Amphibians are given a specific ecological “niche” - they are an important link in the food chains of humid land areas and aquatic biocenoses. Together with birds, amphibians take an active part in maintaining the natural ecological balance.
Sometimes living beings are classified into different groups, assessing the degree of their “usefulness” for their environment. In fact, there are neither “beneficial” nor “harmful” species in nature. Each species has its own ecological niche, position in food chains, place in the cycle of substances, etc. Each individual is a carrier of unique genetic information characteristic of its species. There is a close relationship between animal species. Moreover, each of them is endowed with its own usefulness for the biocenosis, which may not always be understood by us. Although representatives of some species may pose a certain danger to various members of the community - plants, animals, humans. This is especially evident when the ecological balance is disturbed (for example, during the “explosive” mass reproduction of insects or pathogens). In those natural biocenoses that include various types of amphibians, there are also no absolutely beneficial or harmful insects, birds, amphibians, plants, etc. Everything is an interconnected systemic whole. At the same time, amphibians play the role of protectors of the plant world. After all, the food items they need are basically dangerous to the life of many plants, especially with uncontrolled reproduction. At the same time, amphibians practically do not consume the main plant pollinators. Here the “wise interrelation of interests” of representatives of flora and fauna is manifested. The ecological niches of amphibians and birds, constituting single biocenoses, are also interconnected.
Regulators of ecological balance
Birds have a fairly wide range of food items, but it is amphibians that are considered universal plant protectors. Amphibians play an important role as regulators of ecological balance due to their omnivorous and unpretentious nature. For example, the diet of Russian northern frogs and toads includes locusts, weevils, bedbugs, bark beetles, leaf beetles and other beetles, including the most dangerous pest, the Colorado potato beetle. Amphibians destroy large quantities of cutworm caterpillars, moths, and slugs. The unpretentiousness of amphibians in terms of nutrition is also of great importance. They, in much greater numbers than birds, are able to eat insects with an unpleasant odor and taste, hairy caterpillars, and invertebrates with bright, repellent colors. The fact is that the amphibian body is equipped with excellent defense mechanisms against poisonous creatures. Therefore, in most cases, their innate life program does not include a reflex to the bright color of prey, which frightens other animals.
In addition, amphibians have an important hunting feature, which allows them and birds to complement each other in this joint activity. After all, birds that feed on insects hunt mainly during daylight hours and destroy pests active during this period. And many amphibians are able to restrain the excessive reproduction of representatives of many species of insects and mollusks, working at dusk and at night, when birds sleep. For example, an adult toad can eat up to 100 insects, their larvae and slugs in one night.
The advantage of cold-blooded amphibians
The activity of amphibians of various species is especially important in containing (together with birds) the excessive proliferation of invertebrate vegetation destroyers during difficult periods of cold weather and lack of food. After all, birds, being warm-blooded animals, cannot starve for long. Birds need to constantly maintain their body temperature at a level of 39-410C, and for this they must burn enough food in their “furnaces”. When it gets colder, the energy consumption of the bird's body increases sharply. To keep warm, birds need to increase their nutrition, but just at this time insects hide and become inaccessible. Therefore, the birds either die from exhaustion or try to fly to areas with better weather conditions. Even short periods of cold weather and lack of food cause especially serious damage to chicks. However, birds are given an amazing ability - to make long-term weather forecasts with great accuracy. In years when unfavorable living conditions are expected, including a decrease in the number of food items, birds lay fewer eggs than usual. As a result, when warming occurs and insects actively reproduce, feathered plant protectors become clearly insufficient. This is where all the benefits of the life activity of cold-blooded amphibians manifest themselves. Having easily survived the temporary cold snap and lack of food, they take revenge under favorable conditions. Amphibians begin to feed intensively, while curbing the excessive proliferation of plant pests.
In the diet of animals
Amphibians are not only consumers of food, but they themselves are objects of food. And thus amphibians are included in the general biological cycle. Among amphibians, the food items of various animals are mainly tadpoles and adult frogs. Tadpoles are eaten mainly by fish. Grown-up frogs are mainly eaten by birds, snakes, animals and large fish. After all, these amphibians do not hide in shelters during the daytime. They are fully equipped for active hunting of insects at this particular time. In addition, frogs are not provided with skin secretions with such protective properties as the caustic mucus of toads, toads, salamanders, etc. Frogs are consumed by a huge number of animals. First of all, these are many large predatory fish: catfish, pike perch, pike. For them, frogs and tadpoles are quite accessible mass food. The most common fish prey is the grass frog, which, in contrast to the green frog, lacks the behavioral mechanism of burying itself in mud for the winter. Therefore, it turns out to be the food link that expands the diet of fish at the expense of terrestrial food items. Many birds also feed on frogs, including storks, herons, crows, magpies, rooks, harrier gulls, terns, and grebes. For some of them, frogs make up a large proportion of their diet. Ornithologists estimate that at least 90 species of birds prey on frogs, 21 species prey on spadefoot spadefoots, and 18 species prey on toads. To a large extent, frogs provide nutrition for snakes. Small quantities of frogs are consumed by hedgehogs, minks, shrews, foxes, and otters. Toads are eaten by raccoons and raccoon dogs, badgers, and hori. In years when the main food of these animals is scarce, the role of amphibians as food items increases. By feeding on a wide variety of invertebrates, amphibians accumulate organic substances in their bodies, which can then be used by larger vertebrates. Thus, the purpose of amphibians is also to use their lives to support the lives of other animals during unfavorable periods.
The number of most species of frogs in all habitats intended for them is in a certain balance (despite the participation of various animals in the diet). It is mainly due to the enormous fertility of frogs, which quickly restores the losses incurred. In addition, amphibians are distinguished by the relative longevity of individuals. In that part of the amphibians that were destined to avoid danger and survive, several generations can exist side by side, regularly producing offspring of the same fertile amphibians.
Man and amphibians
Amphibians are extremely important animals for humans. Firstly, by feeding on small animals, amphibians, especially frogs and toads, restrain the mass reproduction of agricultural pests. Thanks to this, they, along with insectivorous birds, are included in the category of crop protectors, friends of gardeners and gardeners. Secondly, amphibians destroy insects that are carriers of human diseases, for example, malaria mosquitoes. Thirdly, amphibians are actively used for experiments by many generations of physicians, biologists and scientists in related fields. They helped make a lot of important scientific discoveries in biology and other sciences, including bionics. In addition, amphibians are amazingly touching, gentle and often very beautiful creatures. They admire the phenomenal capabilities of their body, graceful movements and complex behavior. Amphibians, like all living beings, require humane treatment and protection. Let's look at these questions in more detail.
"Utility coefficient" for a person
Living in a wide variety of places and feeding on insects and other invertebrates that are dangerous to plant life, amphibians bring great benefits to gardens, vegetable gardens, fields, forests and meadows (hayfields), and therefore to humans. Among pests that, if uncontrolled, can destroy almost the entire crop, insects occupy the first place. And the vast majority of frogs, toads, tree frogs and salamanders feed on them. In addition, these amphibians destroy countless numbers of slugs.
Scientists who studied the nutrition of our domestic amphibians once proposed a fairly simple formula for calculating the usefulness index for a person of a particular species:
V=t, where n is the number of animals eaten that are harmful to humans, u is the number of useful ones, t is the total number of animals eaten (harmful, beneficial and neutral, found in the stomach) and v is the coefficient of utility for humans.
For general guidance in this matter, the formula gives quite satisfactory results. “Utility coefficients” calculated using this formula as a percentage for some amphibians were as follows:
common newt - 98 lake frog - 50
tree frog - 66 toad - 49
sharp-faced frog - 46 crested newt - 11
grass frog - 59 Asia Minor frog - 27
spadefoot - 57 pond frog - 18
It should be borne in mind that the beneficial activity of amphibians for humans calculated using this formula is purely utilitarian. It fluctuates at different times and in different habitats. And of course, this formula does not reflect the importance of amphibians for ecosystems, biodiversity, etc.
A study of the food range of amphibians showed that they consume mainly insects harmful to plants. Due to the fact that in areas of mass reproduction there are more of them than other insects, in the stomachs of amphibians they make up 80–85% of all food eaten. Moreover, on the ground, insects are hunted mainly by salamanders and frogs. And tropical tree frogs and arboreal salamanders catch their prey on the branches of trees and shrubs. Their sticky tongue, which accurately hits the target, helps them grab insects on the fly. Glider devices help tropical copepods hunt. Unlike many birds, amphibians are capable of eating “inedible” insect pests with an unpleasant odor, taste and bright protective coloring. Some amphibians are able to catch insects and their larvae in the ground. Therefore, plants - from roots to crowns - can be completely protected by amphibians. They have been recognized as having an independent and quite significant role in the extermination of insects harmful to agriculture.
Toads have one important feature - they are the most active consumers of slugs, these nocturnal plant pests and practically omnivorous animals. Slugs destroy the harvest of rye and wheat, peas and carrots, cabbage and potatoes, and tobacco. It is easier to list the crops that they do not eat. Moreover, pests do this from early spring to late autumn, on open ground or penetrating greenhouses. They are especially harmful at the time of harvest ripening, when chemical treatment of plants cannot be carried out. This is where toads demonstrate their beneficial abilities for humans. At dusk, choosing a more secluded path and making small dashes, toads go out hunting. The benefits to people of their night hikes are enormous. In the United States, they have roughly estimated the cost savings that toads bring night after night to farming and forestry. It turned out that this is billions of dollars a year! And every year the profit from each toad is 20 - 30 dollars. The usefulness of toads was also highly appreciated in Europe. It is not for nothing that in the 19th century, for example, in Paris there was a special market where gardeners and peasants bought hundreds of toads to release them into vegetable gardens, fields and orchards. Thus, they saved a huge share of their harvest.
After metamorphosis is completed, juveniles, for example, green toads, leave the water and actively engage in hunting. It makes a significant contribution to the eradication of agricultural pests. Of course, young toads mainly consume small animals, which adult amphibians do not pay attention to. But the little caterpillar manages to eat a lot of greenery before it grows to a size where it becomes “interesting” as a food item for adult animals. Thus, juvenile amphibians enter the ecological niche along with older ones, preventing the enormous damage caused by small plant pests.
Those amphibians that eat disease carriers bring great benefit to humans. Newts play a special role in the destruction of mosquito larvae. The purpose of newts to regulate the reproduction of mosquitoes is due to the fact that the habitat of these amphibians, and most importantly their predatory larvae, is most often small and stagnant warm bodies of water. And they are also breeding grounds for mosquitoes. This food “predilection” of newts is of particular importance in areas of mass breeding of malaria mosquitoes, which carry a dangerous disease to people.
"Martyrs of Science"
Both the first observations of schoolchildren in the biology classroom, and the largest studies of biologists, doctors and other scientists are very often associated with the use of frogs. Most instruments in experimental biology and medicine are designed for these “martyrs of science.” In addition, it was the frog that, more than 200 years ago, gave rise to the development of one of the most important branches of knowledge - the study of electricity. The frog was also of interest for bionics. The purpose of these studies is to use biological knowledge about perfect and unique “devices” and “instruments” of living organisms to solve engineering problems and develop technology. For example, the common frog is endowed with an interesting feature. She practically sees only moving objects, which helps the amphibian to instantly react and grab prey. At the same time, her eye filters out information about stationary objects and tunes only to a moving target. The study of these features of the frog's eye made it possible to create the retinatron device. It does not react to stationary objects and provides observation of moving objects, such as an airplane.
In recognition of the invaluable benefits that modest amphibians brought to the development of world science, monuments are even erected to them. One of the most famous is installed in front of the Pasteur Institute in Paris. With money raised by medical students, a monument was created in Tokyo.
Man inflicts damage on amphibian tribe
The amphibian tribe cannot be seriously threatened by their traditional enemies. The ecological balance inherent in nature is not disturbed naturally. At the same time, some species of amphibians are on the verge of extinction, which is mainly due to the anthropogenic factor - rapidly expanding human economic activity, as well as the consequences of unwise recreation and tourism. The recent decline in the populations of the most beneficial tailless amphibians – frogs and toads – has been especially serious. But the purpose of these eternal workers is to maintain balance in nature. Therefore, the ever-increasing pace of technological progress, the direct and indirect impact of civilization, striking at amphibian populations, also disrupts the general ecological state of the Earth.
The number of reservoirs suitable for the normal life of amphibians, including their reproduction, is catastrophically decreasing. Drainage of swamps and other work to include unused ones in human agricultural activities drive tailless and tailed amphibians into the few “reservations” that have survived so far. When small bodies of water are destroyed and swamps are drained, the groundwater level decreases. The remaining reservoirs dry up, which is detrimental to the tadpoles. And in winter, shallow lakes and swamps freeze to the bottom, causing the death of adult individuals.
Reservoirs are not only drained, but become clogged and polluted by industrial, agricultural and household substances. Moreover, this happens not only as a result of economic activity, but also due to the “costs” of tourism and recreation for people who have not received environmental education. In addition, some species of amphibians, such as the reed toad, are close to extinction from coastal areas due to the fact that natural areas are not left there when creating places for recreation, equipping beaches, and laying roads.
To enrich the soil with nutrients, a large amount of fertilizers of natural and artificial origin is introduced into it, and toxic substances are added to destroy field pests. All this falls with rain and melt water from small and large reservoirs, having a detrimental effect on their inhabitants and coastal living beings. This changes the ecological balance, which affects the food resources of various animals, including amphibians, affecting the very life of individuals. The so-called “chemical war,” while benefiting certain sectors of agriculture, turns into disaster for the peaceful inhabitants of the Earth.
In many countries, people pay with the loss of the number of their own living beings for some positive role of imported animals. Although his animals are no less useful to him, but in other industries. For example, the introduction of such large and aggressive animals as the aga toad or bullfrog from other areas is harmful to the population of amphibian hosts. When the giant aga toad (25 cm long) was brought to Australia from the USA, they counted only on its benefits. Due to its great gluttony, the toad helped actively fight sugar cane pests. But gradually her food habits began to have a negative impact on local animals. First, the snakes disappeared because they died from the poison of the toads after eating them. In this regard, rodents and insects began to actively reproduce, the numbers of which were kept in check by snakes. The number of bees, plant pollinators and honey collectors, to which the aga toad has a special predilection, has decreased. This is what human disruption of ecological balance can lead to.
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Conditions of existence and distribution
Amphibians belong to the group of poikilothermic (cold-blooded) animals, i.e. their body temperature is not constant and depends on the ambient temperature. The life of amphibians is highly dependent on environmental humidity.
This is determined by the large role of skin respiration in their life, complementing and sometimes even replacing imperfect pulmonary respiration. The bare skin of amphibians is always moist, since oxygen diffusion can only occur through a water film. Moisture from the surface of the skin constantly evaporates, and evaporation occurs the faster, the lower the environmental humidity. Evaporation from the surface of the skin constantly lowers body temperature, and the drier the air, the more the temperature will drop. The dependence of body temperature on air humidity in combination with poikilothermy (“cold-bloodedness”) leads to the fact that the body temperature of amphibians not only follows the temperature of the environment, as in fish or reptiles, but, due to evaporation, is usually 2-3° lower than it ( this difference can reach 8-9° when the air is drier).
The great dependence of amphibians on humidity and temperature determines their almost complete absence in deserts and subpolar countries and, conversely, a rapid increase in the number of species towards the equator and their exceptional richness in humid and warm tropical forests. So, if there are 12 species of amphibians in the Caucasus, then in the vast expanses of Central Asia, which are 6 times larger than the Caucasus, only two species live - the green toad and the lake frog. Only a few species penetrate north to the Arctic Circle. These are the grass frog, the sharp-faced frog, and the Siberian four-toed newt.
Skin respiration plays a different role in different species of amphibians. Where the respiratory function of the skin is low, the skin becomes keratinized and evaporation from the surface decreases, and consequently, the body’s dependence on environmental humidity decreases. As a rule, the distribution of species by habitat depends on the degree of skin participation in respiration.
Among our amphibians, the Ussuri clawed newt and the Semirechensk newt are among the species that constantly live in water, in which gas exchange occurs almost exclusively through skin respiration alone. Our green frogs do not move any significant distance from bodies of water, receiving more than 50% of the oxygen they need for breathing through their skin.
Land amphibians include almost all toads, which evaporate half as much water from the surface of the body as green frogs. Some land amphibians spend a significant part of their time buried in the ground, like our spadefoot spadefoot. A number of species live in trees; An example of a typical tree form is the tree frog, which is found in the southern regions of the European part of Russia, in the Caucasus and the Far East.
The peculiarity of the structure of the skin of amphibians has another ecological consequence - representatives of this class are not able to live in salt water with a concentration exceeding 1.0-1.5%, since their osmotic balance is disturbed.
The body of tailless amphibians is short, the neck is not pronounced, there is no tail, the paired limbs are well developed, and the hind limbs are two to three times larger than the front ones and are used for characteristic jumping movement. The uniformity in the structure of anurans is associated with an adaptation to movement by jumping, which was primarily inherent in all representatives of this order.
The simultaneous push of the hind legs resulted in the development of a shortened, wedge-shaped body and elongated hind limbs. At the same time, an additional section arose - the tarsus as an elastic insert that continues the action of the muscles when jumping. The formation of a narrow pelvis in the form of a characteristic disk is also adapted to the fullest use of force when jumping, since with this type of movement it is convenient to have the points of application of forces as shifted as possible. This is also associated with the characteristic lengthening of the iliac bones, which facilitate the transfer of the points of application of forces to the center of gravity of the animal.
If we divide tailless amphibians into frogs (arboreal or waterfowl) and toads (terrestrial), they differ in that frogs have smoother skin, longer hind legs and well-developed membranes between the toes. And toads have a more rounded body, dry, often warty skin and short hind legs, convenient for crawling and short jumps. The membranes on their hind legs are underdeveloped, since toads prefer dry land.
Amphibians have the property of mimicry. For example, toads have a dark protective color on top, and on the bottom on the abdomen and legs the color is bright - orange or yellow with dark spots. In extreme danger, the toad strongly bends its back and turns its paws out, so that the bright color of the underside becomes visible.
In tree frogs, green tones predominate in their varied colors. Some species are able to change color to match the color of the substrate. And a number of frogs change color depending on temperature and humidity.
THREAT TO AMPHIBIANS
Amphibian conservation. The state of natural populations of many amphibian species in areas heavily modified by humans raises concerns due to the rapid decline in the numbers of these animals. The greatest danger is the destruction of natural habitats. During the economic development of natural areas, the greatest threat to amphibians comes from deforestation, drainage and pollution of water bodies, and the use of fertilizers and pesticides. The natural populations of species used by humans for gastronomic purposes, for scientific experiments and in educational practice in the training of doctors and biologists have been severely undermined. Attempts are being made to breed 30 species of amphibians in captivity.
BENEFITS OF AMPHIBIANS
Compared to other vertebrates, amphibians are not of great practical importance. In general, they are very useful for humans. Some amphibians serve as food for valuable fur-bearing predators, such as the black polecat and raccoon dog. The latter's food often consists of more than half (up to 65%) frogs and tadpoles. Many birds, such as ducks, herons, cranes, etc., also feed on frogs and tadpoles. There are experiments in breeding tadpoles for fattening domestic ducks. Finally, in some countries the population eats the meat of frogs and large salamanders.
AMPHIBIAN MIGRATION
In the spring, brown grass frogs awaken earlier than everyone else. Near Moscow they appear in early April, sometimes as early as the end of March. Green frogs emerge later - in the first half of May. Newts awaken quite early - in mid-April, when there is still snow in places in central Russia.
CONDITIONS OF EXISTENCE
In autumn, amphibians migrate to their wintering grounds. At this time, grass frogs gather in fairly large groups. Their daily activity also changes. From nocturnal they become daytime, which is associated with a decrease in temperature at night. It should be taken into account that the decrease in temperature also coincides with the cessation of activity of insects and worms that serve as food for frogs.
Amphibians are given a specific ecological “niche” - they are an important link in the food chains of humid land areas and aquatic biocenoses. Together with birds, amphibians take an active part in maintaining the natural ecological balance.
Sometimes living beings are classified into different groups, assessing the degree of their “usefulness” for their environment. In fact, there are neither “beneficial” nor “harmful” species in nature. Each species has its own ecological niche, position in food chains, place in the cycle of substances, etc. Each individual is a carrier of unique genetic information characteristic of its species. There is a close relationship between animal species. Moreover, each of them is endowed with its own usefulness for the biocenosis, which may not always be understood by us. Although representatives of some species may pose a certain danger to various members of the community - plants, animals, humans. This is especially evident when the ecological balance is disturbed (for example, during the “explosive” mass reproduction of insects or pathogens). In those natural biocenoses that include various types of amphibians, there are also no absolutely beneficial or harmful insects, birds, amphibians, plants, etc. Everything is an interconnected systemic whole. At the same time, amphibians play the role of protectors of the plant world. After all, the food items they need are basically dangerous to the life of many plants, especially with uncontrolled reproduction. At the same time, amphibians practically do not consume the main plant pollinators. Here the “wise interrelation of interests” of representatives of flora and fauna is manifested. The ecological niches of amphibians and birds, constituting single biocenoses, are also interconnected.
Regulators of ecological balance
Birds have a fairly wide range of food items, but it is amphibians that are considered universal plant protectors. Amphibians play an important role as regulators of ecological balance due to their omnivorous and unpretentious nature. For example, the diet of Russian northern frogs and toads includes locusts, weevils, bedbugs, bark beetles, leaf beetles and other beetles, including the most dangerous pest, the Colorado potato beetle. Amphibians destroy large quantities of cutworm caterpillars, moths, and slugs. The unpretentiousness of amphibians in terms of nutrition is also of great importance. They, in much greater numbers than birds, are able to eat insects with an unpleasant odor and taste, hairy caterpillars, and invertebrates with bright, repellent colors. The fact is that the amphibian body is equipped with excellent defense mechanisms against poisonous creatures. Therefore, in most cases, their innate life program does not include a reflex to the bright color of prey, which frightens other animals.
In addition, amphibians have an important hunting feature, which allows them and birds to complement each other in this joint activity. After all, birds that feed on insects hunt mainly during daylight hours and destroy pests active during this period. And many amphibians are able to restrain the excessive reproduction of representatives of many species of insects and mollusks, working at dusk and at night, when birds sleep. For example, an adult toad can eat up to 100 insects, their larvae and slugs in one night.
The advantage of cold-blooded amphibians
The activity of amphibians of various species is especially important in containing (together with birds) the excessive proliferation of invertebrate vegetation destroyers during difficult periods of cold weather and lack of food. After all, birds, being warm-blooded animals, cannot starve for long. Birds need to constantly maintain their body temperature at a level of 39-410C, and for this they must burn enough food in their “furnaces”. When it gets colder, the energy consumption of the bird's body increases sharply. To keep warm, birds need to increase their nutrition, but just at this time insects hide and become inaccessible. Therefore, the birds either die from exhaustion or try to fly to areas with better weather conditions. Even short periods of cold weather and lack of food cause especially serious damage to chicks. However, birds are given an amazing ability - to make long-term weather forecasts with great accuracy. In years when unfavorable living conditions are expected, including a decrease in the number of food items, birds lay fewer eggs than usual. As a result, when warming occurs and insects actively reproduce, feathered plant protectors become clearly insufficient. This is where all the benefits of the life activity of cold-blooded amphibians manifest themselves. Having easily survived the temporary cold snap and lack of food, they take revenge under favorable conditions. Amphibians begin to feed intensively, while curbing the excessive proliferation of plant pests.
In the diet of animals
Amphibians are not only consumers of food, but they themselves are objects of food. And thus amphibians are included in the general biological cycle. Among amphibians, the food items of various animals are mainly tadpoles and adult frogs. Tadpoles are eaten mainly by fish. Grown-up frogs are mainly eaten by birds, snakes, animals and large fish. After all, these amphibians do not hide in shelters during the daytime. They are fully equipped for active hunting of insects at this particular time. In addition, frogs are not provided with skin secretions with such protective properties as the caustic mucus of toads, toads, salamanders, etc. Frogs are consumed by a huge number of animals. First of all, these are many large predatory fish: catfish, pike perch, pike. For them, frogs and tadpoles are quite accessible mass food. The most common fish prey is the grass frog, which, in contrast to the green frog, lacks the behavioral mechanism of burying itself in mud for the winter. Therefore, it turns out to be the food link that expands the diet of fish at the expense of terrestrial food items. Many birds also feed on frogs, including storks, herons, crows, magpies, rooks, harrier gulls, terns, and grebes. For some of them, frogs make up a large proportion of their diet. Ornithologists estimate that at least 90 species of birds prey on frogs, 21 species prey on spadefoot spadefoots, and 18 species prey on toads. To a large extent, frogs provide nutrition for snakes. Small quantities of frogs are consumed by hedgehogs, minks, shrews, foxes, and otters. Toads are eaten by raccoons and raccoon dogs, badgers, and hori. In years when the main food of these animals is scarce, the role of amphibians as food items increases. By feeding on a wide variety of invertebrates, amphibians accumulate organic substances in their bodies, which can then be used by larger vertebrates. Thus, the purpose of amphibians is also to use their lives to support the lives of other animals during unfavorable periods.
The number of most species of frogs in all habitats intended for them is in a certain balance (despite the participation of various animals in the diet). It is mainly due to the enormous fertility of frogs, which quickly restores the losses incurred. In addition, amphibians are distinguished by the relative longevity of individuals. In that part of the amphibians that were destined to avoid danger and survive, several generations can exist side by side, regularly producing offspring of the same fertile amphibians.
Man and amphibians
Amphibians are extremely important animals for humans. Firstly, by feeding on small animals, amphibians, especially frogs and toads, restrain the mass reproduction of agricultural pests. Thanks to this, they, along with insectivorous birds, are included in the category of crop protectors, friends of gardeners and gardeners. Secondly, amphibians destroy insects that are carriers of human diseases, for example, malaria mosquitoes. Thirdly, amphibians are actively used for experiments by many generations of physicians, biologists and scientists in related fields. They helped make a lot of important scientific discoveries in biology and other sciences, including bionics. In addition, amphibians are amazingly touching, gentle and often very beautiful creatures. They admire the phenomenal capabilities of their body, graceful movements and complex behavior. Amphibians, like all living beings, require humane treatment and protection. Let's look at these questions in more detail.
"Utility coefficient" for a person
Living in a wide variety of places and feeding on insects and other invertebrates that are dangerous to plant life, amphibians bring great benefits to gardens, vegetable gardens, fields, forests and meadows (hayfields), and therefore to humans. Among pests that, if uncontrolled, can destroy almost the entire crop, insects occupy the first place. And the vast majority of frogs, toads, tree frogs and salamanders feed on them. In addition, these amphibians destroy countless numbers of slugs.
Scientists who studied the nutrition of our domestic amphibians once proposed a fairly simple formula for calculating the usefulness index for a person of a particular species:
V=t, where n is the number of animals eaten that are harmful to humans, u is the number of useful ones, t is the total number of animals eaten (harmful, beneficial and neutral, found in the stomach) and v is the coefficient of utility for humans.
For general guidance in this matter, the formula gives quite satisfactory results. “Utility coefficients” calculated using this formula as a percentage for some amphibians were as follows:
common newt - 98 lake frog - 50
tree frog - 66 toad - 49
sharp-faced frog - 46 crested newt - 11
grass frog - 59 Asia Minor frog - 27
spadefoot - 57 pond frog - 18
It should be borne in mind that the beneficial activity of amphibians for humans calculated using this formula is purely utilitarian. It fluctuates at different times and in different habitats. And of course, this formula does not reflect the importance of amphibians for ecosystems, biodiversity, etc.
A study of the food range of amphibians showed that they consume mainly insects harmful to plants. Due to the fact that in areas of mass reproduction there are more of them than other insects, in the stomachs of amphibians they make up 80–85% of all food eaten. Moreover, on the ground, insects are hunted mainly by salamanders and frogs. And tropical tree frogs and arboreal salamanders catch their prey on the branches of trees and shrubs. Their sticky tongue, which accurately hits the target, helps them grab insects on the fly. Glider devices help tropical copepods hunt. Unlike many birds, amphibians are capable of eating “inedible” insect pests with an unpleasant odor, taste and bright protective coloring. Some amphibians are able to catch insects and their larvae in the ground. Therefore, plants - from roots to crowns - can be completely protected by amphibians. They have been recognized as having an independent and quite significant role in the extermination of insects harmful to agriculture.
Toads have one important feature - they are the most active consumers of slugs, these nocturnal plant pests and practically omnivorous animals. Slugs destroy the harvest of rye and wheat, peas and carrots, cabbage and potatoes, and tobacco. It is easier to list the crops that they do not eat. Moreover, pests do this from early spring to late autumn, on open ground or penetrating greenhouses. They are especially harmful at the time of harvest ripening, when chemical treatment of plants cannot be carried out. This is where toads demonstrate their beneficial abilities for humans. At dusk, choosing a more secluded path and making small dashes, toads go out hunting. The benefits to people of their night hikes are enormous. In the United States, they have roughly estimated the cost savings that toads bring night after night to farming and forestry. It turned out that this is billions of dollars a year! And every year the profit from each toad is 20 - 30 dollars. The usefulness of toads was also highly appreciated in Europe. It is not for nothing that in the 19th century, for example, in Paris there was a special market where gardeners and peasants bought hundreds of toads to release them into vegetable gardens, fields and orchards. Thus, they saved a huge share of their harvest.
After metamorphosis is completed, juveniles, for example, green toads, leave the water and actively engage in hunting. It makes a significant contribution to the eradication of agricultural pests. Of course, young toads mainly consume small animals, which adult amphibians do not pay attention to. But the little caterpillar manages to eat a lot of greenery before it grows to a size where it becomes “interesting” as a food item for adult animals. Thus, juvenile amphibians enter the ecological niche along with older ones, preventing the enormous damage caused by small plant pests.
Those amphibians that eat disease carriers bring great benefit to humans. Newts play a special role in the destruction of mosquito larvae. The purpose of newts to regulate the reproduction of mosquitoes is due to the fact that the habitat of these amphibians, and most importantly their predatory larvae, is most often small and stagnant warm bodies of water. And they are also breeding grounds for mosquitoes. This food “predilection” of newts is of particular importance in areas of mass breeding of malaria mosquitoes, which carry a dangerous disease to people.
"Martyrs of Science"
Both the first observations of schoolchildren in the biology classroom, and the largest studies of biologists, doctors and other scientists are very often associated with the use of frogs. Most instruments in experimental biology and medicine are designed for these “martyrs of science.” In addition, it was the frog that, more than 200 years ago, gave rise to the development of one of the most important branches of knowledge - the study of electricity. The frog was also of interest for bionics. The purpose of these studies is to use biological knowledge about perfect and unique “devices” and “instruments” of living organisms to solve engineering problems and develop technology. For example, the common frog is endowed with an interesting feature. She practically sees only moving objects, which helps the amphibian to instantly react and grab prey. At the same time, her eye filters out information about stationary objects and tunes only to a moving target. The study of these features of the frog's eye made it possible to create the retinatron device. It does not react to stationary objects and provides observation of moving objects, such as an airplane.
In recognition of the invaluable benefits that modest amphibians brought to the development of world science, monuments are even erected to them. One of the most famous is installed in front of the Pasteur Institute in Paris. With money raised by medical students, a monument was created in Tokyo.
Man inflicts damage on amphibian tribe
The amphibian tribe cannot be seriously threatened by their traditional enemies. The ecological balance inherent in nature is not disturbed naturally. At the same time, some species of amphibians are on the verge of extinction, which is mainly due to the anthropogenic factor - rapidly expanding human economic activity, as well as the consequences of unwise recreation and tourism. The recent decline in the populations of the most beneficial tailless amphibians – frogs and toads – has been especially serious. But the purpose of these eternal workers is to maintain balance in nature. Therefore, the increasing pace of technological progress, direct and indirect impact
“Characteristics of amphibians” - I live in trees. Features of the development of amphibians. Deadlines. The name of the amphibian. Who is in the pond under the lush duckweed. Is it really impossible to love a toad? Toad. Signs. Table. Similarities and differences. Fish. Frog. Naturalists. Crossword. Amphibians. Biological task. Prize.
"Amphibians" - Moisture is absorbed and lost by amphibians through the skin. Caring for offspring. However, there are many intermediate forms. Circulatory system. Cave forms, such as proteas, are colorless, but sometimes acquire color in the light. Dependence on physical environmental factors. It is generally accepted that amphibians descended from lobe-finned fish and gave rise to reptiles.
“Class amphibians” - Legless. Amphibian class. External structure of Amphibians. Imprint of an amphibian from the Devonian period. Internal structure of Amphibians. 2 habitats Development in water External fertilization About 2500 species. Tailless squad. Ancient ancestors of Amphibians. Development of Amphibians. Worms. Tailed. Classification of Amphibians. Legless Squad.
“Structure of amphibians” - We will record the results of our work in “Worksheets”. Peculiarities of structure and life activity of primitive land animals." Hip. Legless squad. Skeleton of the hind limb. Exhalation. Circulatory system. Today we will learn about amazing animals that can live both in water and on land. Foot.
“Species of Frogs” - The digestive system of a frog. Description of appearance. I did. How many are there? Unlike fish, the frog has a cervical vertebra. Reproductive organs. Origin. The most interesting frogs. The sharp-faced frog (Rana arvalis) belongs to the class of amphibians. Nervous system of a frog. Habitat. Different kinds.
“Internal structure of amphibians” - Amphibians have a more complex internal structure compared to fish. Digestive system. Consolidation of new material. The internal structure is associated with the aquatic-terrestrial habitat. Respiratory system of amphibians. The circulatory system of amphibians. Lungs are small elongated sacs with thin elastic walls.
Ecological niche of amphibians
Amphibians are given a specific ecological “niche” - they are an important link in the food chains of humid land areas and aquatic biocenoses. Together with birds, amphibians take an active part in maintaining the natural ecological balance.
Sometimes living beings are classified into different groups, assessing the degree of their “usefulness” for their environment. In fact, there are neither “beneficial” nor “harmful” species in nature. Each species has its own ecological niche, position in food chains, place in the cycle of substances, etc. Each individual is a carrier of unique genetic information characteristic of its species. There is a close relationship between animal species. Moreover, each of them is endowed with its own usefulness for the biocenosis, which may not always be understood by us. Although representatives of some species may pose a certain danger to various members of the community - plants, animals, humans. This is especially evident when the ecological balance is disturbed (for example, during the “explosive” mass reproduction of insects or pathogens). In those natural biocenoses that include various types of amphibians, there are also no absolutely beneficial or harmful insects, birds, amphibians, plants, etc. Everything is an interconnected systemic whole. At the same time, amphibians play the role of protectors of the plant world. After all, the food items they need are basically dangerous to the life of many plants, especially with uncontrolled reproduction. At the same time, amphibians practically do not consume the main plant pollinators. Here the “wise interrelation of interests” is manifested 
» representatives of flora and fauna. The ecological niches of amphibians and birds, constituting single biocenoses, are also interconnected.
Regulators of ecological balance
Birds have a fairly wide range of food items, but it is amphibians that are considered universal plant protectors. Amphibians play an important role as regulators of ecological balance due to their omnivorous and unpretentious nature. For example, the diet of Russian northern frogs and toads includes locusts, weevils, bedbugs, bark beetles, leaf beetles and other beetles, including the most dangerous pest, the Colorado potato beetle. Amphibians destroy large quantities of cutworm caterpillars, moths, and slugs. The unpretentiousness of amphibians in terms of nutrition is also of great importance. They, in much greater numbers than birds, are able to eat insects with an unpleasant odor and taste, hairy caterpillars, and invertebrates with bright, repellent colors. The fact is that the amphibian body is equipped with excellent defense mechanisms against poisonous creatures. Therefore, in most cases, their innate life program does not include a reflex to the bright color of prey, which frightens other animals.
In addition, amphibians have an important hunting feature, which allows them and birds to complement each other in this joint activity. After all, birds that feed on insects hunt mainly during daylight hours and destroy pests active during this period. And many amphibians are able to restrain the excessive reproduction of representatives of many species of insects and mollusks, working at dusk and at night, when birds sleep. For example, an adult toad can eat up to 100 insects, their larvae and slugs in one night.
The advantage of cold-blooded amphibians
The activity of amphibians of various species is especially important in containing (together with birds) the excessive proliferation of invertebrate vegetation destroyers during difficult periods of cold weather and lack of food. After all, birds, being warm-blooded animals, cannot starve for long. Birds need to constantly maintain their body temperature at a level of 39-410C, and for this they must burn enough food in their “furnaces”. When it gets colder, the energy consumption of the bird's body increases sharply. To keep warm, birds need to increase their nutrition, but just at this time insects hide and become inaccessible. Therefore, the birds either die from exhaustion or try to fly to areas with better weather conditions. Even short periods of cold weather and lack of food cause especially serious damage to chicks. However, birds are given an amazing ability - to make long-term weather forecasts with great accuracy. In years when unfavorable living conditions are expected, including a decrease in the number of food items, birds lay fewer eggs than usual. As a result, when warming occurs and insects actively reproduce, feathered plant protectors become clearly insufficient. This is where all the benefits of the life activity of cold-blooded amphibians manifest themselves. Having easily survived the temporary cold snap and lack of food, they take revenge under favorable conditions. Amphibians begin to feed intensively, while curbing the excessive proliferation of plant pests.
In the diet of animals
Amphibians are not only consumers of food, but they themselves are objects of food. And thus amphibians are included in the general biological cycle. Among amphibians, the food items of various animals are mainly tadpoles and adult frogs. Tadpoles are eaten mainly by fish. Grown-up frogs are mainly eaten by birds, snakes, animals and large fish. After all, these amphibians do not hide in shelters during the daytime. They are fully equipped for active hunting of insects at this particular time. In addition, frogs are not provided with skin secretions with such protective properties as the caustic mucus of toads, toads, salamanders, etc. Frogs are consumed by a huge number of animals. First of all, these are many large predatory fish: catfish, pike perch, pike. For them, frogs and tadpoles are quite accessible mass food. The most common fish prey is the grass frog, which, in contrast to the green frog, lacks the behavioral mechanism of burying itself in mud for the winter. Therefore, it turns out to be the food link that expands the diet of fish at the expense of terrestrial food items. Many birds also feed on frogs, including storks, herons, crows, magpies, rooks, harrier gulls, terns, and grebes. For some of them, frogs make up a large proportion of their diet. Ornithologists estimate that at least 90 species of birds prey on frogs, 21 species prey on spadefoot spadefoots, and 18 species prey on toads. To a large extent, frogs provide nutrition for snakes. Small quantities of frogs are consumed by hedgehogs, minks, shrews, foxes, and otters. Toads are eaten by raccoons and raccoon dogs, badgers, and hori. In years when the main food of these animals is scarce, the role of amphibians as food items increases. By feeding on a wide variety of invertebrates, amphibians accumulate organic substances in their bodies, which can then be used by larger vertebrates. Thus, the purpose of amphibians is also to use their lives to support the lives of other animals during unfavorable periods.
The number of most species of frogs in all habitats intended for them is in a certain balance (despite the participation of various animals in the diet). It is mainly due to the enormous fertility of frogs, which quickly restores the losses incurred. In addition, amphibians are distinguished by the relative longevity of individuals. In that part of the amphibians that were destined to avoid danger and survive, several generations can exist side by side, regularly producing offspring of the same fertile amphibians.
