The extinction of some and the appearance of other species of animals occurs as part of evolution, with changes climatic conditions, landscapes, as a result of competitive relationships. Under natural conditions, this process is slow. According to calculations by D. Fisher 11976), before the appearance of man on Earth average duration The life of birds was about 2 million years, of mammals - about 600 thousand years. Man has accelerated the death of many species. It significantly influenced animals already in the Paleolithic, more than 250 thousand years ago, when it mastered fire. Its first victims were large animals. In Europe, as early as 100 thousand years ago, humans contributed to the extinction of the forest elephant, forest chough, giant deer, woolly rhinoceros and mammoth. In North America, about 3 thousand years ago, apparently not without human influence, the mastodon, the giant llama, the black-toothed cat, and the huge stork became extinct. The island fauna turned out to be the most vulnerable. Before the arrival of Europeans in New Zealand, the Maori, local residents, exterminated more than 20 species of huge moa birds. Early period The destruction of animals by humans was called “Pleistocene overfishing” by archaeologists. Since 1600, the extinction of species began to be documented. Since that time, according to the International Union for Conservation of Nature (IUCN), 94 species (1.09%) of birds and 63 species (1.48%) of mammals have become extinct on Earth. The death of more than 75% of mammal species and 86% of birds from the above number is associated with human activity.
Human economic activity has a strong impact on animals, causing an increase in the numbers of some, a decrease in the populations of others, and the extinction of others. Human impact on animals can be direct or indirect.
The direct impact (persecution, extermination and resettlement) is experienced mainly by commercial animals, which are hunted for fur, meat, fat, etc. As a result, their numbers decrease, and certain species disappear.
To combat pests of agricultural and forest plants, the relocation of animals from other areas is widely practiced. At the same time, there are often cases when migrants have a negative impact on new environment a habitat. For example, the mongoose, brought to the Antilles to control rodents, began to harm birds nesting on the ground and spread rabies. With the active or passive participation of humans, new species of animals were introduced and acclimatized to many countries and continents. They began to play an important role in the life of local nature and people. Especially many new species were introduced to Australia, New Zealand and the oceanic islands during the period of mass migration of Europeans to these then uninhabited countries. In New Zealand, with its poor fauna, 31 species of birds, 34 species of mammals, and several species of fish imported from Europe, Asia, Australia, America, and Polynesia have taken root.
In the former Soviet republics, work was carried out to acclimatize more than 137 species of animals. According to incomplete data, 10 species of insects, 5 species of fish and 5 species of mammals were introduced into the fauna.
The unintentional, random dispersal of animals has especially increased due to the development of transport, delivering them to various regions of the globe. For example, during inspections of aircraft at airports in the USA and Hawaii in 1952-1961. 50 thousand species of insects were discovered. A special quarantine service has been introduced at trade ports to prevent the accidental import of animals
Direct human impacts on animals include their death from chemical substances, used to control agricultural pests and weeds. In this case, not only pests, but also animals useful to humans often die. These same cases should include numerous facts poisoning of fish and other animals by fertilizers and toxic substances Wastewater discharged by industrial and household enterprises.
The indirect influence of humans on animals is associated with changes in the environment (during deforestation, plowing of steppes, draining swamps, construction of dams, construction of cities, villages, roads) and vegetation (as a result of pollution of the atmosphere, water, soil, etc.), when Natural landscapes and living conditions for animals are radically transformed.
Some species find favorable conditions in the changed environment and expand their range. Brownie and tree sparrow, for example, along with the advancement of agriculture to the north and east, the forest zone penetrated the tundra and reached the coast Pacific Ocean. Following deforestation and the appearance of fields and meadows, the habitats of the lark, lapwing, starling, and rook moved north into the taiga zone.
Under the influence of economic activity, new anthropogenic landscapes have emerged with specific fauna. The urbanized areas occupied by cities and industrial agglomerations have changed the most. Some animal species found in anthropogenic landscapes favorable conditions. Even in the taiga zone, house and tree sparrows, barn and city swallows, jackdaws, rooks, house mouse, gray rat, some types of insects. The fauna of anthropogenic landscapes has a small number of species and a high density of animal populations.
Most animal species, not adapting to the conditions changed by humans, move to new places or die. As living conditions deteriorate under the influence of human economic activity, many species of natural landscapes reduce their numbers. The bobak (Marmota bobak), a typical inhabitant of the virgin steppes, was in the past widespread in the steppe regions of the European part of Russia. As the steppes expanded, its numbers declined, and now it survives only in isolated areas. Together with the marmot, the shelduck duck, which nested in marmot holes, disappeared from the steppes, and has now lost its nesting sites. Cultivation of the land also had a negative impact on other indigenous inhabitants of the virgin steppe - the bustard and little bustard. In the past they were numerous in the steppes of Europe, Kazakhstan, Western Siberia, Transbaikalia and the Amur region, are now preserved in small numbers only in Kazakhstan and the south of Western Siberia. Shallowing of rivers, drainage of swamps and floodplain lakes, reduction in the area of sea estuaries suitable for nesting, molting and wintering of waterfowl, caused a sharp decline in their species. The negative impact of humans on animals is becoming increasingly widespread. To date, approximately 150 species and subspecies of birds have disappeared in the world. According to the IUCN, one species (or subspecies) of vertebrate animals is killed every year. More than 600 species of birds and about 120 species of mammals, many species of fish, amphibians, reptiles, mollusks, and insects are at risk of extinction.
The main and most ancient types of human influence on the animal world are hunting and fishing.
The direct impact of man on the animal world began in ancient times with hunting for food and clothing, that is, as an organic necessity. As hunting tools improved in a number of places, the number of certain animal species began to decrease noticeably. With the advent of firearms and the development of technology, hunting began to take on exterminatory proportions. Thus, over the course of 27 years, the Steller’s cow, endemic to these places, completely disappeared on the Commander Islands; in a short time, the passenger pigeon in North America was exterminated, the great auk disappeared, etc.
In 1604, Bennett began the walrus fishery because of their tusks. The extermination of walruses quickly spread to the Svalbard archipelago and began to move further east. On Bear Island alone in 1667, 900 walruses were killed in a few hours, and the carcasses were thrown away, although the meat, fat and skin could have been used. In 1923, more than a thousand tuskless walrus carcasses washed up on the shores of Cape Barrow, Alaska. The extermination of sea otters began in 1778 with the voyage of James Cook off the western shores North America. These defenseless animals were beaten with sticks in rookeries for their skins. On the Pribilof Islands in 1786, two men killed 5,000 sea otters.
Poaching with cars, machine guns and machine guns for saigas, goitered gazelles, bustards in Asia, antelopes and zebras in Africa has led to a sharp reduction in the number of many species of wild ungulates. Of all African animals, elephants and rhinoceroses suffered the greatest extermination. In 1920–1930 About 41 thousand elephants were killed annually. In 1957 in national park Tsavo in Kenya, during an anti-poaching campaign, 12.6 tons of ivory were confiscated, 1,280 abandoned elephant carcasses were discovered, and 230 kg of rhino horn were confiscated. By 1980, in Africa, despite bans, 60–70 thousand elephants were killed annually by poachers for ivory, and thousands of tons of edible meat are usually abandoned.
It does not fit into the framework of elementary human morality to conduct such safaris in Africa as wild mass executions of animals, after which the proud “hero” was photographed against the backdrop of a mountain of animals he had killed or trampling underfoot the piles of his victims.
How can we qualify the organizers and participants of the raid in the Isère department in France in 1954, when 5 police brigades, 3,000 hunters and one helicopter took up arms against one she-wolf with two cubs? And what can you call the show of a certain Cody, nicknamed Buffalo Bill, who, in front of the public from a specially arrived train, together with another shooter, drove across the prairie and shot bison to the admiring screams of the gawking crowd! On that day, 115 animals were killed for public consumption. The construction of the transcontinental railroad in the United States led to the rapid and almost complete extermination of animals. Railway stations temporarily became centers wild hunt For example, in the area of the village of Dodge City, 75 thousand bison were killed in 1873 alone, and in 6 years - 2.5 million heads.
Unfortunately, the history of human civilization from ancient times to our time is replete with events that do not at all decorate a person.
Thus, from ancient hunt As a means of obtaining the necessary food and clothing, with the development of technology and civilization, two main directions gradually emerged: “sport hunting” and fishing.
“Sport hunting” is essentially the deliberate killing, sometimes for the purpose of deliberately regulating the numbers of a particular species, but more often for the sake of self-affirmation, vanity or to satisfy the bloodthirsty instincts of the person himself.
Another direction of hunting is also developing - fishing: whaling, sea animals, fur hunting, fishing, etc. Although this direction in the extermination of animals has practical goals related to meeting human needs, however, widespread implementation modern technology led to a sharp decline in the populations of animals that became the object of this fishery. For example, the introduction of a motor whaling fleet led to the death of a large part of right whales and brought species of large minke whales to the brink of destruction.
Satisfaction of human needs is a conditional concept, because needs border on whim and sometimes imperceptibly turn into it. For example, the mass procurement of chum or pressed caviar is probably not generated by a vital human need and, although it does not seem to be a direct killing of animals, leads to a sharp reduction in the reproduction capabilities of this species. And a number of species from the salmon family (chum salmon, pink salmon, salmon, white fish, etc.) are classified as commercial fish, since their representatives have tasty and nutritious meat. This begs the question: which direction of fishing is more rational - the extraction of caviar or fish meat, given that from each kilogram of caviar tens of thousands of fish could be hatched, each of which would produce several kilograms of pure meat? Obviously, when deciding on the fishery issue, since on modern level development of consciousness, humanity is not yet ready to give up food of animal origin and the use various types animal raw materials on the farm, it is necessary to consider the possibilities of the most complete rational and cost-effective use of game animals.
In this regard, let's return to whaling. The bowhead whale was used most extensively by humans. Whale oil was consumed as food, used for lighting streets and homes, and in soap and leather production. After heat treatment (with hot water or steam), whalebone became suitable for stamping and acquired greater strength, so cases, canes, handles, fishing rods, springs for carriages and mattresses were previously made from whalebone plates; thin plates were used to make fans, bandages, dentures, knitting needles for umbrellas, plates for corsets, stand-up collars and crinolines; Clock springs were made from the best types of plates; Wigs, brushes, sieves and fishing lines were made from fringes and fibers of the middle layer. Whales were used especially extensively by northern peoples (Eskimos, Chukchi, Aleuts, etc.): fat, meat and part of the entrails were used as food for people and dogs, and waterproof clothing and containers for storing fat were made from the intestines; they sewed boats together with sinew and made ropes from them; whalebone was used to line sledges, bows, shovels, pikes, harpoons and thin spirals were made from it for laying in meat baits when hunting bears and wolves; stools were made from vertebrae; They built houses and fences from ribs and jaws, made frames for kayaks (light boats), etc.
Now many countries are abandoning whaling. For example, in the USA in 1972, a law was passed prohibiting citizens of this country not only from killing a sea animal, but even from being present when someone kills it. Despite the abandonment of whaling by a number of countries, throughout the globe, whalers kill tens of thousands of whales of all species every year, and in most cases, the use of whales is very incomplete compared to bowhead whales. Professor A.V. Yablokov believes that it is more profitable for us to switch to shepherding - not to send a flotilla to distant lands that will beat everything it comes across, but to graze a herd of 50 or even 30 whales, know them all by nicknames, character and age, and when this the whale turns, say, 30 years old, it will emerge from reproductive age and slaughtering him will not be harmful to the entire herd. By this point, it will be possible to prepare canning factories and obtain so much product that it will supply the entire Magadan region, for example, with whale meat and oil for 3-4 months. This is much more profitable than fishing, in which the products are inevitably not fully used.
Ridiculous fashion fads are leading to an increase in demand for a whole range of products of animal origin. The fashion for ostrich feathers on ladies' hats at the beginning of the century, which led to the mass extermination of ostriches, can hardly be attributed to urgent human needs. The same applies to the fashion for handbags, handbags, wallets, shoes and other products made of snake or crocodile skin. Tanneries process 2 million crocodile skins annually, resulting in several crocodile species being endangered; a fashionable coat made from a South American ocelot, for which 10 animals are killed, costs as much as three Mercedes cars; Predatory extermination of this animal led to a sharp reduction in its population. The population of the marsupial koala bear in Australia has greatly decreased due to women's fashion throw his fur over his shoulders. All this is generated not by the needs, but by the whims of man.
"Harmful" animals: The assessment of the “harmfulness” of this or that animal often turns out to be controversial and even erroneous, because in such an assessment much is relative.
The wild boar, from the point of view of farmers, is a harmful animal, since its raids on potato or oat fields cause damage, but for forestry the wild boar is useful, since in addition plant food destroys a number of forest pests, which has a positive effect on the condition of trees.
The history of man's relationship with birds of prey is interesting. In ancient times and the Middle Ages, people took care of birds of prey and loved them. In England and Denmark, for killing a falcon, a person could go to the executioner. Then birds of prey were declared harmful and they began to be exterminated. For example, in 1962, more than a million “harmful” birds were destroyed in the USSR. And of the 46 species of daytime predators in our country, only two (goshawk and marsh harrier) destroy game, and even then mainly sick and weak birds, thereby improving their populations. In addition, it is necessary to keep in mind that many birds and rodents eaten by raptors are carriers of serious diseases - plague, encephalitis, tularemia, leptospirosis, ornithosis, etc. Therefore, birds of prey turn out to be not enemies, but friends of humans. Only on August 1, 1964, Order No. 173 of the Main Directorate of Game Management and Nature Reserves was issued: “Taking into account new data on the biology of birds of prey and the significant benefits they bring in agriculture, hunting, forestry and health care, I order: to prohibit shooting, catching and destruction of nests all types of birds of prey and owls in hunting grounds common use throughout the entire territory of the RSFSR."
For a long time, the wolf was considered a harmful animal due to its attacks on sheep and other domestic animals. But the wolf more often hunts wild animals - deer, roe deer, improving their populations, since its prey is usually relatively weak and sick animals.
A similar situation has developed in Australia with regard to the wild dog dingo, which herders for a long time considered harmful and exterminated by all possible means. However, for Lately More and more farmers are convinced that dingoes, chasing a flock of sheep, turn out to be a stimulator of their better physical development: sheep, often pursued by dingoes, develop muscles with less fat content, their meat is more valued by consumers and turns out to be more economically profitable for farmers. On the other hand, dingoes are a means of selecting weak, sick and defective sheep and, ultimately, improving the health of the herd. Therefore, more and more farmers are abandoning the persecution of dingoes.
Giant red kangaroos that live on the plains of Australia began to multiply rapidly under the influence of human economic activity. These animals are undemanding to the weather and can go without water for a long time. In those areas where farmers created extensive pastures for livestock, the kangaroo population began to increase rapidly, so that there are now 4 kangaroos per inhabitant of Australia. The invasion of kangaroos into pastures and fields has forced farmers to carry out extermination raids on their herds. The German zoologist B. Grzimek, who studied the Australian fauna, proposes not to exterminate, but to breed kangaroos and use its meat in Food Industry, since it is nutritional value is in no way inferior to the meat of antelopes, deer and saigas. Thus, an animal can turn from “harmful” into useful for humans.
The usual attitude towards the fox is that it is a harmful animal that gets into village chicken coops and destroys many birds, hares and other animals in the forest. Prof. A. Gaber found only the remains of mice in 70% of the stomachs of a large number of foxes he examined killed by hunters.
Instructive story happened with sparrows in China. Since sparrows readily eat grain, they were declared enemy number one and a nationwide struggle was organized against them. Tens of millions of people took to the fields, chasing sparrows, preventing them from landing. Many birds fell dead, they were immediately loaded into trucks and taken away. There were no more sparrows. Soon the number of flies, mosquitoes and many other insects, which the sparrows ate as food and thereby restrained their reproduction, increased sharply. Only after the destruction of the sparrows was it established that they brought more benefit than harm. Bad experience.
Chemical effects on animals It can be direct - when a certain type of animal that is considered “harmful” is purposefully exterminated, and indirect - when there is an unprogrammed effect of pesticides on animals against which they were not intended, as well as when anthropogenic substances harmful to animals enter the biosphere. Both types of influence are often closely intertwined with each other.
In 1874, the German Zeidler invented a powder, the effect of which on insects was studied in 1937 by the Swiss chemist P. Müller, who received the Nobel Prize for this. By the end of World War II, this powder, called DDT in the USA (and known as dust in our country), began to be used in the army against lice, fleas, bedbugs and other insects. After the war, DDT became widespread throughout the world: it was mixed into lime, the walls of buildings were sprayed with it, and forests and swamps where mosquitoes lived were sprayed with it from airplanes. Enormous quantities of it began to be produced and used against agricultural pests. But already in 1947, insects began to appear on which this powder had no effect. A number of new pesticides were released, which began to be sprayed in increasing quantities instead of DDT. Some consequences were unexpected. As pests were destroyed, beneficial insects also began to disappear. Trees pollinated by insects stopped bearing fruit; insectivorous birds and fish, deprived of food in the form of insects and mosquito larvae, died in droves. In many areas, beneficial insects began to die, while harmful ones survived: bees immediately die from DDT, but it has no effect on the Colorado potato beetle and cabbage butterfly.
However, the use of pesticides is growing rapidly. Thus, during the period from 1950 to 1967, the use of pesticides in agriculture increased 3 times in the USA, and 22 times in Japan. At the same time, the arsenal of chemical means of influencing the biosphere is growing and a group of chemicals called “pesticides” - highly active toxic substances - appears. They include: insecticides (to kill harmful insects), rodenticides (to control rodents), bactericides (to kill bacteria that cause diseases of crops), herbicides (to kill weeds), fungicides (to control fungal pathogens) . The massive use of pesticides is caused by the fact that every year a significant part of the agricultural crops are killed by insects, rodents and other pests. By 1975, grain losses reached 85 million tons per year, which could feed 380 million people. This explains the desire of scientists to find radical means of combating agricultural pests.
The massive use of pesticides is accompanied by an increase in unprogrammed negative consequences. Thus, in 1960 in the Netherlands, hundreds of thousands of birds died after parathion was used against rodents. Similar consequences occurred in France, the USA and other countries: after mass spraying, at least 30% of local birds died. In a number of countries Western Europe After spraying the gardens, hares began to disappear; in the spring they fed on the grass near the trunks of the treated trees, which had been exposed to poison. In the California Valley, pesticides were used to kill lygus, an insect that caused enormous damage to cotton plantations. However, on the plantations they treated, by the end of the season, the bollworm, bollworm, and heliotis - other cotton pests - multiplied excessively, since broad-spectrum pesticides destroyed not only the bollworm, but also the natural enemies of the pests. There are many similar examples.
In 1962, Dr. R. Carson’s book “Silent Spring” appeared, in which she published data on the special persistence of pesticides, their ability to concentrate in food products and organisms. Pesticides in the soil were found in concentrations tens of times higher than when sprayed. The alarmed public prompted the US President to create a special committee to study the impact of pesticides on nature. In 1963, the committee presented a report in which it was noted, on the one hand, the great advantages of these pest control products, and on the other hand, that pesticides could be transported over enormous distances by wind, water and animals: they can be found in whale oil , in meat sea fish, in the organisms of Antarctic penguins.
Over the years, the massive use of pesticides has become accompanied by increasingly frequent cases of agricultural pests adapting to them. They began to develop resistance to the deadly effects of pesticides, and this immunity is passed on genetically to subsequent generations of pests. Thus, ants in the southern states of the United States developed immunity against dialdrin and heptachloran, while almost all beneficial insects died. Over the past decades, such immunity has already appeared in 200 species of insects harmful to agriculture, and the number of species of such arthropods is steadily growing.
Against agricultural pests that have developed immunity to pesticides, new ones began to be created. chemicals a narrower and more specialized range of effects. Thus, against rats and mice that have become immune to a number of pesticides, the drug “ratak” was created in England, containing chemical anticoagulants that disrupt natural blood clotting, and rodents die from internal hemorrhage. However, it is unknown how the human body will react if this new drug enters it with food.
A very serious negative side of the use of pesticides is their penetration through trophic chains into human food. For example, in Hungary, winter wheat seed is treated with mercury-containing fungicides. Before the seeds germinated, they were pecked by passing geese and due to poisoning, several hundred per day died. There is a danger of poisoning people due to shooting and eating the meat of such geese. A similar danger has emerged in the western United States, where a potent pesticide used in wheat fields was found in concentrations 20 times higher than safe levels in the bones of game birds, about which hunters were warned by health authorities.
Scientists of the Academy of Sciences of Tajikistan have established that out of 17 herbicides, insecticides and fungicides used for cotton, 5 have mutagenic activity. Humanity does not yet have sufficient coverage, density and information content to monitor the chemical composition and state of the biosphere. Unfortunately, the undesirable consequences of the uncontrolled use of pesticides affect not only those facilities where they are used. Their migration and accumulation can lead to disruption of the ecological balance of biocenoses and even to their destruction.
Total The amount of pesticides used annually on the planet exceeds 1 million tons, which on average is 0.07 kg/ha on the land surface, and in some areas up to 4 kg/ha. It is gratifying that in recent years the most toxic types of pesticides have been banned and withdrawn from use in a number of countries. Scientists are working on creating pesticides with a narrow spectrum of action - for example, action on reproductive system a certain insect, as well as pesticides that are not persistent under the influence of natural agents.
Last years Scientists are increasingly focusing their efforts on finding new ways to combat agricultural pests - without the use of pesticides. In this regard, a promising direction is use of biological protection.
A number of scientific institutions in the country and abroad are conducting research with entomophagous insects, which are natural enemies of plant pests. For example, in the biological laboratory of the Russian plant protection station in Ramenskoye, near Moscow, an experimental technological line on the mechanization of the processes of growing Trichogramma - a small insect similar to a winged ant. One female Trichogramma can destroy up to 30 eggs of pests - winter, cotton, cabbage, garden and other armyworms, corn and meadow moths, apple and pea codling moths, etc. They are also working with the predatory Gallicia fly - the enemy of the melon aphid, with the phytosailus mite, protecting greenhouse cucumbers with lacewing from pests.
Scientists at the Institute of Forest and Wood of the Siberian Branch of the Russian Academy of Sciences used bacteria to prepare a new drug “infectin” against Siberian silkworm, the reproduction of which has been stopped in many areas of Siberia, as well as against pests of cotton and orchards in Central Asia and Moldova. Tests have shown the drug to be harmless to people, animals, birds and beneficial insects. Siberian enterprises have started producing this drug.
The Institute of Biology of the Academy of Sciences of Latvia has found a way to use one of the types of microscopic fungi, the spores of which grow into agricultural pests (aphids and spider mites), destroying living tissue these insects. The spray preparation, created on a fungal basis, is safe for animals, birds and beneficial insects.
Zoologists in Singapore have bred, through targeted selection, tiny carp that feed almost exclusively on mosquito larvae in shallow waters. The first generation of these fish, which have an enviable appetite, has already led to a sharp reduction in the test areas of mosquitoes - dangerous enemies of people and animals in tropical countries.
The direct impact of humans on the animal world is also human resettlement individual species animals to new habitats, and such relocations can affect not only the animal world itself, but in some cases have much broader consequences.
In 1868, the Frenchman Trouvelot, in order to obtain new types of silk from cocoons gypsy moth ordered gypsy moth eggs (eggs) from Europe to the area of Medford, Massachusetts. The silkworm acclimatized well and began to multiply quickly. Eating all the foliage on the trees, the caterpillars crawled into houses in search of food and ate the leaves. indoor plants, causing a lot of trouble to the inhabitants of apartments and houses: they climbed into bed, clothes, exuding an unbearable smell with their bodies and excrement. Domestic and wild animals starved and died from lack of food. People also began to starve due to difficulties with the supply of food: train wheels crushed the thick layer of tracks on the rails, locomotives skidded. People began to move from the area captured by the caterpillars, burned forests infested by them, and cleared roads and homes with fire and caustic liquids. In less than 40 years, the caterpillars covered an area of 11 thousand miles 2. Only after natural enemies of the silkworm were specially brought to America was its aggression limited.
In the 19th century, a large (up to 25 cm long) Achatina snail was exported from the island of Madagascar as a supposed cure for tuberculosis. With human participation, it came to India, Sri Lanka, the Malay Archipelago, the Marquesas Islands and California. The voracious snail caused enormous damage to sugar cane, tea and rubber plantations. They collected it, burned it, tried to drown it in the sea, poisoned it with toxic chemicals, and destroy it in the millions every year, but the struggle continues to this day.
The story of the migration of rabbits to Australia is widely known. Pigs brought to many countries by humans have also found their way to New Zealand. There, released into the wild, they went wild and, becoming addicted to eggs, sharply reduced the populations of a number of species of flightless birds, and the hatteria lizard survived only on small islands on the coast, where pigs did not penetrate.
The opossum was brought there from America. This good-climbing animal liked to eat the tops of trees, which is why in its habitat the trees have shortened, twisted, branching trunks that are unsuitable as building material, which leads to great losses. In addition, possums cause damage to the energy sector: by climbing on poles and swinging on wires, they cause wire breaks and short circuits.
The mongoose was introduced to a number of tropical islands to combat rats and snakes. In Fiji, mongooses have sharply reduced the number of ground-nesting birds, especially the rails and gallinaceans, as well as the Fijian iguana. In Cuba, mongooses have almost completely exterminated the endemic slittooth, and the number of species of non-venomous snakes has decreased.
The raccoon dog was introduced into some areas of our country. It quickly took root and began to destroy the nests and eggs of grouse birds and also turned out to be a carrier of the rabies virus. We had to take measures to reduce the number of this animal.
There are, of course, also known cases of human importation of certain species of animals, which turned out to be successful, without serious consequences, for example, the importation of muskrats to Russia, certain insects to California and Georgia to combat citrus pests, etc. Nevertheless, there are numerous cases of unsuccessful human relocations of individual species of animals convince us of the need for a preliminary comprehensive study of the consequences that may occur as a result of such an experiment.
Relocation of certain animals not programmed by man also happens, although with his participation. Thus, together with the nomads from Asia, the black cockroach came to Europe. Insufficient customs control created the opportunity for the Colorado potato beetle in the holds of ships, along with potatoes, to cross the ocean and get from America to Europe, from where it gradually moves east.
In the 60s, a small deer bloodsucker was discovered in the Moscow region, which appeared in connection with an unsuccessful attempt to acclimatize deer here: the deer did not take root, but the bloodsucker thrives on moose.
The Smirnova beetle arrived from Kenya with cargo to Europe; Now it is found in large quantities in apartments in Moscow, St. Petersburg, Sochi, Sverdlovsk and a number of regions of Western Europe.
In the 50s Black Sea coast In the Caucasus, a Japanese leafhopper was discovered, which was accidentally introduced with some plants from Japan and has now become a serious pest of cultivated plants in the Caucasus.
Has a huge impact on animals economic activity zeros. Deforestation, plowing of land, use of fertilizers and pesticides worsen the living conditions of animals. These conditions change with the draining of swamps, the creation of dams and irrigation systems, the development of mineral resources, and the construction of cities and transport highways. In all of these cases, humans have an indirect impact on animals by changing their habitat.
The direct influence of humans on animals is also great. Excessive hunting has led to the extinction of many animal species. For example, in just 27 years (1741-1768), the Steller's cow (Fig. 15), a sedentary and trusting sea animal that fed on algae in the shallow waters off the Commander Islands, was destroyed. Unfortunately, the animal had delicious meat and he was easy to hunt.
Rice. 15. Steller's cow
By the middle of the 18th century. Large (weighing up to 20 kg) flightless pigeons, the dodo, which lived on the Mascarene Islands, disappeared. The birds nested on the ground, so great harm they were brought by domestic animals brought by Europeans - dogs, cats, pigs, which ate eggs and chicks.
One of the most numerous birds in North America is the passenger pigeon (Fig. 16). It nested in trees in large colonies. Flocks of pigeons reached millions of individuals. The mass extermination of passenger pigeons by European settlers began in the 17th century. Birds were shot, caught in nets, and knocked down with sticks. Pigs were released at the sites of massacres to eat killed birds and chicks that had fallen from their nests. By the end of the last century, passenger pigeons had become rare, but no one could believe it. The last passenger pigeon died at the Cincinnati Zoo (USA) in 1914. Now a museum has been opened in this city. dedicated to the passenger pigeon. This is a sad example of man's deliberate destruction of a once thriving species.
Rice. 16. Passenger Pigeon
The list of animals exterminated by humans is extremely long. It includes the zebra quagga, marsupial wolf, European ibis. In southern Europe, Western Siberia, Kazakhstan and Central Asia, the wild horse, the steppe tarpan, has disappeared (Fig. 17). Before mid-19th And. this species was still found in the Black Sea steppes. The last free Tarpan was killed in 1879, and in captivity, at a stud farm, lived until 1918. Now this wild ancestor of modern horses is no longer on Earth. The forest tarpan was also exterminated. Apparently, Przewalski's horse has also disappeared from nature by now.
Rice. 17. Steppe Tarpan
The fauna of Australia, New Zealand, and the ocean islands have suffered especially hard from the direct and indirect impact of people. There, many species were on the verge of extinction due to human fault. Realizing that the disappearance of any animal species is an irreparable loss, people began to protect rare species and take care of preserving the number of game animals. In 1966, the World (International) Union for Conservation of Nature and natural resources The Red Book was published containing a list of rare and endangered species of animals. Red color is an alarm signal.
The Red Book contains information about rare species - their distribution, numbers, causes of their plight and conservation measures. This information is updated regularly. Subsequently, Red Books of rare animal species from different countries were created. There is a Red Book of Rare Species of Animals of the Russian Federation. Each country is responsible for the conservation of species listed in the Red Book to its people and all humanity. Naturally, causing any harm to such animals is a crime.
To preserve rare animals, their habitat and the entire natural complex, biosphere, state, and republican reserves have been created. So. in Russia, in the Volga delta, since 1919 there has been an Astrakhan reserve for the protection of nesting places of rare aquatic and semi-aquatic birds and their habitats. During their migrations, northern birds stop here to rest and feed.
In cases where the number of a species in nature becomes so low. that he himself cannot recover, he is bred in captivity, and then released into natural environment a habitat. This is what they did with the California condor. It is now bred in several zoos and then released in those places where condors lived before. Scientists are monitoring how released birds feel. In our country, several nurseries have been created for breeding noble falcons (saker falcons, peregrine falcons) and other birds of prey. There is a nursery for birds of prey in the Galichya Gora Nature Reserve in Lipetsk region, cranes are bred in the Oksky Nature Reserve.
Rational use and protection of wildlife are the most important state and public tasks, caring for our national heritage.
Exercises based on the material covered
- Give examples of the negative impact of humans on the number and diversity of animals.
- Name those animals that have disappeared as a result of human activity.
- What measures are being taken in our country and in the world to preserve rare animals?
Direct- human impact directly on individuals of the species (hunting, use of chemicals, feeding birds in winter).
Indirect- when a person does not touch the animals themselves, but changes their habitat and thus influences this type(draining swamps and mowing meadows). The consequences of the second type are much more dangerous, since it affects many species of organisms living in a given area. The plowing of virgin lands and deforestation leads to a sharp reduction in the ranges of many wild ungulates, and this leads to a reduction in the number of predators and an increase in the number of rodents.
Reckless interference in the life of a biocenosis can lead to quick and unpleasant consequences.
The destruction of sparrows in China contributed to an increase in the number of insect pests, the elimination of wolves in the northern Canadian territories initially led to an increase in the number of deer, but then to the spread of diseases among them and a sharp decline in their numbers.
The main threats to biological diversity resulting from human activities are habitat destruction, fragmentation and degradation, including pollution, global climate change, overexploitation of species by humans, invasion exotic species and the increasing spread of disease. About a third of all mammals in Russia are listed in the Red Book (Fig. 2), which means that saving them will not be easy.
Rice. 2. Red Book of Russia ()
True, there are examples when it was possible to restore the number of some animals, for example, the number of saiga, sable, beaver, fur seal(Fig. 3).
Rice. 3. Animals that are experiencing an increase in numbers ()
Fishing- direct removal of organisms by humans from nature. This is the most ancient form of human influence on the animal world. Trades are named after the organisms or products they produce: hunting, fishing, fur fishing, crab fishing, sea cucumber fishing, and so on. There are groups of animals that are considered commercial animals. Any fishery can be successful only if the biology of the game animal is understood. To do this, one condition must be met - the number of hunted animals must be constantly restored through reproduction.
Habitat disruption due to deforestation, plowing of steppes, drainage of swamps, creation of reservoirs and other anthropogenic impacts radically changes the breeding conditions of wild animals and their migration routes, which has a very negative impact on their numbers and survival.
In our country, fishing for some animals is completely prohibited due to the need to protect them, for example whales and dolphins.
The domestication of wild animals and their transformation into domestic ones began millions of years ago. Excavation of settlements primitive man proved that before other animals, back in the Mesolithic era, the dog was domesticated, later the pig, sheep, goat, and only then the horse. There are no more than twenty-five domestic animal species. For domestication, it is necessary for the animal to bear offspring, and then make a selection and, preserving individuals with the most valuable properties, get a real domestic animal after a few hundred years. The domestication of animals is carried out at the present time, work on domestication is known capercaillie, bustard And moose(Fig. 4), in addition, in different time and domestication work is being carried out in different places muskox, deer, eland(Fig. 5).
Rice. 4. Species that are undergoing the process of domestication ()
Rice. 5. Species that are undergoing the process of domestication ()
Work is underway to domesticate mink, arctic fox, quail, pheasant (Fig. 6), as well as silver carp and grass carp (Fig. 7).
Rice. 6. Species that are undergoing the process of domestication ()
Rice. 7. Types of fish that are undergoing the process of domestication ()
The domestication of wild animals took place in different ways. There was also a natural rapprochement between man and animal, when animals gradually got used to being near human habitation. Man and animals were neighbors, they existed next to each other. There was also forced domestication, when people caught wild animals and kept them in captivity. In the process of domestication, under the influence of new environmental conditions, animals developed characteristics that distinguish them from wild ones. The size and shape of the body changed, for example, in a pig, sheep, horse. This had the least impact on animals such as camels and reindeer, whose living conditions in captivity are close to natural.
Nowadays people even use insects - bumblebees and flies. The first is for pollinating greenhouse plants and the second is for recycling manure on pig farms and obtaining animal protein. These insects are no different from wild forms and, of course, cannot be considered domestic; real domestic animals are the honey bee and the silkworm (Fig. 8).
Rice. 8. Domestication of bees and silkworms ()
The domestication of animals is a long process, it is believed that the domestication of reindeer and dogs occurred eighteen thousand years BC, sheep were domesticated eight thousand years ago, goats and pigs - six and a half thousand years ago, cows - five thousand years, and silkworm - four and a half thousand years ago.
Domestication took place in natural habitats: horses - in the steppes of Eurasia, chickens - in India, guinea fowl - in Africa, turkeys - in America, ducks and silkworms - in China, pigeons, geese and cats - in Egypt.
Domestication of pigs, horses and goats occurred independently in several places in the range. After domestication, the spread of animals was facilitated by trade, wars, and accidental introductions. The relocation of animals from one place to another did not always benefit nature and people. There are many known disasters caused by such relocations: rabbits and cats brought to Australia destroy the local flora and fauna, goats North Africa, Spain and Turkey can destroy entire forests.
The domestication of animals involves its further development and selection. Breeds that are interesting to humans are selected, the absence of aggression plays an important role, most often the selection is for the production of some kind of product - eggs, meat, milk, wool, fur. The domestication of an animal radically changes the conditions for the further development of the species. Natural evolutionary development is replaced by artificial selection based on breeding criteria, thus changing the genetic properties of the species as part of domestication.
Animals have developed characteristics that distinguish them from wild ones, and the more significant, the more work and time a person spent on obtaining animals with the properties he needed. The size and shape of the body have changed to the greatest extent in animals whose living conditions are very different from those wild habitat(large cattle, pigs, sheep, horses) and to a lesser extent in animals such as camels and reindeer, whose living conditions in captivity are close to natural. The so-called protective coloring has disappeared; Pets come in a variety of colors. Compared to wild animals, they have a lighter skeleton, less strong bones, and thinner skin. Has undergone changes and internal organs. Many domestic animals have less developed lungs, hearts, and kidneys, but their mammary glands and reproductive organs function better than wild ones (domestic animals, as a rule, are more fertile); many of them have lost seasonality in reproduction. Most domesticated animals are characterized by a decrease in brain size and a decrease in reactivity nervous system, simplification of behavioral reactions, changes in the phenotypic expression of mutations under the influence of an altered gene pool, a general increase in variability.
We discussed the human impact on the animal world and the domestication of animals. Domestication of wild animals on a par with cultivation useful to people plants had great value in development human society. Human-created breeds of domestic animals and varieties of cultivated plants have become important new means of producing food and raw materials for the manufacture of clothing, shoes and other items.
Bibliography
- Latyushin V.V., Shapkin V.A. Biology Animals. 7th grade. - Bustard, 2011.
- Sonin N.I., Zakharov V.B. Biology. Diversity of living organisms. Animals. 8th grade. - M.: Bustard, 2009.
- Konstantinov V.M., Babenko V.G., Kuchmenko V.S. Biology: Animals: Textbook for 7th grade students educational institutions/ Ed. prof. V.M. Konstantinov. - 2nd ed., revised. - M.: Ventana-Graf.
Homework
- What types of impacts on fauna do you know?
- What contributes to the domestication of animals?
- For what purpose does man domesticate insects?
- Internet portal Worldcam.ru ( ).
- Internet portal Alfares.ru ().
- Internet portal Worldofanimals.ru ().
Human activity is a powerful factor influencing the animal world. The ancient Paleolithic man was already engaged in hunting, exterminating now extinct animals - the mammoth and the woolly rhinoceros, the remains of which were discovered at sites. Wild animals, birds and fish provided people with food, material for clothing, shoes and some household items. Most active influence humans on animals begins from the time when people began to eat meat. As F. Engels points out, the use of meat food led to the use of fire and the domestication of animals. As hunting tools improved and some animals were domesticated, human influence on the animal world increased. This influence mainly went in two directions: through the direct destruction of animals and their domestication and changes in other components of natural complexes, especially vegetation. With the transition to cattle breeding, and in the Neolithic era to agriculture, the forms of influence on the animal world became more complex and expanded.
Consequently, as the process of social production developed, human influence on nature, including the animal world, increased. Our forest-steppes in this regard, perhaps, represent the most striking example of the strong transformative influence of man on natural systems, and in particular on the animal world. Chapsky K.K., citing a number of sources, writes that in 1389, during the “third visit of Metropolitan Pimen to Tsar Grad,” travelers, describing the nature of the area along the banks of the Don, indicated: “. . . There are many animals: goats, moose, wolves, foxes, otters, bears, beavers and birds, eagles, geese, swans, cranes and others. . . " In the steppes there were numerous paths laid by herds of tarpans - wild horses, bison, and deer. “Wild goats (roe deer) migrated in countless numbers to the forests for the winter and returned to the steppes for the summer.”
From the chronicles we know about the enormous role of hunting in the life of the Slavs and other peoples who inhabited the forests. The skins of fur-bearing animals, especially beaver, sable, and marten, were used to collect taxes and tributes from the population. Historian N.M. Karamzin wrote that soon after Ermak’s conquest of Siberia, in 1586, “The Moscow sovereign imposed yasaka on the Siberian kingdom, and on Konda the Greater, and on the Konda Lesser, and on the Pelym state, and on Tura, on the Irgiz state , and on the Ob Great, and on all the Ob towns, 200 thousand sables, 10 thousand foxes and 500 thousand squirrels.” Tsar Fyodor Ivanovich in 1594 sent 40,360 sables to Vienna as chain aid for the war with Turkey.
The main threats to biological diversity resulting from human activities are habitat destruction, fragmentation and degradation (including pollution), global climate change, human overexploitation of species, invasion of exotic species and the increasing spread of disease. Most threatened species face at least two or more of these challenges, which accelerate their extinction and hamper efforts to protect them.
All of these seven threats are caused by the ever-increasing use of natural resources with an exponentially growing human population. Until the last few hundred years, population growth was relatively slow, with birth rates only slightly exceeding death rates. The biggest destruction biological communities occurred over the past 150 years, when the world's population grew from 1 billion people. in 1850 to 2 billion people. in 1930, and on October 12, 1998 amounted to 6 billion people. According to estimates, by 2050 it will reach 10 billion people. The population increased as the birth rate remained high and the death rate fell as a result of both modern medical advances (especially disease control) and increased food production. Population growth has slowed in industrialized countries, but is still high in many regions of tropical Africa, Latin America and Asia—the regions with the greatest biological diversity.
Population growth itself is partly responsible for the loss of biodiversity. People use natural resources (fuelwood, game, wild plants) and convert huge amounts of natural habitats to agricultural and urban lands. Some scientists argue that controlling population growth is key to preserving biodiversity. But population growth is not the only reason species extinction and habitat destruction.
In many cases, habitat destruction is caused by large-scale industrial or commercial activities associated with global economy and profit-oriented: mining, livestock farming, commercial fish farming, forestry, plantation Agriculture, manufacturing industry, dam construction. Many such projects are sanctioned, approved and even subsidized by governments and international development banks and are compulsively justified in terms of job creation, goods production and tax revenue. However, the use of natural resources often turns out to be both ineffective and unprofitable, since projects are focused only on obtaining short-term benefits. Such profits come at the cost of long-term disruption to the sustainable existence of natural resources and, as a rule, do not reach the local population.
The world's uneven use of natural resources is also responsible for the destruction of biodiversity in the species-rich tropics. People in industry developed countries(and a wealthy minority in developing countries) consume a disproportionate share of the world's energy, minerals, forests and food. Average resident The US consumes 43 times more gasoline each year, 34 times more aluminum and 386 times more more paper than the average Indian. This depleting consumption of resources cannot continue for long. If a growing child wants to live in a similar way middle class in developing countries, this will lead to even greater environmental destruction. Influential wealthy citizens in developing countries should rein in this depleting consumption of resources and organize their lives in ways that help curb population growth and protect biodiversity.
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