Habitat and environmental factors are general patterns. Ecology as a science. habitat. environmental factors. general patterns of action of environmental factors on organisms. Impact of habitat on biota
General patterns of action of environmental factors on organisms
The total number of environmental factors affecting the body or biocenosis is enormous, some of them are well known and understood, for example, water and air temperature; the effect of others, for example, changes in gravity, has only recently begun to be studied. Despite the wide variety of environmental factors, a number of patterns can be identified in the nature of their impact on organisms and in the responses of living beings.
Law of optimum (tolerance)
According to this law, first formulated by V. Shelford, for a biocenosis, an organism or a certain stage of its development, there is a range of the most favorable (optimal) factor value. Outside the optimum zone there are zones of oppression, turning into critical points beyond which existence is impossible.
The maximum population density is usually confined to the optimum zone. Optimum zones for various organisms are not the same. For some, they have a significant range. Such organisms belong to the group eurybionts(Greek eury – wide; bios – life).
Organisms with a narrow range of adaptation to factors are called stenobionts(Greek stenos - narrow).
Species that can exist in a wide range of temperatures are called eurythermic, and those that are able to live only in a narrow range of temperature values - stenothermic.
The ability to live in conditions with different salinity of water is called euryhaline, at various depths - eurybacy, in places with different soil moisture - euryhygricity etc. It is important to emphasize that the optimum zones in relation to various factors differ, and therefore organisms fully demonstrate their potential if the entire range of factors has optimal values for them.
The ambiguity of the effect of environmental factors on different functions body
Each environmental factor has a different effect on different body functions. The optimum for some processes may be oppressive for others. For example, air temperature from + 40 to + 45 ° C in cold-blooded animals greatly increases the rate of metabolic processes in the body, but at the same time inhibits motor activity, which ultimately leads to thermal torpor. For many fish, the water temperature that is optimal for the maturation of reproductive products turns out to be unfavorable for spawning.
The life cycle, in which at certain periods of time the organism primarily performs certain functions (nutrition, growth, reproduction, settlement, etc.), is always consistent with seasonal changes in the totality of environmental factors. At the same time, mobile organisms can change their habitats to successfully fulfill all the needs of their lives.
Diversity of individual reactions to environmental factors
The ability to endure, critical points, zones of optimum and normal functioning change quite often throughout life cycle individuals. This variability is determined both by hereditary qualities and by age, sex and physiological differences. For example, adult freshwater cyprinids and perch different types fish such as carp, European pike perch, etc. are quite capable of living in the water of inland sea bays with a salinity of up to 5-7 g/l, but their spawning grounds are located only in highly desalinated areas, near river mouths, because the eggs of these fish can It develops normally at a water salinity of no more than 2 g/l. Crab larvae cannot live in fresh water, but adult crabs are found in the estuaries of rivers, where the abundance of organic material carried by the river flow creates a good food supply. The miller moth - one of the dangerous pests of flour and grain products - is critical for life. minimum temperature for caterpillars -7 °C, for adult forms -22 °C, and for eggs -27 °C. A drop in air temperature to -10 °C is fatal for caterpillars, but not dangerous for adult forms and eggs of this species. Thus, the ecological tolerance characteristic of the species as a whole turns out to be broader than the tolerance of each individual at a given stage of its development.
Relative independence of adaptation of organisms to different environmental factors
The degree of endurance of an organism to a particular factor does not mean the presence of a similar tolerance in relation to another factor. Species that can survive in a wide range of temperature conditions may not be able to withstand large fluctuations in water salinity or soil moisture. In other words, eurythermal species can be stenohaline or stenohyric. A set of environmental tolerances (sensitivities) to various environmental factors is called ecological spectrum of the species.
Interaction of environmental factors
The optimum zone and limits of endurance in relation to any environmental factor can shift depending on the strength and combination of other factors acting simultaneously. Some factors can enhance or mitigate the effect of other factors. For example, excess heat can be mitigated to some extent by low air humidity. The wilting of the plant can be stopped both by increasing the amount of moisture in the soil and by lowering the air temperature, thereby reducing evaporation. The lack of light for plant photosynthesis can be compensated for by an increased content of carbon dioxide in the air, etc. It does not follow from this, however, that the factors can be interchangeable. They are not interchangeable. A complete lack of light will lead to the rapid death of the plant, even if the soil moisture and the amount of all nutrients in it are optimal. The combined action of several factors, in which the effect of their influence is mutually enhanced, is called synergy. Synergism is clearly manifested in combinations of heavy metals (copper and zinc, copper and cadmium, nickel and zinc, cadmium and mercury, nickel and chromium), as well as ammonia and copper, synthetic surfactants. With the combined effect of pairs of these substances, their toxic effect increases significantly. As a result, even small concentrations of these substances can be fatal to many organisms. An example of synergy may also be an increased threat of freezing during frost with strong winds than in calm weather.
In contrast to synergy, certain factors can be identified whose impact reduces the power of the resulting effect. The toxicity of zinc and lead salts is reduced in the presence of calcium compounds, and hydrocyanic acid - in the presence of ferric oxide and ferrous oxide. This phenomenon is called antagonism. At the same time, knowing exactly which substance has an antagonistic effect on a given pollutant, you can achieve a significant reduction in its negative impact.
The rule of limiting environmental factors and the law of the minimum
The essence of the rule of limiting environmental factors is that a factor that is in deficiency or excess has a negative effect on organisms and, in addition, limits the possibility of manifestation of the power of other factors, including those at optimum. For example, if the soil contains in abundance all but one chemical or chemical required for the plant. physical factor environment, then the growth and development of the plant will depend precisely on the magnitude of this factor. Limiting factors usually determine the boundaries of distribution of species (populations) and their habitats. The productivity of organisms and communities depends on them.
The rule of limiting environmental factors made it possible to come to the justification of the so-called “law of the minimum.” It is assumed that the law of the minimum was first formulated by the German agronomist J. Liebig in 1840. According to this law, the result of the influence of a set of environmental factors on the productivity of agricultural crops depends primarily not on those elements of the environment that are usually present in sufficient quantities, but on those for which are characterized by minimal concentrations (boron, copper, iron, magnesium, etc.). For example, shortage boron sharply reduces the drought resistance of plants.
In a modern interpretation, this law reads as follows: the endurance of an organism is determined by the weakest link in the chain of its environmental needs. That is, the vital capabilities of an organism are limited by environmental factors, the quantity and quality of which are close to the minimum required for a given organism. Further reduction of these factors leads to to the death of the organism.
Adaptive capabilities of organisms
To date, organisms have mastered four main environments of their habitat, which differ significantly in physicochemical conditions. This is the water, land-air, soil environment, as well as the environment that is the living organisms themselves. In addition, living organisms are found in layers of organic and organomineral substances located deep underground, in groundwater and artesian waters. Thus, specific bacteria were found in oil located at depths of more than 1 km. Thus, the Sphere of Life includes not only the soil layer, but can, under favorable conditions, extend much deeper into the earth’s crust. In this case, the main factor limiting penetration into the depths of the Earth is, apparently, the temperature of the environment, which increases as the depth from the soil surface increases. It is considered active at temperatures above 100 °C life is impossible.
Adaptations of organisms to environmental factors in which they live are called adaptations. Adaptations are any changes in the structure and function of organisms that increase their chances of survival. The ability to adapt can be considered one of the main properties of life in general, since it provides the ability for organisms to survive and reproduce sustainably. Adaptations manifest themselves at different levels: from the biochemistry of cells and the behavior of individual organisms to the structure and functioning of communities and entire ecological systems.
The main types of adaptations at the organism level are the following:
· biochemical - they manifest themselves in intracellular processes and may relate to changes in the work of enzymes or their total quantity;
· physiological - for example, increased respiratory rate and heart rate during heavy traffic, increased sweating with increasing temperature in a number of species;
· morphoanatomical- features of the structure and shape of the body associated with the lifestyle and environment;
· behavioral - for example, the construction of nests and burrows by some species;
· ontogenetic - acceleration or deceleration of individual development, promoting survival when conditions change.
Organisms most easily adapt to those environmental factors that change clearly and steadily.
Detailed development of an ecology lesson, where students reinforce concepts about environmental factors and their classification. The influence of these factors on living organisms is studied; the concept of the basic laws of ecology is given; optimum, pessimum and limiting factor and their significance; concepts are fixed - population, ecosystem, biosphere. This lesson can be used for first-year students of technical specialties of secondary vocational education.
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Lesson topic: Habitat and environmental factors. General patterns of action of environmental factors on the body. Population. Ecosystem. Biosphere.
Lesson objectives:
1 ) educational: study environmental factors and their classification; consider the influence of these factors on living organisms; become familiar with the laws of optimum and limiting factor and their meaning; consolidate the concepts - population, ecosystem, biosphere;
2) developing: promote the development of speech and skills independent work, communication abilities of students;
3) educational: develop students' understanding practical significance environmental knowledge.
Lesson type: combined
Forms of work: individual, group, frontal.
Equipment: presentation, tasks for independent work, didactic material, diagrams, tables.
During the classes
1. Organizational moment.
Greeting students.
Getting students in the mood for work.
II. Updating basic knowledge. Testing of acquired knowledge.
1.Front survey on the following questions:
What does ecology study?
What are the environmental challenges?
2. Individual survey.
History of environmental development.
Ecology sections.
The importance of ecology.
3. Checking and evaluating the schemes “The importance of ecology in human life and in the development of construction specialties.”
4. Solving environmental problems.
a) Literal fulfillment of the slogan “Let’s turn the Earth into a blooming garden!” dangerous from an environmental point of view. Why? Can it lead to the death of the biosphere or individual ecosystems? Which ecosystems will suffer from the implementation of such a slogan?
Answer: The realization of such a “dream” brings death to the steppes, desert, tundra and the biosphere as a whole, because a blooming garden means the destruction of species diversity on the planet.
b) Many plants in our country are newcomers from other places, often even from other continents. Trees and herbs from America are not uncommon among us, but this applies not only to vegetable plants and trees for landscaping, but to plants that are completely indifferent to humans. It made no sense for him to import the seeds of these settlers, but wherever you look, they grow, you can find Californian cocklebur, Canadian small petal, and acorn grass - these are American species. And our plantain has spread throughout America. How do such plants get to other continents, how do they spread there?
Answer: With pieces of soil, seeds stick to shoes, clothes of travelers, with grain, in the cracks of ships and airplanes.
III. Motivation for learning activities. Learning new material.
1.Explanation by the teacher with elements of conversation.
a) Habitat of living organisms.
- What is a habitat called?
- What are the habitats? Give examples of organisms that inhabit these living environments.
b) Environmental factors.
Can living organisms exist separately, without an environment?
Indeed, animals and plants, fungi and bacteria do not exist on their own, but in close interaction with each other and with the environment.
Components or environmental conditions that directly or indirectly affect organisms are calledenvironmental factors.
- Now I will read the poem, and you try to determine into which groups they can be divided (three groups).
The sky is light blue,
The golden sun is shining,
The wind plays with the leaves,
Clouds are passing in the sky.
Flowers, trees and grass,
Mountains, air and foliage,
Birds, animals and forests,
Thunder, fog and dew,
Man and season -
These are natural factors.
Answer: abiotic, biotic and anthropogenic.
2. Search conversation (schemes on tables).
Any organism is influenced by environmental factors.
Remember from your biology course, what types of environmental factors do you know?
1. Abiotic factors - factors of inanimate nature (water, temperature, air, climate, relief, soil).
2. Biotic factors - factors of living nature (all types of relationships between living organisms).
3. Anthropogenic factor - the impact of human activity on nature, can be positive and negative (give examples).
Environmental factors do not act individually, but in conjunction.
Biotic factors– the totality of influences of the life activity of some organisms on the life activity of others.
Intraspecific interactions characterize the relationships between organisms at the population level. They are based on intraspecific competition.
Interspecific interactions characterize the relationships between different species, which can be favorable, unfavorable and neutral.
Accordingly, we denote the nature of the impact +, – or 0. Then the following types of combinations of interspecific relationships are possible:
00 neutralism – both types are independent and have no effect on each other; Rarely found in nature (squirrel and elk, butterfly and mosquito);
0 commensalism – one species benefits, while the other has no benefit, no harm either (large mammals (dogs, deer) serve as carriers of fruits and plant seeds (burdock), receiving neither harm nor benefit);
–0 ammensalism – one species experiences inhibition of growth and reproduction from another (light-loving herbs growing under spruce suffer from shading, but the tree itself does not care);
Symbiosis – mutually beneficial relationships (anemone and hermit crab);
Mutualism – species cannot exist without each other (figs and the bees that pollinate them; lichen);
++ protocooperation– coexistence is beneficial for both species, but is not a prerequisite for survival (pollination of different meadow plants by bees);
Competition – each species has an adverse effect on the other (plants compete with each other for light and moisture);
+ – predation – a predatory species feeds on its prey (pike and crucian carp);
Other environmental factors and ecology terms.
Most environmental factors constantly change in time and space, and this variability can be regular, periodic (for example, changes in daily illumination, seasonal changes in temperature, ebbs and flows, a decrease in the amount of oxygen when climbing a mountain, etc.) or irregular (changes weather, floods, forest fire).
Despite the wide variety of environmental factors and the nature of their impact on organisms, a number of general patterns can be identified.
For organisms to live, a certain combination of conditions is necessary. If all environmental conditions are favorable, with the exception of one, then this condition becomes decisive for the life of the organism in question. It limits (limites) the development of the organism, therefore it is called a limiting factor.
Limiting factor (limiting)- an environmental factor that goes beyond the maximum or minimum, reducing the vital activity of organisms. For the first time, the German chemist J. Liebig drew attention to the existence of limiting or limiting factors.
Why does fish die in reservoirs in winter, why do carps not live in the ocean, why do worms appear on the surface of the earth after rain.
Answer (fish kills in water bodies in winter are caused by a lack of oxygen, carp do not live in the ocean (salt water), migration of soil worms is caused by excess moisture and lack of oxygen).
For trout, the limiting factor is the amount of oxygen (standard: 2 mg per 1 liter of water).
Liebig's law - limiting (limiting) factors sounds as follows:a factor that is in deficiency or excess negatively affects organisms even in the case of optimal combinations of other factors.
Optimal factor, or optimum.
For each organism there is the most suitable combination of factors that is optimal for its growth, development and reproduction.The optimum, or optimal factor, is the best combination of all conditions.
Law of tolerance or range of resistance (Shelford's law).In 1913, V. Shelford formulated the law of tolerance:tolerance - the ability of organisms to tolerate deviations of environmental factors from optimal ones for themselves(Latin “tolerance” - patience).
Organisms react poorly to both deficiency and excess of environmental factors. The range between maximum and minimum constitutes the body's tolerance limits. If the factor goes beyond the limits of tolerance, the body dies.
Pessimum is the worst combination of all conditions.
In ecology, there are the following basic concepts: species, population, biocenosis, biogeocenosis, or ecosystem, biosphere.
Remember the definitions of these terms from your biology course.
Population (from lat. Populatio-population) is a collection of organisms of onekind , living in one territory for a long time and relatively isolated from other individuals of this species.
Ecosystem - biological system (biogeocenosis ), consisting of a community of living organisms (biocenosis ) and their habitats (biotope ).
The main key concept in ecology is the term “ecosystem”, which was proposed by the English scientist A. Tansley (1935) or “biogeocenosis”, proposed by the Russian scientist V. Sukachev (1942).
Biosphere (from Greek “bios” - life and “sphere” - ball) - geological shellEarth , inhabited by the livingorganisms , under their influence, or the totality of all ecosystems of planet Earth.
IV. Consolidation of what has been learned.
- Working with tables.
a) Distribute the animals according to their habitat.
Animal | Ground-air | Water | The soil | Other organisms |
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White shark | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
grass frog | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Common mole | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Human roundworm | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Crayfish | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Starfish | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Amoeba dysentery | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Earthworm | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
mallard duck | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Earthworm | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Beet nematode | 4. Light. 5. Plowing the land. 6. Salinity. 7. Wolf in the forest. 8. Pork tapeworm in the body. 9. Water pollution with petroleum products. 10.Fleas in animal fur. 11. Car exhaust gases. 12. Disposal of radioactive waste in soil. 2. Conversation on issues. - What new did you learn in the lesson? What did you learn by studying the basics of ecology? Where can you apply the knowledge, skills and abilities you have acquired? 3. Determination of types of environmental interactions (work with cards). V. Homework: textbook, notes, draw up diagrams and drawings of biotic relationships.
Section 5 biogeocenotic and biosphere levels organization of living Topic 56. Ecology as a science. Habitat. Environmental factors. General patterns of action of environmental factors on organisms 1. Basic questions of theory Ecology– the science of the patterns of relationships between organisms with each other and with the environment. (E. Haeckel, 1866) Habitat– all conditions of living and inanimate nature under which organisms exist and which directly or indirectly affect them. The individual elements of the environment are environmental factors:
Adaptation of organisms to environmental factors Organisms adapt more easily to the factors acting strictly periodically and purposefully. Adaptation to them is hereditarily determined. Adaptation is difficult organisms to irregularly periodic factors, to factors uncertain actions. In that specificity And anti-ecological anthropogenic factors. General patterns effects of environmental factors on organisms Optimum rule .For an ecosystem or an organism, there is a range of the most favorable (optimal) value of an environmental factor. Outside the optimum zone there are zones of oppression, turning into critical points beyond which existence is impossible. Rule of interacting factors .Some factors can enhance or mitigate the effect of other factors. However, each of the environmental factors irreplaceable. Rule of limiting factors .A factor that is in deficiency or excess negatively affects organisms and limits the possibility of manifestation of the power of other factors (including those at optimum). Limiting factor – a vital environmental factor (near critical points), in the absence of which life becomes impossible. Determines the boundaries of species distribution. Limiting factor – an environmental factor that goes beyond the limits of the body’s endurance. Abiotic factors Solar radiation .The biological effect of light is determined by the intensity, frequency, spectral composition: Ecological groups of plants according to lighting intensity requirements The light regime leads to the appearance multi-tiered And mosaic vegetation cover. Photoperiodism – the body’s reaction to the length of daylight hours, expressed by changes in physiological processes. Associated with photoperiodism seasonal And daily allowance rhythms. Temperature .N : from –40 to +400С (on average: +15–300С). Classification of animals according to the form of thermoregulation Mechanisms of adaptation to temperature
Adaptation to t carried out through the size and shape of the body. Bergman's rule : As you move north, average body sizes in populations of warm-blooded animals increase. Allen's rule: in animals of the same species, the size of the protruding parts of the body (limbs, tail, ears) is shorter, and the body is more massive, the colder the climate. Gloger's Rule: animal species living in cold and humid areas have more intense body pigmentation ( black or dark brown) than the inhabitants of warm and dry areas, which allows them to accumulate a sufficient amount of heat. Adaptations of organisms to vibrations tenvironment Anticipation rule : southern plant species in the north are found on well-warmed southern slopes, and northern species at the southern borders of the range are found on cool northern slopes. Migration– relocation to more favorable conditions. Numbness– a sharp decrease in all physiological functions, immobility, cessation of nutrition (insects, fish, amphibians during t from 00 to +100С). Hibernation– a decrease in the intensity of metabolism, maintained by previously accumulated fat reserves.
Anabiosis– temporary reversible cessation of vital activity. Humidity .Mechanisms for regulating water balance
Ecological groups of plants according to humidity requirements
Halophytes are organisms that prefer excess salts. Air : N 2 – 78%, O2 – 21%, CO2 – 0.03%.N 2 : digested by nodule bacteria, absorbed by plants in the form of nitrates and nitrites. Increases drought resistance of plants. When a person dives underwater N 2 dissolves in the blood, and with a sharp rise is released in the form of bubbles - decompression sickness. O2: CO2: participation in photosynthesis, a product of the respiration of animals and plants. Pressure .N: 720–740 mm Hg. Art. When rising: partial pressure O2 ↓ → hypoxia, anemia (increase in the number of red blood cells by one V blood and contents Nv). At depth: partial pressure of O2 → solubility of gases in the blood increases → hyperoxia. Wind .Reproduction, settlement, transfer of pollen, spores, seeds, fruits. Biotic factors
Interspecies relationships
Living Environments Living environment is a set of conditions that ensure the life of an organism.
Habitat- this is that part of nature that surrounds a living organism and with which it directly interacts. The components and properties of the environment are diverse and changeable. Any Living being lives in a complex, changing world, constantly adapting to it and regulating its life activities in accordance with its changes. Adaptations of organisms to the environment are called adaptations. The ability to adapt is one of the main properties of life in general, since it provides the very possibility of its existence, the ability of organisms to survive and reproduce. Adaptations manifest themselves at different levels: from the biochemistry of cells and the behavior of individual organisms to the structure and functioning of communities and ecological systems. Adaptations arise and change during the evolution of species. Individual properties or elements of the environment that affect organisms are called environmental factors. Environmental factors are diverse. They can be necessary or, conversely, harmful to living beings, promote or hinder survival and reproduction. Environmental factors have different natures and specific actions. Ecological factors are divided into abiotic and biotic, anthropogenic. In the complex of factors, we can identify some patterns that are largely universal (general) in relation to organisms. Such patterns include the rule of optimum, the rule of interaction of factors, the rule of limiting factors and some others. Optimum rule. In accordance with this rule, for an organism or a certain stage of its development there is a range of the most favorable (optimal) factor value. The more significant the deviation of a factor’s action from the optimum, the more this factor inhibits the vital activity of the organism. This range is called the inhibition zone. The maximum and minimum tolerable values of a factor are critical points beyond which the existence of an organism is no longer possible. The maximum population density is usually confined to the optimum zone. Optimum zones for different organisms are not the same. The wider the amplitude of factor fluctuations at which the organism can maintain viability, the higher its stability, i.e. tolerance to one or another factor (from Lat. tolerance - patience). Organisms with a wide amplitude of resistance belong to the group of eurybionts (Greek eury - wide, bios - life). Organisms with a narrow range of adaptation to factors are called stenobionts(Greek stenos - narrow). It is important to emphasize that optimal zones in relation to various factors differ, and therefore organisms fully demonstrate their potential if they exist under conditions of the entire spectrum of factors with optimal values. Rule of interaction of factors. Its essence lies in the fact that some factors can enhance or mitigate the effect of other factors. For example, excess heat can be to some extent mitigated by low air humidity, the lack of light for plant photosynthesis can be compensated by an increased content of carbon dioxide in the air, etc. It does not follow from this, however, that the factors can be interchanged. They are not interchangeable. Rule of limiting factors. The essence of this rule is that a factor that is in deficiency or excess (near critical points) negatively affects organisms and, in addition, limits the possibility of manifestation of the power of other factors, including those at the optimum. Limiting factors usually determine the boundaries of distribution of species and their habitats. The productivity of organisms depends on them. Through his activities, a person often violates almost all of the listed patterns of action of factors. This especially applies to limiting factors (habitat destruction, disruption of water and mineral nutrition, etc.). Habitat- this is that part of nature that surrounds a living organism and with which it directly interacts. The components and properties of the environment are diverse and changeable. Any living creature lives in a complex and changing world, constantly adapting to it and regulating its life activity in accordance with its changes and consuming matter, energy, and information coming from outside. Adaptations of organisms to their environment are called adaptation. The ability to adapt is one of the main properties of life in general, since it provides the very possibility of its existence, the ability of organisms to survive and reproduce. Adaptations manifest themselves at different levels: from the biochemistry of cells and the behavior of individual organisms to the structure and functioning of communities and ecological systems. Adaptations arise and change during the evolution of species. Individual properties or elements of the environment that affect organisms are called environmental factors. Environmental factors are diverse. They can be necessary or, conversely, harmful to living beings, promote or hinder survival and reproduction. Environmental factors have different natures and specific actions. Environmental factors are divided into abiotic, biotic and anthropogenic. Abiotic factors- temperature, light, radioactive radiation, pressure, air humidity, salt composition of water, wind, currents, terrain - these are all properties of inanimate nature that directly or indirectly affect living organisms. Biotic factors- these are forms of influence of living beings on each other. Each organism constantly experiences the direct or indirect influence of other creatures, comes into contact with representatives of its own species and other species - plants, animals, microorganisms, depends on them and itself influences them. The surrounding organic world is an integral part of the environment of every living creature. Mutual connections between organisms are the basis for the existence of biocenoses and populations; their consideration belongs to the field of synecology. Anthropogenic factors- these are forms of activity of human society that lead to changes in nature as the habitat of other species or directly affect their lives. In the course of human history, the development of first hunting, and then Agriculture, industry, transport have greatly changed the nature of our planet. Meaning anthropogenic impacts for the entire living world of the Earth continues to increase rapidly. Although man influences wildlife through changes in abiotic factors and biotic relationships of species, human activity on the planet should be identified as a special force that does not fit into the framework of this classification. Currently, almost the entire fate of the living surface of the Earth and all types of organisms is in the hands of human society and depends on the anthropogenic influence on nature. The same environmental factor has different significance in the life of co-living organisms of different species. For example, strong winds in winter are unfavorable for large, open-living animals, but have no effect on smaller ones that hide in burrows or under the snow. The salt composition of the soil is important for plant nutrition, but is indifferent to most terrestrial animals, etc. Changes in environmental factors over time can be: 1) regularly periodic, changing the strength of the impact in connection with the time of day or season of the year, or the rhythm of ebbs and flows in the ocean; 2) irregular, without clear periodicity, for example, without change weather conditions in different years, catastrophic phenomena - storms, showers, landslides, etc.; 3) directed over certain, sometimes long periods of time, for example, during cooling or warming of the climate, overgrowing of water bodies, constant grazing of livestock in the same area, etc. Environmental environmental factors have various effects on living organisms, i.e. can act as stimuli causing adaptive changes in physiological and biochemical functions; as limitations that make it impossible to exist in given conditions; as modifiers that cause anatomical and morphological changes in organisms; as signals indicating changes in other environmental factors. Despite the wide variety of environmental factors, a number of general patterns can be identified in the nature of their impact on organisms and in the responses of living beings. Here are the most famous ones. J. Liebig's law of minimum (1873):
The law of limiting factors, or F. Blechman's law (1909):environmental factors that have maximum significance in specific conditions especially complicate (limit) the possibility of the species existing in these conditions. W. Shelford's Law of Tolerance (1913): The limiting factor in the life of an organism can be either a minimum or maximum environmental impact, the range between which determines the amount of endurance of the organism to this factor. As an example explaining the law of the minimum, J. Liebig drew a barrel with holes, the water level in which symbolized the endurance of the body, and the holes symbolized environmental factors. Law of Optimum: Each factor has only certain limits positive influence on organisms. The result of the action of a variable factor depends, first of all, on the strength of its manifestation. Both insufficient and excessive action of the factor negatively affects the life activity of individuals. The favorable force of influence is called the zone of optimum of the environmental factor, the inhibitory effect of this factor on organisms (pessimum zone). The maximum and minimum transferable values of a factor are critical points, beyond which existence is no longer possible and death occurs. The limits of endurance between critical points are called the ecological valency of living beings in relation to a specific environmental factor. Representatives of different species differ greatly from each other both in the position of the optimum and in ecological valence. An example of this type of dependence is the following observation. Average daily physiological need in fluoride for an adult is 2000-3000 mcg, and a person receives 70% of this amount from water and only 30% from food. With prolonged consumption of water low in fluoride salts (0.5 mg/dm3 or less), dental caries develops. The lower the concentration of fluoride in water, the higher the incidence of caries in the population. High concentrations of fluoride in drinking water also lead to the development of pathology. So, when its concentration is more than 15 mg/dm 3, fluorosis occurs - a kind of mottling and brownish coloration of the tooth enamel, the teeth are gradually destroyed. Rice. 3.1. The dependence of the result of an environmental factor on its intensity or simply optimum, for organisms of this species. The stronger the deviations from the optimum, the more pronounced Ambiguity of the factor's effect on different functions. Each factor affects different body functions differently. The optimum for some processes may be a pessimum for others. Rule of interaction of factors. Its essence lies in the fact that alone factors can enhance or mitigate the effect of other factors. For example, excess heat can be to some extent mitigated by low air humidity, the lack of light for plant photosynthesis can be compensated by an increased content of carbon dioxide in the air, etc. It does not follow from this, however, that the factors can be interchanged. They are not interchangeable. Rule of limiting factors: factor , which is in deficiency or excess (near critical points), negatively affects organisms and, in addition, limits the possibility of manifestation of the power of other factors, including those at optimum. For example, if the soil contains in abundance all but one thing necessary for a plant chemical elements, then the growth and development of the plant will be determined by the one that is in short supply. All other elements do not show their effect. Limiting factors usually determine the boundaries of distribution of species (populations) and their habitats. The productivity of organisms and communities depends on them. Therefore, it is extremely important to promptly identify factors of minimal and excessive significance, to exclude the possibility of their manifestation (for example, for plants - by balanced application of fertilizers). Through his activities, a person often violates almost all of the listed patterns of action of factors. This especially applies to limiting factors (habitat destruction, disruption of water and mineral nutrition of plants, etc.). To determine whether a species can exist in a given geographic area, it is necessary first to determine whether any environmental factors are beyond its ecological valence, especially during its most vulnerable period of development. Identification of limiting factors is very important in agricultural practice, since by directing the main efforts to their elimination, one can quickly and effectively increase plant yields or animal productivity. Thus, on highly acidic soils, the wheat yield can be slightly increased by using various agronomic influences, but the best effect will be obtained only as a result of liming, which will remove the limiting effect of acidity. Knowledge of limiting factors is thus the key to controlling the life activity of organisms. At different periods of the life of individuals, various environmental factors act as limiting factors, so skillful and constant regulation of the living conditions of cultivated plants and animals is required. The law of energy maximization, or Odum's law: the survival of one system in competition with others is determined by the best organization of the flow of energy into it and the use of its maximum amount in the most effective way. This law also applies to information. Thus, The system that has the best chance of self-preservation is one that is most conducive to the supply, production, and efficient use of energy and information. Any natural system can develop only through the use of material, energy and information capabilities of the environment. Absolutely isolated development is impossible. This law has important practical significance due to the main consequences:
Law of limited natural resources. The one percent rule. Since planet Earth is a natural limited whole, infinite parts cannot exist on it, so everything Natural resources The lands are finite. Inexhaustible resources include energy resources, believing that the energy of the Sun provides an almost eternal source of useful energy. The mistake here is that such reasoning does not take into account the limitations imposed by the energy of the biosphere itself. According to the one percent rule a change in the energy of a natural system within 1% takes it out of equilibrium. All large-scale phenomena on the Earth's surface (powerful cyclones, volcanic eruptions, the process of global photosynthesis) have a total energy that does not exceed 1% of the energy of solar radiation incident on the Earth's surface. The artificial introduction of energy into the biosphere in our time has reached values close to the limit (differing from them by no more than one mathematical order of magnitude - 10 times). Share with friends or save for yourself:
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