The most important environmental factors in human life. Main abiotic factors

1. Abiotic factors. This category of factors includes all physical and chemical characteristics environment. This is light and temperature, humidity and pressure, the chemistry of water, atmosphere and soil, this is the nature of the relief and composition rocks, wind regime. The most potent group of factors is united as climatic factors. They depend on the latitude and position of the continents. There are many secondary factors. Latitude has the greatest effect on temperature and photoperiod. The position of the continents is the reason for the dryness or humidity of the climate. The internal regions are drier than the peripheral ones, which greatly influences the differentiation of animals and plants on the continents. Wind regime, as one of the components of the climatic factor, plays an extremely important role in the formation of life forms of plants.

Global climate is the climate of the planet that determines the functioning and Biodiversity of the biosphere. Regional climate is the climate of continents and oceans, as well as their large topographic subdivisions. Local climate – climate of subordinates landscape-regional socio-geographical structures: climate of Vladivostok, climate of the Partizanskaya river basin. Microclimate (under a stone, outside a stone, grove, clearing).

The most important climatic factors: light, temperature, humidity.

Lightis the most important source of energy on our planet. If for animals light is inferior in importance to temperature and humidity, then for photosynthetic plants it is the most important.

The main source of light is the Sun. The main properties of radiant energy as an environmental factor are determined by the wavelength. Radiation includes visible light, ultraviolet and infrared rays, radio waves, and penetrating radiation.

Orange-red, blue-violet and ultraviolet rays are important for plants. Yellow-green rays are either reflected by plants or absorbed in small quantities. Reflected rays give plants their green color. Ultraviolet rays have a chemical effect on living organisms (they change the speed and direction of biochemical reactions), and infrared rays have a thermal effect.

Many plants have a phototropic response to light. Tropism– this is the directional movement and orientation of plants, for example, a sunflower “follows” the sun.

In addition to the quality of the light rays, the amount of light falling on the plant is also of great importance. The intensity of illumination depends on the geographic latitude of the area, the season, time of day, cloudiness and local dustiness of the atmosphere. The dependence of thermal energy on latitude shows that light is one of the climatic factors.

The life of many plants depends on photoperiod. Day gives way to night and plants stop synthesizing chlorophyll. The polar day is replaced by the polar night and plants and many animals stop actively functioning and freeze (hibernation).

In relation to light, plants are divided into three groups: light-loving, shade-loving and shade-tolerant. Photophilous They can develop normally only with sufficient lighting; they do not tolerate or do not tolerate even slight darkening. Shade-loving found only in shaded areas and never found in high light conditions. Shade-tolerant plants are characterized by a wide ecological amplitude in relation to the light factor.

Temperature is one of the most important climatic factors. The level and intensity of metabolism, photosynthesis and other biochemical and physiological processes depend on it.

Life on earth exists in a wide range of temperatures. The most acceptable temperature range for life is from 0 0 to 50 0 C. For most organisms, these are lethal temperatures. Exceptions: many northern animals, where there is a change in seasons, are able to withstand winter subzero temperatures. Plants are able to tolerate sub-zero winter temperatures when they freeze active work. Under experimental conditions, some seeds, spores and pollen of plants, nematodes, rotifers, protozoan cysts tolerated temperatures of - 190 0 C and even - 273 0 C. But still, the majority of living creatures are able to live at temperatures between 0 and 50 0 C. This is determined properties of proteins and enzyme activity. One of the adaptations to endure unfavorable temperatures is anabiosis– suspension of the body’s vital processes.

On the contrary, in hot countries, fairly high temperatures are the norm. A number of microorganisms are known that can live in sources with temperatures above 70 0 C. Spores of some bacteria can withstand short-term heating up to 160–180 0 C.

Eurythermic and stenothermic organisms– organisms whose functioning is associated with wide and narrow temperature gradients, respectively. The abyssal environment (0˚) is the most constant environment.

Biogeographical zoning(arctic, boreal, subtropical and tropical zones) largely determines the composition of biocenoses and ecosystems. An analogue of climatic distribution based on the latitudinal factor can be mountain zones.

Based on the relationship between the body temperature of the animal and the ambient temperature, organisms are divided into:

– poikilothermic organisms are cold-water with variable temperatures. The body temperature approaches the ambient temperature;

– homeothermic– warm-blooded organisms with a relatively constant internal temperature. These organisms have great advantages in using the environment.

In relation to the temperature factor, species are divided into the following ecological groups:

species that prefer cold are cryophiles And cryophytes.

species with optimum activity in the area of ​​high temperatures belong to thermophiles And thermophytes.

Humidity. All biochemical processes in organisms occur in an aquatic environment. Water is necessary to maintain the structural integrity of cells throughout the body. It is directly involved in the process of formation of the primary products of photosynthesis.

Humidity is determined by the amount of precipitation. The distribution of precipitation depends on geographic latitude, the proximity of large bodies of water, and the terrain. The amount of precipitation is unevenly distributed throughout the year. In addition, it is necessary to take into account the nature of precipitation. Summer drizzle moisturizes the soil better than rain, carrying streams of water that do not have time to soak into the soil.

Plants living in areas with different moisture availability adapt differently to a lack or excess of moisture. Regulation of water balance in the body of plants in arid regions is carried out due to the development of a powerful root system and the suction power of root cells, as well as a decrease in the evaporating surface. Many plants shed leaves and even entire shoots (saxaul) during the dry period; sometimes partial or even complete reduction of leaves occurs. A peculiar adaptation to a dry climate is the rhythm of development of some plants. Thus, ephemerals, using spring moisture, manage to germinate in a very short time (15-20 days), develop leaves, bloom and form fruits and seeds; with the onset of drought they die. The ability of many plants to accumulate moisture in their vegetative organs - leaves, stems, roots - also helps withstand drought..

In relation to humidity, the following ecological groups of plants are distinguished. Hydrophytes, or hydrobionts, are plants for which water is their living environment.

Hygrophytes- plants living in places where the air is saturated with water vapor and the soil contains a lot of droplet-liquid moisture - in flooded meadows, swamps, in damp shady places in forests, on the banks of rivers and lakes. Hygrophytes evaporate a lot of moisture due to stomata, which are often located on both sides of the leaf. The roots are sparsely branched, the leaves are large.

Mesophytes– plants of moderately humid habitats. These include meadow grasses, all deciduous trees, many field crops, vegetables, fruits and berries. They have a well-developed root system, large leaves with stomata on one side.

Xerophytes- plants that have adapted to life in places with arid climates. They are common in steppes, deserts and semi-deserts. Xerophytes are divided into two groups: succulents and sclerophytes.

Succulents(from lat. succulentus- juicy, fat, thick) are perennial plants with juicy fleshy stems or leaves in which water is stored.

Sclerophytes(from Greek skleros– hard, dry) – these are fescue, feather grass, saxaul and other plants. Their leaves and stems do not contain a supply of water, they seem rather dry, due to the large amount of mechanical tissue, their leaves are hard and tough.

Other factors may also be important in plant distribution, e.g. nature and properties of the soil. Thus, there are plants for which the determining environmental factor is the salt content in the soil. This halophytes. A special group consists of lovers of calcareous soils - calciphiles. The same “soil-associated” species are plants that live on soils containing heavy metals.

Environmental factors that influence the life and distribution of organisms also include the composition and movement of air, the nature of the relief, and many, many others.

The basis of intraspecific selection is intraspecific struggle. That is why, as Charles Darwin believed, more young organisms are born than reach adulthood. At the same time, the predominance of the number of organisms born over the number of organisms surviving to maturity compensates for the high mortality rate on early stages development. Therefore, as noted by S.A. Severtsov, the magnitude of fertility is related to the persistence of the species.

Thus, intraspecific relationships are aimed at the reproduction and dispersal of the species.

In the world of animals and plants, there are a large number of devices that facilitate contact between individuals or, conversely, prevent their collision. Such mutual adaptations within a species were called S.A. Severtsov congruences . Thus, as a result of mutual adaptations, individuals have a characteristic morphology, ecology, and behavior that ensure the meeting of the sexes, successful mating, reproduction and raising of offspring. Five groups of congruences have been established:

– embryos or larvae and parental individuals (marsupials);

– individuals of different sexes (genital apparatus of males and females);

– individuals of the same sex, mainly males (horns and teeth of males, used in fights for the female);

– brothers and sisters of the same generation in connection with the herd lifestyle (spots that facilitate orientation when fleeing);

– polymorphic individuals in colonial insects (specialization of individuals to perform certain functions).

The integrity of the species is also expressed in the unity of the breeding population, the homogeneity of its chemical composition and the unity of impact on environment.

Cannibalism– this type of intraspecific relationships is not uncommon in broods of birds of prey and animals. The weakest are usually destroyed by the stronger, and sometimes by their parents.

Self-draining plant populations. Intraspecific competition influences the growth and distribution of biomass within plant populations. As individuals grow, they increase in size, their needs increase and, as a result, competition between them increases, which leads to death. The number of surviving individuals and their growth rate depend on population density. A gradual decrease in the density of growing individuals is called self-thinning.

A similar phenomenon is observed in forest plantations.

Interspecies relationships. The most important and frequently occurring forms and types of interspecific relationships can be called:

Competition. This type of relationship determines Gause's rule. According to this rule, two species cannot simultaneously occupy the same ecological niche and therefore necessarily displace each other. For example, spruce displaces birch.

Allelopathy- this is the chemical effect of some plants on others through the release of volatile substances. Carriers of allelopathic action are active substances – Colin. Due to the influence of these substances, the soil can be poisoned, the nature of many physiological processes can change, and at the same time, plants recognize each other through chemical signals.

Mutualism – extreme degree association between species in which each benefits from being associated with the other. For example, plants and nitrogen-fixing bacteria; cap mushrooms and tree roots.

Commensalism– a form of symbiosis in which one of the partners (comensal) uses the other (host) to regulate its contacts with external environment, but does not enter into close relationships with him. Comensalism is widely developed in coral reef ecosystems - this is housing, protection (tentacles of sea anemones protect fish), living in the body of other organisms or on its surface (epiphytes).

Predation- this is a way of obtaining food by animals (less often plants), in which they catch, kill and eat other animals. Predation occurs in almost all types of animals. During evolution, predators have well developed nervous systems and sensory organs that allow them to detect and recognize prey, as well as means of capturing, killing, eating and digesting prey (sharp retractable claws in cats, poisonous glands of many arachnids, stinging cells of sea anemones, enzymes that break down proteins and other). The evolution of predators and prey occurs in tandem. During this process, predators improve their methods of attack, and victims improve their methods of defense.

communities) among themselves and with their environment. This term was first proposed by the German biologist Ernst Haeckel in 1869. As an independent science, it emerged at the beginning of the 20th century along with physiology, genetics and others. The field of application of ecology is organisms, populations and communities. Ecology views them as a living component of a system called an ecosystem. In ecology, the concepts of population—community and ecosystem—have clear definitions.

A population (from an ecological point of view) is a group of individuals of the same species occupying a certain territory and, usually, to one degree or another, 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 connections.

An ecosystem is a community of organisms with their environment that interact with each other and form an ecological unit.

All ecosystems of the Earth are united into the 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 studying ecosystems are possible.

Ecosystem approach.In the ecosystem approach, the ecologist studies the flow of energy in the ecosystem. Most Interest V in this case represent the relationships of organisms with each other and with the environment. This approach allows us to explain complex structure relationships in the ecosystem and give recommendations for rational environmental management.

Studying communities. With this approach, the species composition of communities and the factors limiting 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 suggests, is the population.
Habitat study. In this case, a relatively homogeneous area of ​​the environment where a given organism lives is studied. It is usually not used separately as an independent area of ​​research, 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 used in combination, but at the moment this is practically impossible due to the significant scale of the objects under study 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.

Methods of environmental research:

• observation
• experiment
• population counting
• modeling method

The environment is a unique set of conditions surrounding a living organism, which affect it, perhaps a combination of phenomena, material bodies, energies. An environmental factor is an environmental factor to which organisms have to adapt. This could be a decrease or increase in temperature, humidity or drought, background radiation, human activity, competition among animals, etc. The term “habitat” inherently means the part of nature in which organisms live, among the influences on them direct or indirect influence. These are factors, because they influence the subject in one way or another. The environment is constantly changing, its components are diverse, so animals, plants and even people have to constantly adapt, adapt to new conditions in order to somehow survive and reproduce.

Classification of environmental factors

Living organisms can be affected by both natural and artificial influences. There are several types of classifications, but the most common types of environmental factors are abiotic, biotic and anthropogenic. All living organisms are influenced in one way or another by phenomena and components of inanimate nature. These are abiotic factors that influence the life activity of humans, plants, and animals. They, in turn, are divided into edaphic, climatic, chemical, hydrographic, pyrogenic, orographic.

Light regime, humidity, temperature, atmospheric pressure and precipitation, solar radiation, wind can be attributed to climatic factors. Edaphic influence living organisms through heat, air and its chemical composition and mechanical structure, groundwater level, acidity. Chemical factors are the salt composition of water and the gas composition of the atmosphere. Pyrogenic - the effect of fire on the environment. Living organisms are forced to adapt to the terrain, elevation changes, as well as to the characteristics of the water and the content of organic and mineral substances in it.

A biotic environmental factor is the relationship of living organisms, as well as the impact of their relationships on the environment. The influence can be both direct and indirect. For example, some organisms are able to influence the microclimate, change, etc. Biotic factors are divided into four types: phytogenic (plants influence the environment and each other), zoogenic (animals influence the environment and each other), mycogenic ( fungi have an impact) and microbiogenic (microorganisms are at the center of events).

An anthropogenic environmental factor is a change in the living conditions of organisms due to human activity. Actions can be either conscious or unconscious. However, they lead to irreversible changes in nature. Man destroys the soil layer, pollutes the atmosphere and water harmful substances, disrupts natural landscapes. Anthropogenic factors can be divided into four main subgroups: biological, chemical, social and physical. All of them, to one degree or another, affect animals, plants, microorganisms, contribute to the emergence of new species and wipe out old ones from the face of the earth.

The chemical influence of environmental factors on organisms mainly has a negative impact on the environment. To achieve good harvests, people use mineral fertilizers and kill pests with poisons, thereby polluting the soil and water. Transport and industrial waste should also be added here. Physical factors involve travel on planes, trains, cars, the use of nuclear energy, the impact of vibration and noise on organisms. We should also not forget about relationships between people and life in society. Biological factors include organisms for which humans are a source of food or habitat, and food products should also be included here.

Environmental conditions

Depending on their characteristics and strengths, different organisms react differently to abiotic factors. Environmental conditions change over time and, of course, change the rules of survival, development and reproduction of microbes, animals, and fungi. For example, the life of green plants at the bottom of a reservoir is limited by the amount of light that can penetrate the water column. The number of animals is limited by the abundance of oxygen. A huge impact temperature affects living organisms, because its decrease or increase affects development and reproduction. During the Ice Age, not only mammoths and dinosaurs became extinct, but also many other animals, birds and plants, thereby changing the environment. Humidity, temperature and light are the main factors that determine the living conditions of organisms.

Light

The sun gives life to many plants; it is not as important for animals as it is for representatives of the flora, but still they cannot do without it. Natural light is a natural source of energy. Many plants are divided into light-loving and shade-tolerant. Different animal species exhibit negative or positive reaction to the light. But the sun has the most important influence on the cycle of day and night, because different representatives of the fauna lead an exclusively nocturnal or diurnal lifestyle. The effect of environmental factors on organisms is difficult to overestimate, but if we talk about animals, then lighting does not affect them directly, it only signals the need to rearrange the processes occurring in the body, due to which living beings respond to changing external conditions.

Humidity

All living beings depend on water very much, because it is necessary for their normal functioning. Most organisms are unable to live in dry air; sooner or later they die. The amount of precipitation falling during a specific period characterizes the humidity of the area. Lichens catch water vapor from the air, plants feed using roots, animals drink water, insects and amphibians are able to absorb it through the integument of the body. There are creatures that obtain liquid through food or through the oxidation of fats. Both plants and animals have many adaptations that allow them to waste water more slowly and save it.

Temperature

Each organism has its own temperature range. If it goes beyond the limits, rising or falling, then he can simply die. The influence of environmental factors on plants, animals and humans can be both positive and negative. Within the temperature range, the body develops normally, but as soon as the temperature approaches the lower or upper limits, life processes slow down and then stop altogether, which leads to the death of the creature. Some need cold, some need warmth, and some can live under different environmental conditions. For example, bacteria and lichens can withstand a wide range of temperatures; tigers thrive in the tropics and Siberia. But most organisms survive only within narrow temperature limits. For example, corals grow in water at 21°C. Low temperatures or overheating are deadly for them.

In tropical areas, weather fluctuations are almost imperceptible, which cannot be said about the temperate zone. Organisms are forced to adapt to the changing seasons; many make long migrations with the onset of winter, and plants die off altogether. Under unfavorable temperature conditions, some creatures hibernate in order to wait out the period that is unsuitable for them. These are just the main ones environmental factors, organisms are also affected by atmospheric pressure, wind, and altitude.

The impact of environmental factors on a living organism

The development and reproduction of living beings is significantly influenced by their environment. All groups of environmental factors usually act in a complex manner, and not one at a time. The strength of influence of one depends on the others. For example, lighting cannot be replaced in any way carbon dioxide, but by changing the temperature, it is quite possible to stop plant photosynthesis. All factors influence organisms to one degree or another differently. The leading role may vary depending on the time of year. For example, in the spring, temperature is important for many plants, during the flowering period - soil moisture, and during ripening - air humidity and nutrients. There is also an excess or deficiency of which is close to the limits of the body’s endurance. Their effect manifests itself even when living beings are in a favorable environment.

The influence of environmental factors on plants

For each representative of the flora, the surrounding nature is considered its habitat. It creates all the necessary environmental factors. The habitat provides the plant with the necessary soil and air moisture, lighting, temperature, wind, and the optimal amount of nutrients in the soil. Normal levels of environmental factors allow organisms to grow, develop and reproduce normally. Some conditions can negatively affect plants. For example, if you plant a crop in a depleted field, the soil of which does not have enough nutrients, then it will grow very weak or not grow at all. This factor can be called limiting. But still, most plants adapt to living conditions.

Representatives of the flora growing in the desert adapt to the conditions with the help of a special form. They usually have very long and powerful roots that can go 30 m deep into the ground. A superficial root system is also possible, allowing them to collect moisture during short rains. Trees and bushes store water in trunks (often deformed), leaves, and branches. Some desert inhabitants are able to wait for several months for life-giving moisture, but others are pleasing to the eye for only a few days. For example, ephemerals scatter seeds that germinate only after rain, then the desert blooms early in the morning, and at noon the flowers fade.

The influence of environmental factors on plants also affects them in cold conditions. The tundra has a very harsh climate, summers are short and cannot be called warm, but frosts last from 8 to 10 months. The snow cover is insignificant, and the wind completely exposes the plants. Representatives of the flora usually have a superficial root system, thick leaf skin with a waxy coating. Plants accumulate the necessary supply of nutrients during the period when Tundra trees produce seeds that germinate only once every 100 years during the period of the most favorable conditions. But lichens and mosses have adapted to reproduce vegetatively.

Plants allow them to develop in the most different conditions. Representatives of the flora are dependent on humidity and temperature, but most of all they need sunlight. It changes their internal structure, appearance. For example, a sufficient amount of light allows trees to grow a luxurious crown, but bushes and flowers grown in the shade seem depressed and weak.

Ecology and people very often take different paths. Human activities have a detrimental effect on the environment. The work of industrial enterprises, forest fires, transport, air pollution from emissions from power plants, factories, water and soil with residues of petroleum products - all this negatively affects the growth, development and reproduction of plants. Behind last years many species of flora were included in the Red Book, many became extinct.

The influence of environmental factors on humans

Just two centuries ago, people were much healthier and physically stronger than they are today. Work activity constantly complicates the relationship between man and nature, but up to a certain point they managed to get along. This was achieved due to the synchronicity of people’s way of life with natural regimes. Each season had its own work spirit. For example, in the spring, peasants plowed the land, sowed cereals and other crops. In the summer they tended crops, grazed livestock, in the fall they harvested crops, in the winter they did household chores and rested. The culture of health was an important element of the general culture of man; the consciousness of the individual changed under the influence of natural conditions.

Everything changed dramatically in the twentieth century, during a period of huge leaps in the development of technology and science. Of course, even before this, human activity significantly harmed nature, but here all records were broken negative influence on the environment. The classification of environmental factors allows us to determine what people influence in to a greater extent, and for what - to a lesser extent. Humanity lives in a production cycle mode, and this cannot but affect its health. There is no periodicity, people do the same work throughout the year, have little rest, and are constantly in a hurry to get somewhere. Of course, working and living conditions have changed for the better, but the consequences of such comfort are very unfavorable.

Today, water, soil, air are polluted, fallout destroys plants and animals, and damages structures and structures. The thinning of the ozone layer also has frightening consequences. All this leads to genetic changes, mutations, people's health is deteriorating every year, and the number of patients with incurable diseases is growing inexorably. Humans are greatly influenced by environmental factors; biology studies this impact. Previously people could die from cold, heat, hunger, thirst; in our time, humanity is “digging its own grave.” Earthquakes, tsunamis, floods, fires - all these natural phenomena take lives, but also more people harms himself. Our planet is like a ship that is heading towards the rocks at high speed. We need to stop before it’s too late, correct the situation, try to pollute the atmosphere less, and become closer to nature.

Human impact on the environment

People complain about sudden changes in the environment, deterioration in health and general well-being, but they rarely realize that they themselves are to blame for this. Various types of environmental factors have changed over the centuries, there have been periods of warming and cooling, seas have dried up, islands have gone under water. Of course, nature forced people to adapt to conditions, but it did not set strict limits for people and did not act spontaneously and quickly. With the development of technology and science, everything has changed significantly. In one century, humanity has polluted the planet so much that scientists are clutching their heads, not knowing how to change the situation.

We still remember mammoths and dinosaurs that went extinct in glacial period due to a sharp cooling, and how many species of animals and plants have been wiped off the face of the earth over the past 100 years, how many more are on the verge of extinction? Big cities they are crammed with plants and factories, villages actively use pesticides that pollute the soil and water, and everywhere there is a saturation of transport. There are practically no places left on the planet that can boast of clean air, unpolluted land and water. Deforestation, endless fires, which can be caused not only by abnormal heat, but also by human activity, pollution of water bodies with oil products, harmful emissions in the atmosphere - all this negatively affects the development and reproduction of living organisms and does not improve human health in any way.

“Either a person will reduce the amount of smoke in the air, or smoke will reduce the number of people on Earth,” these are the words of L. Baton. Indeed, the picture of the future looks depressing. The best minds of humanity are struggling with how to reduce the scale of pollution, programs are being created, various cleaning filters are being invented, and alternatives are being sought for those objects that pollute the environment the most today.

Ways to solve environmental problems

Ecology and people today cannot reach a consensus. Everyone in government must work together to solve existing problems. Everything must be done to transfer production to waste-free, closed cycles; on the way to this, energy- and material-saving technologies can be used. Nature management must be rational and take into account the characteristics of the regions. The increase in species of creatures on the verge of extinction requires the immediate expansion of protected areas. Well, and most importantly, the population should be educated, in addition to general environmental education.

Environmental factors are any external factors that have a direct or indirect effect on the number (abundance) and geographic distribution of organisms.

Environmental factors are very diverse both in nature and in their impact on living organisms. Conventionally, all environmental factors are usually divided into three large groups - abiotic, biotic and anthropogenic.

Abiotic factors- These are factors of inanimate nature.

Climatic (sunlight, temperature, air humidity) and local (relief, soil properties, salinity, currents, wind, radiation, etc.). Can be direct or indirect.

Anthropogenic factors- these are those forms of human activity that, by affecting the environment, change the living conditions of living organisms or directly affect certain species of plants and animals. One of the most important anthropogenic factors is pollution.

Environmental conditions.

Environmental conditions, or ecological conditions, are abiotic environmental factors that vary in time and space, to which organisms react differently depending on their strength. Environmental conditions impose certain restrictions on organisms.

To the most important factors, which determine the conditions for the existence of organisms in almost all living environments, include temperature, humidity and light.

Temperature.

Any organism is able to live only within a certain temperature range: individuals of the species die at too high or too low temperatures. The limits of temperature tolerance vary among different organisms. There are species that can tolerate temperature fluctuations over a wide range. For example, lichens and many bacteria are able to live at very different temperatures. Among animals, warm-blooded animals have the greatest range of temperature tolerance. The tiger, for example, tolerates both the Siberian cold and the heat of the tropical regions of India or the Malay Archipelago equally well. But there are also species that can live only within more or less narrow temperature limits. In the land-air environment and even in many parts of the aquatic environment, the temperature does not remain constant and can vary greatly depending on the season of the year or the time of day. In tropical areas, annual temperature variations may be even less noticeable than daily ones. Conversely, in temperate areas, temperatures vary significantly between seasons. Animals and plants are forced to adapt to the unfavorable winter season, during which active life is difficult or simply impossible. In tropical areas such adaptations are less pronounced. During a cold period with unfavorable temperature conditions, there seems to be a pause in the life of many organisms: hibernation in mammals, shedding of leaves in plants, etc. Some animals make long migrations to places with a more suitable climate.

Humidity.

Water is an integral part of the vast majority of living things: it is necessary for their normal functioning. A normally developing organism constantly loses water and therefore cannot live in completely dry air. Sooner or later, such losses can lead to the death of the body.

The simplest and most convenient indicator characterizing the humidity of a particular area is the amount of precipitation falling there over a year or another period of time.

Plants extract water from the soil using their roots. Lichens can capture water vapor from the air. Plants have a number of adaptations that ensure minimal water loss. All land animals require periodic supply of water to compensate for the inevitable loss of water due to evaporation or excretion. Many animals drink water; others, such as amphibians, some insects and mites, absorb it in a liquid or vapor state through their body coverings. Most desert animals never drink. They satisfy their needs from water supplied with food. Finally, there are animals that obtain water in an even more complex way - through the process of fat oxidation, for example the camel. Animals, like plants, have many adaptations to save water.

Light.

There are light-loving plants, which are able to develop only under the sun's rays, and shade-tolerant plants, which are able to grow well under the forest canopy. This is of great practical importance for the natural regeneration of the forest stand: young shoots of many tree species are able to develop under the cover of large trees. In many animals, normal lighting conditions manifest themselves in a positive or negative reaction to light. Nocturnal insects flock to the light, and cockroaches scatter in search of shelter if only the light is turned on in a dark room. Photoperiodism (the change of day and night) is of great ecological importance for many animals that are exclusively diurnal (most passerines) or exclusively nocturnal (many small rodents, bats). Small crustaceans, floating in the water column, stay in surface waters at night, and during the day they descend to the depths, avoiding too bright light.

Light has almost no direct effect on animals. It serves only as a signal for the restructuring of processes occurring in the body.

Light, humidity, and temperature do not at all exhaust the set of environmental conditions that determine the life and distribution of organisms. Factors such as wind, atmospheric pressure, and altitude are also important. Wind has an indirect effect: by increasing evaporation, it increases dryness. Strong winds contribute to cooling. This action is important in cold places, high mountains or polar regions.

Anthropogenic factors. Anthropogenic factors are very diverse in their composition. Man influences living nature by laying roads, building cities, conducting agriculture, blocking rivers, etc. Modern human activity is increasingly manifested in environmental pollution with by-products, often poisonous. In industrial areas, concentrations of pollutants sometimes reach threshold values, that is, lethal for many organisms. However, no matter what, there will almost always be at least a few individuals of several species that can survive in such conditions. The reason is that resistant individuals are rarely found in natural populations. As pollution levels increase, resistant individuals may be the only survivors. Moreover, they can become the founders of a stable population that has inherited immunity to this type of pollution. For this reason, pollution gives us the opportunity to, as it were, observe evolution in action. However, not every population is endowed with the ability to resist pollution. Thus, the effect of any pollutant is twofold.

Law of Optimum.

Many factors are tolerated by the body only within certain limits. The organism dies if, for example, the environmental temperature is too low or too high. In environments where temperatures are close to these extremes, living inhabitants are rare. However, their number increases as the temperature approaches the average value, which is the best (optimal) for a given species. And this pattern can be transferred to any other factor.

The range of factor parameters at which the body feels comfortable is optimal. Organisms with wide limits of resistance, of course, have a chance of more wide use. However, wide limits of endurance for one factor do not mean wide limits for all factors. The plant may be tolerant of large temperature fluctuations, but have narrow ranges of water tolerance. An animal like trout can be very temperature sensitive but feed on a wide variety of foods.

Sometimes during the life of an individual, its tolerance (selectivity) may change. The body, finding itself in harsh conditions, after a while gets used to it and adapts to it. The consequence of this is a change in the physiological optimum, and the process is called adaptation or acclimatization.

Law of the minimum was formulated by the founder of the science of mineral fertilizers, Justus Liebig (1803-1873).

Yu. Liebig discovered that plant yield can be limited by any of the basic nutritional elements, if only this element is in short supply. It is known that different environmental factors can interact, that is, a deficiency of one substance can lead to a deficiency of other substances. Therefore, in general, the law of the minimum can be formulated as follows: an element or factor of the environment that is at a minimum limits (limites) the vital activity of the organism to the greatest extent.

Despite the complexity of the relationships between organisms and their environment, not all factors have the same ecological significance. For example, oxygen is a factor of physiological necessity for all animals, but with ecological point In terms of vision, it becomes limiting only in certain habitats. If fish die in a river, the oxygen concentration in the water must first be measured, since it is highly variable, oxygen reserves are easily depleted and there is often not enough oxygen. If the death of birds is observed in nature, it is necessary to look for another reason, since the oxygen content in the air is relatively constant and sufficient from the point of view of the requirements of terrestrial organisms.

Self-test questions:

List the main living environments.

What are environmental conditions?

Describe the living conditions of organisms in soil, aquatic and land-air habitats.

Give examples of how organisms adapt to living in different habitats?

What are the adaptations of organisms that use other organisms as a habitat?

What effect does temperature have on different types of organisms?

How do animals and plants get the water they need?

What effect does light have on organisms?

How does the impact of pollutants on organisms manifest?

Explain what environmental factors are and how they affect living organisms?

What factors are called limiting?

What is acclimatization and what significance does it have in the dispersal of organisms?

How do the laws of optimum and minimum manifest themselves?

The environment that surrounds living beings consists of many elements. They affect the life of organisms in different ways. The latter react differently to various environmental factors. Individual elements of the environment that interact with organisms are called environmental factors. Conditions of existence are a set of vital environmental factors, without which living organisms cannot exist. In relation to organisms, they act as environmental factors.

Classification of environmental factors.

All environmental factors accepted classify(distribute) 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. Anthropogenic (anthropogenic) factors in recent years have been identified as an independent group of factors among biotic ones, due to their great value. These are factors of direct or indirect influence of a person 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 act 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 penetrating and reaching them.

Solar radiation.

Among the variety of environmental factors, solar radiation is of greatest importance. (solar radiation). This is a continuous stream of elementary particles (speed 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 solar radiation Life originated on Earth, has gone a long way in 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 are determined by the wavelength. Waves passing through the atmosphere and reaching the Earth are measured in the range of 0.3 to 10 microns.

Based on 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.

Short-wave ultraviolet rays are almost completely absorbed by the atmosphere, namely its ozone screen. Minor amount ultraviolet rays penetrates to the surface of the earth. Their wavelength lies in the range of 0.3-0.4 microns. They account for 7% of solar radiation energy. Short-wave rays have a detrimental effect on living organisms. They can cause changes in hereditary material - mutations. Therefore, in the process of evolution, organisms that long time are influenced by solar radiation and have developed devices to protect against ultraviolet rays. Many of them produce additional amounts of black pigment in their integument - melanin, which protects against the penetration of unwanted rays. This is why people get a tan 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 ultraviolet radiation, but due to pollution by soot and environmental dust, the elements of which usually become darker. Against such a dark background, darker forms of organisms survive (are well camouflaged).

Visible light appears within wavelengths from 0.4 to 0.7 µm. It accounts for 48% of solar radiation energy.

It also adversely affects living cells and their functions in general: it changes the viscosity of protoplasm, the size electric charge cytoplasm, disrupts the permeability of membranes and changes the movement of the cytoplasm. Light affects the state of protein colloids and the course 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 chemical bonds in the products of photosynthesis, and then 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 their living conditions, animals have adapted to varying degrees illumination Some animal species are diurnal, while others are most active at dusk or at night. Most mammals and birds lead a twilight lifestyle, have difficulty distinguishing colors and see everything in black and white (canines, cats, hamsters, owls, nightjars, etc.). Living in twilight or low light conditions often leads to eye hypertrophy. Relatively huge eyes, capable of capturing tiny fractions of light, characteristic of nocturnal animals or those that live in complete darkness and are guided by the luminescent organs 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 temperature factor on Earth are solar radiation and geothermal processes. Although the core of our planet is characterized by extremely high temperatures, its influence on the surface of the planet is insignificant, except for zones of volcanic activity and the release of geothermal waters (geysers, fumaroles). Consequently, the main source of heat within the biosphere can be considered solar radiation, namely infrared rays. Those rays that reach the Earth's surface are absorbed by the lithosphere and hydrosphere. Lithosphere, how solid, heats up faster and cools just as quickly. The hydrosphere has a higher heat capacity than the lithosphere: it heats up slowly and cools down 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 airless space. And yet, the Earth's atmosphere helps retain heat in the surface layers of the troposphere. Thanks to its properties, the atmosphere transmits short-wave infrared rays and blocks long-wave infrared rays emitted by the heated surface of the Earth. This atmospheric phenomenon has a name greenhouse effect. It was thanks to him that the world became possible life. The greenhouse effect helps retain heat in the surface layers of the atmosphere (where most organisms are concentrated) and smoothes 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 which has 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 magma of volcanoes and the lowest temperatures of Antarctica). The limits within which life known to us can exist are quite narrow and are equal to approximately 300 ° C, from -200 ° C (freezing at liquefied gases) up 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 to the following temperature values ​​(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 heat-stimulating plants. They are able to tolerate overheating up to 55-65° C (some cacti). Species growing in conditions of high temperatures tolerate them more easily due to a significant shortening of the size of the leaves, the development of a tomentose (hairy) or, conversely, waxy coating, etc. Plants are able to withstand prolonged exposure without harming their development 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 its combination with other abiotic factors.

Humidity.

Humidity is an important abiotic factor, which is determined 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 in the atmosphere is always present 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 is relative humidity. Temperature is the main factor affecting the ability of air to hold water vapor. For example, at a temperature of +27°C, 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 higher 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 processes associated with it cannot take place. 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 loss and there is always a need to replenish its reserves. For normal existence, plants and animals must maintain a certain balance between the flow of water into the body and its loss. Big losses body water (dehydration) lead to a decrease in his vital activity, and subsequently to death. Plants satisfy their water needs through precipitation and air humidity, and animals also through food. The resistance of organisms to the presence or absence of moisture in the environment varies 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 hygrophobias(animals).

Need the most moisture hygrophilic 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 are among the herbaceous plants that grow in shaded forests (oxalis, ferns, violets, gap-grass, etc.) and in open places (marigold, sundew, etc.).

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

Mesophilic organisms require moderate amounts of moisture and are usually associated with moderately warm conditions and good conditions mineral nutrition. These can be forest plants and plants of open areas. Among them there are trees (linden, birch), shrubs (hazel, buckthorn) and even more herbs (clover, timothy, fescue, lily of the valley, hoofed grass, 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 regions of land.

Xerophilic organisms - This is a fairly diverse ecological group of plants and animals that have adapted to arid living conditions through the following means: limiting evaporation, increasing water production, and creating water reserves for long periods of lack of water supply.

Plants that live in dry conditions cope with them in different ways. Some do not have the structural arrangements to cope with the lack of moisture. their existence is possible in arid conditions only due to the fact that at a critical moment they are in a state of rest in the form of seeds (ephemeri) or bulbs, rhizomes, tubers (ephemeroids), very easily and quickly switch to active life and completely disappear in a short period of time annual development cycle. Ephemery mainly distributed in deserts, semi-deserts and steppes (stonefly, spring ragwort, turnip, etc.). Ephemeroids(from Greek ephemeral And to look like)- these are perennial herbaceous, mainly spring, plants (sedges, cereals, tulip, etc.).

Very unique categories of plants that have adapted to tolerate drought conditions are succulents And sclerophytes. Succulents (from Greek. juicy) are able to accumulate large amounts of water and gradually waste it. For example, some cacti of North American deserts can contain from 1000 to 3000 liters of water. Water accumulates in the leaves (aloe, sedum, agave, young) or stems (cacti and cactus-like milkweeds).

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

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

Some animal species that do not consume water by direct drinking can consume it by absorbing it through the entire surface of the skin. Insects and larvae that live in soil moistened with tree dust have their integuments permeable to water. The Australian moloch lizard absorbs moisture from precipitation through its skin, which is extremely hygroscopic. Many animals get moisture from succulent food. Such succulent food can be grass, juicy fruits, berries, bulbs and plant tubers. The steppe tortoise, which lives in the Central Asian steppes, consumes water only from succulent food. In these regions, in areas where vegetables are planted or in melon fields, turtles cause great damage by feeding on melons, watermelons, and cucumbers. Some predatory animals also obtain 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 obtain 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. Thus, the red-tailed gerbil sometimes feeds only on dry seeds. There are known experiments where, in captivity, a North American deer mouse lived for about three years, eating only dry barley grains.

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 edaphos- soil). Soils have their own structure, composition and properties.

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

For example, certain species of plants and animals love soils with a certain acidity, namely: sphagnum mosses, wild currants, and alder 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 (microelements). Some of the plants selectively accumulate certain rare elements. Cruciferous and umbelliferous plants, for example, accumulate sulfur in their bodies 5-10 times more than other plants.

Excessive 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, deformed hooves, etc. Later it turned out that in this valley there was increased selenium content. When this element entered the body of sheep in excess, it caused chronic selenium toxicosis.

The soil has its own thermal regime. Together with moisture, it affects soil formation and various processes occurring in the soil (physicochemical, 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 the 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 frosty night, the temperature in the gerbil burrows was +19°C.

Soil is a unique combination of physical and chemical properties of the surface of the lithosphere and the living organisms that inhabit it. It is impossible to imagine soil without living organisms. No wonder the famous geochemist V.I. Vernadsky called soils bioinert body.

Orographic factors (relief).

Relief does not relate 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.

c Depending on the size of the forms, the relief of several orders is quite conventionally distinguished: macrorelief (mountains, lowlands, intermountain depressions), mesorelief (hills, ravines, ridges, etc.) and microrelief (small depressions, unevenness, 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. Thus, even minor drops of several tens of centimeters create conditions of high humidity. Water flows from elevated areas to lower ones, where favorable conditions are created for moisture-loving organisms. The northern and southern slopes have different lighting and thermal conditions. In mountainous conditions, significant altitude amplitudes 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 humidification mode, gas composition air, etc.

For example, with a rise above sea level, the air temperature decreases by 6 ° C for every 1000 m. Although this is a characteristic of the troposphere, due to the relief (hills, mountains, mountain plateaus, etc.), terrestrial organisms may find themselves in conditions not similar to those in neighboring regions. For example, the Kilimanjaro volcanic mountain range in Africa is surrounded by savannas at the foot, and higher up the slopes there 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. In temperate zones, a decrease in temperature for every 6° C corresponds to a movement of 800 km towards high latitudes.

Pressure.

Pressure manifests itself in both air and water environments. In atmospheric air, pressure changes seasonally, depending on weather conditions and altitude. Of particular interest are the adaptations of organisms that live in conditions of low pressure and rarefied air in the highlands.

The pressure in the aquatic environment changes depending on the depth: it increases by approximately 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 from the depths of the world) are able to withstand great pressure, but they never rise to the surface of the sea, because for them this 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 up to 1 km, and seabirds - up to 15-20 m, where they get their food.

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

Terrestrial animals, perceiving minor changes in pressure, can predict changes in weather conditions through their behavior.

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

Hydrological factors.

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

Such characteristics of water as thermal conductivity, fluidity, transparency, salinity, manifest themselves differently in reservoirs and are environmental factors, which in this case are called hydrological. For example, aquatic organisms have adapted differently to varying degrees of water salinity. There are freshwater and marine organisms. Freshwater organisms do not amaze with their species diversity. First, 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 numerically 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, the shells of mollusks, the edible mussel (Mytilus edulis) and the Lamarck's mussel (Cerastoderma lamarcki), which live in bays Baltic Sea at a salinity of 2-6%o, 2-4 times smaller than the individuals that live in that same sea, only at a salinity of 15%o. The crab Carcinus moenas in the Baltic Sea is small in size, whereas in desalinated lagoons and estuaries it is much larger. Sea urchins grow smaller in lagoons than in the sea. The brine shrimp (Artemia salina) at a salinity of 122%o has dimensions 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 heartfish lives up to 9 years in the waters of the North Atlantic, and in less salty waters Sea of ​​Azov - 5.

The temperature of water bodies 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 reservoirs - 30-35° C. What can we say about the deep layers of water, which are characterized by a constant thermal regime.

Biotic factors.

Organisms that live on our planet require not only abiotic conditions for their life, they interact with each other and are often very dependent on each other. Set of factors organic world that influence organisms directly or indirectly are called biotic factors.

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

Clements and Shelford (1939) proposed their 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. Types of interactions between organisms belonging to the same species are homotypic reactions. Heterotypic reactions call the forms of interaction between two organisms of different species.

Homotypic reactions.

Among the interactions 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 also form groups. Under such conditions they survive better. When living together, it is easier for animals to defend themselves, obtain food, protect their offspring, and survive adverse environmental factors. Thus, the group effect has positive influence for all group members.

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

Simple aggregations (temporary or permanent) can develop into complex groups consisting of specialized individuals that perform their inherent function in that 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 combining into groups, especially large ones, some overpopulation also occurs, but there is a big difference between group and mass effects. The first gives advantages to each member of the association, while the other, on the contrary, suppresses the life activity of everyone, that is, it has Negative consequences. For example, the mass effect occurs when vertebrate animals gather together. If a large number of experimental rats are kept in one cage, then their behavior will manifest acts of aggressiveness. When animals are kept in such conditions for a long time, the embryos of pregnant females dissolve, aggressiveness increases so much that the rats gnaw off each other's tails, ears, and limbs.

The mass effect of highly organized organisms leads to a stressful state. In humans, this can cause mental disorders and nervous breakdowns.

Intraspecific competition.

There is always a kind of competition between individuals of the same species to obtain the best living conditions. The greater the population density of a particular group of organisms, the more intense the competition. Such competition between organisms of the same species 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, decreased 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 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 separately, has a spherical crown; it is quite spreading, since the lower side branches receive a sufficient amount of light. In oak plantings in the forest, the lower branches are shaded by the upper ones. Branches that do not receive enough light die. 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 active 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 also forced, like plants (or attached species of animals), to adapt to the conditions with which they have to be content.

Heterotypic reactions.

Table 1.2.4. Forms of interspecific interactions

	Species occupy		Species occupy
Form of interaction (coactions)	one territory (live together)		different territories (live separately)
	View A	View B	View A	View B
Neutralism
Comensalism (type A - commensal)
Protocooperation
Mutualism
Amensalism (type A - amensal, type B - inhibitor)
Predation (species A - predator, species B - prey)
Competition

0 - interaction between species does not produce gains and does not cause damage to either side;

Interactions between species produce positive consequences; --interaction between species produces 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. The forest is home to a large number of species 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, upon detailed study, one can still find not direct, but indirect, rather subtle and at first glance, invisible connections.

Eat. Doom, in his “Popular Ecology,” gives a humorous but very apt example of such connections. He writes that in England, old single women support the power of the king's guards. And the connection between guardsmen and women is quite simple. Single women, as a rule, breed cats, and cats hunt mice. The more cats, the fewer mice in the fields. Mice are the enemies of bumblebees because they destroy their holes where they live. The fewer mice, the more bumblebees. Bumblebees, as you know, are not the only pollinators of clover. More bumblebees in the fields means a larger clover harvest. Horses are grazed on clover, and the guards like to eat horse meat. Behind this example in nature you can find many hidden connections between different organisms. Although in nature, as can be seen from the example, cats have neutral relations with horses or jmels, but they are indirectly related to them.

Comensalism.

Many types of organisms enter into relationships that benefit only one party, while the other does not suffer from this and nothing is useful. This form of interaction between organisms is called commensalism. Comensalism often manifests itself as the coexistence of different organisms. Thus, insects often live in mammal burrows or bird nests.

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

In nature, there is even a species called the commensal crab. This small, graceful crab willingly settles in the mantle cavity of oysters. By doing this, he does not disturb the mollusk, but he himself receives shelter, fresh portions of water and nutrient particles that reach him with the water.

Protocooperation.

The next step in the joint positive coaction of two organisms of different species is proto-cooperation, 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, this mutually beneficial, but not obligatory, form of interaction arises when crabs and gutters come together. Anemones, for example, often settle on the dorsal side of crabs, camouflaging and protecting them with their stinging tentacles. In turn, the sea anemones receive from the crabs pieces of food that remain from their food, and use the crabs as vehicle. Both crabs and sea anemones are able to exist freely and independently in a reservoir, but when they are nearby, the crab even uses its claw to transplant the sea anemone onto itself.

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 dependence. If in protocooperation the organisms that enter into communication can exist separately and independently of each other, then in mutualism the existence of these organisms separately is impossible.

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

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

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

Amensalism.

IN natural environment Not all organisms have a positive effect on each other. There are many cases when, in order to ensure their livelihoods, one species harms another. This form of co-action, in which one type of organism suppresses the growth and reproduction of an organism of another species without losing anything, is called amensalism (antibiosis). A depressed look in a couple that interacts is called amensalom, and the one who suppresses - inhibitor.

Amensalism is best studied in plants. During their life, plants release chemicals into the environment, which are factors influencing other organisms. Regarding plants, amensalism has its own name - allelopathy. It is known that due to the release of toxic substances by its roots, Nechuyviter volokhatenki displaces other annual plants and forms continuous single-species thickets over large areas. In fields, wheatgrass and other weeds are crowded out or suppressed cultivated plants. Walnut and oak suppress herbaceous vegetation under their crowns.

Plants can secrete alelopathic substances not only from their roots, but also from the aboveground part of their body. Volatile alelopathic substances released into the air by plants are called phytoncides. Basically, they have a destructive effect on microorganisms. Everyone is well aware of the antimicrobial preventive effect of garlic, onions, and horseradish. Coniferous trees produce a lot of phytoncides. One hectare of common juniper plantings produces more than 30 kg of phytoncides per year. Coniferous species are often used in populated areas to create sanitary protective strips around various industries, which helps clean the air.

Phytoncides negatively affect not only microorganisms, but also animals. Various plants have long been used in everyday life to control insects. So, baglitsa and lavender are good remedy to fight moths.

Antibiosis is also known in microorganisms. It was first discovered. Babesh (1885) and rediscovered by A. Fleming (1929). Penicillin mushrooms have been shown to secrete a substance (penicillin) that inhibits the growth of bacteria. It is widely known that some lactic acid bacteria acidify their environment so that putrefactive bacteria, which require an alkaline or neutral environment, cannot exist in it. Alelopathic chemicals from microorganisms are known as antibiotics. Over 4 thousand antibiotics have already been described, but only about 60 of their varieties are widely used in medical practice.

Animals can also be protected from enemies by secreting 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 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 consumption of some organisms by others, i.e. such relationships between organisms in which some use others as food. With this understanding, the hare is a predator in relation to the grass 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 systematic terms (for example, insects that feed on insects; fish that feed on fish; birds that feed on reptiles, birds and mammals; mammals that that feed on birds and mammals). The extreme case of predation, in which a species feeds on organisms of its own species, is called cannibalism.

Sometimes a predator selects prey in such numbers that it does not negatively affect its population size. By doing this, the predator contributes to the better condition of the prey population, which has also already adapted to the pressure of the predator. The birth rate in prey populations is higher than that required to normally maintain its population. Figuratively speaking, the prey population takes into account what the predator should select.

Interspecific competition.

Between organisms of different species, as well as between organisms of the same species, interactions arise through which they try to obtain 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 the process of selection, which leads to the diversity of species that exist in a particular community or region.

Competitive interaction may concern space, food or nutrients, light and many other factors. Interspecific competition, depending on what it is based on, can lead either to the establishment of equilibrium between two species, or, with more severe competition, to the replacement of a population of one species by a population of another. Also, the result of competition may be that one species displaces another to another place or forces it to switch to other resources.