Factors affecting the environment. Fundamentals of ecology

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Nature for humanity is the environment of life, as well as the only source of resources necessary for existence, to meet the material needs of man. Man is an integral part of nature, he consumes natural goods and has environment tangible impact.

With the development of productive forces, as well as an increase in the turnover of substances involved in economic circulation, the impact of human activity on nature is steadily growing.

Thus, at the dawn of civilization Negative influence nature was limited to grazing, burning and cutting down forests for agriculture, and hunting for wild animals. Entire regions were devastated as a result of wars.

After the industrial revolution of the 20th century, serious changes began in biospheric processes. It became possible to compare human activity with natural energy and material processes occurring in the biosphere. The development of chemistry, energy, transport, and mechanical engineering led to this.

Remark 1

Mankind consumes material resources and energy on a scale proportional to population growth.

Consequences of anthropogenic activity of mankind:

depletion of natural resources;
destruction of natural ecosystems;
pollution of the environment by production waste;
changing of the climate;
change in the structure of the surface of the planet Earth.

Remark 2

The result of human anthropogenic impact is a violation of the flow of almost all biogeochemical cycles.

General characteristics of environmental pollution

Definition 2

Pollution is the process of occurrence in the natural environment as a result of human activity or natural phenomena components that are not characteristic of this region.

Pollution is characterized by the presence in the natural environment of harmful compounds that can disrupt the functioning of ecological systems, leading to a decrease in the quality of the environment for human habitation and economic activity.

Ecological action can affect both individual organisms and more high levels organization of living beings: populations, biocenoses, ecosystems, biosphere.

The negative impact of pollution is manifested in

violation of the physiological functions of the body;
lower rates of growth and development;
decrease in the adaptive capacity of the body to the effects of negative environmental factors;
change in the abundance and biomass of populations;
change in annual migration cycles;
violation of quantitative ratios in the biocenosis;
change in the spatial structure of communities of living organisms;
degradation of ecosystems.

Pollutants resulting from human anthropogenic activity are very diverse: sulfur, carbon, nitrogen compounds, organic compounds, heavy metals, radioactive elements, etc.

Anthropogenic impact is manifested in the depletion of the natural resources of the biosphere. As a result of the huge scale of the use of natural resources, landscapes (coal basins) have changed significantly in many regions.

Ways to solve environmental problems

Rational management of natural resources solves a common problem: finding the optimal and best ways to exploit ecosystems.

The solution of this problem is complicated by the need for many optimization criteria:

Reducing production costs.
Getting the best harvest.
Preservation of the species diversity of communities, ensuring the normal functioning of ecosystems.
Maintaining a clean environment.

Restoration of natural resources and environmental protection provide for:

development of new, sparing technologies for the extraction of natural resources;
recultivation of used lands;
the most complete extraction of minerals from deposits;
waste-free use of raw materials;
use of production waste;
use of secondary raw materials;
application closed cycles production;
use of energy saving technologies;
restoration and preservation of forests from fires, diseases, pests;
expansion of protected areas, national parks unique natural complexes;
environmental education of the population;
breeding and protection of rare species of flora and fauna, etc.

A person in the environment, on the one hand, is an object of interaction of environmental factors, on the other hand, he himself has an impact on the environment. From this point of view, man and humanity as a whole are characterized important features. Important feature human as an environmental factor lies in the awareness, purposefulness and massive impact on nature.[ ...]

Any species has limited energy resources, which limits its impact on the environment. For example, green plants use the energy of the Sun, consumers - part of the energy of organic substances formed by organisms of the previous trophic level. Mankind in the process of labor and intellectual activity expands the range of available energy sources up to the use of nuclear and thermonuclear reactions. This allowed people to overcome the natural growth limits of their numbers.[ ...]

The growth of population, energy supply, technical equipment of people creates the prerequisites for the settlement of any ecological niches. Mankind is the only species on Earth with worldwide distribution. This turns a person into an ecological factor with a global impact.[ ...]

Thanks to the impact on all the main components of the biosphere, the impact of mankind reaches the most remote ecological zones of the planet, an example is the detection of DDT in the liver of penguins and seals caught in Antarctica, where insecticides have never been used.[ ...]

As a result of labor activity, a person creates an artificial habitat around him. Natural ecosystems are being replaced by anthropogenic ecosystems, in which man is the absolutely dominant factor.[ ...]

As a result of human activity, changes in the physical environment occur - gas composition air, water and food quality, climate, solar energy flow and other factors that affect the health and performance of people. In deviant extreme conditions a lot of effort and money is spent on the artificial creation and maintenance of optimal environmental conditions.[ ...]

Scale of interaction modern society with nature are determined not by the biological needs of man, but by the continuously increasing level of technical and social development. The technical power of man has reached scales commensurate with biospheric processes. For example, construction and mining machinery transport more material to the Earth's surface every year than is carried to the sea by all the world's rivers as a result of water erosion. Human activity on the planet changes the climate, affects the composition of the atmosphere and the oceans.[ ...]

IN AND. Vernadsky in the first half of the twentieth century predicted the development of the biosphere and its transition to the noosphere - the sphere of reason. Determining the current stage in the development of the biosphere and human society, we can say that technological and anthropogenic processes play an ever-increasing role.[ ...]

The complex hierarchical organization of living nature contains huge reserves of self-regulation. To unlock these reserves, competent intervention in the processes taking place in the biosphere is necessary. The strategy for such intervention can be determined by ecology, based on the achievements of the natural and social sciences.

Communities) with each other and with the environment. This term was first proposed by the German biologist Ernst Haeckel in 1869. As an independent science, it stood out at the beginning of the 20th century along with physiology, genetics and others. The scope of ecology is organisms, populations and communities. Ecology considers them as a living component of a system called an ecosystem. In ecology, the concepts of population - communities and ecosystems have clear definitions.

A population (in terms of ecology) is a group of individuals of the same species, occupying a certain territory and, usually, to some extent isolated from other similar groups.

A community is any group of organisms of different species living in the same area and interacting with each other through trophic (food) or spatial relationships.

An ecosystem is a community of organisms with their environment interacting with each other and forming an ecological unit.

All ecosystems of the Earth are combined into or ecosphere. It is clear that it is absolutely impossible to cover the entire biosphere of the Earth with research. Therefore, the point of application of ecology is the ecosystem. However, an ecosystem, as can be seen from the definitions, consists of populations, individual organisms and all factors of inanimate nature. Based on this, several different approaches to the study of ecosystems are possible.

Ecosystem Approach.With the ecosystem approach, the ecologist studies the flow of energy in the ecosystem as well. The greatest interest in this case is the relationship of organisms with each other and with the environment. This approach makes it possible to explain the complex structure of interconnections in an ecosystem and give recommendations for rational nature management.

Community studies. With this approach, the species composition of communities and the factors that limit the distribution of specific species are studied in detail. In this case, clearly distinguishable biotic units (meadow, forest, swamp, etc.) are studied.
an approach. The point of application of this approach, as the name implies, is the population.
Habitat research. In this case, a relatively homogeneous area of the environment where the given organism lives is studied. Separately, as an independent line of research, it is usually not used, but it provides the necessary material for understanding the ecosystem as a whole.
It should be noted that all of the above approaches should ideally be applied in combination, but in currently this is practically impossible due to the large scale of the studied objects and the limited number of field researchers.

Ecology as a science uses a variety of research methods to obtain objective information about the functioning of natural systems.

Ecological research methods:

observation
experiment
population count
simulation method

The environment that surrounds living beings consists of many elements. They affect the life of organisms in different ways. The latter respond differently to various factors environment. Separate elements of the environment interacting with organisms are called environmental factors. The conditions of existence are a set of vital environmental factors, without which living organisms cannot exist. With regard to organisms, they act as environmental factors.

Classification of environmental factors.

All environmental factors accepted classify(distributed) into the following main groups: abiotic, biotic And anthropic. V Abiotic (abiogenic) factors are physical and chemical factors of inanimate nature. biotic, or biogenic, factors are the direct or indirect influence of living organisms both on each other and on the environment. Antropical (anthropogenic) factors in recent years have been singled out as an independent group of factors among biotic ones, due to their great value. These are factors of direct or indirect impact of man and his economic activity on living organisms and the environment.

abiotic factors.

Abiotic factors include elements of inanimate nature that act on a living organism. Types of abiotic factors are presented in Table. 1.2.2.

Table 1.2.2. Main types of abiotic factors

climatic factors.

All abiotic factors manifest themselves and operate within the three geological shells of the Earth: atmosphere, hydrosphere And lithosphere. Factors that manifest themselves (act) in the atmosphere and during the interaction of the latter with the hydrosphere or with the lithosphere are called climatic. their manifestation depends on the physical and chemical properties of the geological shells of the Earth, on the amount and distribution of solar energy that penetrates and enters them.

Solar radiation.

Solar radiation is of the greatest importance among the variety of environmental factors. (solar radiation). This is a continuous flow of elementary particles (velocity 300-1500 km/s) and electromagnetic waves(speed 300 thousand km / s), which carries a huge amount of energy to the Earth. Solar radiation is the main source of life on our planet. Under a continuous stream of solar radiation, life originated on Earth, passed long haul its evolution and continues to exist and depend on solar energy. The main properties of the radiant energy of the Sun as an environmental factor is determined by the wavelength. Waves passing through the atmosphere and reaching the Earth are measured in the range from 0.3 to 10 microns.

According to the nature of the impact on living organisms, this spectrum of solar radiation is divided into three parts: ultraviolet radiation, visible light And infrared radiation.

shortwave ultraviolet rays almost completely absorbed by the atmosphere, namely its ozone layer. A small amount of ultraviolet rays penetrates the earth's surface. The length of their waves lies in the range of 0.3-0.4 microns. They account for 7% of the energy of solar radiation. Shortwave rays have a detrimental effect on living organisms. They can cause changes in hereditary material - mutations. Therefore, in the process of evolution, organisms that are under the influence of solar radiation for a long time have developed adaptations to protect themselves from ultraviolet rays. In many of them, an additional amount of black pigment, melanin, is produced in the integument, which protects against the penetration of unwanted rays. That is why people get tanned by being outdoors for a long time. In many industrial regions there is a so-called industrial melanism- darkening of the color of animals. But this does not happen under the influence of ultraviolet radiation, but due to pollution with soot, environmental dust, the elements of which usually become darker. Against such a dark background, darker forms of organisms survive (well masked).

visible light manifests itself within the wavelength range from 0.4 to 0.7 microns. It accounts for 48% of the energy of solar radiation.

It also adversely affects living cells and their functions in general: it changes the viscosity of the protoplasm, the magnitude of the electrical charge of the cytoplasm, disrupts the permeability of membranes and changes the movement of the cytoplasm. Light affects the state of protein colloids and the flow of energy processes in cells. But despite this, visible light was, is and will continue to be one of the most important sources of energy for all living things. Its energy is used in the process photosynthesis and accumulates in the form of chemical bonds in the products of photosynthesis, and then is transmitted as food to all other living organisms. In general, we can say that all living things in the biosphere, and even humans, depend on solar energy, on photosynthesis.

Light for animals is necessary condition perception of information about the environment and its elements, vision, visual orientation in space. Depending on the conditions of existence, animals have adapted to varying degrees of illumination. Some animal species are diurnal, while others are most active at dusk or at night. Most mammals and birds lead a twilight lifestyle, do not distinguish colors well and see everything in black and white (dogs, cats, hamsters, owls, nightjars, etc.). Life in twilight or in low light often leads to hypertrophy of the eyes. Relatively huge eyes capable of capturing an insignificant fraction of the light characteristic of nocturnal animals or those that live in complete darkness and are guided by the organs of luminescence of other organisms (lemurs, monkeys, owls, deep-sea fish, etc.). If, in conditions of complete darkness (in caves, underground in burrows), there are no other sources of light, then the animals living there, as a rule, lose their organs of vision (European proteus, mole rat, etc.).

Temperature.

The sources of the creation of the temperature factor on Earth are solar radiation and geothermal processes. Although the core of our planet is characterized by an extremely high temperature, its influence on the surface of the planet is insignificant, except for the zones of volcanic activity and the release of geothermal waters (geysers, fumaroles). Consequently, solar radiation, namely, infrared rays, can be considered the main source of heat within the biosphere. Those rays that reach the Earth's surface are absorbed by the lithosphere and hydrosphere. the lithosphere as solid heats up faster and cools down just as fast. The hydrosphere is more heat-capacious than the lithosphere: it heats up slowly and cools slowly, and therefore retains heat for a long time. The surface layers of the troposphere are heated due to the radiation of heat from the hydrosphere and the surface of the lithosphere. The earth absorbs solar radiation and radiates energy back into the airless space. Nevertheless, the Earth's atmosphere contributes to the retention of heat in the surface layers of the troposphere. Due to its properties, the atmosphere transmits short-wave infrared rays and delays long-wave infrared rays emitted by the heated surface of the Earth. This atmospheric phenomenon is called greenhouse effect. It was thanks to him that life on Earth became possible. The greenhouse effect helps to retain heat in the surface layers of the atmosphere (most organisms are concentrated here) and smooths out temperature fluctuations during the day and night. On the Moon, for example, which is located in almost the same space conditions as the Earth, and on which there is no atmosphere, daily temperature fluctuations at its equator appear in the range from 160 ° C to + 120 ° C.

The range of temperatures available in the environment reaches thousands of degrees (hot volcanic magma and the lowest temperatures of Antarctica). The limits within which life known to us can exist are quite narrow and equal to approximately 300 ° C, from -200 ° C (freezing in liquefied gases) to + 100 ° C (boiling point of water). In fact, most species and most of their activity is tied to an even narrower temperature range. The general temperature range of active life on Earth is limited by the following temperatures (Table 1.2.3):

Table 1.2.3 Temperature range of life on Earth

Plants adapt to different temperatures and even extreme ones. Those that tolerate high temperatures are called fertile plants. They are able to tolerate overheating up to 55-65 ° C (some cacti). Species growing at high temperatures tolerate them more easily due to a significant shortening of the size of the leaves, the development of a felt (pubescent) or, conversely, wax coating, etc. Plants without prejudice to their development are able to withstand prolonged exposure to low temperatures (from 0 to -10 ° C) are called cold-resistant.

Although temperature is an important environmental factor affecting living organisms, its effect is highly dependent on the combination with other abiotic factors.

Humidity.

Humidity is important abiotic factor, which is predetermined by the presence of water or water vapor in the atmosphere or lithosphere. Water itself is a necessary inorganic compound for the life of living organisms.

Water is always present in the atmosphere in the form water couples. The actual mass of water per unit volume of air is called absolute humidity, and the percentage of vapor relative to the maximum amount that air can contain, - relative humidity. Temperature is the main factor affecting the ability of air to hold water vapor. For example, at a temperature of +27°C, the air can contain twice as much moisture as at a temperature of +16°C. This means that the absolute humidity at 27°C is 2 times greater than at 16°C, while the relative humidity in both cases will be 100%.

Water as an ecological factor is extremely necessary for living organisms, because without it metabolism and many other related processes cannot be carried out. The metabolic processes of organisms take place in the presence of water (in aqueous solutions). All living organisms are open systems, therefore, they constantly experience water losses and there is always a need to replenish its reserves. For a normal existence, plants and animals must maintain a certain balance between the intake of water in the body and its loss. Large loss of body water (dehydration) lead to a decrease in its vital activity, and in the future - to death. Plants satisfy their water needs through precipitation, air humidity, and animals also through food. The resistance of organisms to the presence or absence of moisture in the environment is different and depends on the adaptability of the species. In this regard, all terrestrial organisms are divided into three groups: hygrophilic(or moisture-loving), mesophilic(or moderately moisture-loving) and xerophilic(or dry-loving). Regarding plants and animals separately, this section will look like this:

1) hygrophilic organisms:

- hygrophytes(plants);

- hygrophiles(animal);

2) mesophilic organisms:

- mesophytes(plants);

- mesophiles(animal);

3) xerophilic organisms:

- xerophytes(plants);

- xerophiles, or hygrophobia(animals).

Need the most moisture hygrophilous organisms. Among plants, these will be those that live on excessively moist soils with high air humidity (hygrophytes). In the conditions of the middle zone, they include among herbaceous plants that grow in shaded forests (sour, ferns, violets, gap-grass, etc.) and in open places (marigold, sundew, etc.).

Hygrophilous animals (hygrophiles) include those ecologically associated with the aquatic environment or with waterlogged areas. They need a constant presence of a large amount of moisture in the environment. These are animals of tropical rainforests, swamps, wet meadows.

mesophilic organisms require moderate amounts of moisture and are usually associated with moderate warm conditions and good mineral nutrition conditions. It can be forest plants and plants of open places. Among them there are trees (linden, birch), shrubs (hazel, buckthorn) and even more herbs (clover, timothy, fescue, lily of the valley, hoof, etc.). In general, mesophytes are a broad ecological group of plants. To mesophilic animals (mesophiles) belongs to the majority of organisms that live in temperate and subarctic conditions or in certain mountainous land regions.

xerophilic organisms - This is a fairly diverse ecological group of plants and animals that have adapted to arid conditions of existence with the help of such means: limiting evaporation, increasing the extraction of water and creating water reserves for a long period of lack of water supply.

Plants living in arid conditions overcome them in different ways. Some do not have structural adaptations to carry the lack of moisture. their existence is possible in arid conditions only due to the fact that at a critical moment they are at rest in the form of seeds (ephemeris) or bulbs, rhizomes, tubers (ephemeroids), they very easily and quickly switch to active life and in a short period of time completely pass annual cycle of development. Efemeri mainly distributed in deserts, semi-deserts and steppes (stonefly, spring ragwort, turnip "box, etc.). Ephemeroids(from Greek. ephemeri And to look like)- these are perennial herbaceous, mainly spring, plants (sedges, grasses, tulips, etc.).

A very peculiar category of plants that have adapted to endure drought conditions is succulents And sclerophytes. Succulents (from the Greek. juicy) are able to accumulate a large amount of water in themselves and gradually use it. For example, some cacti of the North American deserts can contain from 1000 to 3000 liters of water. Water accumulates in leaves (aloe, stonecrop, agave, young) or stems (cacti and cactus-like spurges).

Animals obtain water in three main ways: directly by drinking or absorbing through the integument, along with food and as a result of metabolism.

Many species of animals drink water and in large enough quantities. For example, caterpillars of the Chinese oak silkworm can drink up to 500 ml of water. Some species of animals and birds require regular water consumption. Therefore, they choose certain springs and regularly visit them as watering places. Desert bird species fly daily to the oases, drink water there and bring water to their chicks.

Some animal species do not consume water by direct drinking, but can consume it by absorbing it with the entire surface of the skin. In insects and larvae that live in soil moistened with tree dust, their integuments are permeable to water. The Australian Moloch lizard absorbs rainfall moisture with its skin, which is extremely hygroscopic. Many animals get moisture from succulent food. Such succulent foods can be grass, succulent fruits, berries, bulbs and tubers of plants. The steppe tortoise living in the Central Asian steppes consumes water only from succulent food. In these regions, in places where vegetables are planted or on melons, turtles cause great damage by eating melons, watermelons, and cucumbers. Some predatory animals also get water by eating their prey. This is typical, for example, of the African fennec fox.

Species that feed exclusively on dry food and do not have the opportunity to consume water get it through metabolism, that is, chemically during the digestion of food. Metabolic water can be formed in the body due to the oxidation of fats and starch. This is an important way of obtaining water, especially for animals that inhabit hot deserts. For example, the red-tailed gerbil sometimes feeds only on dry seeds. Experiments are known when, in captivity, the North American deer mouse lived for about three years, eating only dry grains of barley.

food factors.

The surface of the Earth's lithosphere constitutes a separate living environment, which is characterized by its own set of environmental factors. This group of factors is called edaphic(from Greek. edafos- soil). Soils have their own structure, composition and properties.

Soils are characterized by a certain moisture content, mechanical composition, content of organic, inorganic and organo-mineral compounds, a certain acidity. Many properties of the soil itself and the distribution of living organisms in it depend on the indicators.

For example, certain types of plants and animals love soils with a certain acidity, namely: sphagnum mosses, wild currants, alders grow on acidic soils, and green forest mosses grow on neutral ones.

Beetle larvae, terrestrial mollusks and many other organisms also react to a certain acidity of the soil.

The chemical composition of the soil is very important for all living organisms. For plants, the most important are not only those chemical elements that they use in large quantities (nitrogen, phosphorus, potassium and calcium), but also those that are rare (trace elements). Some of the plants selectively accumulate certain rare elements. Cruciferous and umbrella plants, for example, accumulate 5-10 times more sulfur in their body than other plants.

Excess content of some chemical elements in the soil can negatively (pathologically) affect animals. For example, in one of the valleys of Tuva (Russia), it was noticed that sheep were suffering from some specific disease, which manifested itself in hair loss, deformation of hooves, etc. Later it turned out that in this valley in the soil, water and some plants there was high selenium content. Getting into the body of sheep in excess, this element caused chronic selenium toxicosis.

The soil has its own thermal regime. Together with moisture, it affects soil formation, various processes taking place in the soil (physico-chemical, chemical, biochemical and biological).

Due to their low thermal conductivity, soils are able to smooth out temperature fluctuations with depth. At a depth of just over 1 m, daily temperature fluctuations are almost imperceptible. For example, in the Karakum Desert, which is characterized by a sharply continental climate, in summer, when the soil surface temperature reaches +59°C, in the burrows of gerbil rodents at a distance of 70 cm from the entrance, the temperature was 31°C lower and amounted to +28°C. In winter, during a frosty night, the temperature in the burrows of gerbils was +19°C.

The soil is a unique combination of physical and chemical properties of the surface of the lithosphere and the living organisms that inhabit it. The soil cannot be imagined without living organisms. No wonder the famous geochemist V.I. Vernadsky called the soil bio-inert body.

Orographic factors (relief).

The relief does not refer to such directly acting environmental factors as water, light, heat, soil. However, the nature of the relief in the life of many organisms has an indirect effect.

Depending on the size of the forms, the relief of several orders is rather conventionally distinguished: macrorelief (mountains, lowlands, intermountain depressions), mesorelief (hills, ravines, ridges, etc.) and microrelief (small depressions, irregularities, etc.). Each of them plays a certain role in the formation of a complex of environmental factors for organisms. In particular, relief affects the redistribution of factors such as moisture and heat. So, even slight depressions, a few tens of centimeters, create conditions of high humidity. From elevated areas, water flows into lower areas, where favorable conditions are created for moisture-loving organisms. The northern and southern slopes have different lighting and thermal conditions. In mountainous conditions, significant amplitudes of heights are created in relatively small areas, which leads to the formation of various climatic complexes. In particular, their typical features are low temperatures, strong winds, changes in the humidification regime, the gas composition of the air, etc.

For example, with rise above sea level, the air temperature drops by 6 ° C for every 1000 m. Although this is a characteristic of the troposphere, but due to the relief (highlands, mountains, mountain plateaus, etc.), terrestrial organisms may find themselves in conditions that are not similar to those in neighboring regions. For example, the mountainous volcanic massif of Kilimanjaro in Africa at the foot is surrounded by savannahs, and higher up the slopes are plantations of coffee, bananas, forests and alpine meadows. The peaks of Kilimanjaro are covered with eternal snow and glaciers. If the air temperature at sea level is + 30 ° C, then negative temperatures will appear already at an altitude of 5000 m. temperate zones every 6°C decrease in temperature corresponds to a movement of 800 km towards higher latitudes.

Pressure.

Pressure is manifested in both air and water environments. In atmospheric air, the pressure varies seasonally, depending on the state of the weather and the height above sea level. Of particular interest are the adaptations of organisms that live in conditions of low pressure, rarefied air in the highlands.

The pressure in the aquatic environment varies depending on the depth: it grows by about 1 atm for every 10 m. For many organisms, there are limits to the change in pressure (depth) to which they have adapted. For example, abyssal fish (fish of the deep world) are able to endure great pressure, but they never rise to the surface of the sea, because for them it is fatal. Conversely, not all marine organisms are capable of diving to great depths. The sperm whale, for example, can dive to a depth of 1 km, and seabirds - up to 15-20 m, where they get their food.

Living organisms on land and aquatic environment clearly respond to pressure changes. At one time it was noted that fish can perceive even slight changes in pressure. their behavior changes when atmospheric pressure changes (eg, before a thunderstorm). In Japan, some fish are specially kept in aquariums and the change in their behavior is used to judge possible changes in the weather.

Terrestrial animals, perceiving slight changes in pressure, can predict changes in the state of the weather with their behavior.

Pressure unevenness, which is the result of uneven heating by the Sun and heat distribution both in water and in atmospheric air, creates conditions for mixing water and air masses, i.e. the formation of currents. Under certain conditions, the flow is a powerful environmental factor.

hydrological factors.

Water as an integral part of the atmosphere and lithosphere (including soil) plays an important role in the life of organisms as one of the environmental factors, which is called humidity. At the same time, water in the liquid state can be a factor that forms its own environment - water. Due to its properties, which distinguish water from all other chemical compounds, it in a liquid and free state creates a set of conditions for the aquatic environment, the so-called hydrological factors.

Such characteristics of water as thermal conductivity, fluidity, transparency, salinity manifest themselves in different ways in water bodies and are environmental factors, which in this case are called hydrological. For example, aquatic organisms have adapted differently to varying degrees of water salinity. Distinguish between freshwater and marine organisms. Freshwater organisms do not amaze with their species diversity. Firstly, life on Earth originated in sea waters, and secondly, fresh water bodies occupy a tiny part of the earth's surface.

Marine organisms are more diverse and quantitatively more numerous. Some of them have adapted to low salinity and live in desalinated areas of the sea and other brackish water bodies. In many species of such reservoirs, a decrease in body size is observed. For example, shells of mollusks, edible mussel (Mytilus edulis) and Lamarck's heartworm (Cerastoderma lamarcki), which live in bays Baltic Sea at a salinity of 2-6% o, 2-4 times smaller than individuals that live in the same sea, only at a salinity of 15% o. The crab Carcinus moenas is small in the Baltic Sea, while it is much larger in desalinated lagoons and estuaries. Sea urchins grow smaller in lagoons than in the sea. The crustacean Artemia (Artemia salina) at a salinity of 122% o has a size of up to 10 mm, but at 20% o it grows to 24-32 mm. Salinity can also affect life expectancy. The same Lamarck's heartworm in the waters North Atlantic lives up to 9 years, and in the less saline waters of the Sea of \u200b\u200bAzov - 5.

The temperature of bodies of water is a more constant indicator than the temperature of land. This is due physical properties water (heat capacity, thermal conductivity). The amplitude of annual temperature fluctuations in the upper layers of the ocean does not exceed 10-15 ° C, and in continental waters - 30-35 ° C. What can we say about the deep layers of water, which are characterized by a constant thermal regime.

biotic factors.

The organisms that live on our planet not only need abiotic conditions for their life, they interact with each other and are often very dependent on each other. The totality of factors of the organic world that affect organisms directly or indirectly is called biotic factors.

Biotic factors are very diverse, but despite this, they also have their own classification. According to the simplest classification Biotic factors are divided into three groups, which are caused by plants, animals and microorganisms.

Clements and Shelford (1939) proposed their own classification, which takes into account the most typical forms of interaction between two organisms - co-actions. All co-actions are divided into two large groups, depending on whether organisms of the same species or two different ones interact. The types of interactions of organisms belonging to the same species is homotypic reactions. Heterotypic reactions name the forms of interaction between two organisms different types.

homotypic reactions.

Among the interaction of organisms of the same species, the following coactions (interactions) can be distinguished: group effect, mass effect And intraspecific competition.

group effect.

Many living organisms that can live alone form groups. Often in nature you can observe how some species grow in groups plants. This gives them the opportunity to accelerate their growth. Animals are also grouped together. Under such conditions, they survive better. With a joint lifestyle, it is easier for animals to defend themselves, get food, protect their offspring, and survive adverse environmental factors. Thus, the group effect has a positive effect on all members of the group.

Groups in which animals are combined can be of different sizes. For example, cormorants, which form huge colonies on the coasts of Peru, can exist only if the colony has at least 10 thousand birds, and 1 square meter territory has three nests. It is known that for the survival of African elephants, the herd must consist of at least 25 individuals, and the herd of reindeer - from 300-400 animals. A pack of wolves can number up to a dozen individuals.

Simple aggregations (temporary or permanent) can turn into complex groups consisting of specialized individuals that perform their own function in this group (families of bees, ants or termites).

Mass effect.

A mass effect is a phenomenon that occurs when a living space is overpopulated. Naturally, when united in groups, especially large sizes, there is also some overpopulation, but there is a big difference between group and mass effects. The first gives advantages to each member of the association, and the other, on the contrary, suppresses the vital activity of all, that is, it has Negative consequences. For example, the mass effect is manifested in the accumulation of vertebrates. If large numbers of experimental rats are kept in one cage, then acts of aggressiveness will appear in their behavior. With prolonged keeping of animals in such conditions, embryos dissolve in pregnant females, aggressiveness increases so much that rats gnaw off each other's tails, ears, and limbs.

The mass effect of highly organized organisms leads to stressful state. It can cause a person mental disorders and nervous breakdowns.

Intraspecific competition.

Between individuals of the same species there is always a kind of competition in obtaining the best living conditions. The greater the population density of a particular group of organisms, the more intense the competition. Such competition of organisms of the same species among themselves for certain conditions of existence is called intraspecific competition.

Mass effect and intraspecific competition are not identical concepts. If the first phenomenon occurs for a relatively short time and subsequently ends with a rarefaction of the group (mortality, cannibalism, reduced fertility, etc.), then intraspecific competition exists constantly and ultimately leads to a wider adaptation of the species to environmental conditions. The species becomes more ecologically adapted. As a result of intraspecific competition, the species itself is preserved and does not destroy itself as a result of such a struggle.

Intraspecific competition can manifest itself in anything that organisms of the same species can claim. In plants that grow densely, competition may occur for light, mineral nutrition, etc. For example, an oak tree, when it grows alone, has a spherical crown, it is quite spreading, since the lower side branches receive a sufficient amount of light. In oak plantations in the forest, the lower branches are shaded by the upper ones. Branches that receive insufficient light die off. As the oak grows in height, the lower branches quickly fall off, and the tree takes on a forest shape - a long cylindrical trunk and a crown of branches at the top of the tree.

In animals, competition arises for a certain territory, food, nesting sites, etc. It is easier for mobile animals to avoid tough competition, but it still affects them. As a rule, those that avoid competition often find themselves in unfavorable conditions, they are forced, like plants (or attached animal species), to adapt to the conditions with which they have to be content.

heterotypic reactions.

Table 1.2.4. Forms of interspecies interactions

	Species occupy		Species occupy
Form of interaction (co-shares)	same territory (living together)		different territories (live separately)
	View A	View B	View A	View B
Neutralism
Comensalism (type A - comensal)
Protocooperation
Mutualism
Amensalism (type A - amensal, type B - inhibitor)
Predation (type A - predator, type B - prey)

Competition

0 - interaction between species does not benefit and does not harm either side;

Interactions between species produce positive consequences; -interaction between species has negative consequences.

Neutralism.

The most common form of interaction occurs when organisms of different species, occupying the same territory, do not affect each other in any way. A large number of species live in the forest, and many of them maintain neutral relationships. For example, a squirrel and a hedgehog inhabit the same forest, but they have a neutral relationship, like many other organisms. However, these organisms are part of the same ecosystem. They are elements of one whole, and therefore, with a detailed study, one can still find not direct, but indirect, rather subtle and imperceptible connections at first glance.

Eat. Doom, in his Popular Ecology, gives a playful but very apt example of such connections. He writes that in England old single women support the power of the royal guards. And the connection between guardsmen and women is quite simple. Single women, as a rule, breed cats, while cats hunt mice. The more cats, the less mice in the fields. Mice are enemies of bumblebees, because they destroy their holes where they live. The fewer mice, the more bumblebees. Bumblebees are not known to be the only pollinators of clover. More bumblebees in the fields - more clover harvest. Horses graze on clover, and the guardsmen like to eat horse meat. Behind such an example in nature, one can find many hidden connections between various organisms. Although in nature, as can be seen from the example, cats have a neutral relationship with horses or jmels, they are indirectly related to them.

Commensalism.

Many types of organisms enter into relationships that benefit only one side, while the other does not suffer from this and nothing is useful. This form of interaction between organisms is called commensalism. Commensalism often manifests itself in the form of coexistence of various organisms. So, insects often live in the burrows of mammals or in the nests of birds.

You can often observe such a joint settlement, when in the nests of large birds of prey or storks are nested by sparrows. For birds of prey, the neighborhood of sparrows does not interfere, but for the sparrows themselves, this is a reliable protection of their nests.

In nature, there is even a species that is named like that - the commensal crab. This small, graceful crab readily settles in the mantle cavity of oysters. By this, he does not interfere with the mollusk, but he himself receives a shelter, fresh portions of water and nutrient particles that get to him with water.

Protocooperation.

The next step in the joint positive co-action of two organisms of different species is protocooperation, in which both species benefit from interaction. Naturally, these species can exist separately without any losses. This form of interaction is also called primary cooperation, or cooperation.

In the sea, such a mutually beneficial, but not obligatory, form of interaction arises when crabs and intestinales are combined. Anemones, for example, often take up residence on the dorsal side of crabs, camouflaging and protecting them with their stinging tentacles. In turn, the sea anemones receive from the crabs the pieces of food that remain from their food, and use the crabs as vehicle. Both crabs and sea anemones are able to freely and independently exist in the reservoir, but when they are nearby, the crab, even with its claws, transplants the sea anemones onto itself.

The joint nesting of birds of different species in the same colony (herons and cormorants, waders and terns of different species, etc.) is also an example of cooperation in which both parties benefit, for example, in protection from predators.

Mutualism.

Mutualism (or obligate symbiosis) is the next stage of mutually beneficial adaptation of different species to each other. It differs from protocooperation in its dependency. If during protocooperation the organisms that enter into a relationship can exist separately and independently of each other, then under mutualism the existence of these organisms separately is impossible.

This type of coaction often occurs in quite different organisms, systematically remote, with different needs. An example of this would be the relationship between nitrogen-fixing bacteria (bubble bacteria) and legumes. Substances secreted by the root system of legumes stimulate the growth of bubble bacteria, and the waste products of bacteria lead to deformation of the root hairs, which begins the formation of bubbles. Bacteria have the ability to assimilate atmospheric nitrogen, which is deficient in the soil but an essential macronutrient for plants, which in this case is of great benefit to leguminous plants.

In nature, the relationship between fungi and plant roots is quite common, called mycorrhiza. The fungus, interacting with the tissues of the root, forms a kind of organ that helps the plant more effectively absorb minerals from the soil. Mushrooms from this interaction receive the products of photosynthesis of the plant. Many tree species cannot grow without mycorrhiza, and certain types of fungi form mycorrhiza with the roots of certain tree species (oak and White mushroom, birch and boletus, etc.).

A classic example of mutualism is lichens, which combine the symbiotic relationship of fungi and algae. The functional and physiological connections between them are so close that they are considered as a separate group organisms. The fungus in this system provides the algae with water and mineral salts, and the algae, in turn, gives the fungus organic substances that it synthesizes itself.

Amensalism.

In the natural environment, not all organisms positively influence each other. There are many cases when one species harms another in order to ensure its life. This form of coaction, in which one type of organism suppresses the growth and reproduction of an organism of another species without losing anything, is called amensalism (antibiosis). The suppressed species in a pair that interacts is called amensalom, and the one who suppresses - inhibitor.

Amensalism is best studied in plants. In the course of life, plants release into the environment chemical substances, which are the factors of influence on other organisms. Regarding plants, amensalism has its own name - allelopathy. It is known that, due to the excretion of toxic substances by the roots, the Volokhatensky nechuiweter displaces other annual plants and forms continuous single-species thickets over large areas. In fields, wheatgrass and other weeds crowd out or suppress cultivated plants. Walnut and oak oppress grassy vegetation under their crowns.

Plants can secrete allelopathic substances not only by their roots, but also by the aerial part of their body. Volatile allelopathic substances released by plants into the air are called phytoncides. Basically, they have a destructive effect on microorganisms. Everyone is well aware of the antimicrobial preventive effect of garlic, onion, horseradish. Many phytoncides are produced by coniferous trees. One hectare of common juniper plantations produces more than 30 kg of phytoncides per year. Often conifers are used in settlements to create sanitary protection belts around various industries, which helps to purify the air.

Phytoncides negatively affect not only microorganisms, but also animals. In everyday life, various plants have long been used to fight insects. So, buglitsa and lavender is a good remedy to fight moths.

Antibiosis is also known in microorganisms. Its first time was opened By. Babesh (1885) and rediscovered by A. Fleming (1929). Penicillu fungi have been shown to secrete a substance (penicillin) that inhibits bacterial growth. It is widely known that some lactic acid bacteria acidify their environment so that putrefactive bacteria that need an alkaline or neutral environment cannot exist in it. The allelopathic chemicals of microorganisms are known as antibiotics. More than 4 thousand antibiotics have already been described, but only about 60 of their varieties are widely used in medical practice.

Protection of animals from enemies can also be carried out by isolating substances that have an unpleasant odor (for example, among reptiles - vulture turtles, snakes; birds - hoopoe chicks; mammals - skunks, ferrets).

Predation.

Theft in the broad sense of the word is considered to be a way of obtaining food and feeding animals (sometimes plants), in which they catch, kill and eat other animals. Sometimes this term is understood as any eating of some organisms by others, i.e. relationships between organisms in which one uses the other as food. With this understanding, the hare is a predator in relation to the grass that it consumes. But we will use a narrower understanding of predation, in which one organism feeds on another, which is close to the first in a systematic way (for example, insects that feed on insects; fish that feed on fish; birds that feed on reptiles, birds and mammals; mammals, that feed on birds and mammals). An extreme case of predation, in which a species feeds on organisms of its own species, is called cannibalism.

Sometimes a predator selects a prey in such quantity that it does not negatively affect the size of its population. By this, the predator contributes to a better state of the prey population, which, moreover, has already adapted to the pressure of the predator. The birth rate in the populations of the prey is higher than is required for the usual maintenance of its numbers. Figuratively speaking, the prey population takes into account what the predator must select.

Interspecies competition.

Between organisms of different species, as well as between organisms of the same species, interactions arise due to which they try to get the same resource. Such co-actions between different species are called interspecific competition. In other words, we can say that interspecific competition is any interaction between populations of different species that adversely affects their growth and survival.

The consequences of such competition may be the displacement of one organism by another from a certain ecological system (the principle of competitive exclusion). At the same time, competition promotes the emergence of many adaptations through selection, which leads to the diversity of species that exist in a particular community or region.

Competitive interaction may involve space, food or nutrients, light, and many other factors. Interspecific competition, depending on what it is based on, can lead either to an equilibrium between two species, or, with more intense competition, to the replacement of a population of one species by a population of another. Also, the result of competition may be such that one species will displace the other in a different place or force it to move to other resources.

A person has a conscious, purposeful impact on the environment (of course, not always reasonable). F. Engels wrote: “The animal only uses external nature and makes changes in it simply by virtue of its presence; man, by the changes he makes, forces it to serve its purposes, dominates it.

· Anthropogenic factor in terms of strength, intensity and global impact currently has no equal in nature. People have expanded the range of available energy sources up to the use of nuclear and thermonuclear reactions.

· Man creates artificial habitats, can stay in outer space and under water for a long time, influencing nature.

Today human environment the environment is practically an artificial ecosystem created by man or natural ecosystems, modified to one degree or another by his activities. There are no absolutely unchanged ecosystems on the planet!

All ecosystems, depending on the degree of anthropogenic impact on them, are divided into natural cenoses, agrocenoses and urban cenoses.

natural cenoses characterized by a wide variety of wild plant and animal species. They correspond to different landscape zones: tundra, forest-tundra, taiga, mixed and broad-leaved forests, steppes, deserts, subtropics and tropics.

Environmental characteristic:

A wide variety of species composition of plants and animals.

· Ecological homeostasis is maintained by self-regulation.

· Natural circulation of substances and use of solar energy.

People get into natural cenoses when studying natural conditions, resources, engineering and geological conditions in the area being developed. At this stage of development of nature, people are at risk of infection with natural focal diseases, suffer from the attack of midges, ticks and adverse weather conditions, which leads to respiratory diseases, adaptation syndromes from the outside. of cardio-vascular system, neuroses, increased traumatism.

Examples: the change of forest landscape to meadow-field landscape in central Russia led to a change in the composition of mouse-like rodents and the emergence of new natural foci of tularemia. Development of the taiga regions of Siberia and Far East was accompanied by the appearance of human cases of taiga encephalitis.

Agrocenoses. Under the influence of agricultural production, artificial ecological systems arise - agrocenoses (fields, hayfields, pastures, gardens, parks, forest plantations).

Ecological characteristic :

· The number of species of animals and plants is limited, but their numbers are sometimes enormous. Usually these are just a few crops, weeds and pests of agricultural plants, a small number of domestic animal species. They are under the control of artificial selection.

· Unlike natural biogeocenoses, for normal functioning, artificial ecological systems need a person to maintain their homeostasis, i.e. managed them (destruction of harmful and protection of beneficial species).

· The cycle of substances is distorted, because a person removes certain substances, makes fertilizers.

· To save agrocenoses, additional energy costs are needed: equipment and physical strength.

About 60% of agricultural land is used extensively with the involvement of the muscular strength of humans and animals. Only 40% of cultivated lands are intensively cultivated agrocenoses, in which the yield of agricultural plants reaches a biologically possible maximum.

Biomedical characteristic:

In agrocenoses, the loss of agricultural land is progressively increasing due to the washing out of the fertile humus layer, wind erosion of soils, and an increase in the length of ravines and shifting sands. The soil is saturated with pesticides and mineral fertilizers, water bodies are polluted with domestic sewage.

Urban cenoses- anthropoecosystems of cities and towns. The first cities appeared in the 3rd millennium BC. IN early XIX century, 3% of the population lived in them, in 1900 - 13%, in 1995 - 71% in the USA, 91% in Great Britain, in Russia - 74%, and in early XXI century in Russia, this number will reach 80-90%.

The construction of cities is a progressive phenomenon. Industrial enterprises are concentrated in them, the problems of employment, food supply, medical care are more easily solved, there are various educational, scientific and cultural institutions. In cities there are all conditions for production activities and the organization of people's lives.

But, on the other hand, cities are characterized by the most pronounced changes. natural environment, many of which are negative.

Environmental characteristic:

· Poor species composition of fauna and flora.

Large crowds of people.

· Predominance of synanthropic animal species.

· Non-closed circulation of substances, which involves metals, plastics, not destroyed by natural decomposers.

· Artificial maintenance of homeostasis, which is aimed at preserving the human population.

Use of additional energy sources.

Biomedical characteristic:

During the construction of cities, there is a complete or partial destruction of ecological systems at the site of the construction of the city, the geological environment changes: the natural microrelief disappears, the state and properties change. rocks, the level of groundwater changes, an irreversible intake of water and oxygen is observed, and technogenic deposits are created.

The climate is changing: in cities, the intensity of solar radiation decreases, the average annual temperature rises by 1-2 °, the temperature amplitude appears - in the center of the city the temperature is 2-8 ° higher than in the periphery, the amount of fog, precipitation increases, the wind regime changes significantly.

The air environment changes: the chemical composition of atmospheric air, its optical properties, thermal characteristics. Air pollution is associated with emissions of gaseous substances and particulate matter. Dust and smoky air in cities reduce the amount of ultraviolet rays reaching the earth's surface by 30% in winter. The duration of sunlight is reduced by 5-15%. Climate change combined with air pollution lead to the formation of smog over cities, which includes carbon monoxide, nitrogen oxide, sulfur oxides and many other compounds dangerous to people. People affected by smog develop respiratory diseases. The number of microorganisms in the air is increasing (200 times compared to rural areas), and the incidence of infectious diseases among people is increasing.

In cities, surface water changes runoff, chemistry and temperature regime. The groundwater level rises or falls. Water consumption is 150-200 l/day per city dweller. Water may contain organic, inorganic, synthetic and radioactive substances.

There is a mineralization of soils, tamping and removal of the fertile layer, pollution with liquid and solid waste, salts of heavy metals. The natural process of destruction of various substances is disturbed.

The vegetation cover of cities is depleted, large single-species groupings of plants appear, in the fruits and leaves of which toxic substances accumulate.

Overcrowding, noise, physical inactivity and a busy pace of life create conditions for the development of diseases of the nervous system, circulatory organs, and upper respiratory tract. Changes in atmospheric pressure lead to headaches, weakness and rapid fatigue of people. Metabolism is disturbed, obesity develops. The level of these diseases is 1.5-2 times higher than in rural areas. Traffic injuries are also on the rise in cities.