sharp decrease in the ability to obtain food. In the course of evolutionary development, many species of animals and plants have acquired peculiar adaptive mechanisms in order to survive in an unfavorable season. In some species of animals, the instinct to create food supplies arose and became firmly established; others have developed another adaptation — migration. Astoundingly long flights of many species of birds, migrations of some species of fish and other representatives of the animal world are known. However, in the process of evolution in many animal species, another perfect physiological mechanism of adaptation was noticed - the ability to fall into a seemingly lifeless state, which manifests itself in different ways in different animal species and has different names (anabiosis, hypothermia, etc.). Meanwhile, all these states are characterized by inhibition of the body's vital functions to the minimum that allows it to survive unfavorable winter conditions without eating. Those species of animals that are not able to provide themselves with food in winter and for them there is a danger of death from cold and hunger fall into a similar state of imaginary death. And all this worked out in the process of evolution is subject to strict natural expediency - the need to preserve the species.

Hibernation is a widespread phenomenon in nature, despite the fact that its manifestations are different in representatives of certain groups of animals, whether they are animals with a variable body temperature (poikilothermic), also called cold-blooded, in which the body temperature depends on the ambient temperature, or animals with a constant body temperature (homeothermal), also called warm-blooded.

Among animals with variable body temperature, various types of mollusks, crustaceans, arachnids, insects, fish, amphibians and reptiles fall into hibernation, and among animals with constant body temperatures, several species of birds and many species of mammals.

How do snails winter?

From the soft-bodied type, many species of snails (for example, all land snails) fall into hibernation. Common garden snails hibernate in October and hibernate until early April. After a long preparatory period, during which they accumulate the necessary nutrients in their bodies, snails find or dig holes so that several individuals can winter together deep underground, where the temperature will be maintained at 7 - 8 ° C. Having well clogged the burrows, the snails descend to the bottom and lie with the shell opening upwards. They then close this opening, releasing a mucous substance, which soon hardens and becomes elastic (like a film). With a significant cold snap and a lack of nutrients in the body, snails burrow even deeper into the ground and form another film, thus creating air chambers that play the role of an excellent insulator. It has been established that during long wintering snails lose more than 20% of their weight, with the greatest loss occurring in the first 25-30 days. This is due to the fact that all metabolic processes gradually fade in order to reach the minimum at which the animal falls into an almost suspended state of suspended animation with subtle vital functions. During hibernation, the snail does not feed, breathing almost stops. In spring, when the first warm days come and the soil temperature reaches 8-10 ° C, when vegetation begins to develop and the first rains fall, snails crawl out of their winter shelters. Then begins an intensive activity to restore the depleted food reserves in their body; this is expressed in the absorption of a huge amount of food in comparison with their body.

Water snails, pond snails, also hibernate - most of them burrow into silt at the bottom of the reservoir in which they live.

Where do crayfish winter?

Everyone knows the popular threat: "I'll show you where the crayfish winter!" It is believed that this proverb appeared during the time of serfdom, when the landowners, punishing the guilty serfs, forced them to catch crayfish in the winter. Meanwhile, it is known that this is almost impossible, since crayfish hibernate, deeply buried in holes at the bottom of reservoirs.

From the point of view of taxonomy, the class of crustaceans is divided into two subclasses - higher and lower crustaceans.

Of the higher crustaceans, river, marsh and lacustrine crayfish fall into a state of hibernation. Males hibernate in groups in deep pits at the bottom, and females - alone in burrows, and in November they glue fertilized eggs to their short legs, from which ant-sized crustaceans hatch only in June.

Of the lower crustaceans, water fleas (genus Daphnia) are of interest. They lay, depending on the conditions, two types of eggs - summer and winter. Winter eggs have a strong shell and are formed when unfavorable living conditions occur. For some species of lower crustaceans, drying out and even freezing of eggs is a prerequisite for their continued development.

Diapause in insects

In terms of the number of species, insects are superior to all other classes. Their body temperature depends on the environment, which has a strong effect on the rate of life effects, and low temperatures greatly reduce this rate. At negative temperatures, the entire development of the insect slows down or practically stops. This anabiotic condition, known as “diapause,” is a reversible arrest of developmental processes and is caused by external factors. Diapause occurs when conditions unfavorable for life occur and continues throughout the winter until conditions become more favorable with the onset of spring.

The onset of the winter season finds different species of insects at different stages of their development, in which they hibernate - in the form of eggs, larvae, pupae or adult forms, but usually each individual species enters diapause at a certain stage of its development. For example, the seven-spotted ladybug hibernates as an adult.

It is characteristic that the wintering of insects is preceded by a certain physiological preparation of their body, consisting of the accumulation of free glycerin in their tissues, which does not allow freezing. This occurs at the stage of insect development in which they will hibernate.

Even with the onset of the first signs of a cold snap in autumn, insects find comfortable shelters (under stones, under the bark of trees, under fallen leaves in burrows in the soil, etc.), where after a snowfall, the temperature is moderately low and uniform.

The duration of diapause in insects is in direct proportion to the body's fat reserves. The bees do not go into long-term diapause, but nevertheless, at temperatures from 0 to 6 ° C, they become numb and in this state they can stay for 7-8 days. At lower temperatures, they die.

It is also interesting how insects determine the exact moment when they should come out of anabiotic state. Scientist N.I. Kalabukhov studied suspended animation in some species of butterflies. He found that the duration of diapause in individual species is different. For example, the peacock's eye butterfly was in a state of suspended animation for 166 days at a temperature of 5.9 ° C, while the silkworm took 193 days at a temperature of 8.6 ° C. According to the scientist, even differences in geographic area affect the duration of diapause.

Do fish hibernate?

Some species of a wide class of fish also adapt in a peculiar way to low water temperatures in winter. The usual body temperature in fish is not constant and corresponds to the temperature of the water. With a sudden sharp drop in water temperature, fish fall into a state of shock. It is enough, however, for the water to warm up, and they quickly “come to life”. Experiments have shown that frozen fish come to life only when their blood vessels are not frozen.

Some fish living in Arctic waters adapt originally to low water temperatures in winter: they change their blood composition. With a decrease in water temperature in the fall, salts accumulate in their blood in such a concentration as is characteristic of sea water, and at the same time the blood freezes with great difficulty (a kind of antifreeze).

Of freshwater fish, as early as November, carp, ruff, perch, catfish and others fall into hibernation. When the water temperature drops below 8 - 10 ° С, these fish move to deeper parts of water bodies, burrow in large groups in silt and remain there in a state of hibernation throughout the winter.

Some marine fish also endure extreme cold during hibernation. For example, herring approach the coast of the Arctic Ocean in autumn in order to hibernate at the bottom of some small bay. Black Sea anchovy also winters in the southern regions of the sea - off the coast of Georgia, at this time it is inactive and does not consume food. And the Azov anchovy, before the onset of the winter period, migrates to the Black Sea, where it gathers in groups in a relatively sedentary state.

Hibernation in fish is characterized by their extremely limited activity, complete cessation of nutrition and a sharp decrease in metabolism. At this time, their body is supported by the reserves of nutrients accumulated due to abundant nutrition in the autumn.

Hibernation of amphibians

By way of life and structure, the class of amphibians is transitional between typically aquatic vertebrates and typically terrestrial animals. It is known that various types of frogs, newts, salamanders also spend the unfavorable winter season in a state of numbness, since these are animals with a variable body temperature, which depends on the ambient temperature.

It was found that frogs hibernation lasts from 130 to 230 days and its duration depends on the duration of winter.

In reservoirs, in order to spend the winter, frogs gather in groups of 10-20 specimens, burrow into silt, into underwater depressions and other voids. During hibernation, frogs breathe only through their skin.

In winter, newts usually nestle under the warm, rotten stumps and trunks of fallen trees. If they do not find such comfortable “apartments” nearby, then they are satisfied with cracks in the soil.

Reptiles hibernate too

From the class of reptiles, almost all species of our fauna fall into a state of hibernation in winter. Low winter temperatures are the main reason for this phenomenon.

Winter quarters are usually underground caves or voids that have formed around large old tree stumps with rotten roots, cracks in rocks, and other places that are inaccessible to their enemies. In such shelters, a large number of snakes gather, forming huge snake balls. It has been established that the temperature of snakes during hibernation is almost the same as the ambient temperature.

Most species of lizards (meadow, striped, green, forest, spindle) also hibernate, burrowing in the soil, in holes that are not threatened by flooding. On warm sunny days in winter, lizards can “wake up” and crawl out of their winter shelters for several hours to hunt, after which they again hide in their burrows, falling into a state of numbness.

Marsh turtles spend the winter burrowing in the silt of the reservoirs in which they live, while terrestrial turtles climb to a depth of 0.5 m into the soil in some natural shelters or burrows of moles, foxes, rodents, covered with peat, moss and wet leaves.

Preparation for wintering begins in October, when the turtles accumulate fat. In spring, with a temporary warming, they wake up, sometimes for a whole week.

Are there birds hibernating?

Most animals with variable body temperatures that depend on their environment go into hibernation. But surprisingly, many animals with a constant body temperature, such as birds, can also hibernate during unfavorable seasons. It is known that most of the birds avoid unfavorable winter conditions by flying. Even Aristotle in his multivolume "History of Animals" drew attention to the fact that "some birds fly away to winter in warm countries, while others take refuge in different shelters, where they hibernate."

This conclusion was also reached by the prominent Swedish naturalist Karl Linnaeus, who wrote in his work “System of Nature”: “In the fall, when a cold snap begins, swallows, not finding enough insects to feed, begin to seek refuge for wintering in reed thickets along the shores of lakes and rivers ”.

The numbness into which some species of birds fall is significantly different from the hibernation inherent in many mammals. First of all, the body of birds not only does not accumulate energy reserves in the form of fat, but, on the contrary, consumes a significant part of them. While mammals hibernate, gaining noticeably in weight, birds lose a lot of weight before torpor. That is why the phenomenon of numbness in birds, according to the Soviet biologist R. Potapov, should not be called hibernation, but hypothermia.

Until now, the mechanism of hypothermia in birds is not fully understood. The falling of birds into a state of numbness under unfavorable living conditions is an adaptive physiological reaction that has become entrenched in the process of evolution.

What mammals hibernate?

As in those animals that were discussed earlier, in mammals, hibernation is a biological adaptation for experiencing an unfavorable season of the year. Despite the fact that animals with a constant body temperature usually endure the conditions of a cold climate, the lack of suitable food in winter has become the reason for the acquisition and gradual consolidation in the process of evolution by some of them of this peculiar instinct - to spend an unfavorable winter season in an inactive state of hibernation.

There are three types of hibernation according to the degree of numbness:

1) slight torpor, which easily stops (raccoons, badgers, bears, raccoon dogs);

2) complete numbness, accompanied by periodic awakenings only on warmer winter days (hamsters, chipmunks, bats);

3) real continuous hibernation, which is a stable, prolonged torpor (ground squirrels, hedgehogs, marmots, jerboas).

Hibernation of mammals is preceded by a certain physiological preparation of the body. It consists primarily of the accumulation of fat stores, mainly under the skin. In some people sleeping in winter hibernation, subcutaneous fat reaches 25% of the total body weight. For example, ground squirrels get fat at the beginning of autumn, increasing their body weight three times compared to the spring-summer weight. Before hibernation, both hedgehogs and brown bears, as well as all bats, become significantly fat.

Other mammals, such as hamsters and chipmunks, do not accumulate large reserves of fat, but store food in their shelter to use during their short awakening periods in winter.

During hibernation, all types of mammals lie motionless in their burrows, curled up in a ball. This is the best way to keep warm and limit heat exchange with the environment. The winter road of the apartment of many mammals is the natural void of the stems and hollows of trees.

From insectivorous mammals, the hedgehog, preparing for hibernation, collects moss, leaves, hay in a secluded place and makes a nest for itself. But it “settles” in its new home only when the temperature is kept below 10 ° C for a long time. Before that, the hedgehog eats abundantly in order to accumulate energy in the form of fat.

The hibernation of brown bears is mild numbness. In nature, in summer, the bear accumulates a thick layer of subcutaneous fat and, just before the onset of winter, settles down in its den for hibernation. Usually the den is covered with snow, so it is much warmer inside than outside. During hibernation, the accumulated fat reserves are used by the bear's body both as a source of nutrients, and also protect the animal from freezing.

From a physiological point of view, the hibernation of mammals is characterized by a weakening of all vital functions of the organism to the minimum that would allow them to survive unfavorable winter conditions without food.

The main ways of adaptation of organisms to the environment

Many organisms during their life periodically experience the influence of factors far removed from the optimum. They have to endure extreme heat, and severe frosts, and summer droughts, and drying up of water bodies, and a lack of food. How do they adapt to such extreme situations when normal life is very difficult?

The life span of dormant plant seeds depends on storage conditions. An increase in humidity and temperature increases the expenditure of the semen reserves on respiration, and they are eventually depleted. Oak acorns are stored for no more than three years. Dry seeds can lie for a long time without losing germination: poppy seeds - up to 10 years, caryopses of rye, barley and wheat - up to 32, dandelion fruits - up to 68, lotus - up to 250 years. There is a known case when lotus seeds sprouted, found in the peat of a swamp that dried up 2,000 years ago. The fruits of this plant are covered with a thick, gas- and waterproof shell.

In Central Antarctica, Russian researchers conducted a microbiological analysis of ice samples from the depths of the glacier. The age of ice layers in which viable microorganisms were found reaches 10-13 thousand years. Found mainly bacteria, as well as spores of fungi and yeast. Later, viable bacteria were found in rock samples under the Antarctic glacier. Their age ranged from 10 thousand to 10 million years.

When environmental conditions deteriorate, many species are able to suspend their vital activity and pass into a state of latent life. This phenomenon was discovered at the beginning of the 18th century, who first observed the world of small organisms through a microscope he made. He noticed and described that some of them can dry completely in air and then "come to life" in water. When dried, they appear completely lifeless. This state of apparent death was later called suspended animation ("Ana"- No, "Bios"- a life).

Deep hibernation is an almost complete cessation of metabolism. In contrast to death, organisms can then return to active life. The transition to a state of suspended animation greatly expands the survival of organisms in the most severe conditions. In experiments, dried seeds and plant spores, some small animals - rotifers, nematodes withstand for a long time the temperature of liquid air (-190 ° C) or liquid hydrogen (-259.14 ° C).

Rotifer- actively swimming and in a state of suspended animation

The state of suspended animation is possible only with complete dehydration of organisms. In this case, it is important that the loss of water by the cells of the body is not accompanied by a violation of intracellular structures.

Most species are not capable of this. For example, in the cells of higher plants, there is usually a large central vacuole with a moisture reserve. When it dries, it disappears, the cell changes shape, shrinks, and its internal structure is disturbed. Therefore, deep hibernation is rare in nature. However, a slowdown in metabolism and a decrease in vital activity in adverse conditions is a widespread phenomenon. In this case, the cells of the body are partially dehydrated, and another restructuring of their composition also occurs. The state of organisms, close to suspended animation, is called cryptobiosis or hidden life ("Kryptos"- hidden). In a state of reduced metabolism, organisms sharply increase their stability and spend energy very sparingly.

The phenomena of hidden life include insect numbness, winter dormancy of plants, hibernation of vertebrates, preservation of seeds and spores in the soil, and small inhabitants in drying up water bodies. In an inactive state, many types of bacteria are often found in nature until favorable conditions for their reproduction arise.

Bat long-eared and gopher hibernating

Have gopher in a state of activity, the heart rate is about 300 beats per minute, and during hibernation - only 3. The body temperature drops to +5 ° C. Despite the low metabolic rate, animals lose a lot of weight during hibernation and can die of exhaustion if they do not accumulate enough fat by winter.

Hidden life is a very important ecological adaptation. It is an opportunity to experience adverse changes in the habitat. When the necessary conditions are restored, organisms again pass to active life.

Moving into a state of numbness or dormancy, plants and animals seem to obey environmental influences , while saving the cost of its existence.

Another, directly opposite way of survival of organisms is associated with maintaining the constancy of the internal environment despite fluctuations in the impact of external factors. Living in conditions of variable temperature, warm-blooded animals - birds and mammals - maintain a constant temperature inside themselves, optimal for biochemical processes in the cells of the body.

The vacuoles of the cells of terrestrial plants contain moisture reserves, which allows them to live on land. Many plants are able to withstand severe droughts and grow even in hot deserts.

Sugar beet stalk cell: 1 - chloroplasts; 2 - core; 3 - vacuoles; 4 - cytoplasm; 5 - mitochondria; 6 - cell membrane

Such resistance to the influence of the external environment requires a large expenditure of energy and special adaptations in the external and internal structure of organisms.

Several species live in dry Central Asian deserts wood lice... These are small terrestrial crustaceans that, like their closest aquatic relatives, need a high environmental humidity. Living in deserts, they are able to avoid heat and dryness. Woodlice dig vertical burrows in clay soil, in the depths of which the temperature is sharply reduced, and the air is saturated with water vapor. They feed on plant debris on the soil surface, leaving their burrows only at the time of day when the surface layer of air is humidified. In hot hours, the female plugs the hole with her anterior segments, bearing impenetrable integuments, in order to maintain moisture and protect her offspring from drying out.

Each of the two described survival paths has its own advantages and disadvantages. If it is possible to inhibit metabolism and switch to hidden life, organisms save energy and increase resistance, but are not capable of activity when conditions deteriorate. By regulating the temperature and moisture reserves in the body, representatives of various species can maintain normal vital activity in a very wide range of external conditions, but they spend a lot of energy, which they need to constantly replenish. In addition, such organisms are very unstable to deviations in the regime of their internal environment. For example, in a person, an increase in body temperature by only 1 ° C indicates ill health.

In addition to submission and resistance to the influence of the external environment, a third way of survival is also possible - avoidance of adverse conditions and an active search for other, more favorable habitats.

Reindeer roaming: 1 - northern border of the forest-tundra; 2 - northern border of the taiga; 3 - wintering places

This path of adaptations is accessible only to mobile animals that can move in space.

Warm-blooded animals can live in very cold areas, withstanding frosts down to -50 ° C. In such cases, the temperature difference between the animal itself and the environment can be 80-90 ° C. Have penguins constant body temperature is + 37-38 ° С, at reindeer + 38-39 ° C. To maintain heat balance, animals spend energy reserves of fat. The role of heat-insulating covers (down, feathers, fur) is also very important. By winter, these covers become thicker and fluffier, providing an air gap around the body that retains heat.

For example, wintering black grouse and hazel grouse for most of the day they burrow into the snow, where it is much warmer. Many animals arrange dwellings - holes and nests that protect them from external influences. This is also a way to avoid unfavorable factors.

Animal nests and burrows. Above: left - a common squirrel's nest; on the right is the nest of a baby mouse. Below are the summer (left) and winter (right) burrows of midday gerbils

Long-distance flights of birds are a striking example of avoiding winter food shortages and cold weather.

Barn Swallow Migration Map

All three survival paths can be combined in representatives of the same species. For example, plants cannot maintain a constant body temperature, but many of them are able to regulate water exchange. Cold-blooded animals obey unfavorable factors, but can also avoid their effects. On the whole, we see that with a huge variety of living nature in it, only a few main ways of adaptive development of species can be distinguished.

Increasing the resistance of organisms in a state of hidden life is widely used in economic practice. In special storages, special regimes are created for long-term storage of plant seeds, cultures of microorganisms, sperm of valuable farm animals. In medical practice, special conditions have been developed for the preservation of donor blood, transplanted organs and tissues. There are projects to preserve the germ cells of endangered species of animals and plants in order to be able to restore them in nature in the future.

Unlike plants, animals - heterotrophs. This is the name for organisms that are unable to create organic substances from inorganic ones. They create the organic substances necessary for their body from organic substances supplied with food. Unlike animals, plants form organic substances from inorganic ones, using the energy of light for this. But in animal life light also plays an important role. Many animals have organs of vision that allow them to navigate in space, distinguish individuals of their own species from others, look for food, make migrations, etc. Some species of animals are active during the day ( falcon, swallows, zebras), others - at night ( cockroaches, owls, hedgehogs).

Most animal species live in conditions that change throughout the year. In spring, the duration of daylight hours gradually increases, and with the approach of autumn, it begins to decrease. By reacting to changes in the length of daylight hours, animals can prepare in advance for the onset of changes in nature. The reaction of organisms to changes in the length of daylight is called photoperiodism.

Another important factor of inanimate nature that affects the life of organisms is temperature... Have cold-blooded animals (invertebrates, fish, amphibians, reptiles) body temperature depends on the ambient temperature. At low temperatures, they fall into a state of numbness.

Warm-blooded animals (birds, mammals) are able to maintain body temperature, regardless of its changes in the environment, at a more or less constant level. To do this, they need to spend a lot of energy. Therefore, in winter, they face an acute problem of finding food.

Animals living in low temperatures are called cold-loving (penguins, polar bear, deep sea fish and etc.). These animals have well-developed hair or feathers, a layer of subcutaneous fat, etc.

Species that live in high temperatures are called heat-loving (madrepore corals, antelope, hippos, in a bogey way and etc.) (fig. 276, 4-6). Many species are able to live in conditions of periodic temperature changes. They are called cold-resistant (wolves, foxes, hoodie and etc.) .

Another environmental factor that plays an important role in animal life is humidity . The body of many animals contains 50-60% water, and the body of jellyfish up to 98%. Water ensures the transport of substances throughout the body, takes part in their chemical transformations, regulation of body temperature, elimination of end products of metabolism, etc. Among animals, there are hygrophilous, drought-resistant and dry-loving... TO hygrophilous include those species of animals that can live only in conditions of high humidity (for example, wood lice, earthworms, amphibians). Unlike them, dry-loving species (sacred scarab beetle, desert species the serpent and lizards and others) are able to effectively retain water in their body. This gives them the opportunity to live in arid steppes and deserts. Many species of animals are classified as drought-resistant: they are able to survive certain periods of drought (many species Zhukov, reptiles, mammals and etc.).

For animals living in the aquatic environment, it is important salt composition of water... Some species of protozoa, crustaceans, fish can live only in fresh water bodies, others - only in the seas. Material from the site

Experiencing animals for long periods of unfavorable conditions. Animals experience periods of unfavorable conditions in different ways. For example, in winter, some species of animals hibernate (brown bear, hedgehog, badger, etc.). This allows them to reduce the waste of energy in the absence of food. Inhabitants of the desert may hibernate in summer, during dry periods. Unicellular animals endure unfavorable conditions at the stage of cysts. Many invertebrates experience unfavorable conditions at the egg stage (among crustaceans - shchitny, many insects).

Among factors of inanimate nature the greatest impact on animals is carried out by:

light;
temperature;
humidity;
salt composition of water.

On this page material on topics:

Inanimate habitat factors
What factor of inanimate nature affects pine
Unfavorable conditions of nature
Influence of various factors for WWII of biological nature
How animals affect inanimate nature

Questions about this material:

The causes of imaginary death (suspended animation) in plant and animal organisms

allowing them to survive the unfavorable winter conditions.

OK Smirnova, teacher of biology of the highest category of Lyceum No. 103, Rostov-on-Don.

Goals: to increase the area of knowledge of students; learn to analyze the phenomenon of temporary cessation of vital activity in living organisms, using it as a means to adapt and survive in adverse conditions.

Equipment: tables of molluscs, crustaceans, insects, fish, amphibians, reptiles, birds, mammals.

How do snails winter?

Water snails, pond snails, also hibernate - most of them burrow into silt at the bottom of the reservoir in which they live.

Where do crayfish winter?

From the point of view of taxonomy, the class of crustaceans is divided into two subclasses - higher and lower crustaceans.

Diapause in insects.

In terms of the number of species, insects are superior to all other classes. Their body temperature depends on the environment, which has a strong effect on the rate of life effects, and low temperatures greatly reduce this rate. At negative temperatures, the entire development of the insect slows down or practically stops. This anabiotic condition, known as diapause, is a reversible arrest of developmental processes and is caused by external factors. Diapause occurs when conditions unfavorable for life occur and continues throughout the winter until conditions become more favorable with the onset of spring.

Do fish hibernate?

Some species of a wide class of fish also adapt in a peculiar way to low water temperatures in winter. The usual body temperature in fish is not constant and corresponds to the temperature of the water. With a sudden sharp drop in water temperature, fish fall into a state of shock. It is enough, however, for the water to warm up, and they quickly "come to life". Experiments have shown that frozen fish come to life only when their blood vessels are not frozen.

Hibernation of amphibians

It was found that frogs hibernation lasts from 130 to 230 days and its duration depends on the duration of winter.

In winter, newts usually nestle under the warm, rotten stumps and trunks of fallen trees. If they do not find such comfortable "apartments" nearby, then they are satisfied with cracks in the soil.

Reptiles hibernate too

From the class of reptiles, almost all species of our fauna fall into a state of hibernation in winter. Low winter temperatures are the main reason for this phenomenon.

Most species of lizards (meadow, striped, green, forest, spindle) also hibernate, burrowing in the soil, in holes that are not threatened by flooding. On warm sunny days in winter, lizards can "wake up" and crawl out of their winter shelters for several hours to hunt, after which they again hide in their burrows, falling into a state of numbness.

Preparation for wintering begins in October, when the turtles accumulate fat. In spring, with a temporary warming, they wake up, sometimes for a whole week.

Are there birds hibernating?

This conclusion was also reached by the prominent Swedish naturalist Karl Linnaeus, who wrote in his work The System of Nature: “In the fall, when a cold snap begins, swallows, not finding enough insects to feed, begin to seek refuge for wintering in reed thickets along the shores of lakes and rivers ".

What mammals hibernate?

There are three types of hibernation according to the degree of numbness:

1) slight torpor, which easily stops (raccoons, badgers, bears, raccoon dogs);

2) complete numbness, accompanied by periodic awakenings only on warmer winter days (hamsters, chipmunks, bats);

3) real continuous hibernation, which is a stable, prolonged torpor (ground squirrels, hedgehogs, marmots, jerboas).

Other mammals, such as hamsters and chipmunks, do not accumulate large reserves of fat, but store food in their shelter to use during their short awakening periods in winter.

From insectivorous mammals, the hedgehog, preparing for hibernation, collects moss, leaves, hay in a secluded place and makes a nest for itself. But he "settles" in his new home only when the temperature is kept below 10 ° С for a long time. Before this, the hedgehog eats abundantly in order to store energy in the form of fat.

By winter or dry summer, the body accumulates reserve energy substances that help to survive the difficult season, for example, glycogen. Animals get fat to some extent. In some species, fat accounts for up to 25% of the total body weight. For example, a small ground squirrel weighs about 100-150 g in spring, and up to 400 g in mid-summer.

Adaptation to unfavorable environmental conditions is also expressed in migrations. So, in the fall, as feeding conditions deteriorate, the bulk of polar foxes and reindeer migrate from the tundra to the south, to the forest-tundra and even to the taiga, where it is easier to get food from under the snow. Following the deer, tundra wolves also migrate to the south. In the northern regions of the tundra, white hares at the beginning of winter make massive migrations to the south, in the spring - in the opposite direction. By summer, mountain ungulates ascend to the upper belts of the mountains with their rich grass stand, while in winter, as the depth of the snow cover increases, they descend. And in this case, migrations of some predators, such as wolves, combined with ungulates, are observed.

In general, migrations are characterized by relatively fewer species than birds and fish. They are most developed in sea animals, bats and ungulates, while among the species of the most numerous groups - rodents, insectivores and small predators - they are practically absent.

Hibernation is an alternative to migrations in these animals. Distinguish between optional seasonal and continuous seasonal hibernation. In the first case, body temperature, the number of respiratory movements and the general level of metabolic processes decrease slightly. Sleep is easily interrupted by a change in the environment or by anxiety (bears, raccoons). Real continuous seasonal hibernation is characterized by a loss of the ability to thermoregulation, a sharp reduction in the number of respiratory movements and contractions of the heart muscle, a drop in the general level of metabolism (marmots, ground squirrels).

An important adaptation to the experience of unfavorable conditions is the collection of feed stocks. Among other vertebrates, only a few groups of birds (passerines, owls, woodpeckers) collect food for the winter, but the size of the reserves and the adaptive value of this activity in them is negligible compared to mammals.

Burial of surplus production is common at. So, weasels and ermines collect 20-30 voles and mice, black chorises put several dozen frogs under the ice, minks - several kilograms of fish. Larger predators (martens, wolverines, cats, bears) hide the remains of their prey in secluded places, under fallen trees, under stones. Leopards often hide some of their prey in tree branches. A characteristic feature of the storage of food by predators is that no special storerooms are built for its burial, only one individual who built it uses the stock. In general, stocks serve only as a small help for experiencing a period of malnutrition, and they cannot prevent a sudden lack of food. Different rodents and pikas store food in a different way, although in this case, there is a different degree of perfection of storage and its value. Flying squirrels collect several tens of grams of end twigs and earrings of alder and birch, which they fold into hollows. Proteins are buried in fallen leaves, in hollows and in the ground, acorns and nuts. They also hang mushrooms on tree branches. One squirrel in the dark coniferous taiga stores up to 150-300 mushrooms, and in the belt forests of Western Siberia, where feeding conditions are worse than in the taiga, up to 1500-2000 mushrooms, mainly boletus. The reserves made by the squirrel are used by many individuals of this species.

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