The role of fire in human life. The Importance of Using Fire Fire is a reliable defense against predators.

It is difficult to imagine the life of a modern person without the use of fire. Thanks to him, people live in comfortable conditions - in warm houses, lighted rooms, eat delicious food and use objects created with the help of fire every day. The process of obtaining and subjugating the fire was very complex and lengthy. Thanks to the ancient man, we can use this resource.

The role of fire in the life of primitive man

One and a half million years ago, man was able to subdue fire. Ancient man was able to create himself lighting, a warm home, delicious food and protection from predators.

The taming of fire by man is a rather long process. According to legends, the first fire that a person could use was heavenly fire. The phoenix bird, Prometheus, Hephaestus, the god Agni, the firebird - they were gods and beings who bring fire to people. Man deified natural phenomena - lightning and volcanic eruptions. He made fire by igniting torches from other, natural ignitions. The first attempts to produce fire gave a person the opportunity to warm up in winter, illuminate territories at night and defend against constant attacks of predatory animals.

After long-term use of natural fire, a person had a need to independently extract this resource, because natural fire was not always available.

The first way to get a flame was by striking a spark. A man watched for a long time how the collision of some objects causes a small spark, and decided to find a use for it. For this process, people had special devices made of prismatic stones, which were firefighters. The man hit the fires with rough prismatic knives, causing a spark. Later, the fire was produced in a slightly different way - they used flint and flint. Flammable sparks set fire to moss and fluff.

Friction was another way of making fire. People quickly rotated dry branches and sticks inserted into a tree hole between their palms. This method of extracting the flame was used by the peoples of Australia, Oceania, Indonesia, in the Kukukuku and Mbovambov tribes.

Later, man learned to make fire by drilling with a beam. This method made life easier for the ancient man - no longer had to put a lot of effort, rotating the stick with your palms. The burning hearth could be used for 15 minutes. From it, people set fire to thin birch bark, dry moss, tow and sawdust.

Thus, fire played a leading role in the development of mankind. In addition to the fact that he became a source of light, warmth and protection, he also reflected on the intellectual development of ancient people.

Thanks to the use of fire, a person had a need and an opportunity for constant activity - it had to be obtained and maintained. At the same time, it was necessary to ensure that he did not transfer to the houses and was not extinguished by a sudden downpour. It was at this point that the division of labor between men and women began to take shape.

Fire served as an indispensable tool in the manufacture and processing of weapons and utensils. And most importantly, he gave man the opportunity to develop new lands.

The role of fire in the life of a modern person

The life of a modern person cannot be imagined without fire. Almost everything that people use is based on fire. Thanks to him, the houses are warm and light. A person daily uses the energy of fire in everyday life. People cook, wash, clean. Light, electricity, heating and gas - all of this would not be possible without a small spark.

The energy of fire is also used in various enterprises. In order to make a car, an airplane, a diesel locomotive and an ordinary fork, metal is needed. It is with the help of fire that a person extracts it - melts the ore.

An ordinary lighter burns using a slightly modified method of ancient people - improved fire. Gas lighters use a mechanical spark, while electric lighters use an electric spark.

Fire is used in virtually every human endeavor - ceramics, metallurgy, glass making, steam engines, the chemical industry, transportation, and nuclear power.

The significance of fire in the life of mankind at all stages of its existence deserves a separate discussion. For half a million years now, fire has become an indispensable attribute of human life. In those infinitely distant times, its practical significance was enormous. Fire is the most reliable defense against predators. Fire is a source of heat, which made it possible to fry meat, bake fruits and roots. And, finally, fire is an important means of processing wooden tools (both spears and cudgels began to be burned for strength three hundred thousand years ago) ...

However, he played an equally important role in strengthening purely human, social relations. Sacred fire is a symbol of the unity of the collective, the source of its strength, a wayward friend and guardian. He must be loved and cherished and be careful with him, so that his violent power does not turn against the person himself. "The warmth of the hearth" - how far into the depths of human history this concept goes! It is familiar to all of us, although our homes have long been heated not by hearths, but by central heating batteries and electrical appliances. But, perhaps, that craving for fire, for a living flame, which makes modern people build fireplaces in their apartments, extinguish electricity and light candles on a festive table, gather around campfires, leads to even deeper antiquity.

By the time of the appearance of the Upper Paleolithic tribes of mammoth hunters, mankind had long known fire and perfectly mastered the main methods of its production. Judging by ethnographic data, there were three such methods: "fire plow", "fire saw" and "fire drill".

The first method is the simplest and fastest, although it requires a lot of effort: the end of a wooden stick is driven over a wooden plank lying on the ground with strong pressure - as if "plowed". A narrow groove is formed, and in it there is wood powder and thin shavings, which, from heating with friction, begins to smolder. A highly flammable tinder is connected to it and a fire is fanned. This method is relatively little widespread; most often it was used on the islands of Polynesia (Charles Darwin learned it from the inhabitants of the island of Tahiti). It was occasionally used by Australians, Tasmanians, Papuans, and some backward tribes in India and Central Africa, although other methods were preferred everywhere here.

"Fire saw" has many varieties, but they all boil down to one principle: a soft dry piece of wood lying on the ground, as it were, "sawing" across the grain with a piece of hard wood. Interestingly, the Australians, who quite often resort to this method, use a wooden shield as a base, and a spear thrower as a saw. Then everything happened in the same way as during "plowing" (only there the work was carried out along the fibers): wood powder was formed and ignited. Often, with this method, tinder was placed in a previously prepared gap. Sometimes, instead of a wooden plank, a flexible plant cord was used as a "saw". This method was used in Australia, New Guinea, the Philippine Islands, Indonesia and in some places in India and West Africa.

Drilling is the most common firefighting technique. It is as follows. A small plate with a pre-carved recess is placed on the ground and clamped with the soles of the feet. The end of a hard stick is inserted into the recess, which is quickly rotated between the palms, with simultaneous downward pressure. This is done so skillfully that the hands, involuntarily sliding down, periodically return to their original position, and the rotation does not stop and does not slow down. A few minutes later, smoke appears from the depression, and then a smoldering light, which is blown up with the help of tinder. This method is common in almost all backward peoples of the Earth. In an improved form, a stop is attached to the rod from above, and a belt is attached to the sides, which is alternately pulled by the ends, driving the drill into rotation. By attaching a small bow to the ends of such a belt, we get the simplest mechanism, quite common in primitive times: a bow drill. Not every modern person is able to make fire by rotating a wand between his palms: great skill is needed here, even when the starting materials are well chosen. But with the help of a bow drill, this, apparently, is available to many ... Try it yourself, just remember: the board should be made of soft and dry wood, and the stick should be made of hard wood.

But what about the carving of fire by striking flint on flint? It would seem, observing the sparks arising from the splitting of flint, it would be easier for people to think of such a method of producing fire than to invent rather complex operations with wood. Some scholars think so. BF Porshnev, for example, believed that the cutting of fire, which arose in the process of making stone tools, preceded the methods of obtaining it by friction. The same point of view was held by the English archaeologist C.P. Oakley. However, ethnographic data suggest otherwise.

The most backward peoples in the 19th century produced fire everywhere by friction, while striking fire (especially by striking flint on flint) was very poorly spread among them. On the other hand, peoples at a higher stage of development produced fire mainly by carving (with flint on iron or iron ore - pyrite). Sometimes they also used friction - but only for ritual, cult purposes. And experiments show that although a spark is constantly formed when a flint strikes a flint, it is quite difficult to "turn" it into fire, while the kindling of a flame by friction is accessible, with a certain diligence, even to a modern person.

It is possible, however, that in some cases people really first learned to strike fire, and only then began to produce it by friction. At least in the language of one of the South American Indian tribes, the term for making fire comes from the word "blow-cutting." This clearly speaks of some old (perhaps really original!), And later forgotten tradition. I say “forgotten” - because even here, until recently, friction was again the main method of making fire. However, this is the only exception.

Mammoth Hunter Hearths

Primitive peoples are distinguished by their great skill in keeping and maintaining fire. Here is what, for example, the famous Russian ethnographer N. A. Butinov writes about the Australians: “The Australians are very skillful in arranging and maintaining a fire, it burns evenly, not giving a large and too bright flame. They laugh at the European colonists, who make such big fires that it is dangerous to approach them, but they are of little use, and they do not know how to support them for a long time. On the contrary, by his little fire, the Australian sleeps peacefully all night, and bakes and roasts food on it. "

There is no doubt that people have mastered this art a very long time ago. Evidence of this is the remains of fireplaces and hearths found by archaeologists. Particularly interesting and varied are the foci in settlements dating from the second half of the Upper Paleolithic, primarily in sites with long-term dwellings. Here, along with simple hearths, which are a bowl-shaped depression filled with ash and coal, there are much more complex structures. Stone covering of hearths has been used for a long time; It is also known in some centers of the Willendorf-Kostenko culture of mammoth hunters (Zaraiskaya site, upper cultural layer). In other monuments of this culture, besides the cladding, clay was applied. In the same place where the ceramic animal figurines were made (Dolny Vestonice, Kostenki 1/1), individual hearths with clay coating resembled the simplest furnaces.

Small pits were dug in the ground in the immediate vicinity of many Upper Paleolithic foci. Some of them were used for baking food, others served as supports for the posts (sometimes there are vertically protruding bones in them that jammed these posts). Now we install a crossbar on such supports, on which we hang the kettle in order to boil tea or cook fish soup, and then they could serve as the basis for skewers on which meat was fried.

Grooves have been dug at the base of some of the hearths. Sometimes such a groove left the hearth to the side. What for? Petersburg archaeologist Pavel Iosifovich Boriskovsky, who found such a hearth during the excavation of the Kostenki 19 site, which existed about 20 thousand years ago and was also abandoned by mammoth hunters, suggested that air entered the hearth through such a groove, intensifying the combustion process. An experiment was set up: two foci were dug next to each other: with and without a groove. Indeed, in the first of them, the flame burned much better.

The role of fire in human life.

· Repeat the knowledge of children about the seasons, the role of the sun in the change of day and night, seasons.

· To acquaint with the role of fire in human life, its negative and positive sides.

· To teach how to properly handle household appliances, to introduce them to the phone number of the fire department.

Preliminary work:

Acquaintance with the children's encyclopedia "The World Around Us", consideration of the schemes "Change of seasons", "Change of day and night", d \ and "When does it happen?", "Magic wand", keeping a diary of observations of the weather.

Material:

A ball, weather patterns, a mask-cap "Sun", paintings with a picture of fire, electrical appliances, v / f "Smeshariki. Dangerous Games "," Smeshariki. Careful Handling of Electrical Appliances ".

The course of the lesson.

I. "Weather forecast".

We begin each of our lessons by celebrating the weather. Today ________________ is the chief meteorologist.

(using diagrams: sun, cloud, precipitation, wind, the child on the board indicates the weather of the day)

All agree ? (additions and corrections are accepted)

II. D / I "Magic ball"

The teacher makes a riddle:

Snow everywhere, houses in snow

Brought it ... WINTER.

I love winter, and who else loves winter? (Throws the ball to one of the children with the question: “Why do you like winter?”

What time of year will come after winter? What happens in nature in spring? What time of year will come after spring? Why do you love summer? When do the leaves on the trees turn colorful? What else happens in nature with the onset of autumn? Why are the seasons changing? (the earth revolves around the sun) Why is there a change of day and night? (the earth rotates on its axis)

Game m / p "Change of day and night"

III. The role of fire in human life.

Give me a quick answer: what gives people light? (sun, stars, fire ...)

Of course fire! After all, both the sun and the stars are all giant balls of fire, they are just so far from us that we see either a small ball (sun) or small dots (stars). There would be no sun, there would be no life on our planet. Why do you think ? (it would be cold and dark). Right. If we turn our hands to the sun, what will we feel? (heat). Imagine that the entire sky is overcast. A week has passed and there is no sun. And suddenly it came out, when everyone was already tired of waiting, what will we feel? ( joy, it will become more fun, everyone will smile ...) It will become joyful and sunny for all of us. For a long time, people really wanted to have a little sun at home. Remember fairy tales: the feather of the Firebird, the Scarlet Flower (showing illustrations). Even the ancient caveman wanted to have a small flame (the story of how the caveman learned to make fire).

Physical minute.

Years passed, centuries passed. Man learned to illuminate his path with a torch, a stick with a depression into which resin was poured. Then people realized that oil does not burn badly either. This is how oil lamps appeared - clay or metal "teapots" with oil, through the spout of which a wick was passed. These lamps have been smoked for many, many centuries. And only then did they learn how to make candles. In the Russian hut, they lit a torch - a thin dry chip. It was strengthened over a trough with water, where coals fell (why?) More than a hundred years ago, people learned how to get kerosene from oil and invented kerosene lamps. Our Russian engineer Lodygin made the first light bulb, but Edison began to produce it in production, which is why it is called Edison's light bulb. This is how man learned to fight the darkness. But do we only need fire for this? Remember where the fire lives in your house, what is it for?

These are all good deeds of fire. But fire hides a terrible power. If it gets out of control - be in trouble! What kind of misfortune can happen? ( you can burn yourself, burn hole in the shirt, fire, etc.)... Your friends Smeshariki will teach you what to do in such cases.

IV. View in \ f "Smeshariki. Dangerous Games "," Smeshariki. Careful handling of electrical appliances "

Why did the trouble happen to Barash and Losyash? Who helped them? Conclusion: "A match for children is not a toy!"

Why did Nyusha have a fire? Who helped her? What number should I call in case of fire?

"The Golden Cockerel"

ecology lesson from the "Element of Fire" block

in the preparatory group

Fight for fire

The Significance of Fire in Human Evolution - An Integrated Lesson *

Equipment.

Musical excerpts: L. Beethoven, ballet "Creations of Prometheus", or A. Scriabin, symphonic work "Prometheus" ("Poem of Fire"), or F. Liszt, symphonic poem "Prometheus").

Related texts (see Appendices), a geographical map of deserts and semi-deserts, reproductions of drawings from the sites of ancient people in Africa.

DURING THE CLASSES

In a darkened classroom, a candle burns on the teacher's desk. A teacher (or a student with artistic abilities) expressively reads an excerpt from the book by J. Roni the Elder "Fight for Fire" (Appendix 1). After the end of the reading of the passage, the candle is extinguished. The class is in darkness for a while. Then candles are lit on the tables of the students in groups.

Teacher. Guys, imagine how our ancestors sat by the fire and looked at it in enchantment ten thousand, one thousand, one hundred years ago - just as we look now ... In our electric household there are fireplaces, candles, even flickering electric fireplaces with fake wood. Wild animals are afraid of fire; domesticated people get used to it; only dogs are innately a fire-lover.

Zoologists say: in two manifestations, man is unique in the animal kingdom - he uses speech and fire. The use of fire is utilitarian, but the craving for fire in a person is unconscious, instinctive. This is the only instinct that animals do not know. Human instinct. It originated from our distant ancestors and survived with us. But as soon as he was not refracted in consciousness! Fire worship cults. The destructive bliss of pyromaniacs. Burned and rebuilt Rome. Pioneer bonfires. Eternal flame in honor of the fallen ...

Let's return again to an excerpt from the book by J. Roni the Elder "The Fight for Fire".

A discussion begins (texts with an excerpt from the book are on the students' tables). The teacher asks questions, students work with the text, answer.

How did these people keep the fire?

(Answer. In special cages: four women and two warriors fed him day and night.)

What was the significance of fire for ancient people?

(Answer. Fire scared away predators, helped along the way, made it possible to cook more delicious food, fire was used in the manufacture of tools, it created a sense of community in people.)

What means of expression does the author use when describing fire?

(Answer. Impersonation, comparison. Fire-beast: "mighty face", "red teeth", "burst out of the cage", "devoured trees", "cruel and wild." "Father, guardian, savior.")

What means of expression does the author use to denote a dying fire?

(Answer. Impersonation with an animal: weakened, turned pale, decreased, “trembled like a sick animal,” “a small insect.”)

How is the grief of the ulamras conveyed in the text?

(Answer."There are no stars", "heavy sky", "heavy waters", "cold light", "chalk layers of clouds", "greasy, like a mountain resin, waters", "abscesses of algae." Sound writing: cold plant stems, the rustling of reptiles, numb lizards, a withered tree, plants trembling from the cold.)

The teacher brings the class to a general conclusion: fire was personified in ancient people with a living being, which is inherent in life and death.

Setting the goals and objectives of the lesson. Consider the problem of the positive and negative influence of fire on human evolution, narrowing it down to the positions "Fire-life" and "Fire-death".

Organization of work in groups... Preliminarily, the class is divided into three groups (optional): supporters of the positions "fire-life" and "fire-death" and observers (arbiters, judges). Symbolic scales are set on the teacher's table, black and white balls are placed next to it.

Fire-life ( presentation by representatives of the advocating group). The question of how long we have owned fire has worried humanity for many millennia. One of the proofs of such searches is the "Legend of Prometheus". Reading ( against the background of the musical piece "Prometheus") and discussion of the text "Prometheus" (Appendix 2). Conclusion: fire brought reason to humanity. White ball. ( A representative of the Fire-Life group puts a white ball on the scales.)

Atlas and Prometheus, who is tormented by the eagle of Zeus

Fire-death ( presentation by students from the group adhering to this position). The mythological interpretation of the image of Prometheus is far from so unambiguous. In Hesiod, Prometheus is a cunning, albeit kind to people, deceiver of Zeus, punished not without reason by him. Moreover, in antiquity there was a tradition (it belongs to the Roman authors) of the condemning image of Prometheus. For Horace, the impudent Prometheus committed an "evil deception" by bringing fire, which led to disastrous consequences. In creating man, he put into him the "malice" and "madness" of the lion. Prometheus cared only about the human body, and hence all the troubles of human life and enmity among people. Black ball. ( After completing the performance, the representative of the Fire-Death group puts a black ball on the other side of the scales).

The meaning of fire in human evolution

Teacher. The earliest traces of the use of fire are found in one South African cave. Below the level corresponding to the time of 1.3-1.0 million years ago, such traces are not found, but above this horizon there are bones that have been fired at a fireplace. The use of fire was a technological advance, second only in importance to the invention of stone tools. In the Chou-Gou-Tien cave in China, where the remains of Sinanthropus and their numerous stone tools were found, traces of fire were also found: coals, ash, burnt stones. Obviously, the first hearths burned here more than 500 thousand years ago.

Fire is life. The ability to use fire made food more digestible and tasty. ( White ball.)

Fried food is easier to chew, and this could not but affect the appearance of people: the selection pressure, aimed at maintaining a powerful jaw apparatus, disappeared. Gradually, the teeth began to decrease, the lower jaw no longer protruded so much forward, the massive bone structure required for the attachment of powerful masticatory muscles was no longer necessary. The human face acquired modern features. ( White ball.)
The main advantage of the ape-man was its increased migratory ability. A big game hunter, one of the highest order predators, he more and more often left the tropical zone for high latitudes - there hunting was more productive, since with a decrease in species diversity, the number of each species increases. However, it was cold there, and Pithecanthropus had to adapt to the cold. It was this ancestor of ours who learned to preserve and use the fire of forest fires and volcanic eruptions. But the Pithecanthropus themselves did not know how to make fire. Fire made man independent of the climate, allowed him to settle over the entire surface of the Earth. ( White ball.)
Fire not only greatly expanded the availability of power sources, but also gave humanity constant and reliable protection from wild animals. People used the flame to defend themselves against large rival predators, and could use it to reclaim comfortable dwellings - caves - from animals. ( White ball.)
With the help of fire, people could make more advanced tools. For example, wood spearheads and spearheads burned in a fire were hardened. ( White ball.)
With the advent of fire and hearth, a completely new phenomenon arose - a space strictly reserved for people. By the fire, bringing warmth and safety, people could calmly make tools, eat and sleep, communicate with each other. Gradually, the feeling of "home" became stronger - a place where women could take care of children and where men returned from hunting. ( White ball.)

"Fiery Revolution"

Fire is life. As the tools improved, man was able to penetrate areas with less favorable climates and more efficiently use the environment. However, the tools by themselves did not bring dramatic changes to his life: man continued to be just another predator among many. He changed his position in nature when he began to use fire to burn vegetation. This can be considered the first ecological revolution, comparable in its consequences with the later ones - agricultural and industrial.
The point of burning the land was to get rid of forests and clear a place for meadows and pastures. Forests grow in conditions of a certain minimum amount of precipitation. Where there is less rainfall, meadows become the natural form of vegetation cover. Hunters are well aware that there are more game in the meadows and steppes (savannas), which, moreover, is easier to hunt than in a dense forest. Therefore, the hunting tribes usually practiced the burning of forests; as a result, the meadows spread to areas where there was more rain. ( White ball.)
Fire was also used to feed game, with environmental change being an additional side benefit. Although hunting was later replaced by pastoralism, the practice of burning grass to keep an area treeless continues to this day, and carefully controlled burning of forests to stimulate the growth of some tree species and suppress others is one of the well-known techniques in modern forestry. ( White ball.)

Fire death. Let's look at other consequences of human use of fire to burn vegetation. There is no doubt about the reality of the onset of deserts, or "desertification". This is a formidable process in which the existing deserts of the world, such as the Sahara in Africa, are expanding their limits. In Africa, deforestation began, undoubtedly, already from the time that man took possession of fire - more than 50 thousand years ago, when the first foci appeared in the east of the continent during the period of the Acheulean culture. Fire is an important tool in shifting agriculture, and while fires do occur from time to time for natural causes, deliberately set fires have had a much greater impact on vegetation. First of all, this is explained by the fact that artificial arson was carried out at the same place more often than natural fires happened. Even in areas with high rainfall, the forest ecosystem does not recover well after it has been disturbed over a large area. The destruction of forests entails a rapid deterioration in the condition of soils, which eventually become so bad that the land can only be used for pasture, and then they generally turn into semi-desert and deserts.
Let's compare two maps of Africa. On one of them the main finds of the sites of ancient people are marked; on the other, modern geographic zoning. An amazing pattern: people once lived on the territory of deserts, semi-deserts, dry steppes. A particularly impressive sight for the famous Sahara and Kalahari deserts. If we also take into account that fossils of various animals and plants, as well as traces of rivers, streams and lakes, are found here, then there is no doubt: in the past, these now desert lands did not have an acute shortage of water. Rock carvings left by our distant ancestors testify to the abundance of flora and fauna on the site of the modern deserts of Africa. For example, the rock carvings in the Tassili region of the Sahara reflect the rise and fall of the culture of the ancient inhabitants of the region. About 7000 BC these were hunters who hunted giraffes, antelopes and other savannah animals. Then people began to raise livestock here - frescoes that appeared 2000 years later depict countless herds. The latest drawings - with images of camels - date back to about 3000-2000 years BC, after which this culture disappeared under the onslaught of the conquerors. Let's take it as a hypothesis: the landscapes of the Sahara at the end of the Stone Age were subjected to serious environmental pressure from hunters and gatherers. According to biogeographer I. Schmithusen, “natural fires are rarely observed in the herbaceous spaces of periodically dry tropics ... vegetation in these areas. With the exception of the flooded savannahs, all other savannahs ... arose with direct human influence. " Conclusion: the famous deserts of Africa - Sahara and Kalahari - are of anthropogenic origin ( Black ball.)

Judges. Over the past 150 thousand years, the territory of the Sahara and Kalahari deserts has repeatedly decreased and increased due to climate change, without human participation.

Fire death. Aridization of the North African climate since 5000 BC was largely provoked and accelerated by human economic activity.
Let's turn to the events that took place in another part of the world. Dutch navigator A.Ya. Tasman and his team, who were the first Europeans to see the shores of the island called Tasmania, did not meet the aborigines, but paid attention to the clouds of smoke rising in different places above the forest. Subsequent explorers of the island constantly observed forest fires, an abundance of fires made by the aborigines. And although the Tasmanians were engaged in hunting, fishing, gathering, the main "lever" with which they "turned" their land - radically rebuilt landscapes - was fire. “The ecological effect of these systematic fires,” writes V.R. Cabo is very large. Vegetation has changed over the vast expanses of Tasmania; there have been changes in the nature of the soil, the climate has changed. " The Tasmanians used fire not only to hunt animals, but, perhaps, even on a larger scale - to increase the area of ​​open spaces and increase the fertility of pastures on which wild animals grazed. It was, one might say, a kind of primitive animal husbandry with the help of "pyrogenic processing" of hunting grounds.

Conclusion: the use of fire by the aborigines of Tasmania led to a change in flora and fauna and, as a result, negatively affected the ecosystem of the island as a whole. ( Black ball.)

In a similar way, man mastered Australia. Travelers and missionaries of the past have often mentioned the widespread use of fire by Australian aborigines for a variety of purposes. The hunting tribes of Australia that the Europeans met were constantly wandering. According to rough estimates, each tribe, or rather, each nomadic group, annually burned about 100 km2 of forests, savannas, steppes - purposefully or involuntarily. Thousands of such groups for 20-30 millennia could be many times - dozens of times! - to burn out vegetation throughout the continent. This is how pyrogenic landscapes were created over vast areas. Of course, they were not formed everywhere, but in territories with a certain climate and vegetation cover. But the general nature of the changes during such active exploitation is expressed in the depletion of biological resources and desertification.

Conclusion: modern deserts and semi-deserts of Australia are of anthropogenic origin. ( Black ball.)

Judges. The conclusion was drawn very sharply, without proof.

Fire death. Unlike Tasmania, Australia's climate is drier, with 200–300 mm of rainfall per year in the central regions. The situation is complicated by constant deviations from the average value: sometimes 3-4 times less, then twice as much. In dry years or seasons, a feedback mechanism began to operate: fires caused especially severe damage to forests, and the disappearance of forests - soil moisture stabilizers - caused drying and erosion of soils. Forest-steppe, steppe and semi-steppe territories have existed in Australia for a long time, even before the appearance of man here. However, the activities of nomadic groups of hunters and gatherers ultimately led to a reduction in the total area of ​​forests, an increase in desertified areas. According to the British explorer W. Chesling, who lived for a long time among the Australian tribes of the Julengors, the latter set fire to the forest while hunting. By October, when the wind dies down, the fires have time to destroy all the humus. Now the burning sun is completing its destructive work - the country is turning into a heap of ash. In December, the wind changes direction; strongly saturated with moisture, it blows from the north-west, streams of rain flood the country ... Loose soil, sand, ash, humus - everything is washed off into the swamps or carried away to the sea. " How deep such transformations can be can be judged, in particular, according to the testimony of the Australian scientist Charles Moundford, who described the pyrogenic landscapes of Central Australia: “Standing on a bare hill and watching the hot eddies rising from the bottom of the dried lake, I could not believe that, when the first white people reached the Manna Mountains, this huge depression was full of water, in which hundreds of ducks and other waterfowl splashed. "

About 6-10 millennia ago, in a completely different part of the world, in the Arctic Circle, in the territory of Yakutia, Taimyr, Kamchatka, Chukotka, Alaska, the so-called Sumagin culture of the Late Paleolithic was widely spread. Such a significant distribution in high latitudes is explained by the favorable climate. The border of the forest and tundra was shifted 300–400 km to the north. The people of the Sumagin culture undoubtedly influenced the landscapes of the Arctic. Their main weapon was fire. Trees and shrubs in the polar regions grow very slowly and regenerate poorly. The destruction of the vegetation cover during burns and fires caused a chain of processes that ultimately led to very serious consequences.

After the destruction of vegetation, the soil froze faster and deeper in winter, but thawed faster and deeper in summer too. In the forest-tundra, the second process is often decisive. Intensification of summer thawing often leads to solifluction - the sliding of thawed soil on the slopes, and in the presence of underground ice - to a very wide development of thermokarst. Snow blown away by the wind accumulates in subsidence funnels in winter, which makes it difficult to freeze, and in summer melt water stimulates thawing and a further increase in the size of the funnel. Many lakes and swamps are formed. Even in very severe winters, the thickness of ice in lakes does not exceed 2–2.5 m. Therefore, bottom sediments of water bodies with a greater depth remain unfrozen, and if the width of the lake is more than twice the thickness of permafrost, a through talik appears under it. But the gradual accumulation of the peaty horizon in the bogs slows down the summer thawing more and more, and the permafrost begins to regain its surrendered positions.

The destruction of the forest near the northern border of the taiga zone, where the thickness of the snow cover does not reach 20 cm, leads to the cooling of the soil, and with high snow thickness - to its warming. Permafrost responds accordingly to these changes. What is the reason for this? The fact is that the snow cover affects the temperature regime of the underlying soil in two ways. On the one hand, it is highly reflective and reduces the influx of radiant energy. On the other hand, snow is a good heat insulator, which means that it inhibits winter cooling of the soil. Therefore, snow cover of different thickness has opposite effects. With a thin cover, the dominant role belongs to the reflection of heat. With a more significant thickness of the snow cover, its heat-insulating properties begin to play a decisive role. Finally, with an even greater power, the snow again turns out to be a cooler (in terms of the average annual temperature), because it melts longer in summer.

Thus, under different conditions, human activity can lead to different results: due to fires, permafrost can degrade, or areas of pyrogenic tundra with colder soils appear.

Conclusion: the formation of anthropogenic (pyrogenic) tundras began as early as the time of the Sumagin culture (6–10 thousand years ago). Human activities contributed to the expansion of the tundra zone and the retreat to the south of the northern border of the taiga. The modern boundaries of the tundra have developed under the influence of anthropogenic impact. ( Black ball.)

(When studying changes in biota in the geological past, it is important to correctly place accents, taking into account the influence of both external (climate, influence of large mammals) and internal (stage of development of the biome, as a thermodynamic system) factors that stimulate these changes. and the Atlantic periods - 10,000–5,000 years ago) there was an active advance of the forest both to the north and south of the current borders of the forest zone, and only a cooling of the climate caused by the growth of the ice cap in the north, which came after 4,500 years ago (subboreal period) caused a reverse process - the aridization of the southern part of the forest zone and the gradual retreat of the forest to the south in the north.Now, by the way, against the background of the modern warming of the climate, the advance of the forest to the north is observed again (the advance of the taiga on the tundra), despite the intense anthropogenic load in this The human impact on vegetation, which was similar throughout the early and middle the Holocene, only provoked these processes only in the period when unfavorable climatic conditions were formed for their course. Therefore, one cannot speak so categorically about the anthropogenic origin of the tundra. With permafrost, it’s also not quite the same. Suffice it to point out, for example, the fact that in the taiga zone of Eastern Siberia, on the permafrost layer starting from a depth of 15–30 cm, larch trees from Larix davurica grow beautifully. - Approx. ed.)

Fire and metallurgical production

Fire is life. The Age of Metal is the next page in the history of human culture after the Neolithic. The oldest traces of bronze in Mesopotamia and Egypt date back to the 4th millennium BC. e. The beginning of the smelting of ore iron dates back to 1300 BC. e. If earlier the material from which the tool is made is wood, stone, bone, etc. - was something given, ready, now the process of making a tool was preceded by the process of making material for this tool - a material with new properties. Mining is impossible without the use of fire. ( White ball.)

Fire death. The main causes of technogenic pollution of the atmosphere are the combustion of natural fuel and metallurgical production. If in the XIX and early XX centuries. The products of combustion of coal and liquid fuel entering the environment have been almost completely assimilated by the vegetation of the Earth, but at present the content of harmful technogenic emissions in the atmosphere is steadily increasing. A large amount of pollutants gets into the air from stoves, fireboxes, exhaust pipes of cars. Among them are sulfur dioxide, nitrogen oxides, carbon monoxide, lead compounds, various hydrocarbons - acetylene, ethylene, methane, propane, toluene, benzopyrene, etc. Together with water droplets, they form a poisonous fog - smog, which has a harmful effect on the human body and vegetation. cities. Liquid and solid particles (dust) suspended in the air reduce the amount of solar radiation reaching the Earth's surface. So, in big cities, solar radiation decreases by 15%, ultraviolet radiation by 30% (and in the winter months it can completely disappear).

Billions of tons of carbon dioxide are released into the atmosphere each year as a result of fuel combustion. About half of the carbon dioxide from fossil fuel combustion is absorbed by the ocean and green plants, and half remains in the air. The content of CO 2 in the atmosphere is gradually increasing and has increased by more than 10% over the past 100 years. Carbon dioxide interferes with the release of heat into outer space, which leads to the so-called "greenhouse effect". Changes in the content of CO 2 in the atmosphere have a significant effect on the Earth's climate. All this is a consequence of man's assimilation of fire. ( Black ball.)

Lesson summary

The judges will count the number of black and white balls. There are more whites. Discussion of the results obtained. Students are free to express their opinions.

Teacher. Accidental use and, possibly, maintenance of a lighted fire by primitive people began about 1–0.5 million years ago. About 50 thousand years ago, man himself learned how to make fire from sparks by striking flint on flint or by friction. About 20 thousand years ago, energy consumption averaged 10 thousand kJ per person per day, and now in economically developed countries - over 1 million kJ. An even more striking increase in the total energy consumption of all mankind during this time is 10 million times. It is due to this million-fold increase in the use of solar energy reserves by man, conserved in organic fuel, that the entire complex of modern life support of mankind has been created and functions.

If many millennia ago none of our distant ancestors, basking by a tree set on fire by lightning, had thought of throwing several new branches into a dying fire, we would still have lived in caves.

In ecological terms, the burning of wood in a primitive fire is the very first and therefore the most significant step of mankind towards the search for new, more and more efficient energy carriers, which ultimately led to an unprecedented increase in the pressure of one species - man - on the nature of the entire planet.

Therefore, do not forget about the black balls on the scales. Changes in landscapes, climate on our planet - all these are detrimental consequences of the mastery of fire. Sometimes humanity resembles a child who finds a box of matches and secretly from adults indulges in early spring on a sunny hillock, setting fire to last year's dry grass. Tongues of flame, at first barely noticeable and harmless, fanned by the spring breeze in seconds turn into a roaring monster, sweeping away in its path both a haystack, and outbuildings, and the house in which the child lives. The house we live in.

Remember this. The future of our planet belongs to you, the younger generation.

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Appendix

J. Roni the Elder

Fire death

In the impenetrable night the ulamras fled, mad with suffering and fatigue; all their efforts were in vain in the face of the misfortune that befell them: the fire was dead! They supported him in three cages. According to the custom of the tribe, four women and two warriors fed him day and night.

Even in the most difficult times they kept it alive, protected it from bad weather and floods, carried it across rivers and swamps; bluish in the daylight and crimson at night, he never parted with them. His mighty face made lions, cave and gray bears, mammoth, tiger and leopard flee. His red teeth protected man from the vast and terrible world; all the joys lived only around him. He extracted delicious smells from meat, made the ends of spears hard, made stones crack, he encouraged people in dense forests, in endless savannah, in the depths of caves. This fire was the father, the guardian, the savior; when he broke out of his cage and devoured trees, he became more cruel and wild than mammoths.

And now he's dead! The enemy destroyed two cells; in the third, which survived during the flight, the fire weakened, turned pale and gradually diminished. He was so weak that he could not even eat marsh grasses; he trembled like a sick animal, turning into a small reddish insect, and every breath of wind threatened to extinguish him ... then he disappeared altogether ... The Ulamrs fled, orphaned, on an autumn night. There were no stars. A heavy sky fell over the heavy waters; the plants stretched out their cold stems over the fugitives, you could only hear the rustling of reptiles. Men, women, children were swallowed up in darkness. Listening to the voices of their leaders, they tried to move on dry and solid ground, wading through the streams and marshes they encountered. Three generations have known this path. At dawn, they approached the savannah. Cold light filtered through the chalk layers of clouds. The wind whirled in the oily waters like mountain tar. Algae swelled like abscesses, numb lizards lay curled up among the water lilies. A heron sat on a withered tree. Finally, in the red fog, a savannah with plants shivering from the cold unfolded. The people perked up and, having passed through the thickets of reeds, they finally found themselves among the grasses, on solid ground. But then feverish excitement fell, people lay down on the ground, froze in immobility; women, more resilient than men, having lost their children in the swamps, howled like she-wolves, those who saved their little ones lifted them up to the clouds. When day dawned, Faum recounted his tribe with his fingers and twigs. Each branch corresponded to the number of fingers on both hands. Remaining: four branches of warriors, more than six branches of women, about three branches of children, several old people.

Old Gong said that one man in five, one woman in three, and one child from a whole branch survived.

The Ulamry felt the immensity of the misfortune. They realized that their offspring were in danger of death. The forces of nature became more and more formidable. People will roam the earth, miserable and naked.

To be continued

* The lesson can be conducted while studying the topic "The origin of man" in the course "General biology. 11th grade ", as well as when studying the topic" Anthropogenic impact of man on nature "in the course" Ecology "