Abstract the influence of primitive and modern man on the environment. The influence of human activity on the environment in the process of formation of society How did it affect the environment?
Question 1. How did the activities of primitive man affect the environment?
The economic basis of life in paleonite(Stone Age - 20,000-30,000 years ago) there was hunting for large animals: red deer, reindeer, woolly rhinoceros, donkey, horse, mammoth, aurochs. Intensive extermination of large herbivores led to a fairly rapid reduction in their numbers and the extinction of many species. The result of the hunt was the disappearance of a number of species of large mammals and birds (mammoths, bison, sea cows, etc.). Many species have become rare and are on the verge of extinction.
According to paleontologists, approximately 500-800 years after the settlement of any area by humans, first large herbivores and then carnivores completely disappeared from the area.
Question 2. To what period of development of human society does the origin of agricultural production belong?
During the Neolithic era (9000-10,000 years ago), the first attempts were made to domesticate animals and breed plants. Shifting agriculture developed and metal processing techniques emerged. The development of agriculture led to the development of ever new territories for growing cultivated plants. Forests and other natural biocenoses were replaced by agrocenoses - plantations of agricultural crops poor in species composition. Tropical forests in Africa and Latin America (Amazon basin) are still being destroyed as a result of slash farming.
Question 3. Who first introduced the term “noosphere” into science?
The concept of the “noosphere, as an ideally thinking shell of the Earth, was introduced into science at the beginning of the 20th century (1927) by French scientists and philosophers P. Teilhard de Chardin and E. Leroy. P. Teilhard de Chardin considered man as the pinnacle of evolution and a transformer of matter by including into the creativity of evolution. The scientist assigned the leading place in evolutionary constructions to the collective and the spiritual factor, without diminishing the role of technical progress and economic development.
V.I. Vernadsky, speaking about the noosphere, emphasized the need for a reasonable organization of interaction between society and nature, meeting the interests of man, all humanity and the world around him. The scientist wrote: “Humanity, taken as a whole, is becoming a powerful geological force. And before him, before his thought and work, is the question of restructuring the biosphere in the interests of free-thinking humanity as a whole. This is a new state of the biosphere, to which we, without noticing This, we are approaching, is the noosphere." Now humanity is using for its needs an ever larger part of the planet's territory and ever greater amounts of mineral resources.
varieties and strains of microorganisms. a) genetics; b) evolution; c) selection.
2. The first stage of animal selection is….A. Unconscious selection. B. Hybridization. C. Domestication. D. Methodical selection.
3. How is the effect of heterosis expressed? a) decreased vitality and productivity; b) increased vitality and productivity; c) increased fertility.
4. Does the effect of heterosis persist with further reproduction of hybrids? a) yes; b) no; c) sometimes.
5. In which organisms does polyploidy occur? a) plants; b) animals; c) microbes.
6. In the early stages of domestication, humans made selection:
A) natural; B) methodical; C) stabilizing; D) unconscious
7. The production of mules in animal breeding was achieved by applying the method:
A) artificial selection; B) artificial mutagenesis;
B) interspecific hybridization; D) cloning;
8. Centers of origin of cultivated plants were opened
A) I.V. Michurin; B) S. Chetverikov; C) V.N. Vavilov; D) K.A. Timiryazev9. 9.Inbreeding is otherwise called:
A) outbreeding; B) inbreeding; C) heterosis; d) cloning;
10. Artificial selection as opposed to natural:
A) more ancient; B) carried out by environmental factors;
C) carried out by humans; D) preserves individuals with traits useful for the body.
1) 1 3) 3
2) 2 4) 4
A 12. The picture shows red blood cells. What organism contains such formed elements in the blood?
1 person
2) mouse
3) horse
4) frog.
A 13. Which statement correctly describes the movement in the systemic circulation?
1) begins in the left ventricle and ends in the right atrium
2) begins in the left ventricle and ends in the left atrium
3) begins in the right ventricle and ends in the left atrium
4) begins in the right ventricle and ends in the right atrium.
A 14. Respiratory movements in humans occur due to
1) changes in the speed of blood movement through the vessels of the pulmonary circulation
2) contraction of smooth muscles
3) wave-like movements of the ciliated epithelium of the respiratory tract
4) changes in the volume of the chest cavity.
A 15. Which organ in the picture is indicated by the letter A?
1) blood vessel
2) bladder
3) renal pelvis
4) ureter.
A 16. Which analyzer's receptors are excited by gaseous chemicals?
1) olfactory 3) auditory
2) skin 4) taste.
A 17. An example of a dynamic stereotype is
1) suddenly finding a way out when solving a mathematical problem
2) salivation at the word “cake”
3) cycling in the park
4) flight of a night insect into the bright light of a lantern.
A 18. In a smoker, gas exchange in the lungs is less efficient because he:
1) the walls of the alveoli become covered with foreign substances
2) death of cells in the respiratory tract mucosa occurs
3) the activity of nerve centers deteriorates
4) hypertension develops.
A 19. Which vessel is damaged in Figure A?
1) lymphatic
2) capillary
3) vein
4) artery.
3. The influence of primitive and modern man
on the environment
People rely on natural resources to provide their basic needs, including food, shelter and clothing, but they also compete for space occupied by natural habitats. Thus, population growth and human development affect biodiversity both directly and indirectly. Human impacts on the environment, including the use of land and other natural resources, are the most important factors behind the decline in biodiversity.
In the past, low population densities and regulated use of natural resources maintained the balance of ecosystems. However, over the last thousand years, human impact on the earth has increased.
Man began to change natural systems already at the primitive stage of the development of civilization, during the period of hunting and gathering, when he began to use fire. The domestication of wild animals and the development of agriculture expanded the area of manifestation of the consequences of human activity. As industry developed and muscle power was replaced by fuel energy, the intensity of anthropogenic influence continued to increase. In the 20th century Due to the particularly rapid rate of population growth and its needs, it has reached unprecedented levels and spread throughout the world.
The most important environmental postulates formulated in Tyler Miller's book "Living in the Environment."
1. Whatever we do in nature, everything causes certain consequences in it, often unpredictable.
2. Everything in nature is interconnected, and we all live in it together.
3. Earth's life support systems can withstand significant pressure and rough interventions, but there is a limit to everything.
4. Nature is not only more complex than we think about it, it is much more complex than we can imagine.
All human-created complexes (landscapes) can be divided into two groups depending on the purpose of their creation:
– direct – created by purposeful human activity: cultivated fields, gardening complexes, reservoirs, etc., they are often called cultural;
– accompanying – not intended and usually undesirable, which were activated or brought to life by human activity: swamps along the banks of reservoirs, ravines in fields, quarry-dump landscapes, etc.
Each anthropogenic landscape has its own history of development, sometimes very complex and, most importantly, extremely dynamic. In a few years or decades, anthropogenic landscapes can undergo profound changes that natural landscapes will not experience in many thousands of years. The reason for this is the continuous intervention of man in the structure of these landscapes, and this interference necessarily affects the man himself.
Anthropogenic changes in the environment are very diverse. By directly influencing only one of the components of the environment, a person can indirectly change the others. In both the first and second cases, the circulation of substances in the natural complex is disrupted, and from this point of view, the results of the impact on the environment can be classified into several groups.
The first group includes impacts that lead only to changes in the concentration of chemical elements and their compounds without changing the form of the substance itself. For example, as a result of emissions from motor vehicles, the concentration of lead and zinc increases in the air, soil, water and plants, many times higher than their normal levels. In this case, the quantitative assessment of exposure is expressed in terms of the mass of pollutants.
The second group - impacts lead not only to quantitative, but also qualitative changes in the forms of occurrence of elements (within individual anthropogenic landscapes). Such transformations are often observed during mining, when many ore elements, including toxic heavy metals, pass from mineral form into aqueous solutions. At the same time, their total content within the complex does not change, but they become more accessible to plant and animal organisms. Another example is changes associated with the transition of elements from biogenic to abiogenic forms. Thus, when cutting down forests, a person, cutting down a hectare of pine forest and then burning it, converts about 100 kg of potassium, 300 kg of nitrogen and calcium, 30 kg of aluminum, magnesium, sodium, etc. from biogenic form into mineral form.
The third group is the formation of man-made compounds and elements that have no analogues in nature or are not characteristic of a given area. There are more and more such changes every year. This is the appearance of freon in the atmosphere, plastics in soils and waters, weapons-grade plutonium, cesium in the seas, widespread accumulation of poorly decomposed pesticides, etc. In total, about 70,000 different synthetic chemicals are used every day in the world. About 1,500 new ones are added every year. It should be noted that little is known about the environmental impact of most of them, but at least half of them are harmful or potentially harmful to human health.
The fourth group is the mechanical movement of significant masses of elements without a significant transformation of the forms of their location. An example is the movement of rock masses during mining, both open-pit and underground. Traces of quarries, underground voids and waste heaps (steep-sided hills formed by waste rocks transported from mines) will exist on Earth for many thousands of years. This group also includes the movement of significant masses of soil during dust storms of anthropogenic origin (one dust storm can move about 25 km3 of soil).
The real scale of modern anthropogenic influence is as follows. Every year, over 100 billion tons of minerals are extracted from the depths of the Earth; 800 million tons of various metals are smelted; produce more than 60 million tons of synthetic materials unknown in nature; They introduce over 500 million tons of mineral fertilizers and approximately 3 million tons of various pesticides into the soils of agricultural lands, 1/3 of which enters water bodies with surface runoff or lingers in the atmosphere. For their needs, people use more than 13% of river flow and annually discharge more than 500 billion m3 of industrial and municipal wastewater into water bodies. The above is enough to realize the global impact of man on the environment, and therefore the global nature of the problems arising in connection with this. Let us consider the consequences of three main types of human economic activity.
1. Industry - the largest branch of material production - plays a central role in the economy of modern society and is the main driving force of its growth. Over the last century, global industrial production has increased more than 50 times, with 4/5 of this growth occurring since 1950, i.e. a period of active implementation of scientific and technological progress into production. Naturally, such a rapid growth of industry, which ensures our well-being, primarily affected the environment, the load on which has increased many times over.
2. Energy is the basis for the development of all sectors of industry, agriculture, transport, public utilities. This is an industry with very high rates of development and huge scale of production. Accordingly, the share of participation of energy enterprises in the load on the natural environment is very significant. Annual energy consumption in the world is more than 10 billion tons of standard fuel, and this figure is continuously increasing2. To obtain energy, they use either fuel - oil, gas, coal, wood, peat, shale, nuclear materials, or other primary energy sources - water, wind, solar energy, etc. Almost all fuel resources are non-renewable - and this is the first stage of impact on the environment in the energy industry - the irreversible removal of masses of substances.
3. Metallurgy. The impact of metallurgy begins with the extraction of ores of ferrous and non-ferrous metals, some of which, such as copper and lead, have been used since ancient times, while others - titanium, beryllium, zirconium, germanium - have been actively used only in recent decades (for the needs of radio engineering, electronics , nuclear technology). But since the middle of the 20th century, as a result of the scientific and technological revolution, the extraction of both new and traditional metals has sharply increased, and therefore the number of natural disturbances associated with the movement of significant masses of rocks has increased.
In addition to the main raw material – metal ores – metallurgy quite actively consumes water. Approximate figures for water consumption for the needs of ferrous metallurgy: the production of 1 ton of cast iron requires about 100 m 3 of water; for the production of 1 ton of steel – 300 m 3; for the production of 1 ton of rolled products - 30 m 3 of water.
But the most dangerous side of the impact of metallurgy on the environment is the technogenic dispersion of metals. Despite all the differences in the properties of metals, they are all impurities in relation to the landscape. Their concentration can increase tens and hundreds of times without external changes in the environment. The main danger of trace metals lies in their ability to gradually accumulate in the bodies of plants and animals, which disrupts food chains.
126
. Air exchange, air exchange rate, air conditioning. Relationship between ventilation parameters and the content of harmful substances in the air of the working area.
Calculation of the release of harmful substances and moisture.
Moisture release
The amount of moisture released by workers: W
=
,
Where n– number of people in the room; w– moisture release from one person.
Gas emissions
It is necessary to take into account gas emissions during technological operations.
Calculation of heat releases.
Heat emissions from people
The calculations use sensible heat, i.e. heat that affects the change in air temperature in the room. It is believed that a woman produces 85% of the heat generated by an adult man.
Heat release from solar radiation
For glazed surfaces: Q ost. = F ost. .
q ost. .
A ost., W,
Where F ost.– glazing surface area, m2; q ost.– heat release from solar radiation, W/m 2, through 1 m 2 of the glazing surface (taking into account the orientation to the cardinal points); A ost.– factor taking into account the nature of the glazing.
Heat emissions from artificial lighting sources
- Q osv. = N osv. .
h, W,
Heat emissions from equipment
Manual soldering irons with a power of 40 W?
- Q about. = N about. .
h
The required air flow is determined by harmful factors that cause a deviation of the air parameters in the working area from the standardized ones (the entry of harmful substances, moisture, excess heat).
Required air exchange when harmful substances enter the air of the working area
The amount of air required to dilute the concentrations of harmful substances to acceptable levels:
G = , m 3 / h,
Where IN– the amount of harmful substances released into the room in 1 hour, g/h; q 1 , q 2 – concentration of harmful substances in the supply and exhaust air, g/m3, q 2 is accepted to be equal to the maximum permissible concentration for the substance in question (lead and its inorganic compounds - 0.1.10 -4 g/m 3, hazard class - I).
Selection and configuration of ventilation systems.
Selection of ventilation systems
Since the obtained value of the amount of air will require huge expenditures of electricity and material resources, it is advisable to use a system of local suction, which will significantly reduce air exchange.
When removing harmful substances directly from the place of their release, the greatest effect of ventilation is achieved, because in this case, large volumes of air are not polluted and harmful substances released by small volumes of air can be removed. In the presence of local suction, the volume of supply air is assumed to be equal to the volume of the exhaust (minus 5% to eliminate the possibility of polluted air flowing into adjacent rooms).
Calculation of local ventilation (exhaust).
Air exchange when harmful substances enter the air of the working area
Misalignment angle j between the axes of the torch of harmfulness and suction is assumed to be 20 o for design reasons. The air flow rate for suction, which removes heat and gases, is proportional to the characteristic air flow rate in the convective flow rising above the source:
L ots. = L 0 . TO P . TO IN . TO T ,
Where L 0 – characteristic flow rate, m 3 / h; TO P– dimensionless factor, taking into account the influence of geometric and operating parameters characterizing the “source-suction” system; TO IN– coefficient taking into account the speed of air movement in the room; TO T– coefficient taking into account the toxicity of harmful emissions.
- L 0
=
,
- s
=
,
- D =
,
- TO IN
=
,
K T is determined depending on parameter C:
WITH = ,
Where M– consumption of harmful substances (7.5 - 10 -3 mg/s); L ots.1– air consumption by suction at K T = 1; MPC– maximum permissible concentration of harmful substances in the air of the working area (0.01 mg/m3); q etc.– concentration of harmful substance in the supply air, mg/m3.
Calculation of general ventilation (supply).
Since supply ventilation is designed on the principle of exhaust compensation (air exchange), to ensure a speed in the network of 6.5 m/s it is advisable to use an air duct with a cross-section of 200? 200, to ensure the required inflow, use 10 double adjustment grilles PP 200? 200.
The “fan - electric motor” set can be used the same as in the exhaust network, because the resistance (air intake grille, air filter, heater and grilles in the room) will be of the same order as in the exhaust network.
Under the influence of the equipment and technological processes used, a certain external environment is created in the work area. It is characterized by: microclimate; content of harmful substances; levels of noise, vibration, radiation; workplace illumination.
The content of harmful substances in the air of the working area should not exceed maximum permissible concentrations (MPC).
MPCs are concentrations that, when exposed to people during their daily work, except weekends, for 8 hours (or another duration, but not more than 41 hours per week) throughout their entire work experience, cannot cause diseases or diseases detectable by modern research methods or deviations in the state of health both among the workers themselves during their work activities and in the subsequent period of life, and among subsequent generations.
Maximum permissible concentrations for most substances are maximum one-time, i.e., the content of a substance in the breathing zone of workers is averaged over a period of short-term air sampling: 15 minutes for toxic substances and 30 minutes for substances with a predominantly fibrogenic effect (causing cardiac fibrillation). For highly cumulative substances, along with the maximum one-time maximum, a shift-average MPC has been established, i.e. the average concentration obtained by continuous or intermittent air sampling for a total time of at least 75% of the duration of the work shift, or the time-weighted average concentration of the duration of the entire shift in the breathing zone of workers at their places of permanent or temporary stay.
In accordance with SN 245-71 and GOST 12.1.007-76, all harmful substances, according to the degree of impact on the human body, are divided into four hazard classes:
extremely dangerous – MPC less than 0.1 mg/m3 (lead, mercury - 0.001 mg/m3);
highly hazardous – MPC from 0.1 to 1 mg/m3 (chlorine - 0.1 mg/m3; sulfuric acid - 1 mg/m3);
moderately hazardous – MPC from 1.1 to 10 mg/m3 (methyl alcohol - 5 mg/m3; dichloroethane - 10 mg/m3);
low-hazard - MPC more than 10 mg/m3 (ammonia - 20 mg/m3; acetone - 200 mg/m3; gasoline, kerosene - 300 mg/m3; ethyl alcohol - 1000 mg/m3).
Based on the nature of their impact on the human body, harmful substances can be divided into: irritants (chlorine, ammonia, hydrogen chloride, etc.); asphyxiants (carbon monoxide, hydrogen sulfide, etc.); narcotics (nitrogen under pressure, acetylene, acetone, carbon tetrachloride, etc.); somatic, causing disturbances in the functioning of the body (lead, benzene, methyl alcohol, arsenic).
When several harmful substances of unidirectional action are simultaneously contained in the air of the working area, the sum of the ratios of the actual concentrations of each of them in the air (K1, K2, ..., Kn) to their maximum permissible concentrations (MPC1, MAC2, ..., MACn) should not exceed one :
Problem 1/2
At a meat processing plant located in the suburbs, an unlined container containing G=5 tons of ammonia NH 3 ( r =0.68 t/m 3). A cloud of contaminated air moves towards the city center, where at a distance of R=1.5 km from the meat processing plant there is a store with N=70 people. Provision of gas masks X=20%.. The area is open, wind speed in the surface layer V=2 m/s, inversion.
Determine the size and area of chemical contamination, the time of approach of the infected cloud to the store, the time of the damaging effect of chlorine, the loss of people who ended up in the store.
Solution.
- 1. Determine the possible area of an ammonia spill using the formula:
Where G– mass of chlorine, t; p– chlorine density, t/m3; 0.05 – thickness of the spilled chlorine layer, m.
2. Determine the depth of the chemical contamination zone (D)
For an unbanked container, at a wind speed of 1 m/s; For G=5 t; isotherm Г 0 =0.7 km.
For this problem: with inversion for a wind speed of 2 m/s G=G 0? 0.6? 5=0.7? 0.6? 5=2.1 km.
3. Width of the chemical contamination zone (W) during inversion: W=0.03? G=0.03? 2.1=0.063 km.
4. Area of the chemical contamination zone ( S h):
5. Time of passage of contaminated air to a populated area located in the direction of the wind ( t podkh), according to the formula:
6. Time of damaging action (t pores) for ammonia, unbanked storage t pores,0 = 1.2. For a wind speed of 2 m/s, we introduce a correction factor of 0.7.
t time = 1.2? 0.7=0.84 s.
7. Possible losses of people (P) caught in the store.
For a 20% supply of gas masks, the number of affected people is P = 70? 40/100=28 people. of which 7 people had mild damage, 12 people had moderate and severe damage, and 9 people had a fatal outcome.
What actions need to be taken to ensure the safety of people in the store? How to provide first aid to an ammonia victim?
Answers:
Protection against hazardous chemicals is achieved by using individual and collective protective equipment. To eliminate the consequences of infection, facilities are degassed and personnel are sanitized. The suddenness of accidents at chemically hazardous facilities, the high speed of formation and spread of a cloud of contaminated air requires the adoption of prompt measures to protect people from hazardous chemicals.
Therefore, the protection of the population is organized in advance. A system is created and a procedure is established for notification of emergency situations occurring at facilities. Personal protective equipment is accumulated and the order of their use is determined. Protective structures, residential and industrial buildings are being prepared. Ways to move people to safe areas are being outlined. Management bodies are being prepared. The population living in areas adjacent to the enterprise is purposefully trained. To ensure timely adoption of protective measures, a warning system is activated. It is based on local systems created at chemically hazardous facilities and around them, which provide notification not only to the enterprise personnel, but also to the population of nearby areas.
Protection against hazardous chemicals is provided by filtering industrial and civil gas masks, gas respirators, insulating gas masks and civil defense shelters. Industrial gas masks reliably protect the respiratory organs, eyes and face from damage. However, they are used only where the air contains at least 18% oxygen, and the total volume fraction of vapor and gaseous harmful impurities does not exceed 0.5%.
If the composition of gases and vapors is unknown or their concentration is higher than the maximum permissible, only insulating gas masks (IP-4, IP-5) are used.
Boxes of industrial gas masks are strictly specialized in purpose (according to the composition of absorbers) and differ in coloring and markings. Some are made with aerosol filters, others without. A white vertical stripe on the box means it has a filter. To protect against chlorine, you can use industrial gas masks of brands A (the box is painted brown), BKF (protective), B (yellow), G (half black, half yellow), as well as civilian gas masks GP-5, GP-7 and children's. What if they don't exist? Then apply a cotton-gauze bandage moistened with water, or better yet, a 2% solution of baking soda.
Civilian gas masks GP-5, GP-7 and children's PDF-2D (D), PDF-2Sh (Sh) and PDF-7 reliably protect against hazardous chemicals such as chlorine, hydrogen sulfide, sulfur dioxide, hydrochloric acid, tetraethyl lead, ethyl mercaptan, phenol , furfural.
For the population, available skin protection products, complete with gas masks, are recommended. These can be ordinary waterproof capes and raincoats, as well as coats made of dense thick material, and cotton jackets. For feet - rubber boots, boots, galoshes. For hands - all types of rubber and leather gloves and mittens.
In the event of an accident involving the release of hazardous substances, civil defense shelters provide reliable protection. Firstly, if the type of substance is unknown or its concentration is too high, you can switch to complete isolation (third mode), you can also stay in a room with a constant volume of air for some time. Secondly, filter absorbers of protective structures prevent the penetration of chlorine, phosgene, hydrogen sulfide and many other toxic substances, ensuring the safe stay of people.
You need to leave the infection zone in one direction, perpendicular to the direction of the wind, focusing on the readings of a weather vane, the waving of a flag or any other piece of material, and the slope of trees in an open area. Voice information about an emergency situation should indicate where and on which streets or roads it is advisable to exit (exit) so as not to fall under an infected cloud. In such cases, you need to use any transport: buses, trucks and cars.
Time is the deciding factor. You must leave your houses and apartments for a period of time - 1-3 days: until the toxic cloud passes and the source of its formation is localized.
Medical care for those affected by hazardous chemicals
Contaminants can enter the human body through the respiratory tract, gastrointestinal tract, skin and mucous membranes. When entering the body, they cause disruption of vital functions and pose a danger to life.
According to the speed of development and nature, acute, subacute and chronic poisonings are distinguished.
Acute poisonings are those that occur within a few minutes or several hours from the moment the poison enters the body. The general principles of emergency care for damage to hazardous chemicals are:
- stopping further poison entering the body and removing what is not absorbed;
- accelerated removal of absorbed toxic substances from the body;
- use of specific antidotes (antidotes);
- pathogenetic and symptomatic therapy (restoration and maintenance of vital functions).
In case of inhalation of hazardous substances (through the respiratory tract), put on a gas mask, remove or remove from the contaminated area, rinse the mouth, if necessary, sanitize.
In case of contact with the skin - mechanical removal, use of special degassing solutions or washing with soap and water, if necessary, complete sanitization. Immediately rinse eyes with water
etc.................
Question 1. How did the activities of primitive man affect the environment?
Already more than 1 million years ago, Pithecanthropus obtained food by hunting. Neanderthals used a variety of stone tools for hunting and hunted their prey collectively. Cro-Magnons created snares, spears, spear throwers and other devices. However, all this did not make serious changes to the structure of ecosystems. Human impact on nature intensified during the Neolithic era, when cattle breeding and agriculture began to become increasingly important. Man began to destroy natural communities, without, however, yet having a global impact on the bio-sphere as a whole. Nevertheless, unregulated grazing of livestock, as well as clearing of forests for fuel and crops, already at that time changed the state of many natural ecosystems.
Question 2. To what period of development of human society does the origin of agricultural production belong?
Agriculture appeared after the end of glaciation in the Neolithic era (New Stone Age). This period is usually dated to 8-3 millennia BC. e. At this time, man domesticated several species of animals (first the dog, then the ungulates - pig, sheep, goat, cow, horse) and began to cultivate the first cultivated plants (wheat, barley, legumes).
Question 3. Name the reasons for the possible occurrence of water shortages in a number of areas of the world.
A lack of water can arise as a result of various human actions. With the construction of dams and changes in river beds, a redistribution of water flow occurs: some territories are flooded, others begin to suffer from drought. Increased evaporation from the surface of reservoirs leads not only to the formation of water shortages, but also changes the climate of entire regions. Irrigated agriculture depletes surface and soil water supplies. Deforestation on the border with deserts contributes to the formation of new territories with a lack of water. Finally, the reasons may be high population density, excessive industrial needs, as well as pollution of existing water supplies.
Question 4. How does the destruction of forests affect the state of the bio-sphere?Material from the site
Deforestation catastrophically worsens the condition of the biosphere as a whole. As a result of logging, surface water flow increases, which increases the likelihood of floods. Intensive soil erosion begins, leading to the destruction of the fertile layer and pollution of water bodies with organic substances, water blooms, etc. Deforestation increases the amount of carbon dioxide in the atmosphere, which is one of the factors increasing the greenhouse effect; the amount of dust in the air is growing; The danger of a gradual decrease in the amount of oxygen is also relevant.
Cutting down large trees destroys established forest ecosystems. They are replaced by much less productive biocenoses: small forests, swamps, semi-deserts. At the same time, dozens of species of plants and animals may disappear irrevocably.
Currently, the main “lungs” of our planet are the equatorial tropical forests and taiga. Both of these groups of eco-systems require extremely careful treatment and protection.
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