Ecological factors are any external factors that have a direct or indirect effect on the number (abundance) and geographical 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 are factors of inanimate nature.

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

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

environment conditions.

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

The most important factors that 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 thermal endurance in different organisms are different. 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 are characterized by the largest range of temperature endurance. 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 only live 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 on the time of day. In tropical areas, annual temperature fluctuations can be even less noticeable than daily ones. Conversely, in temperate regions, temperatures vary considerably at different times of the year. Animals and plants are forced to adapt to the unfavorable winter season, during which an active life is difficult or simply impossible. In tropical areas, such adaptations are less pronounced. In a cold period with unfavorable temperature conditions, there seems to be a pause in the life of many organisms: hibernation in mammals, leaf shedding 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 beings: it is necessary for their normal functioning. A normally developing organism constantly loses water and therefore cannot live in absolutely dry air. Sooner or later, such losses can lead to the death of the organism.

The simplest and most convenient indicator characterizing the humidity of a particular area is the amount of precipitation falling here for 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 terrestrial animals need a periodic supply 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 through the integument of the body in a liquid or vapor state. Most desert animals never drink. They meet their needs with water from food. Finally, there are animals that receive water in an even more complex way - in the process of fat oxidation, for example, a camel. Animals, like plants, have many adaptations to conserve water.

Light.

There are light-loving plants that can develop only under the sun's rays, and shade-tolerant plants that can grow well under the forest canopy. This is of great practical importance for the natural regeneration of the forest stand: the young shoots of many tree species are able to develop under the cover of large trees. In many animals, normal light conditions manifest themselves in a positive or negative reaction to light. Nocturnal insects flock to the light, and cockroaches scatter in search of cover, if only a 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 hovering in the water column stay at night in surface waters, and during the day they sink 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 the processes occurring in the body.

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

anthropogenic factors. Anthropogenic factors are very diverse in their composition. Man influences living nature by laying roads, building cities, farming, blocking rivers, etc. Modern human activity is increasingly manifested in environmental pollution with by-products, often poisonous products. In industrial areas, the concentrations of pollutants sometimes reach threshold values, that is, fatal for many organisms. However, in spite of everything, there will almost always be at least a few individuals of several species that can survive in such conditions. The reason is that in natural populations, resistant individuals occasionally come across. As pollution levels rise, resistant individuals may be the only survivors. Moreover, they can become the founders of a stable population that inherits immunity to this type of pollution. For this reason, pollution makes it possible for us, as it were, to observe evolution in action. However, not every population is endowed with the ability to resist pollution. Thus, the effect of any pollutant is twofold.

The law of optimum.

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

The range of factor parameters in which the body feels comfortable are optimal. Organisms with wide limits of resistance, of course, have a chance for a wider distribution. However, wide limits of endurance in one factor do not mean wide limits in all factors. The plant can be tolerant of large temperature fluctuations, but have narrow tolerances to water. An animal like a trout can be very demanding in terms of temperature, but eat a variety of foods.

Sometimes during the life of an individual, its tolerance (selectivity) may change. The body, getting into harsh conditions, after a while, as it were, gets used to it, adapts to them. 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 the yield of plants can be limited by any of the main nutrients, if only this element is in short supply. It is known that different environmental factors can interact, that is, the lack 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 environmental factor that is at a minimum, to the greatest extent, limits (limits) the vital activity of the organism.

Despite the complexity of the relationship 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 from an ecological point of view, it becomes limiting only in certain habitats. If fish die in a river, the first thing to be measured is the oxygen concentration in the water, as it is highly variable, oxygen reserves are easily depleted and often lacking. 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.

Questions for self-examination:

List the main environments of life.

What are environmental conditions?

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

Give examples of organisms adapting 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 is the effect of pollutants on organisms manifested?

Justify what environmental factors are, how they affect living organisms?

What are the limiting factors?

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

How are the laws of optimum and minimum manifested?

Environmental factors

The interaction of man and his environment has been the object of study of medicine at all times. To assess the effects of various environmental conditions, the term "environmental factor" was proposed, which is widely used in environmental medicine.

Factor (from the Latin factor - making, producing) - the reason, the driving force of any process, phenomenon, which determines its nature or certain features.

An environmental factor is any environmental impact that can have a direct or indirect effect on living organisms. An environmental factor is an environmental condition to which a living organism reacts with adaptive reactions.

Environmental factors determine the conditions for the existence of organisms. The conditions for the existence of organisms and populations can be considered as regulatory environmental factors.

Not all environmental factors (for example, light, temperature, humidity, presence of salts, availability of nutrients, etc.) are equally important for the successful survival of an organism. The relationship of the organism with the environment is a complex process in which the weakest, "vulnerable" links can be distinguished. Those factors that are critical or limiting for the life of an organism are of greatest interest, primarily from a practical point of view.

The idea that the endurance of an organism is determined by the weakest link among

all his needs, was first expressed by K. Liebig in 1840. He formulated the principle, which is known as Liebig's law of the minimum: "The crop is controlled by a substance that is at a minimum, and the magnitude and stability of the latter in time is determined."

The modern formulation of J. Liebig's law is as follows: "The life possibilities of an ecosystem are limited by those of the ecological environmental factors, the quantity and quality of which are close to the minimum required by the ecosystem, their reduction leads to the death of the organism or the destruction of the ecosystem."

The principle, originally formulated by K. Liebig, is currently extended to any environmental factors, but it is supplemented by two restrictions:

Applies only to systems that are in a stationary state;

It refers not only to one factor, but also to a complex of factors that are different in nature and interact in their influence on organisms and populations.

According to prevailing ideas, the limiting factor is considered to be such a factor, according to which, in order to achieve a given (sufficiently small) relative change in the response, a minimum relative change in this factor is required.

Along with the influence of a lack, a "minimum" of environmental factors, the influence of an excess, that is, a maximum of factors such as heat, light, moisture, can also be negative. The concept of the limiting influence of the maximum along with the minimum was introduced by W. Shelford in 1913, who formulated this principle as the "law of tolerance": The limiting factor for the prosperity of an organism (species) can be both a minimum and a maximum of environmental impact, the range between which determines the value of endurance ( tolerance) of the body in relation to this factor.

The law of tolerance, formulated by W. Shelford, was supplemented with a number of provisions:

Organisms may have a wide tolerance range for one factor and a narrow tolerance for another;

The most widespread are organisms with a large range of tolerance;

The range of tolerance for one environmental factor may depend on other environmental factors;

If the conditions for one ecological factor are not optimal for the species, then this also affects the range of tolerance for other environmental factors;

The limits of tolerance significantly depend on the state of the organism; thus, the limits of tolerance for organisms during the breeding season or at an early stage of development are usually narrower than for adults;

The range between the minimum and maximum of environmental factors is commonly called the limits or range of tolerance. To indicate the limits of tolerance to environmental conditions, the terms "eurybiontic" - an organism with a wide tolerance limit - and "stenobiont" - with a narrow one are used.

At the level of communities and even species, the phenomenon of factor compensation is known, which is understood as the ability to adapt (adapt) to environmental conditions in such a way as to weaken the limiting influence of temperature, light, water and other physical factors. Species with a wide geographical distribution almost always form populations adapted to local conditions - ecotypes. In relation to people, there is the term ecological portrait.

It is known that not all natural environmental factors are equally important for human life. So, the most significant consider the intensity of solar radiation, air temperature and humidity, the concentration of oxygen and carbon dioxide in the surface layer of air, the chemical composition of soil and water. The most important environmental factor is food. To maintain life, for the growth and development, reproduction and preservation of the human population, energy is needed, which is obtained from the environment in the form of food.

There are several approaches to the classification of environmental factors.

In relation to the body, environmental factors are divided into: external (exogenous) and internal (endogenous). It is believed that external factors, acting on the organism, are themselves not subject to or almost not subject to its influence. These include environmental factors.

External environmental factors in relation to the ecosystem and to living organisms are the impact. The response of an ecosystem, biocenosis, populations and individual organisms to these impacts is called a response. The nature of the response to the impact depends on the ability of the body to adapt to environmental conditions, adapt and acquire resistance to the influence of various environmental factors, including adverse effects.

There is also such a thing as a lethal factor (from Latin - letalis - deadly). This is an environmental factor, the action of which leads to the death of living organisms.

When certain concentrations are reached, many chemical and physical pollutants can act as lethal factors.

Internal factors correlate with the properties of the organism itself and form it, i.e. are included in its composition. Internal factors are the number and biomass of populations, the amount of various chemicals, the characteristics of the water or soil mass, etc.

According to the criterion of "life" environmental factors are divided into biotic and abiotic.

The latter include non-living components of the ecosystem and its external environment.

Abiotic environmental factors are components and phenomena of inanimate, inorganic nature that directly or indirectly affect living organisms: climatic, soil and hydrographic factors. The main abiotic environmental factors are temperature, light, water, salinity, oxygen, electromagnetic characteristics, and soil.

Abiotic factors are divided into:

Physical

Chemical

Biotic factors (from the Greek biotikos - life) - factors of the living environment that affect the vital activity of organisms.

Biotic factors are divided into:

Phytogenic;

microbiogenic;

Zoogenic:

Anthropogenic (socio-cultural).

The action of biotic factors is expressed in the form of mutual influences of some organisms on the vital activity of other organisms and all together on the environment. Distinguish between direct and indirect relationships between organisms.

In recent decades, the term anthropogenic factors has been increasingly used, i.e. caused by man. Anthropogenic factors are opposed to natural, or natural factors.

The anthropogenic factor is a set of environmental factors and impacts caused by human activity in ecosystems and the biosphere as a whole. Anthropogenic factor - direct human impact on organisms or impact on organisms through human change in their habitat.

Environmental factors are also divided into:

1. Physical

Natural

Anthropogenic

2. Chemical

Natural

Anthropogenic

3. Biological

Natural

Anthropogenic

4. Social (socio-psychological)

5. Informational.

Environmental factors are also divided into climatic-geographical, biogeographical, biological, as well as soil, water, atmospheric, etc.

physical factors.

Physical natural factors include:

Climatic, including the microclimate of the area;

geomagnetic activity;

Natural radiation background;

Cosmic radiation;

Terrain;

Physical factors are divided into:

Mechanical;

vibration;

Acoustic;

EM radiation.

Physical anthropogenic factors:

Microclimate of settlements and premises;

Pollution of the environment by electromagnetic radiation (ionizing and non-ionizing);

Noise pollution of the environment;

Thermal pollution of the environment;

Deformation of the visible environment (changes in the terrain and colors in settlements).

chemical factors.

Natural chemicals include:

Chemical composition of the lithosphere:

Chemical composition of the hydrosphere;

The chemical composition of the atmosphere,

The chemical composition of food.

The chemical composition of the lithosphere, atmosphere and hydrosphere depends on the natural composition + the release of chemicals as a result of geological processes (for example, impurities of hydrogen sulfide as a result of the eruption of a volcano) and the vital activity of living organisms (for example, impurities in the air of phytoncides, terpenes).

Anthropogenic chemical factors:

household waste,

Industrial waste,

Synthetic materials used in everyday life, agriculture and industrial production,

pharmaceutical industry products,

Food additives.

The effect of chemical factors on the human body can be due to:

Excess or deficiency of natural chemical elements in

environment (natural microelementoses);

Excess content of natural chemical elements in the environment

environment associated with human activities (anthropogenic pollution),

The presence in the environment of unusual chemical elements

(xenobiotics) due to anthropogenic pollution.

Biological factors

Biological, or biotic (from the Greek biotikos - life) environmental factors - factors of the living environment that affect the vital activity of organisms. The action of biotic factors is expressed in the form of mutual influences of some organisms on the vital activity of others, as well as their joint influence on the environment.

Biological factors:

bacteria;

Plants;

Protozoa;

Insects;

Invertebrates (including helminths);

Vertebrates.

Social environment

Human health is not completely determined by the biological and psychological properties acquired in ontogenesis. Man is a social being. He lives in a society governed by state laws, on the one hand, and on the other, by the so-called generally accepted laws, moral principles, rules of conduct, including those involving various restrictions, etc.

Every year society becomes more and more complex and has an increasing impact on the health of the individual, population, and society. For enjoying the benefits of a civilized society, a person must live in rigid dependence on the way of life accepted in society. For these benefits, often very dubious, the person pays with part of his freedom, or completely with all his freedom. And a person who is not free, dependent cannot be completely healthy and happy. Some part of man's freedom, given to a technocritical society in exchange for the advantages of a civilized life, constantly keeps him in a state of neuropsychic tension. Constant neuro-psychic overstrain and overstrain leads to a decrease in mental stability due to a decrease in the reserve capabilities of the nervous system. In addition, there are many social factors that can lead to the disruption of a person's adaptive capabilities and the development of various diseases. These include social disorder, uncertainty about the future, moral oppression, which are regarded as the leading risk factors.

Social factors

Social factors are divided into:

1. social system;

2. production sphere (industry, agriculture);

3. household sphere;

4. education and culture;

5. population;

6. zo and medicine;

7. other spheres.

There is also the following grouping of social factors:

1. Social policy that forms a sociotype;

2. Social security, which has a direct impact on the formation of health;

3. Environmental policy that forms the ecotype.

Sociotype is an indirect characteristic of the integral social burden in terms of the totality of factors of the social environment.

Sociotype includes:

2. working conditions, rest and life.

Any environmental factor in relation to a person can be: a) favorable - contributing to his health, development and realization; b) unfavorable, leading to his illness and degradation, c) influencing both. It is no less obvious that in reality most influences are of the latter type, having both positive and negative sides.

In ecology, there is a law of optimum, according to which any ecological

the factor has certain limits of positive influence on living organisms. The optimal factor is the intensity of the environmental factor that is most favorable for the organism.

The impacts can also differ in scale: some affect the entire population of the country as a whole, others affect the inhabitants of a particular region, others affect groups identified by demographic characteristics, and others affect an individual citizen.

Interaction of factors - simultaneous or sequential total impact on organisms of various natural and anthropogenic factors, leading to a weakening, strengthening or modification of the action of a single factor.

Synergism is the combined effect of two or more factors, characterized by the fact that their combined biological effect significantly exceeds the effect of each component and their sum.

It should be understood and remembered that the main harm to health is caused not by individual environmental factors, but by the total integral environmental load on the body. It consists of an ecological burden and a social burden.

Environmental burden is a combination of factors and conditions of the natural and man-made environment that are unfavorable for human health. An ecotype is an indirect characteristic of an integral ecological load based on a combination of factors of the natural and man-caused environment.

Ecotype assessments require hygiene data on:

The quality of housing

drinking water,

air,

Soil, food,

Medicines, etc.

Social burden is a set of factors and conditions of social life unfavorable for human health.

Environmental factors that shape the health of the population

1. Climatic-geographical characteristics.

2. Socio-economic characteristics of the place of residence (city, village).

3. Sanitary and hygienic characteristics of the environment (air, water, soil).

4. Features of nutrition of the population.

5. Characteristics of labor activity:

Profession,

Sanitary and hygienic working conditions,

The presence of occupational hazards,

Psychological microclimate at work,

6. Family and household factors:

family composition,

The nature of the housing

Average income per family member,

Organization of family life.

Distribution of non-working time,

Psychological climate in the family.

Indicators that characterize the attitude to the state of health and determine the activity to maintain it:

1. Subjective assessment of one's own health (healthy, sick).

2. Determining the place of personal health and the health of family members in the system of individual values ​​(hierarchy of values).

3. Awareness about the factors contributing to the preservation and promotion of health.

4. The presence of bad habits and addictions.

Ecology and biosphere

test

1. Name groups of environmental factors and give examples. What is the peculiarity of human activity as an environmental factor

Elements of the environment that affect living organisms are called environmental factors. They are subdivided:

1. Abiotic;

2. Biotic;

3. Anthropogenic.

Abiotic factors include elements of inanimate nature: light, temperature, humidity, precipitation, wind, atmospheric pressure, background radiation, chemical composition of the atmosphere, water, soil, and the like.

Biotic factors are living organisms (bacteria, fungi, plants, animals) that interact with this organism.

Anthropogenic factors include features of the environment due to human labor activity. With the growth of the population and the technical equipment of mankind, the proportion of anthropogenic factors is constantly increasing.

In the process of nature management, humanity annually moves more than 4 trillion tons of waste on our planet. tons of matter, creates thousands of new chemical compounds, most of which are not included in the cycle of substances and, ultimately, accumulate in the biosphere, causing its pollution. As a result of industrial activity, pollution of the natural environment occurs, a decrease in the level of solar radiation over large geographical regions.

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Environmental factors- properties of the environment that have any effect on the body. For example, the presence of minerals, oxygen access, soil moisture, soil temperature, soil looseness. Indifferent elements of the environment, such as inert gases, are not environmental factors.

modes

By the nature of the impact

• Direct acting
• Indirectly acting
• Conditionally operating- the influence of ecosystem elements (biogeocenosis) enhanced or weakened by the action of other environmental factors

Origin

• abiotic- factors of inanimate nature:
  • climatic
  • edaphic (edaphogenic)
  • orographic
  • chemical
  • physical: noise, magnetic fields, thermal conductivity and heat capacity, radioactivity, solar radiation intensity ***** hydrographic: water density, flow, transparency, etc.
    • pyrogenic: fire factors[ source unspecified 824 days] (Odum, 1975, 1986)
• Biotic
  • phytogenic- influence of plants
  • mycogenic- influence of mushrooms
  • zoogenic- animal influence
  • microbiogenic- influence of microorganisms
• Anthropogenic (anthropic) factor:
  • In 1912 the Russian scientist prof. G.F.Morozov in his book "The Doctrine of the Forest" defined the impact of man on nature as a separate environmental factor and divided it according to the nature of the impact on the natural environment into direct, indirect and conditional anthropogenic impact [Morozov, 1949].
  • Direct anthropogenic impact- direct human impact on the components of the ecosystem (biogeocenosis). This is picking berries, mushrooms, cutting down trees, etc.
  • Indirect anthropogenic impact– human influence through an intermediate level. This is a change in the level of groundwater, a change in the temperature regime, radiation pollution, etc.
  • Conditional anthropogenic impact- this is the effect of biotic and abiotic factors, enhanced or weakened by human exposure.
  • In 1981, the definition of "Anthropogenic factor [anthropogenic impact] is any impact on the environment, leading to quantitative and qualitative changes in its components, associated with both conscious and unconscious human activity [Popa, 1981].
  • In 2011, a scale of anthropogenic digression of biogeocenoses (ecosystems), developed on the example of broad-leaved forests of the steppe zone, was published, including 12 stages of environmental destruction by humans, from the state of conditionally undisturbed ecosystems to the stage of complete loss of vital functions by biogeocenoses [Popa, 2011].

By spending

• Resources
• Conditions

By direction

• Vectorized
• perennial-cyclic

• monodominance
• Synergy
• Antagonism
• provocative

extreme values

Life curve of a perennial plant. Annual plants are not able to go into a dormant state and their zone of life coincides with the zone of vital activity.

plastic

life curve points and zones:

• cardinal points:
  • points minimum and maximum
  • dot optimum
• Zones:
  • zone optimum
  • zones pessimism
  • zone vital activity
  • zones rest
  • zone life

reaction rate

abundance or frequency of occurrence

Bibliography

• Sahney, S., Benton, M.J. and Ferry, P.A. (2010). "Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land" (PDF). Biology Letters 6 (4): 544–547. DOI:10.1098/rsbl.2009.1024. PMID 20106856.
• David L. Hawksworth. Biodiversity and Conservation in Europe. - Springer, 2008. - P. 3390. - ISBN 1402068646..
• Bampton, M. "Anthropogenic Transformation" in Encyclopedia of Environmental Science, D. E. Alexander and R. W. Fairbridge, Kluwer Academic Publishers, Dordrecht, The Netherlands.
• Worm, Boris (2006-11-03). "Impacts of Biodiversity Loss on Ocean Ecosystem Services". Science 314 (5800): 787–790. DOI:10.1126/science.1132294. PMID 17082450.
• Morozov G.F. Forest teaching. 7th edition. M.: Goslesbumizdat, 1949. 455 p.
• Popa Yu.N. Anthropogenic transformation of forest biogeocenoses in Codri Moldavia. Abstract dis. cand. biol. Sciences: 03.00.16 - Ecology. Krasnoyarsk, 1981. p.6.
• Popa Yu.N. Restoration of biogeocenoses in anthropogenically transformed ecotopes in the steppe zone: monograph. ed. Corresponding Member NAS of Ukraine, Doctor of Biol. sciences, prof. A. P. Travleeva; National Aviation University. - Kyiv: Ukrainian bestseller, 2011. - 437 p.

Environmental factors

Adaptation of organisms to the environment

Basic living environments

Environmental factors

Organism and environment

Lecture 6. Fundamentals of autecology. Organism and environment

Autecology studies the relationship of members of one species with its environment. It is based on the study of the processes of adaptation of species to the environment (factorial ecology). Human ecology also studies the influence (rationing) of environmental factors, its extreme effects on the body.

The living world around us consists of organisms that constantly reproduce themselves. One aphid can leave more than 300 million offspring in a summer. It has the ability to multiply indefinitely. But there is no unlimited growth in numbers, the main limiter is the lack of resources. For plants - mineral salts, carbon dioxide, water, light. For animals - food, water. stocks of these resources restrain reproduction. The second limiter is the influence of various unfavorable conditions, which slows down growth and reproduction. Plant growth depends on the weather. The reproduction of aquatic life is inhibited by the low oxygen content in the water. In addition, screening and death of already produced embryos or young individuals occurs. For example, not all acorns germinate. High fecundity is distinguished by species in which the death of individuals in nature is very high.

The body, experiencing the need for an influx of matter, energy and information, is completely dependent on the environment.

Law - the results of the development of an organism are determined by the ratio of its internal characteristics and the characteristics of the environment in which it is located.

Evolutionarily arisen adaptation of organisms to environmental conditions, expressed in a change in their external and internal features - adaptation. Le Chatelier's principle: "The evolution of any system goes in the direction of reducing the potential danger." According to this principle, the evolution of an organism contributes to its adaptation to changing external influences.

Environmental factors- these are certain conditions and elements of the environment that have a specific effect on the body.

Environmental factors: 1- abiotic. 2 - biotic. 3- anthropogenic.

Abiotic factors- a set of factors of the inorganic environment that affect the life and distribution of animals and plants

Abiotic factors

physical chemical edaphic (soil)

Biotic factors- a set of influences of the vital activity of some organisms on the vital activity of others, as well as on the inanimate habitat

Biotic factors

intraspecific interspecific influence on

interactions interactions abiotic factors

(commonwealth)

Commensalism

(one gain)

Amensalism

(one species inhibits the growth of another)

Anthropogenic factors– factors generated by man and affecting the environment (pollution, soil erosion, deforestation, etc.)

The general nature of the action of environmental factors.

In the life process, the interaction of organisms with the environment and its components is based on the transfer between the elements of the system of mass flows of matter and their compounds, energies of all types and information. In accordance with the law of preservation of life by Yu. N. Kurazhkovsky: “Life can exist only in the process of movement through a living body of flows of matter, energy and information.”

The interaction of the organism with the environment is subject to the following laws. Main law optimum (tolerance). Liebig's law It is expressed in the fact that any environmental factor has certain limits of positive impact on the body. When deviating from these limits, the sign of the impact changes to the opposite. For example, animals do not tolerate heat and severe frosts; Drought and heavy rains are unfavorable for the crop. The curves of the optimum of any factor for different species will not coincide. Camels and jerboas cannot stand the conditions of the northern deserts, and reindeer and lemmings of the hot southern ones. A number of species can live within narrow limits of the optimum, while others can live within wide limits. The touchy plant dies if there is no moisture in the air; it does not die from feather grass even in drought. The optimum and limits of endurance are not constant during the life of the organism. The optimum can be shifted (temperature hardening).

In accordance with the optimum rule for an organism, there is a range of the most favorable (optimal) value of the factor. Outside the optimum lie zones of oppression, turning into critical points. For some organisms, the optimum zone has a wide range. They're called - eurybionts(Greek wide, life). Organisms with a narrow range - stenobionts(narrow).

The range of factor values ​​(between critical points) is called environmental valency. Synonymous with valence tolerance.( lat tolerance - patience), or plasticity (variability) if the environment is relatively constant, little changeable, then there are more stenobionts in it (for example, in the aquatic environment). If the environment is dynamic, for example, water-air, eurybionts are more likely to survive in it. The optimum zone and ecological valency are wider in warm-blooded animals.

The effect of the temperature factor. If the range of tolerance lies within a wide range (-5; +25), then such organisms are called eurythermal, if it is narrow, stenothermic. May be euryhaline (salinity)

Rice. 1. Dependence of life potential on the intensity of the impact factor

1. - zone of optimum (comfort);

2. - zone of permissible life activity;

3. - zone of oppression;

4. - zone of death.

Tolerance - the ability of the body to tolerate the adverse effects of a particular environmental factor.

Optimum zone with a comfort point (maximum point - life potential) - the area of ​​\u200b\u200boptimal life.

Zones of permissible activity - the values ​​of the permissible values ​​of the impact factor are the area of ​​normal life.

Zones of oppression - zones with large deviations of the factor from the optimum, in which the body experiences depression of vital activity.

Kill zone – the limits of tolerance for the factor of influence coincide with the values ​​of the minimum and maximum of the factor, beyond which the existence of the organism is not possible.

It should be borne in mind that some factors can enhance or mitigate the effect of others. Excess heat can be mitigated by low air humidity. . The law of independence of factors by V. R. Williams: “The conditions of life are equivalent, none of the factors of life can be replaced by another”

2nd law - the limiting factor. The most significant factor is the one that deviates the most from the optimal values. A factor that is in deficiency or excess (near critical points) negatively affects the body. Limiting factors determine the boundaries of the distribution of species - the range. The productivity of organisms and communities depends on them.

The limiting factor rule in agronomy. If the soil lacks 50% phosphorus and 20% calcium, the yield will be 5 times less. If calcium is added, the yield is 59%.

A person, by his activity, often violates all the patterns of the action of factors - habitat destruction, violation of the regime of water and mineral nutrition.

The law of the optimum and the limiting factor can be expressed in one law W. Shelford's law of tolerance:“The limiting factor for the prosperity of a population (organism) can be both a minimum and a maximum of environmental impact, and the range between them determines the amount of endurance (tolerance limit) of an organism to a given factor”

Environmental factors are:

Environmental factors

Environmental factors- properties of the environment that have any effect on the body. Indifferent elements of the environment, for example, inert gases, are not environmental factors.

Environmental factors are highly variable in time and space. For example, the temperature varies greatly on the surface of the land, but is almost constant at the bottom of the ocean or in the depths of caves.

One and the same environmental factor has a different meaning in the life of cohabiting organisms. For example, the salt regime of the soil plays a primary role in the mineral nutrition of plants, but is indifferent to most land animals. The intensity of illumination and the spectral composition of light are extremely important in the life of phototrophic organisms (most plants and photosynthetic bacteria), while in the life of heterotrophic organisms (fungi, animals, a significant part of microorganisms), light does not have a noticeable effect on life.

Environmental factors can act as irritants that cause adaptive changes in physiological functions; as constraints that make it impossible for certain organisms to exist under given conditions; as modifiers that determine morpho-anatomical and physiological changes in organisms.

Organisms are affected not by static unchanging factors, but by their modes- the sequence of changes over a certain time.

Classifications of environmental factors

By the nature of the impact

• Direct acting- directly affecting the body, mainly on metabolism
• Indirectly acting- influencing indirectly, through a change in directly acting factors (relief, exposure, altitude, etc.)

Origin

• abiotic- factors of inanimate nature:
  • climatic: annual sum of temperatures, average annual temperature, humidity, air pressure
  • edaphic (edaphogenic): mechanical composition of the soil, air permeability of the soil, acidity of the soil, chemical composition of the soil
  • orographic: terrain, elevation, slope steepness and exposure
  • chemical: gas composition of air, salt composition of water, concentration, acidity
  • physical: noise, magnetic fields, thermal conductivity and heat capacity, radioactivity, solar radiation intensity
• Biotic- associated with the activities of living organisms:
  • phytogenic- influence of plants
  • mycogenic- influence of mushrooms
  • zoogenic- animal influence
  • microbiogenic- influence of microorganisms
• :
  • physical: the use of nuclear energy, travel in trains and planes, the impact of noise and vibration
  • chemical: the use of mineral fertilizers and pesticides, pollution of the Earth's shells with industrial and transport waste
  • biological: Food; organisms for which a person can be a habitat or source of food
  • social- associated with human relations and life in society

By spending

• Resources- elements of the environment that the body consumes, reducing their supply in the environment (water, CO 2 , O 2 , light)
• Conditions- elements of the environment that are not consumed by the body (temperature, air movement, soil acidity)

By direction

• Vectorized- directionally changing factors: swamping, soil salinization
• perennial-cyclic- with alternating multi-year periods of strengthening and weakening of the factor, for example, climate change due to the 11-year solar cycle
• Oscillatory (impulse, fluctuation)- fluctuations in both directions from a certain average value (daily fluctuations in air temperature, change in the average monthly precipitation during the year)

The effect of environmental factors on the body

Environmental factors affect the body not separately, but in combination, respectively, any reaction of the body is multifactorial conditioned. At the same time, the integral influence of factors is not equal to the sum of the influences of individual factors, since various kinds of interactions occur between them, which can be divided into four main types:

• monodominance- one of the factors suppresses the action of the others and its value is of decisive importance for the organism. Thus, the complete absence, or the presence in the soil of mineral nutrition elements in a sharp deficiency or excess, prevents the normal assimilation of other elements by plants.
• Synergy- Mutual amplification of several factors due to positive feedback. For example, soil moisture, nitrate content and illumination, with an improvement in the supply of any of them, increase the effect of the impact of the other two.
• Antagonism- Mutual extinction of several factors due to negative feedback: an increase in the locust population contributes to a decrease in food resources and its population is declining.
• provocative- a combination of positive and negative effects for the body, while the influence of the latter is enhanced by the influence of the former. So, the earlier the thaw occurs, the more the plants suffer from subsequent frosts.

The influence of factors also depends on the nature and current state of the organism, so they have an unequal effect both on different species and on one organism at different stages of ontogenesis: low humidity is detrimental to hydrophytes, but harmless to xerophytes; low temperatures are tolerated without harm by adult conifers of the temperate zone, but are dangerous for young plants.

Factors can partially replace each other: with a decrease in illumination, the intensity of photosynthesis will not change if the concentration of carbon dioxide in the air is increased, which usually happens in greenhouses.

The result of exposure to factors depends on the duration and frequency of their action. extreme values throughout the life of the organism and its descendants: short-term effects may not have any consequences, while long-term effects through the mechanism of natural selection lead to qualitative changes.

The body's response to changing environmental factors

Life curve of a perennial plant. Annual plants are not able to go into a dormant state and their zone of life coincides with the zone of vital activity.
Note: 1 - optimum point, 2 - minimum and maximum points, 3 - lethal points

Organisms, especially those leading an attached, like plants, or a sedentary lifestyle, are characterized by plastic- the ability to exist in more or less wide ranges of values ​​of environmental factors. However, with different values ​​of the factor, the organism behaves differently.

Accordingly, its value is distinguished, in which the body will be in the most comfortable state - to grow rapidly, multiply, and show competitive abilities. As the value of the factor increases or decreases relative to the most favorable, the body begins to experience depression, which manifests itself in the weakening of its vital functions and, at extreme values ​​of the factor, can lead to death.

Graphically, a similar reaction of the organism to a change in the values ​​of the factor is depicted as life curve(environmental curve), in the analysis of which it is possible to identify some points and zones:

• cardinal points:
  • points minimum and maximum - extreme values ​​of the factor at which the vital activity of the organism is possible
  • dot optimum - the most favorable value of the factor
• Zones:
  • zone optimum - limits the range of the most favorable factor values
  • zones pessimism (upper and lower) - ranges of values ​​of the factor in which the body experiences strong inhibition
  • zone vital activity - the range of factor values ​​in which it actively manifests its vital functions
  • zones rest (upper and lower) - extremely unfavorable values ​​of the factor at which the organism remains alive, but goes into a state of rest
  • zone life - the range of values ​​of the factor in which the organism remains alive

Beyond the boundaries of the life zone are the lethal values ​​of the factor at which the organism is not able to exist.

Changes that occur with an organism within the range of plasticity are always phenotypic, while only a measure of possible changes is encoded in the genotype - reaction rate, which determines the degree of plasticity of the organism.

On the basis of an individual vital activity curve, it is possible to predict the specific one. However, since a species is a complex supraorganismal system consisting of many populations distributed over various habitats with unequal environmental conditions, when assessing its ecology, generalized data are used not for individual individuals, but for entire populations. On the gradient of the factor, generalized classes of its values ​​are plotted, representing certain types of habitats, and environmental reactions are most often considered abundance or frequency of occurrence kind. In this case, one should speak no longer about the curve of vital activity, but about the curve of the distribution of abundances or frequencies.

Section 1. Theoretical aspects of ecology

Topic 1.1. Autoecology (factorial ecology)

Autoecology is a branch of ecology that studies the relationship of an organism with its environment. This section is devoted to the study of specific features of the response of animals and plants to environmental factors and the way of life of the species.

As part of this topic, we are with you today and will consider the following questions

The main environments for the existence of organisms

Patterns of the influence of environmental factors on living organisms

Environmental factors and their classification

The concept of "habitat" is different from the concept of "existence conditions" - a set of vital environmental factors without which living organisms cannot exist (light, heat, moisture, air, soil). Other environmental factors, although they have a significant impact on organisms, are not vital for them (for example, wind, natural and artificial ionizing radiation, atmospheric electricity, etc.).

2 . Any organism can exist only in a certain temperature range. When the environment temperature is too low or too high, the organism dies. Where the temperature is close to extremes, representatives of this species are rare, but as the temperature approaches the average value, which is optimal for them, their number increases. This pattern is valid for any other factor a, affecting the course of certain life processes (humidity, wind strength, current speed, etc.).

If we draw a curve on the graph that characterizes the speed of a particular process (respiration, movement, nutrition, etc.) depending on one of the environmental factors (of course, provided that this factor has an impact on the main life processes), then this curve will almost always be bell-shaped (Fig. 1). Such curves are called tolerance curves (from Latin tolerahtia - patience). The position of their top indicates the conditions that are optimal for this process. Some species are characterized by curves with very sharp peaks; this means that the range of optimal conditions for them is very narrow. Smooth curves correspond to a wide range of tolerance, i.e., resistance to a given factor.

Organisms with wide limits of resistance to many factors, of course, have a chance for a wider distribution.

In widespread species populations, living in climatically different zones, often turn out to be the best adapted precisely to the conditions of a given area. This is due to their ability to form local forms, or ecotypes, characterized by different limits of resistance to temperature, light, or other factors.

As an example, consider the ecotypes of one of the species of jellyfish. As you know, jellyfish move in water like a rocket - with the help of rhythmic contractions. muscles pushing water out of the central cavity. The optimal pulsation rate is 15-20 contractions per minute. Individuals of one species of jellyfish living in northern latitudes move at the same speed as jellyfish of the same species in southern latitudes, although the water temperature in the north can be 20 C lower. This means that both forms of jellyfish were able to best adapt to local conditions.

Law of the Minimum.

The intensity of certain biological processes is often sensitive to two or more environmental factors. In this case, the decisive importance will belong to the one that is available in the minimum amount from the point of view of the needs of the body. This simple rule was first formulated by the founder of the science of mineral fertilizers, the German chemist and agricultural chemist Justus Liebig (1803-1873) and was called the law of the minimum . Yu. Liebig discovered that the crop of plants can be limited to one - any - of the main nutrients, unless this element is not enough in the soil.

Different environmental factors can interact, i.e. a lack of one substance can lead to a deficiency in other substances. For example, the lack of moisture in the soil limits the intake of all other substances necessary for plant nutrition. Therefore, in general, the law of the minimum can be formulate as follows : the successful survival of living organisms depends on a complex of conditions; limiting, or limiting, factor is any state of the environment that approaches or goes beyond the stability limit for. organisms of this species.

environmental factors. Elements of the environment that cause adaptive reactions (adaptations) in living organisms and their communities are called environmental factors.

According to the origin and nature of the action, environmental factors classified: abiotic (elements of inorganic, or inanimate, nature); biotic (forms of the impact of living beings on each other); anthropogenic ( all forms of human activity that affect the living environment genus).

Abiotic factors are divided into physical , or climatic (light, air and water temperature, air and soil humidity, wind); edaphic, or soil and ground (mechanical composition of soils, their chemical and physical properties); topographic, or orographic (features of the terrain); chemical

Anthropogenic (anthropic) factors are all forms of activity of human society that change nature as the habitat of living organisms or directly affect their life. The allocation of anthropogenic factors into a separate group is due to the fact that at present the fate of the vegetation cover of the Earth and all currently existing species of organisms is practically in the hands of human society.

Environmental factors act on organisms in different ways. They can act as irritants, causing adaptive changes in physiological functions; as limiters, causing the impossibility of the existence of certain organisms in these conditions; as modifiers,

/ ecology 1 lecture

Lecture 1

BASICS OF ECOLOGY

Subject, tasks and methods of ecology

Habitat and conditions for the existence of organisms

Environmental factors

Patterns of the action of environmental factors on the body

Interaction of environmental factors

Influence of the main abiotic factors on living organisms

Biotic environment.

Trophic (food) chain

Forms of biotic relationships.

Energy cycles in ecosystems

Subject, tasks and methods of ecology .Ecology(Greek, oikos - dwelling, residence, logos - science) - the biological science of the relationship between living organisms and their habitats. This term has been proposed in 1866. German zoologist Ernst Haeckel.

area(lat. area - area, space) - part of the land surface or water area, within which individuals of a given species (genus, family or a certain type of community) are distributed and go through a full cycle of their development.

Ecology objects are predominantly systems above the level of organisms, i.e., the study of the organization and functioning of supraorganismal systems: populations, biocenoses(communities), biogeocenoses(ecosystems) and biosphere generally. In other words, the main object of study in ecology are ecosystems, i.e., unified natural complexes formed by living organisms and the environment.

population- (lat. populus - people, population). a grouping of individuals of the same species, inhabiting a certain part of the range for a long time, interbreeding freely and relatively isolated from others, aggregates of the same species, is called a population

View- a group of organisms that have common features in body structure, physiology and ways of interacting with the environment, capable of interbreeding with each other to form fertile offspring, but not able to do this with organisms of other species.

Biocenosis- a set of organisms inhabiting an ecosystem, interconnected by the exchange of substances, energy and information.

Biogeocenosis - ecosystem

Biosphere, according to the definition of V.I. Vernadsky, this is the environment of our life, this is the "nature" that surrounds us.

Biosphere component of the city includes, in addition to humans, all types of green spaces, urban populations of animals. (pigeons, sparrows, crows, jackdaws, waterfowl wintering on thawed areas of water bodies, rats and mice, "domesticated" insects such as flies, mosquitoes, fleas and cockroaches, bedbugs, and finally, the microbial and viral population of multi-storey buildings and city apartments) .

home theoretical and practical problem of ecology- to uncover general patterns of life organization and on this basis to develop principles rational use of natural resources under conditions of ever-increasing influence of man on the biosphere.

The most important problem of our time the interaction of human society and nature, since the situation that develops in the relationship of man with nature often becomes critical. The reserves of fresh water and minerals (oil, gas, non-ferrous metals, etc.) are being exhausted, the condition of soils, water and air basins is deteriorating, desertification of vast territories is taking place, and the fight against diseases and pests of agricultural crops is becoming more difficult.

Anthropogenic changes affected almost all ecosystems of the planet, the gas composition of the atmosphere, the energy balance of the Earth. It means that human activity is in conflict with nature, resulting in many parts of the world violated her dynamic balance.

For solutions these global problems and above all, the problems of intensification and rational use, conservation and reproduction of biosphere resources, ecology combines in the scientific search efforts of all specialists in biology. The range of environmental issues also includes issues environmental education and enlightenment, moral, ethical, philosophical and even legal issues. Therefore, ecology becomes science not only biological, but also social.

Ecology methods subdivided into:

field(the study of the life of organisms and their communities in natural conditions, that is, long-term observation in nature using various equipment) and

experimental(experiments in stationary laboratories, where it is possible not only to vary, but also strictly control the effect of any factors on living organisms according to a given program).

At the same time, ecologists operate not only biological, but also modern physical and chemical methods, use modeling of biological phenomena, i.e., reproduction in artificial ecosystems of various processes occurring in wildlife. Through modeling, it is possible to study the behavior of any system in order to assess the possible consequences of applying various resource management strategies and methods, i.e. for environmental forecasting.

To study and predict natural processes, it is also widely used mathematical modeling method. Such ecosystem models are built on the basis of numerous data accumulated in field and laboratory conditions.

At the same time, well-formed mathematical models help see what which is difficult or impossible to test experimentally. The combination of field and experimental research methods allows the ecologist to find out all aspects of the relationship between living organisms and numerous environmental factors, which will allow not only to restore the dynamic balance of nature, but also to manage ecosystems.

Habitat and conditions for the existence of organisms . Part of nature (a set of specific abiotic and biotic conditions) that directly surrounds living organisms and has a direct or indirect effect on their condition, growth, development, reproduction, survival called habitat.

From the concept habitat» it is necessary to distinguish the concept « conditions of existence" - This a set of vital environmental factors without which living organisms cannot exist(light, heat, moisture, air, soil). Unlike them, other environmental factors, although they have a significant impact on organisms, are not vital for them (for example, wind, natural and artificial ionizing radiation, atmospheric electricity, etc.).

Environmental factors - This elements of the environment that cause adaptive reactions (adaptations) in living organisms and their communities.

According to the origin and nature of the action, environmental factors are divided into abiotic(elements of inorganic or inanimate nature), biotic(forms of the impact of living beings on each other) and anthropogenic(all forms of human activity that affect wildlife).

Abiotic factors divide by physical, or climatic(light, air temperature and oxen, air and soil humidity, wind), edaphic, or soil and ground(mechanical composition of soils, their chemical and physical properties), topographic, or orographic(features of the terrain), chemical(water salinity, gas composition of water and air, soil and water pH, etc.).

Anthropogenic (anthropic) factors- This all forms of activity of human society that change nature as the habitat of living organisms or directly affect their life. The allocation of anthropogenic factors into a separate group is due to the fact that at present the fate of the vegetation cover of the Earth and all currently existing species of organisms is practically in the hands of human society.

One and the same factor environment has different meaning in the lives of living organisms. For example, the salt regime of the soil plays a primary role in the mineral nutrition of plants, but is indifferent to most land animals. Light intensity and the spectral composition of light exclusively important in the life of phototrophic plants, and in the life of heterotrophic organisms (fungi and aquatic animals), light does not have a noticeable effect on their vital activity.

Environmental factors are at work on organisms differently. They can act as irritants that cause adaptive changes physiological functions; as limiters, causing the impossibility of the existence of certain organisms in given conditions; as modifiers, determining morphological and anatomical changes in organisms.

Patterns of the action of environmental factors on the body . The reaction of organisms to the influence of abiotic factors. The impact of environmental factors on a living organism is very diverse. Some factors have a stronger influence, others are weaker; some affect all aspects of life, others - on a specific life process. Nevertheless, in the nature of their impact on the body and in the responses of living beings, a number of general patterns can be identified that fit into some general scheme of the effect of the environmental factor on the life of the organism. The range of the environmental factor is limited by the corresponding extreme threshold values(points of minimum and maximum), at which the existence of an organism is still possible. These points are called lower and upper limits of endurance (tolerance) living beings in relation to a specific environmental factor.

The best indicators of vital activity of the body- This dot optimum . For most organisms, it is often difficult to determine the optimal value of the factor with sufficient accuracy, so it is customary to talk about optimum zone.

Extreme states of oppression of organisms with a severe lack or factor excess, called areas pessimism or stress . Close to critical points lie sublethal factor values, a outside the survival zone - lethal.

This regularity of the reaction of organisms to the impact of environmental factors allows us to consider it as a fundamental biological principle: for each species of plants and animals there is an optimum, a zone of normal life, pessimal zones and limits of endurance in relation to each environmental factor(Fig. 1)

7 6 2 1 3 5 8

1- optimum point; 2-3 - optimum zone ; 3-5 - 2-6 - limits of endurance (tolerance); 5.8 - 6,7 - extreme states of oppression of organisms - areas of pessimism or stress.

Different types of living organisms differ markedly from each other both in the position of the optimum and in the limits of endurance. For example, Arctic foxes in the tundra can tolerate fluctuations in air temperature in the range of about 80°С (from +30 to -55°С), some warm-water crustaceans withstand changes in water temperature in the range of no more than 6°С (from 23 to 29°С) cyanobacterium oscillatoria, living on the island of Java in water with a temperature of 64 ° C, dies at 68 ° C after 5-10 minutes.

organisms, for the existence of which strictly defined, relatively constant environmental conditions, called stenobiont(Greek Stenos - narrow, bion - living), and those who live in a wide range of variability of environmental conditions, - eurybiontic (Greek eurys - wide). At the same time, organisms of the same species can have a narrow amplitude with respect to one factor and a wide amplitude with respect to another (for example, adaptability to a narrow temperature range and a wide range of water salinity). In addition, the same dose of a factor can be optimal for one species, pessimal for another, and go beyond endurance limits for a third.

The ability of organisms to adapt to a certain range of factor variability environments called ecological plasticity. This feature is one of the most important properties of all living things: by regulating their vital activity in accordance with changes in environmental conditions, organisms acquire the ability to survive and leave offspring. Eurybiont organisms are environmentally the most plastic which provides them wide use, a stenobiont, on the contrary, differ weak ecological plasticity and, as a result, they usually have limited distribution areas.

Interaction of environmental factors . Environmental factors affect a living organism jointly and simultaneously. Wherein the effect of one factor depends from that with what force and in what combination other factors act simultaneously. This rule has received the name of the interaction of factors. For example, heat or frost is easier to bear in dry rather than moist air. The rate of evaporation of water from plant leaves (transpiration) is much higher if the air temperature is high and the weather is windy.

However, if the value of at least one of the vital environmental factors approaching to the critical value or goes beyond it(below the minimum or above the maximum), then despite the optimal combination of other conditions, individuals are in danger of death. Such factors are called limiting(limiting).

Limiting factors environments determine the geographic range of the species. Thus, the movement of the species to the north can be limited by a lack of heat, and to areas of deserts and dry steppes - by a lack of moisture or too high temperatures. Biotic relations can also serve as a factor limiting the distribution of organisms, for example, the occupation of the territory by a stronger competitor or the lack of pollinators for flowering plants. The identification of limiting factors and the elimination of their action, i.e., the optimization of the habitat of living organisms, is an important practical goal in increasing the yield of agricultural crops and the productivity of domestic animals.

Influence of the main abiotic factors on living organisms . Characterization of light as an environmental factor. Living nature cannot exist without light, since solar radiation reaching the Earth's surface is practically the only source of energy for maintaining the thermal balance of the planet, creating organic substances by phototrophic organisms of the biosphere, which ultimately ensures the formation of an environment that can satisfy the vital needs of all living beings.

The biological effect of sunlight depends on its spectral composition, duration, intensity, daily and seasonal periodicity.

Solar radiation is electromagnetic radiation in a wide range of waves constituting a continuous spectrum from 290 to 3,000 nm.

Ultra-violet rays(UFL) shorter than 290 nm, harmful to living organisms, are absorbed by the ozone layer and do not reach the Earth.

Lands reach mainly infrared(about 50% of total radiation) and visible (45%) rays of the spectrum. The share of UFL, having a wavelength of 290-380 nm, accounts for 5% of radiant energy. Long-wave UVL, which have high photon energy, are distinguished by high chemical activity. In small doses, they have a powerful bactericidal effect, promote the synthesis of certain vitamins and pigments in plants, and in animals and humans - vitamin D; in addition, they cause sunburn in humans, which is a protective reaction of the skin. Infrared rays with a wavelength of more than 710 nm have a thermal effect.

In ecological terms, the most important is the visible region of the spectrum.(390-710 nm), or photosynthetically active radiation (PAR), which is absorbed by chloroplast pigments and thus is of decisive importance in plant life. Visible light is needed by green plants for the formation of chlorophyll, the formation of the structure of chloroplasts; it regulates the functioning of the stomatal apparatus, affects gas exchange and transpiration, stimulates the biosynthesis of proteins and nucleic acids, and increases the activity of a number of photosensitive enzymes. Light also affects the division and elongation of cells, growth processes and the development of plants, determines the timing of flowering and fruiting, and has a shaping effect.

Light conditions on our planet are extremely great: from such strongly illuminated areas as highlands, deserts, steppes, to twilight illumination in water depths and caves.

The reaction of organisms to the daily rhythm of illumination, expressed in a change in the processes of trust and development, is called photoperiodism. The regularity and constant repetition from year to year of this phenomenon allowed organisms in the course of evolution to coordinate their most important life processes with the rhythm of these time intervals. Under photoperiod control there are almost all metabolic processes associated with the growth, development, vital activity and reproduction of plants and animals.

Photoperiodic reaction is characteristic of both plants and and animals.

The seasonal rhythm in animals is most clearly manifested in the change of plumage in birds and wool in mammals, the frequency of reproduction and migration, hibernation of some animals, etc.

Biological rhythms are also characteristic of humans. Daily rhythms are expressed in the alternation of sleep and wakefulness, fluctuations in body temperature within 0.7-0.8 ° C (at dawn it decreases, rises by noon, reaches a maximum in the evening, and then decreases again, especially quickly after a person falls asleep ), cycles of activity of the heart and kidneys, etc.

Living organisms are able to navigate in time, that is, they have a biological clock. In other words, many organisms are characterized by the ability to sense diurnal, tidal, lunar and annual cycles, which allows them to prepare in advance for upcoming environmental changes.

Temperature limits of life. The necessity of heat for the existence of organisms is primarily due to the fact that all life processes are possible only on a certain thermal background, determined by the amount of heat and the duration of its action. The temperature of organisms and, as a result, the speed and nature of the course of all chemical reactions that make up the metabolism depend on the ambient temperature.

The boundaries of the existence of life are the temperature conditions under which there is no denaturation of proteins, irreversible changes in the colloidal properties of the cytoplasm, disturbances in the activity of enzymes, respiration. For most organisms, this temperature range is from 0 to +500. However, a number of organisms have specialized enzyme systems and are adapted to active existence at temperatures outside these limits.

Species whose optimal living conditions are confined to the region of high temperatures are classified as ecological group of thermophiles(bacteria inhabiting the thermal springs of Kamchatka with a water temperature of 85-93 ° C, several types of green algae, scale lichens, seeds of desert plants located in the upper hot layer of soil. The temperature limit of representatives of the animal world usually does not exceed + 55-58 ° C ( testate amoebae, nematodes, mites, some crustaceans, larvae of many Diptera).

Plants and animals that remain active at temperatures from 0 to -8°C. refer to ecological group of cryophiles(Greek Kryos - cold, ice). Cryophilia is characteristic of many bacteria, fungi, lichens, arthropods and other creatures that live in the tundra, arctic and antarctic deserts, high mountains, cold polar waters, etc.

Representatives of most species of living organisms do not have the ability to actively thermoregulate their bodies. Their activity depends, first of all, on the heat coming from outside, and the body temperature - on the value of the ambient temperature. Such organisms are called poikilothermic (ectothermic). Poikilothermia is characteristic of all microorganisms, plants, invertebrates and most of the chordates.

Only birds and mammals the heat generated in the process of intensive metabolism serves as a fairly reliable source of increasing body temperature and maintaining it at a constant level regardless of the ambient temperature. This is facilitated by good thermal insulation created by the coat, dense plumage, and a thick layer of subcutaneous adipose tissue. Such organisms are called homoiothermic (endothermic, or warm-blooded). endothermic property allows many species of animals (polar bears, pinnipeds, penguins, etc.) active lifestyle at low temperatures.

special case homoiothermy - heterothermy- characteristic of animals that fall into hibernation or temporary torpor during an unfavorable period of the year (ground squirrels, hedgehogs, bats, dormice, etc.). Active they support high body temperature, and in the case low body activity - reduced, which is accompanied by a slowdown in metabolic processes and, as a result, low heat transfer.

The ecological role of the ox. Water is a necessary condition for the existence of all living organisms on Earth. The importance of water in life processes is determined by the fact that it is the main environment in the cell, where metabolic processes are carried out, it serves as the most important initial, intermediate or final product of biochemical reactions.

When studying the ecological role of water taken into account Not only amount precipitation, but and the ratio of their size and evaporation. Areas in which evaporation exceeds the annual amount of precipitation are called arid(dry, arid). AT humid (wet) areas plants are provided with sufficient water.

Higher terrestrial plants leading an attached lifestyle, to a greater extent than animals, depend on the availability of the substrate and air with moisture. There are three main groups of plants:

Hygrophytes- plants of excessively moistened habitats with high humidity of air and soil. The most typical hygrophytes are herbaceous plants and epiphytes of tropical rainforests and lower tiers of wet forests in different climatic zones. which are cultivated plants.

Xerophytes- plants of dry habitats, able to tolerate prolonged drought, while remaining physiologically active. These are plants of deserts, dry steppes, savannahs, dry subtropics, sand dunes and dry, strongly heated slopes.

The group of xerophytes includes succulents- plants with succulent fleshy leaves or stems containing a highly developed aquifer. There are leaf succulents (agaves, aloe, juveniles, stonecrops) and stem succulents, in which the leaves are reduced, and the aerial parts are represented by fleshy stems (cacti, some spurges, stocks, etc.) ..

Succulents are confined mainly to the arid zones of Central America, South Africa, and the Mediterranean.

Mesophytes occupy an intermediate position between hygrophytes and xerophytes. They are common in moderately humid zones with a moderately warm regime and a fairly good supply of mineral nutrition. Mesophytes include plants of meadows, herbaceous cover of forests, deciduous trees and shrubs from areas of temperate humid climate, as well as most cultivated plants and weeds. Mesophytes are characterized by high ecological plasticity, which allows them to adapt to changing environmental conditions.

Adaptations of animals to the water regime. Ways of regulation of water balance in animals are more diverse than in plants. They can be divided into behavioral, morphological and physiological.

Among the behavioral adaptations include the search for water bodies, the choice of habitats, digging burrows, etc. In burrows, air humidity approaches 100%, which reduces evaporation through the covers, saves moisture in the body.

To morphological ways of maintaining normal water balance include formations that contribute to the retention of water in the body; these are the shells of terrestrial mollusks, the absence of skin glands and the keratinization of the integument of reptiles, the chitinized cuticle of insects, etc.

Physiological adaptations of the regulation of water metabolism can be divided into three groups:

1) the ability of a number of species to form metabolic water and to be satisfied with moisture supplied with food (many insects, small desert rodents);

The term "ecology" was introduced into science by the German scientist Ernst Haeckel (E. Haeckel) in 1869. It is quite easy to give a formal definition, since the word "ecology" comes from the Greek words "oikos" - dwelling, shelter and "logos" - science. Therefore, ecology is often defined as the science of the relationship between organisms or groups of organisms (populations, species) with their environment. In other words, the subject of ecology is a set of connections between organisms and the conditions of their existence (environment), on which the success of their survival, development, reproduction, distribution, and competitiveness depends.

In botany, the term "ecology" was first used by the Danish botanist E. Warming in 1895.

In a broad sense, the environment (or environment) is understood as the totality of material bodies, phenomena and energy, waves and fields, one way or another affecting. However, different environments are far from equally perceived by a living organism, since their significance for life is different. Among them there are practically indifferent to plants, for example, inert gases contained in the atmosphere. Other elements of the environment, on the contrary, have a noticeable, often significant effect on the plant. They are called environmental factors. These are, for example, light, water in the atmosphere and soil, air, salinization of groundwater, natural and artificial radioactivity, etc.). With the deepening of our knowledge, the list of environmental factors is expanding, since in a number of cases it is found that plants are able to respond to elements of the environment that were previously considered indifferent (for example, a magnetic field, strong noise exposure, electric fields, etc.).

Classification of environmental factors

It is possible to classify environmental factors in different conceptual coordinate systems.

Distinguish, for example, resource and non-resource environmental factors. Resource factors are substances and (or) involved in the biological cycle by the plant community (for example, light, water, the content of mineral nutrients in the soil, etc.); accordingly, non-resource factors do not participate in the cycles of matter and energy transformation and ecosystems (for example, relief).

There are also direct and indirect environmental factors. The former directly affect metabolism, shaping processes, growth and development (light), the latter affect the body through a change in other factors (for example, transabiotic and transbiotic forms of interactions). Since in different ecological situations many factors can act both directly and indirectly, it is better to speak not about the separation of factors, but about their direct or indirect effect on the plant.

The most widely used classification of environmental factors according to their origin and nature of action:

I. Abiotic factors:

a) climatic - light, heat (its composition and movement), moisture (including precipitation in various forms, air humidity), etc .;

b) edaphic (or soil-ground) - physical (granulometric composition, water permeability) and chemical (pH of soils, content of mineral nutrition elements, macro- and microelements, etc.) properties of soils;

c) topographic (or orographic) - relief conditions.

II. Biotic factors:

a) phytogenic - direct and indirect impact of plant cohabitants;

b) zoogenic - direct and indirect influence of animals (eating, trampling, digging activities, pollination, distribution of fruits and seeds);

c) prokaryotic factors - the influence of bacteria and blue-green algae (negative effect of phytopathogenic bacteria, positive effect of free-living and symbiotically associated nitrogen-fixing bacteria, actinomycetes and cyanides);

Read more about biotic factors in the article

The specific forms of human impact on the vegetation cover, their direction, and scale make it possible to single out anthropogenic factors as well.

III. Anthropogenic factors associated with the multilateral forms of human agricultural activity (grazing, haymaking), its industrial activity (gas emissions in, construction, mining, transport communications and pipelines), with space exploration and recreational activities.

Far from everything fits into this simplest classification, but only the main environmental factors. There are other plants that are less essential for life (atmospheric electricity, the Earth's magnetic field, ionizing radiation, etc.).

We note, however, that the above division is to a certain extent conditional, since (and this is important to emphasize both in theoretical and practical terms) the environment affects the organism as a whole, and the separation of factors and their classification is nothing more than a methodological technique, facilitating the knowledge and study of the patterns of relationships between the plant and the environment.

General patterns of influence of environmental factors

The influence of environmental factors on a living organism is very diverse. Some factors - leading ones - have a stronger effect, others - secondary ones - act weaker; some factors affect all aspects of plant life, others - on any particular life process. Nevertheless, it is possible to present a general scheme of the dependence of the body's reaction under the influence of an environmental factor.

If the intensity of the factor in its physical expression is plotted along the abscissa (X) axis ( , salt concentration in the soil solution, pH, illumination of the habitat, etc.), and along the ordinate (Y) - the reaction of the organism or population to this factor in its quantitative expression (intensity of one or another physiological process - photosynthesis, water absorption by roots, growth, etc.; morphological characteristic - plant height, leaf size, number of seeds produced, etc.; population characteristics - number of individuals per unit area , frequency of occurrence, etc.), we get the following picture.

The range of action of the ecological factor (the area of ​​tolerance of the species) is limited by the minimum and maximum points, which correspond to the extreme values ​​of this factor, at which the existence of the plant is possible. The point on the abscissa axis, corresponding to the best indicators of the plant's vital activity, means the optimal value of the factor - this is the optimum point. Due to the difficulties in accurately determining this point, one usually speaks of a certain optimum zone, or a comfort zone. The optimum, minimum, and maximum points make up three cardinal points that determine the possibilities of a species' reaction to a given factor. The extreme sections of the curve, expressing the state of oppression with a sharp lack or excess of the factor, are called areas of pessimum; they correspond to the pessimal values ​​of the factor. Sub-lethal values ​​of the factor lie near the critical points, and lethal values ​​lie outside the tolerance zone.

Species differ from each other by the position of the optimum within the gradient of the ecological factor. For example, the attitude to heat in arctic and tropical species. The width of the range of the factor (or optimum zone) can also be different. There are species, for example, for which a low level of illumination (cave bryophytes) or a relatively high level of illumination (alpine alpine plants) is optimal. But species are also known that grow equally well both in full light and in significant shading (for example, the team hedgehog - Dactylis glomerata).

In the same way, some meadow grasses prefer soils with a certain, rather narrow range of acidity, while others grow well in a wide pH range - from strongly acidic to alkaline. The first case testifies to a narrow ecological amplitude of plants (they are stenobiont or stenotopic), the second - to a wide ecological amplitude (plants are eurybiont or eurytopic). Between the categories of eurytopicity and stenotopicity lies a number of intermediate qualitative categories (hemieurytopic, gemistenotopic).

The breadth of the ecological amplitude in relation to different environmental factors is often different. It is possible to be stenotopic with respect to one factor and eurytopic with respect to another: for example, plants can be confined to a narrow range of temperatures and a wide range of salinity.

Interaction of environmental factors

Environmental factors act on the plant jointly and simultaneously, and the effect of one factor depends to a large extent on the "ecological background", that is, on the quantitative expression of other factors. This phenomenon of interaction of factors is clearly seen in the experiment with the aquatic moss Fontinalis. This experiment clearly shows that illumination has a different effect on the intensity of photosynthesis at different CO 2 content in .

The experiment also shows that a similar biological effect can be obtained by partially replacing the action of one factor with another. Thus, the same intensity of photosynthesis can be achieved either by increasing the illumination to 18 thousand lux, or, at lower illumination, by increasing the concentration of CO 2 .

Here, the partial interchangeability of the action of one environmental factor with another is manifested. At the same time, none of the necessary environmental factors can be replaced by another: a green plant cannot be grown in complete darkness even with very good mineral nutrition or on distilled water with optimal thermal conditions. In other words, there is a partial substitution of the main ecological factors and, at the same time, their complete indispensability (in this sense, they are sometimes also spoken of as equally important for plant life). If the value of at least one of the necessary factors goes beyond the tolerance range (below the minimum and above the maximum), then the existence of the organism becomes impossible.

Limiting factors

If any of the factors that make up the conditions of existence has a pessimal value, then it limits the effect of the remaining factors (no matter how favorable they may be) and determines the final result of the environment's action on the plant. This end result can only be changed by acting on the limiting factor. This "law of the limiting factor" was first formulated in agricultural chemistry by the German agricultural chemist, one of the founders of agricultural chemistry, Justus Liebig in 1840 and is therefore often called Liebig's law.

He noticed that with a lack of one of the necessary chemical elements in the soil or nutrient solution, no fertilizers containing other elements affect the plant, and only the addition of “minimum ions” gives an increase in yield. Numerous examples of the action of limiting factors, not only in experiment, but also in nature, show that this phenomenon is of general ecological significance. One example of the operation of the “law of the minimum” in nature is the suppression of herbaceous plants under the canopy of beech forests, where, under optimal thermal conditions, high carbon dioxide content, sufficiently rich soils and other optimal conditions, the possibilities for grass development are limited by a sharp lack of light.

The identification of "factors at a minimum" (and at a maximum) and the elimination of their limiting effect, in other words, the optimization of the environment for plants, constitute an important practical task in the rational use of vegetation cover.

Autecological and synecological range and optimum

The attitude of plants to environmental factors closely depends on the influence of other plant co-habitants (primarily on competitive relations with them). Often there is a situation when a species can successfully grow in a wide range of action of some factor (which is determined experimentally), but the presence of a strong competitor forces it to be limited to a narrower zone.

For example, Scots pine (Pinus sylvestris) has a very wide ecological range in relation to soil factors, but in the taiga zone it forms forests mainly on dry poor sandy soils or on highly waterlogged peatlands, i.e., where there are no competing tree species. Here, the real position of the optima and areas of tolerance is different for plants that experience or do not experience biotic influence. In this regard, a distinction is made between the ecological optimum of a species (in the absence of competition) and the phytocenotic optimum corresponding to the actual position of the species in the landscape or biome.

In addition to the position of the optimum, the limits of the endurance of the species are distinguished: the ecological range (the potential limits of the distribution of the species, determined only by its relation to this factor) and the real phytocenotic range.

Often in this context one speaks of a potential and real optimum and area. In foreign literature, they also write about the physiological and ecological optimum and range. It is better to talk about the autecological and synecological optimum and the range of the species.

In different species, the ratio of the ecological and phytocenotic ranges is different, but the ecological range is always wider than the phytocenotic one. As a result of the interaction of plants, the range narrows and often the optimum shifts.