With the advent and improvement of man, the evolutionary processes of the biosphere have undergone significant changes. At the dawn of his appearance, man had a predominantly local impact on the environment. This was expressed, first of all, in satisfaction minimum needs in food and shelter. Ancient hunters, when the number of game animals decreased, moved to hunt in other places. Ancient farmers and cattle breeders, if the soil was depleted or there was less food, developed new lands. The population of the planet was small. There was almost no industrial production of any kind. The small amount of waste and pollution generated at that time as a result of human activity did not pose a danger. Everything could be disposed of due to the destructive function of living matter.
The growth of the planet's population, the successful development of animal husbandry, agriculture and scientific and technological progress have determined the further development of mankind.
Now there are more than 7 billion people living on Earth, by 2030 this number will grow to 10 billion, and by 2050 - to 12.5 billion people. Providing the world's population with food and energy resources is already an acute problem. Today, about 70% of the world's population lives in countries where there is a constant shortage of food. Non-renewable natural resources are being reduced catastrophically quickly. For example, according to scientists' forecasts, humanity will use up all its metal reserves within the next 200 years.
Human economic activity on modern stage increasingly demonstrates negative examples of impact on the biosphere. These include: environmental pollution, depletion natural resources, desertification, soil erosion. Natural communities are also disturbed, forests are cut down, and rare species plants and animals.
Environmental pollution
Environmental pollution- the entry into the environment of new, uncharacteristic solid, liquid and gaseous substances or an excess of their natural level in the environment, which has a negative impact on the biosphere.
Air pollution
Clean air is essential for the life of all living organisms. In many countries, the problem of maintaining its purity is a government priority. The main cause of air pollution is the burning of fossil fuels. Of course, it still plays a leading role in providing energy to all sectors of the economy. Today, the planet's vegetation is no longer able to completely assimilate the combustion products of liquid and solid fuels.
Carbon oxides (CO and CO 2) entering the atmosphere as a result of fuel combustion are the cause of the greenhouse effect. Sulfur oxides (SO 2 and SO 3), formed as a result of the combustion of fuel containing sulfur, interact with water vapor in the atmosphere. The end products of such a reaction are solutions of sulfurous (H 2 SO 3) and sulfuric (H 2 SO 4) acids. These acids fall to the surface of the earth with precipitation, cause acidification of the soil, and lead to human diseases. Forest ecosystems, especially conifers, suffer the most from acid precipitation. They experience destruction of chlorophyll, underdevelopment of pollen grains, drying and falling of needles.
Nitrogen oxides (NO and NO 2) exposed to ultraviolet rays, participate in the formation of free radicals in the atmosphere. Nitrogen oxides lead to the development of a number of pathological conditions in humans and animals. These gases, for example, irritate the respiratory tract, cause pulmonary edema, etc.
Chlorine compounds make a significant contribution to the destruction of the planet's ozone layer. For example, one free chlorine radical can destroy up to 100 thousand ozone molecules, which causes ozone holes in the atmosphere.
Reasons radioactive contamination atmosphere are accidents at nuclear power plants (for example, at the Chernobyl nuclear power plant in 1986). Nuclear weapons testing and improper disposal of nuclear waste also contribute to this process. Radioactive particles released into the atmosphere are scattered over long distances, polluting the soil, air, and water bodies.
Transport should also be mentioned as a source of air pollution. Exhaust gases from internal combustion engines contain a wide range of pollutants. Among them are carbon and nitrogen oxides, soot, as well as heavy metals and compounds that have a carcinogenic effect.
Hydrosphere pollution
Fresh water shortage is a global environmental problem. Along with water consumption and shortages, growing pollution of the hydrosphere is a concern.
The main cause of water pollution is direct discharge into aquatic ecosystems industrial waste and municipal wastewater. IN in this case With chemicals, biological contaminants (for example, pathogenic bacteria) also enter the aquatic environment. When heated wastewater is discharged, physical (thermal) pollution of the hydrosphere occurs. Such discharges reduce the amount of oxygen in water, increase the toxicity of impurities and often lead to death (death of aquatic organisms).
Soil pollution
Depletion of natural resources
Natural resources- the means of subsistence of people that are not created by their labor, but are found in nature. The main problem of their current state is the reduction in the amount of exhaustible and deteriorating quality of inexhaustible natural resources. Especially it concerns animals And plant resources. Habitat destruction, environmental pollution, overuse of natural resources, poaching are significantly reduced species diversity plants and animals.
During the existence of mankind, about 70% of forest lands have been cut down and destroyed. This caused the extinction of plant species that lived in herbaceous and shrub layers. They could not exist in conditions of direct solar radiation. Due to deforestation, the animal world has also changed. Animal species that had close connections with tree layers either disappeared or migrated to other places.
It is believed that since 1600, as a result of human activity, about 250 species of animals and 1000 species of plants have completely disappeared from the face of the Earth. About 1,000 animal species and 25,000 plant species are currently under threat of extinction.
Animal and plant resources are capable of constant restoration. If the rate of their use does not exceed the rate of natural renewal, then these resources can exist for a very long time. However, the speed of their renewal is different. Animal populations can recover within a few years. Forests grow over several decades. And soils that have lost fertility restore it very slowly—over several millennia.
A very important resource problem for the planet is maintaining quality fresh water. As you know, the total reserves of water on the planet are inexhaustible. However, fresh water accounts for only about 3% of the entire hydrosphere. Moreover, only 1% of fresh water is suitable for direct human consumption without preliminary purification. Approximately 1 billion people on Earth do not have regular access to fresh drinking water. Therefore, humanity must consider fresh water as a finite natural resource. The fresh water problem is getting worse every year due to the shallowing of rivers and lakes as a result of reclamation activities. Water consumption for the needs of agriculture and industry is increasing, and water bodies are becoming polluted by industrial and household waste.
The lack of fresh water and its poor quality also affect people's health. It is known that the most dangerous infectious diseases (cholera, dysentery, etc.) occur in places where access to clean water is difficult.
Desertification
Desertification- a set of processes that lead to the loss of continuous vegetation cover by a natural community with the impossibility of its restoration without human intervention. The causes of desertification are predominantly anthropogenic factors. This is deforestation, irrational use of water resources during land irrigation, etc. For example, excessive cutting of arboreal mountain vegetation causes natural disasters - mudflows, landslides, avalanches. Excessive load on pastures with an increase in the scale of livestock farming can also lead to desertification. The vegetation cover, eaten away by animals, does not have time to recover, and
the soil is subject to various types of erosion.
Soil erosion is the destruction of the fertile layer of soil under the influence of wind and water.
Soil erosion occurs due to the massive inclusion of more and more land into active land use by humans.
Desertification is most common in areas with arid climates (deserts, semi-deserts) - countries in Africa and Asia (especially China).
Today this problem is of an interethnic nature. Therefore, the UN adopted the International Convention to Combat Desertification, which was signed by almost 200 states.
The main consequences of human economic activity are environmental pollution, depletion of natural resources and desertification of lands. Preventing the destructive influence of the anthropogenic factor on the biosphere is today an important universal problem in which every inhabitant of the Earth must participate in the solution.
In accordance with population density, the degree of human impact on the environment also changes. However, at the current level of development of productive forces, the activities of human society affect the biosphere as a whole. Humanity, with its social laws of development and powerful technology, is quite capable of influencing the centuries-old course of biosphere processes.
Air pollution.
In the course of their activities, people pollute the air. Over cities and industrial areas in the atmosphere, the concentration of gases increases, which in rural areas are contained in very small quantities or are completely absent. Polluted air is harmful to health. In addition, harmful gases, combining with atmospheric moisture and falling in the form of acid rain, deteriorate the quality of the soil and reduce crop yields.
The main causes of air pollution are the combustion of natural fuels and metallurgical production. If in the 19th century the products of combustion of coal and liquid fuel entering the environment were almost completely assimilated by the vegetation of the Earth, now the content of harmful combustion products is steadily increasing. From stoves, furnaces, and car exhaust pipes, it gets into the air. whole line pollutants. Among them, sulfur dioxide is especially prominent - a poisonous gas that is easily soluble in water.
The concentration of sulfur dioxide in the atmosphere is especially high in the vicinity of copper smelters. It causes the destruction of chlorophyll, underdevelopment of pollen grains, drying and falling of pine leaves. Some SO 2 is oxidized to sulfuric anhydride. Solutions of sulfurous and sulfuric acids, falling with rain on the surface of the Earth, cause harm to living organisms and destroy buildings. The soil becomes acidic, and humus (humus) is washed out of it - an organic substance containing components necessary for the development of plants. In addition, it reduces the amount of calcium, magnesium, and potassium salts. IN acidic soils The number of animal species living in it also decreases, and the rate of decomposition of litter slows down. All this creates unfavourable conditions for plant growth.
Every year, billions of tons of CO 2 are released into the atmosphere as a result of fuel combustion. Half of the carbon dioxide produced by the combustion of fossil fuels is absorbed by the ocean and green plants, while half remains in the air. The CO 2 content in the atmosphere is gradually increasing and has increased by more than 10% over the past 100 years. CO 2 prevents thermal radiation into outer space, creating the so-called “greenhouse effect”. Changes in CO 2 content in the atmosphere significantly affect the Earth's climate.
Industrial enterprises and cars cause the release of many toxic compounds into the atmosphere - nitrogen oxide, carbon monoxide, lead compounds (each car emits 1 kg of lead per year), various hydrocarbons - acetylene, ethylene, methane, propane, etc. Together with droplets of water they form a toxic fog - smog, which has a harmful effect on the human body and the vegetation of cities. Liquid and solid particles (dust) suspended in the air reduce the amount of solar radiation reaching the Earth's surface. Thus, in large cities, solar radiation decreases by 15%, ultraviolet radiation by 30% (and in the winter months it may completely disappear).
Fresh water pollution.
The use of water resources is increasing rapidly. This is due to population growth and improvement of sanitary and hygienic conditions of human life, the development of industry and irrigated agriculture. Daily water consumption for household needs in rural areas is 50 liters per person, in cities - 150 liters.
Huge amounts of water are used in industry. To melt 1 ton of steel, 200 m 3 of water is required, and to produce 1 ton of synthetic fiber - from 2500 to 5000 m 3. Industry absorbs 85% of all water used in cities.
Even more water is needed for irrigation. During the year, 12-14 m3 of water is consumed per 1 hectare of irrigated land. In our country, more than 150 km 3 is spent annually on irrigation.
The constant increase in water consumption on the planet leads to the danger of “water hunger,” which necessitates the development of measures for the rational use of water resources. Except high level water shortage is caused by its growing pollution due to the discharge of industrial and especially waste into rivers chemical production. Bacterial pollution and toxic chemicals (for example, phenol) lead to the death of water bodies. Harmful effects There is also a mole rafting of timber along rivers, which is often accompanied by congestion. When wood stays in water for a long time, it loses its commercial qualities, and the substances washed out of it have a detrimental effect on fish.
They are also washed out of the soil by rain and enter rivers and lakes. mineral fertilizers- nitrates and phosphates, which in high concentrations can dramatically change the species composition of water bodies, as well as various pesticides - pesticides used in agriculture to control insect pests. For aerobic organisms living in fresh waters, the discharge of warm water by enterprises is also an unfavorable factor. Oxygen is poorly soluble in warm water and its deficiency can lead to the death of many organisms.
Pollution of the World Ocean. The waters of the seas and oceans are subject to significant pollution. With river runoff, as well as from sea transport, pathogenic waste, petroleum products, salts of heavy metals, toxic organic compounds, including pesticides, enter the seas. Pollution of the seas and oceans reaches such proportions that in some cases caught fish and shellfish are unsuitable for consumption.
Anthropogenic changes in the soil.
The fertile layer of soil takes a very long time to form. At the same time, tens of millions of tons of nitrogen, potassium, and phosphorus - the main components of plant nutrition - are removed from the soil every year along with the harvest. Humus, the main factor of soil fertility, is contained in chernozems in an amount of less than 5% of the mass of the arable layer. On poor soils there is even less humus. In the absence of replenishment of soils with nitrogen compounds, its supply can be used up in 50-100 years. This does not happen, since cultural farming involves the introduction of organic and inorganic (mineral) fertilizers into the soil.
Added to the soil nitrogen fertilizers used by plants by 40-50%. The rest is reduced by microorganisms to gaseous substances, evaporates into the atmosphere or is washed out of the soil. Thus, mineral nitrogen fertilizers are quickly consumed, so they have to be applied annually. With insufficient use of organic and inorganic fertilizers, the soil is depleted and yields fall. Unfavorable changes in the soil also occur as a result of incorrect crop rotations, that is, annual sowing of the same crops, for example potatoes.
Anthropogenic soil changes include erosion (corrosion). Erosion is the destruction and removal of soil cover by water flows or wind. Water erosion is widespread and most destructive. It occurs on slopes and develops due to improper cultivation of the land. Together with melt and rainwater, millions of tons of soil are carried away from fields into rivers and seas every year. If nothing prevents erosion, small gullies turn into deeper ones and, finally, into ravines.
Wind erosion occurs in areas with dry, bare soil and sparse vegetation cover. Excessive grazing in steppes and semi-deserts contributes to wind erosion and rapid destruction of grass cover. To restore a 1 cm thick layer of soil in natural conditions it takes 250-300 years. Consequently, dust storms bring irreparable loss of fertile soil layer.
Significant territories with formed soils are withdrawn from agricultural use due to the open-pit mining method for minerals lying at shallow depths. Open way production is cheap, as it eliminates the need to build expensive mines and complex system communications and is also more secure. Dug deep quarries and dumps of soil destroy not only the lands to be developed, but also the surrounding areas, while the hydrological regime of the area is disrupted, water, soil and atmosphere are polluted, and agricultural yields are reduced.
Human influence on flora and fauna.
Human impact on wildlife consists of direct influence and indirect changes in the natural environment. One form of direct impact on plants and animals is forest cutting. Selective and sanitary cuttings, which regulate the composition and quality of the forest and are necessary to remove damaged and diseased trees, do not significantly affect the species composition of forest biocenoses.
Another thing is clear cutting of trees. Finding themselves suddenly in open habitat conditions, plants in the lower tiers of the forest experience the adverse effects of direct solar radiation. In shade-loving plants of the herbaceous and shrub layers, chlorophyll is destroyed, growth is inhibited, and some species disappear. Light-loving plants that are resistant to elevated temperature and lack of moisture. The animal world is also changing: species associated with the tree stand disappear or migrate to other places.
Mass visits to forests by vacationers and tourists have a noticeable impact on the state of vegetation. In these cases, the harmful effect is trampling, compaction of the soil and its pollution. The direct influence of man on the animal world is the extermination of species that provide food or other material benefits to him. It is believed that since 1600, more than 160 species and subspecies of birds and at least 100 species of mammals have been exterminated by humans. The long list of extinct species includes the aurochs, a wild bull that lived throughout Europe.
In the 18th century was exterminated, described by the Russian naturalist G.V. Steller's sea cow (Steller's cow) is an aquatic mammal belonging to the order Sirenidae. A little over a hundred years ago, the wild Tarpan horse, which lived in southern Russia, disappeared. Many animal species are on the verge of extinction or are preserved only in nature reserves. This is the fate of the bison, tens of millions of whom inhabited the prairies. North America, and bison, formerly widespread in the forests of Europe. In the Far East, sika deer have been almost completely exterminated. Intensified fishing for cetaceans has brought several species of whales to the brink of destruction: gray, bowhead, and blue.
The number of animals is also influenced by human economic activities not related to fishing. The number of Ussuri tigers has sharply decreased. This occurred as a result of the development of territories within its range and a reduction in the food supply. IN Pacific Ocean Every year, several tens of thousands of dolphins die: during the fishing season, they get caught in nets and cannot get out of them. Until recently, before fishermen took special measures, the number of dolphins dying in nets reached hundreds of thousands.
The effects of water pollution are very unfavorable for marine mammals. In such cases, a ban on catching animals is ineffective. For example, after the ban on catching dolphins in the Black Sea, their numbers have not recovered. The reason is that many toxic substances enter the Black Sea with river water and through straits from the Mediterranean Sea. These substances are especially harmful to baby dolphins, whose high mortality rate prevents the growth of the population of these cetaceans.
The disappearance of a relatively small number of animal and plant species may not seem very significant. Each species occupies a certain place in the biocenosis, in the chain, and no one can replace it. The disappearance of one or another species leads to a decrease in the stability of biocenoses. More importantly, each species has unique properties that are unique to it. The loss of genes that determine these properties and were selected during long-term evolution deprives a person of the opportunity in the future to use them for his practical purposes (for example, for selection).
Radioactive contamination of the biosphere.
The problem of radioactive contamination arose in 1945 after the explosion of atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki. Nuclear weapons tests carried out in the atmosphere before 1963 caused global radioactive contamination. When atomic bombs explode, very strong ionizing radiation is generated; radioactive particles are scattered over long distances, contaminating the soil, water bodies, and living organisms. Many radioactive isotopes have long half-lives, remaining dangerous throughout their existence. All these isotopes are included in the cycle of substances, enter living organisms and have a detrimental effect on cells.
Testing nuclear weapons (and even more so when using these weapons for military purposes) has another negative side. At nuclear explosion A huge amount of fine dust is formed, which remains in the atmosphere and absorbs a significant part of solar radiation. Calculations by scientists from around the world show that even with limited, local use of nuclear weapons, the resulting dust will block most of the solar radiation. A long-term cooling (“nuclear winter”) will occur, which will inevitably lead to the death of all life on Earth.
Currently, almost any territory of the planet from the Arctic to Antarctica is subject to diverse anthropogenic influences. The consequences of the destruction of natural biocenoses and environmental pollution have become very serious. The entire biosphere is under increasing pressure from human activity, so environmental protection measures are becoming an urgent task.
Acidic atmospheric deposition on land.
One of the most pressing global problems of our time and the foreseeable future is the problem of increasing acidity of atmospheric precipitation and soil cover. Areas of acidic soils do not experience droughts, but their natural fertility is reduced and unstable; They are quickly depleted and their yields are low. Acid rain not only causes acidification of surface waters and upper soil horizons. Acidity with downward flows of water spreads across the entire soil profile and causes significant acidification of groundwater.
Acid rain occurs as a result of human economic activity, accompanied by the emission of colossal amounts of oxides of sulfur, nitrogen, and carbon. These oxides, entering the atmosphere, are transported over long distances, interact with water and turn into solutions of a mixture of sulfur, sulfur, nitrogen, nitrogen and carbonic acid, which fall in the form of “acid rain” on land, interacting with plants, soils, and waters. The main sources in the atmosphere are the combustion of shale, oil, coal, and gas in industry, agriculture, and everyday life.
Human economic activity has almost doubled the release of oxides of sulfur, nitrogen, hydrogen sulfide and carbon monoxide into the atmosphere. Naturally, this affected the increase in acidity of atmospheric precipitation, surface and groundwater. To solve this problem, it is necessary to increase the volume of systematic representative measurements of compounds of air pollutants over large areas.
All humanity faces the most important task - preserving the diversity of all organisms living on Earth. All species (vegetation, animals) are closely interconnected. The destruction of even one of them leads to the disappearance of other species associated with it.
From the very moment man invented tools and became more or less intelligent, his comprehensive influence on the nature of the planet began. The more man developed, the greater the impact he had on the Earth's environment. How does man influence nature? What is positive and what is negative?
Negative points
There are both pros and cons of human influence on nature. First, let's look at negative examples of harmful things:
- Deforestation associated with the construction of highways, etc.
- Soil pollution occurs due to the use of fertilizers and chemicals.
- Reduction in population numbers due to the expansion of fields for fields through deforestation (animals, deprived of their normal habitat, die).
- The destruction of plants and animals due to the difficulties of their adaptation to a new life, greatly changed by man, or simply their extermination by people.
- and water by diverse people themselves. For example, in the Pacific Ocean there is a “dead zone” where a huge amount of garbage floats.
Examples of human influence on the nature of the ocean and mountains, on the state of fresh water
The change in nature under human influence is very significant. The flora and fauna of the Earth are severely affected, and water resources are polluted.
Typically, light debris remains on the surface of the ocean. In this regard, access of air (oxygen) and light to the inhabitants of these territories is difficult. Numerous species of living creatures are trying to look for new places for their habitat, which, unfortunately, not everyone succeeds in.
Every year, ocean currents bring in millions of tons of trash. This is a real disaster.
Deforestation on mountain slopes also has a negative impact. They become bare, which contributes to erosion and, as a result, the soil loosens. And this leads to devastating collapses.
Pollution occurs not only in the oceans, but also in fresh water. Thousands of cubic meters of sewage or industrial waste flow into rivers every day.
And they are contaminated with pesticides and chemical fertilizers.
The terrible consequences of oil spills, mining
Just one drop of oil renders approximately 25 liters of water unfit for drinking. But that's not the worst thing. A fairly thin film of oil covers the surface of a huge area of water - approximately 20 m 2 of water. This is destructive for all living things. All organisms under such a film are doomed to slow death, because it prevents the access of oxygen to the water. This is also a direct influence of man on the nature of the Earth.
People extract minerals from the depths of the Earth, formed over several million years - oil, coal, etc. Such industrial production, along with cars, emit carbon dioxide into the atmosphere in huge quantities, which leads to a catastrophic decrease in the ozone layer of the atmosphere - the protector of the Earth's surface from deadly ultraviolet radiation from the Sun.
Over the past 50 years, the air temperature on Earth has increased by only 0.6 degrees. But that's a lot.
Such warming will lead to an increase in the temperature of the world's oceans, which will contribute to the melting of polar glaciers in the Arctic. Thus, the most global problem arises - the ecosystem of the Earth's poles is disrupted. Glaciers are the most important and voluminous sources of clean fresh water.
Benefit of people
It should be noted that people bring certain benefits, and considerable ones.
From this point of view, it is necessary to note the influence of man on nature. The positive lies in the activities carried out by people to improve the ecology of the environment.
In many vast territories of the Earth in different countries, protected areas, reserves and parks are organized - places where everything is preserved in its original form. This is the most reasonable influence of man on nature, a positive one. In such protected areas, people contribute to the conservation of flora and fauna.
Thanks to their creation, many species of animals and plants have survived on Earth. Rare and already endangered species are necessarily included in the man-made Red Book, according to which fishing and collection of them is prohibited.
People also create artificial water channels and irrigation systems that help maintain and increase
Planting of diverse vegetation is also carried out on a large scale.
Ways to solve emerging problems in nature
To solve problems, it is necessary and important, first of all, to have an active influence of man on nature (positive).
As for biological resources (animals and plants), they should be used (extracted) in such a way that individuals always remain in nature in quantities that contribute to the restoration of the previous population size.
It is also necessary to continue work on organizing nature reserves and planting forests.
Carrying out all these activities to restore and improve the environment is a positive human impact on nature. All this is necessary for the benefit of oneself.
After all, the well-being of human life, like all biological organisms, depends on the state of nature. Now all humanity faces the most important problem - creating a favorable state and sustainability of the living environment.
Detailed solution Paragraph § 32 in biology for 6th grade students, authors Pasechnik V.V. 2014
1. What factors influence the development of the plant world?
Over many hundreds of millions of years, the main influence on vegetable world were influenced by natural factors: light, heat, moisture, interaction of plants and animals. With the advent of Homo sapiens, his activities began to have an increasing impact on the world around him.
2. What adaptations to natural conditions are developed in plants?
Adaptations of organisms to the environment are called adaptation. The ability to adapt is one of the main properties of life in general, ensuring the possibility of its existence, the ability of organisms to survive and reproduce.
Adaptations manifest themselves at different levels - from the biochemistry of cells and the behavior of individual organisms to the structure and functioning of communities and ecological systems. All adaptations of organisms to existence in different conditions developed historically.
For example, plants in arid regions are capable of adapting to atmospheric and soil drought in the process of individual development. Characteristic features are the small size of their evaporating surface, as well as small sizes aboveground part compared to underground. They also have insignificant transpiration, high osmotic pressure, and the cytoplasm is highly elastic and viscous. Some plants in arid areas are capable of shedding leaves and even entire branches.
There are many examples that can be given, because For specific conditions, plants develop certain adaptations.
3. What is the importance of plants in human life?
Cultivated plants are grown by humans to obtain food products, agricultural feed, medicines, industrial and other raw materials.
By observing the plants that are most sensitive to pollution, scientists can very accurately judge environmental pollution. Pollution-resistant plants are used for landscaping in cities with developed industry and an abundance of cars. These plants actively absorb various harmful substances from the air and are good dust collectors.
Questions
1. What impact does human economic activity have on the plant world?
Rapid human activity: plowing land, uprooting and burning forests, grazing pastures and trampling grass by domestic animals - has led to serious changes in nature. Man began to notice that as a result of his economic activities, dense forests thinned out, the number of species of wild animals decreased, and some disappeared completely. Deforestation caused shallowing of rivers and a decrease in fish catches. The soils became depleted, there were more ravines, dry winds and black storms became more frequent.
Particularly strong changes occurred around cities. Vast dumps of garbage and waste grew. In many reservoirs, the water has become undrinkable. Polluted water, air, and soil caused disturbances and sometimes the death of natural communities.
Similar changes in nature have occurred everywhere, in many countries around the world. Over the past millennia, 2/3 of all forests on the globe have been cut down and burned, over 500 million hectares of fertile land have turned into deserts. Many species of plants and animals have disappeared from our planet. The numbers of some species have declined.
2. For what purpose are reserves created? How are they different from nature reserves?
Unlike nature reserves, on the territory of nature reserves not the entire natural complex is protected, but only that part of it that ensures the existence of certain plants and animals.
3. How is nature protected in our country?
State and public environmental organizations are actively working in our country.
Currently, in our country, laws are being adopted and measures are being taken aimed at “protecting the environment from harmful influences on it.”
Greater role in security rare plants botanical gardens, experimental stations and other similar institutions play.
4. What is the role of plants in improving the environment?
The plants that are most sensitive to pollution can serve as indicators of the state of the environment, and the resistant ones should be used for landscaping cities with developed industry and an abundance of cars. These plants actively absorb various harmful substances from the air and are good dust collectors.
Forests around industrial centers play an important ecological and health role. Being a stable plant community with a large number of species, the forest is especially active in absorbing and processing harmful substances.
Man ends up living off green plants- the main producers of organic substances and oxygen.
5. Why should nature conservation be the concern of all people on the planet?
Nature protection and rational use of its resources are important not only for one state, but also for the entire globe as a whole, i.e. for every person. Only in this case can the most productive results be achieved.
By protecting, restoring and increasing the vegetation cover of our planet, we create conditions for life not only of our contemporaries, but also of future generations.
Summer assignments
1. Study the species composition of trees, shrubs and floral and ornamental (used in landscaping) plants. Determine in what period (flowering, fruiting, etc.) each species is most decorative. Which plants should be used more widely in landscaping?
Pollution-resistant plants should be used more widely in landscaping, especially for landscaping cities with developed industry and an abundance of cars. The most resistant to atmospheric air pollution are white acacia, yellow acacia (Caragana), poplar, chestnut, birch, alder, willow, hawthorn, lilac, larch, etc. These plants actively absorb various harmful substances from the air and are good dust collectors. Plants skillfully used in landscaping not only purify the air from substances harmful to health, but also make populated areas cozy and beautiful.
2. Study the species composition of one of the plant communities. Make a list of plants growing in different layers.
The species composition of deciduous forest is diverse:
In the deciduous forest there are oaks, lindens, birches, maples, elms and others large trees form the first, upper tier;
Rowan, bird cherry, hazel (hazel), forest honeysuckle - second tier;
Euonymus, raspberry - third tier (shrubs);
Chin, hoof, raven eye, snowflake, several types of bells, chickweed, anemone, lily of the valley, lungwort, yellow green grass and many other plants - the fourth (herbs and ferns);
Fifth - lichens, mosses and mushrooms.
3. Study the structural features of plants belonging to various ecological groups. Describe 2-3 plants you studied from different ecological groups.
Plants are divided into ecological groups in relation to various environmental factors. The most important of them are humidity and light.
In relation to moisture, five ecological groups of plants are distinguished:
1) hydatophytes - aquatic grasses that are completely submerged in water, their leaves are very thin, and nutrients are absorbed by the entire surface of the body. Among them are flowering plants, which were secondarily transferred to water image life (for example, elodea). When taken out of the water, these plants quickly dry out and die. They have no stomata and no cuticle. There is no transpiration in such plants, and water is released through special cells. Shoots supported by water often do not have mechanical tissues; aerenchyma (air-bearing tissue) is well developed in them;
2) hydrophytes - plants partially submerged in water, usually living along the banks of reservoirs in damp meadows and swamps. These include common reed. They have better developed conductive and mechanical tissues than hydatophytes. Aerenchyma is well expressed. Hydrophytes have an epidermis with stomata, the rate of transpiration is very high, and they can grow only with constant intensive absorption of water;
3) hygrophytes - plants in damp places with high humidity air.
4) mesophytes - plants living in conditions of moderate moisture, moderate temperatures and good mineral nutrition.
5) xerophytes - plants in habitats that are not sufficiently humidified, where there is little water in the soil and the air is hot and dry. Among them there are herbs and woody plants. They have devices that allow them to obtain water when there is a shortage of it, limit the evaporation of water, or store it during drought. Xerophytes are better able to regulate water metabolism than all other plants, and therefore remain active during prolonged drought. These are plants of deserts, steppes, hard-leaved evergreen forests and bush thickets, sand dunes. Among xerophytes, a distinction is made between dry (sclerophytes - adapted to strict water conservation) and succulent (succulents - have fleshy stems and/or leaves). For example, feather grass, saxaul, camel thorn - sclerophytes, aloe, crassula, prickly pear, cereus - succulents.
Prickly pear (Opuntia vulgaris) powerful perennial, up to 4-6 m tall, from the subtropics of South America.
Prickly pears are able to grow quickly and form bizarre-shaped bushes. These are large cacti with dark green stalks. Their segments (cladodes) - the size of a palm - are juicy, thick, light green, oblong or obovate, growing from one another. The flattened stems are sometimes mistaken for leaves.
In the areoles on young segments, rudimentary leaves pressed to the surface grow, which then fall off. The leaves are small, juicy, awl-shaped, bright green.
Spines develop somewhat later on mature segments. Usually they are located singly in the areoles (although sometimes there are 2-4 spines in the areole). They are large and needle-shaped.
In addition to spines and leaves in the areoles with gray pubescence, there are also yellowish glochidia. Glochidia are small, fragile spines, very sharp and hard. But the main thing is that they are equipped with microscopic serrated serrations and hooks along their entire length and grow in large quantities in bunches around the areoles. Glochidia easily fly away from the cactus and have a protective function, since they fall off the plant at the slightest touch and dig into the skin. They can cause swelling or irritation, and most importantly, they are difficult to see and remove.
From April to September, this cactus is decorated with yellow shiny flowers. They are formed both at the top and along the edges of the segments, and amaze with the abundance of petals and stamens. This is a characteristic of prickly pears - they bloom brightly and luxuriantly during the day, although sometimes the flowers can remain open for 30-48 hours, attracting huge numbers of bees.
Large wheel-shaped bisexual flowers on a short tubular pedicel develop one at a time on the areoles. Prickly pear stamens usually have short corollas. They are attached to a concave, cup-shaped receptacle and even with a light touch they immediately curl.
The fruits ripen from mid-July to mid-August. The outside of the ovary is covered with scales, and in the axil of the scales there are bunches of spines. These beams are located surprisingly geometrically - in a checkerboard pattern, at the same distance from each other. The resulting green “bumps” of the fruit quickly increase in size, are brightly colored, ripen and become red-burgundy. The fruit of Opuntia vulgaris is a pear-shaped berry and is edible. The fruits of prickly pears are fleshy, juicy, and quite large (up to 5-7.5 cm long, sometimes up to 10 cm, and weighing 70-300 g). The berries contain light-colored seeds with an ossified shell the size of a lentil grain.
The root system of prickly pear is superficial. The main root extends down from the subcotyledon (hypocotyl). It gradually branches, forming a whole system of lateral roots (at a depth of 5-6 cm from the soil surface, root system up to 7 m in length).
4. Study the features and differences in the structure of the vegetative organs of plants of the same species growing in different conditions a habitat.
For example, as a result of a plant’s adaptation to low light, its appearance changes somewhat. The leaves become dark green and slightly increase in size (linear leaves lengthen and become narrower), and the internodes of the stem begin to stretch, which at the same time loses its strength. Then their growth gradually decreases, because The production of photosynthetic products used for the regeneration of the plant body decreases sharply. With a lack of light, many plants stop blooming.
With excess light, chlorophyll is partially destroyed and the color of the leaves becomes yellow-green. In strong light, plant growth slows down, they become more squat with short internodes and wide, short leaves.
5. Find out the effect of sowing density on the growth and development of plants. Sow carrot (beet, radish) seeds in two identical plots (control and experimental). After the seedlings appear on the experimental plot, thin them out, and repeat the thinning after 10-15 days. Observe the development of plants. Determine which plot has more yield. Record your results in a journal.
On the control plot, the carrots will grow large and even (provided there is no negative impacts on plants). And the second one is shallow, crooked, the harvest is smaller. That. with thinning, the result will be better - the root crops will be larger and more even.
6. Remove side shoots from several tomato plants. By comparing these plants with those whose side shoots were not removed, determine which plants produced the greater yield.
Plants from which side shoots have been removed will produce greater yields. Due to this more nutrients will flow to the fruits, and they will be larger.
7. Select several (2-3) trees and shrubs growing near your home and observe them: note the size, crown shape, branching, bark features, location of buds and leaves on the shoot, observe the development of shoots, flowering, etc. d. Write down all data in a diary. Continue observations in the fall.
Silver birch
At favorable conditions reaches 25-30 m in height and up to 80 cm in diameter.
The crown is branched, but not dense. Young branches hang down, which gives the birch crown a very characteristic appearance (the name is silver birch).
Branching is sympodial.
The bark of young trees is brown, and from 8-10 years it turns white. Juveniles can be confused with alder species. In adulthood, it is clearly distinguishable from other trees by its white bark. In older trees, the bark in the lower part of the trunk becomes deeply cracked and black.
The buds are sessile, pointed, sticky, covered with imbricated scales. The leaf arrangement is regular. Leaves are rhombic-ovate to triangular-ovate, 3.5-7 cm long, 2-5 cm wide, pointed at the apex with a broadly cuneate or almost truncated base, smooth, sticky when young, smooth on both sides; the edges are double-toothed. Petioles are bare 0.8-3 cm.
Young shoots are reddish-brown, covered with numerous resinous, rough warts - wax glands; in adult trees, shoots with single glands are bare. The apical and lateral buds are formed on the shoots of the current year in the summer and bloom in the spring.
The flowers are regular, small, inconspicuous, unisexual, collected in ear-shaped, pendulous inflorescences at the ends of the branches. It blooms before the leaves bloom (according to some sources - simultaneously with the leaves blooming) - in May.
Fruiting continues annually. The fruits ripen towards the end of summer and begin to disperse. Dispersal occurs gradually throughout autumn and winter. The fruit is a small winged nut.
Rose hip
Rose hips are not a tall bush, 1.5-2.5 m in height.
An upright shrub with arched hanging branches covered with strong sickle-shaped thorns.
The shoots are branched, green, brown, dark red, dark brownish, sometimes violet-brown, brown, black-brown, brown-red or gray with felt pubescence; as a rule, with straight, curved or hooked spines, often admixed with numerous bristles and hairs, with stalked glands.
The buds are distant, reddish, less often of a different color, bare or hairy, small, with three to six outer bud scales.
The leaf arrangement is regular. The leaflets are elliptical to round in shape, with a wedge-shaped, rounded or slightly heart-shaped base, and serrate at the edges.
Bush forms of rose hips have two types of branches: erect and arched, curved downwards. They form numerous vegetative shoots in the first year, sometimes reaching 1-1.5 m in height and 10-12 mm in diameter, with soft and thin spines of various sizes, flowering and fruiting in subsequent years. Young shoots have a greenish-red tint with small bristles and thorns.
The flowers are pink or white-pink, with five free petals, the corolla is up to 5 cm in diameter. Rose hips bloom in May-June.
The fruit is a specially shaped polynut, called cynarrhodia, 1-1.5 cm in diameter, crowned with sepals, red, orange, purple-red, sometimes black when ripe, usually fleshy, sometimes dry, bare or covered with bristles or spines, coarsely hairy inside , with numerous fruit-nuts, ripen in September-October.
8. Study the structure of flowers of insect-pollinated plants. Determine the duration of flowering and what insects pollinate them.
Linden cordate
The flowers are regular, bisexual, with a double five-part perianth, up to 1-1.5 cm in diameter, yellowish-white, fragrant, collected in pendulous corymbose inflorescences of 3-11 pieces, the inflorescences have an oblong yellowish-green stipule. There are many stamens in a flower. It blooms from the beginning of July for 10-15 days. Pollination is carried out by bees and other insects.
9. Take part in the production of visual teaching aids using plants from a school educational experiment or personal plot. Make herbariums and thematic collections using only cultivated, weedy or widespread plants, for example, “Simple and compound leaves”, “Leaf venation”, “Pest damage to leaves”, “Phases of wheat development”, “Medicinal plants”, etc.
From century to century, people have used the surrounding nature as a source of resource consumption. But until a certain time, this activity did not have a detrimental effect on the world around humans. For example, plants have always served as a source of food for humans, building material for huts, and plants were used to feed livestock.
As humanity developed, it consumed more and more plant raw materials, and with the advent of various devices, mechanisms, and production, the plant world began to suffer serious losses. For example, if a couple of decades ago about 5 thousand types of products were made from wood, now there are already about 15 thousand types of products.
Man strives to make his life better, more comfortable, and therefore takes away more and more resources from nature. As a result, this human influence on plants results in the return of toxic production waste, which is difficult to dispose of. In turn, this becomes a threat to both humans and the environment.
Only at the end of the last century did scientists pay attention to the results of the harmful effects of human economic activity on the plant world. In this regard, scientific programs began to be created and grants were issued to develop ways to improve the environmental situation.
Human economic activity and flora
Industrial emissions have a detrimental effect on plants. For example, phytotoxicants released into the air have a detrimental effect on coniferous forests - these substances cause the forests to dry out. Lately from industrial facilities Tropical forests, which are the main suppliers of oxygen to the surrounding atmosphere, also began to suffer. Restoring tropical forests is a very difficult and extremely time-consuming task.
To produce electricity, hydroelectric power stations and water storage facilities are built on rivers. As a result, large areas of soil are flooded. Improper human activity in cultivating floodplains of rivers and lakes provoked their siltation, which means the disappearance of many aquatic plants.
Population increase, urbanization
It should be noted that the degree of detrimental human influence on the plant world also depends on the size of the population. Indeed, in connection with this, more and more food and energy resources are required, housing problems need to be solved, etc. The population is constantly growing, new generations require more and more resources. But, unfortunately, the possibilities and resources of the planet are not limitless. Therefore, now we need to seriously and quickly solve the problem of insufficient resources.
In addition, the rapid growth of the world's population causes urbanization, which means that there are more and more cities and they occupy larger areas. But at the site of their construction and expansion, natural areas are destroyed. Therefore, often where new cities appear, even the climate becomes different.
Flora - as an object of protection
Under the influence of human activity (direct or indirect), many plant species have been brought to the brink of destruction. They have become rare, disappearing, or have already disappeared completely. Currently, about 30 thousand plant species are known to be completely endangered.
As an object of protection, all plants are divided into aquatic, soil, underground and terrestrial:
Aquatic vegetation growing in water bodies is extremely important for the ecosystem of the water bodies themselves and the organisms living in them. Humans make little use of this group of plants.
Soil vegetation consists of fungi, bacteria, and some algae. All of them have an effect on the soil, making it more fertile. People also do not actively use them.
Terrestrial plants growing on the surface of the earth are most actively used by humans. It was from this group that most plants disappeared.
As a result of its activities, huge areas wild plants replaced by agricultural crops, as man constantly transforms the surrounding nature in his own interests. In addition, plants are disappearing due to unsystematic grazing by farm animals. They eat plants, and those that remain are damaged by their hooves. As a result, degeneration of pastures occurs, and water and wind soil erosion occurs.
If the presence and constantly growing number of industrial enterprises and power plants can be justified by production necessity, then spontaneous landfills and massive littering of haylands and pastures cannot be justified by anything. Spontaneous garbage dumps and the removal of industrial waste to places not intended for this purpose have the most negative impact on the fragile ecosystem. Unorganized collection also has a very detrimental effect on the plant world. medicinal plants, flowers and the activities of tourists leaving behind mountains of garbage.
People increasingly began to face the depletion of recently green corners of nature, pastures, meadows and forests. Thus, he has to study more and more deeply the laws of nature of the surrounding world. Humanity has begun to realize the serious danger of the further harmful effects of its activities on plants, which means that humanity will find ways to reduce it.
