What is called an environmental factor that goes beyond. The interaction of factors. limiting factor. Most difficult habitat
Despite the wide variety of environmental factors, a number of general patterns can be revealed in the nature of their effects on organisms and in the responses of living things.
The law of tolerance (the law of optimum or the law of W. Shelford) -each factor has certain limits on the positive effects on organisms. Both inadequate and excessive effect of the factor negatively affects the life of individuals (a lot of “good” - also “not good”).
Environmental factors are quantified. In relation to each factor, we can distinguish optimum zone (zone of normal life), pessimum zone (zone of oppression) and endurance limits organism. The optimum is such an amount of environmental factor at which the intensity of the vital activity of organisms is maximum. In the pessimum zone, the vital activity of organisms is inhibited. Beyond stamina, the existence of an organism is impossible. There are lower and upper endurance limits.
The ability of living organisms to tolerate quantitative fluctuations in the action of the environmental factor to one degree or another is called ecological valency (tolerance, stability, plasticity).
The values \u200b\u200bof the environmental factor between the upper and lower limits of endurance is called zone of tolerance. Species with a wide tolerance zone are called eurybiontic with narrow - stenobiontic . Organisms that undergo significant temperature fluctuations are called eurythermic, and adapted to a narrow temperature range - stenothermal. In the same way, with respect to pressure, evry- and stenobathic organisms, in relation to the degree of salinization of the medium - evry- and stenohalinein relation to nutrition evry- and stenotrophs (as applied to animals, the terms evry- and stenophages) etc.
The environmental valencies of individual individuals do not match. Therefore, the ecological valency of the species is wider than the ecological valency of each individual.
Ecological valencies of the species to different environmental factors can vary significantly. The set of ecological valencies in relation to various environmental factors is ecological spectrum of the species.
The environmental factor, the quantitative value of which goes beyond the endurance of the species, is called limiting (limiting) factor.
2. The ambiguity of the effect of the factor on different functions -each factor differently affects different functions of the body. Optimum for some processes may be a pessimum for others. So, for many fish, the water temperature optimal for the maturation of reproductive products is unfavorable for spawning.
3. A variety of individual reactions to environmental factors -degree of endurance, critical points, optimal and pessimal zones of individual individuals of the same species do not match. This variability is determined both by the hereditary qualities of individuals, and by gender, age and physiological differences. For example, a butterfly of a mill ognevka, one of the pests of flour and grain products, has a critical minimum temperature of -7 ° С for caterpillars, -22 ° С for adults, and -27 ° С for eggs. Frost at -10 ° C destroys caterpillars, but is not dangerous for adults and eggs of this pest. Consequently, the ecological valency of a species is always wider than the ecological valency of each individual.
4. The relative independence of the adaptation of organisms to various factors - the degree of endurance to any factor does not mean the corresponding ecological valency of the species in relation to other factors. For example, species that undergo wide temperature changes do not necessarily have to be adapted to wide fluctuations in humidity or salt regime. Eurythermic species can be stenohaline, stenobath or vice versa.
5. Mismatch of the ecological spectra of individual species - each species is specific in its environmental capabilities. Even species that are close in their ways of adapting to the environment have differences in attitudes toward any particular factors.
6. Interaction of factors - the optimal zone and endurance limits of organisms with respect to any environmental factor can shift depending on how strong and in what combination other factors act simultaneously. For example, heat is easier to carry in dry rather than humid air. The threat of freezing is much higher in frost with a strong wind than in calm weather.
7. The law of the minimum (the law of J. Liebig or the rule of limiting factors) -the possibility of the existence of organisms is primarily limited by those environmental factors that are most removed from the optimum. If at least one of the environmental factors approaches or exceeds critical limits, then, despite the optimal combination of other conditions, individuals are at risk of death. So, the advance of the species to the north can be limited (limited) by a lack of heat, in arid areas - by a lack of moisture or too high temperatures. Identification of limiting factors is very important in agricultural practice.
8. The hypothesis of the indispensability of fundamental factors (V. R. Williamson) - the complete absence in the environment of the complete absence in the environment of fundamental environmental factors (physiologically necessary; for example, light, water, carbon dioxide, nutrients) cannot be compensated (replaced) by other factors. Thus, according to the Guinness Book of Records, a person can live up to 10 minutes without air, 10-15 days without water, and up to 100 days without food.
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A certain pressure in the environment. ”How do you understand this statement?
Task number 6. Currently, each inhabitant of our planet has an average of about 1 ton of garbage per year (MSW - solid household waste), and this is not counting the millions of worn and wrecked cars. There are three main options for handling solid waste: 1 - burial, incineration, sorting and processing. Which of these methods is the most environmentally friendly. Give evidence.
Choose one correct answer
Unified natural complexes formed by organisms and habitat
1) ecosystems
2) biosphere
3) populations
4) biomass
Section of ecology, exploring the individual relationships of individual organisms (species, individuals) with the environment
1) autecology
2) biochemistry
3) geoecology
4) synecology
5) demecology
3. The system of a higher order, covering all the phenomena of life on our planet
1) biosphere
2) atmosphere
3) the stratosphere
4) apobiosphere
5) aerobiosphere
The most difficult habitat
1) ground-air
3) atmospheric
4) social environment
5) ecological environment
5. Various forms of influence of living organisms on each other and on the environment are:
1) biotic factors
2) biological factors
3) symbiotic factors
4) edaphic factors
5) extreme factors
Unstable ecosystem with artificially created and depleted species producing agricultural products
1) agorocenosis
2) biogeocenosis
3) agrobiogeocenosis
4) biocenosis
5) agroforestry complex
7. The stability of biogeocenosis is mainly determined by:
1) by consumers
2) producers - photosynthetics
3) great species diversity
4) reducers
5) chemosynthetic producers
Producers of the ecosystem - organisms that synthesize organic substances from inorganic substances are called
1) heterotrophs
2) autotrophs
3) symbionts
4) anaerobic bacteria
5) consumers
Global environmental disasters in the biosphere have arisen
1) before the appearance of man
2) this period is not precisely defined
3) after the appearance of man
4) during the onset of the biosphere
5) after the ice age
Succession is characterized by
1) ecosystem biotope change
4) seasonal community change
5) phytocenosis change
When exposed to an environmental factor of low intensity, most of the population
1) adapts
2) is under compensation
3) is in the stage of decompensation
4) dies
5) actively multiplies
Endemic diseases include
1) fluorosis
3) ascariasis
4) fascioliasis
5) tuberculosis
An environmental factor that goes beyond endurance is called
1) stimulating
2) abiotic
3) limiting
4) man-made
5) biotic
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Environmental factors always act on organisms in the complex. Moreover, the result is not the sum of the effects of several factors, but rather a complex process of their interaction. In this case, the viability of the organism changes, specific adaptive properties arise that allow it to survive in certain conditions, to tolerate fluctuations in the values \u200b\u200bof various factors.
The influence of environmental factors on the body can be represented in the form of a diagram (Fig. 94).
The intensity of the environmental factor most favorable for the body is called optimal or optimum.
Deviation from the optimal action of the factor leads to inhibition of the vital activity of the body.
The boundary beyond which the existence of an organism is impossible is called endurance limit.
These boundaries are different for different species and even for different individuals of the same species. For example, outside the endurance limits for many organisms are the upper atmosphere, thermal springs, and the icy desert of Antarctica.
An environmental factor that goes beyond the stamina of an organism is called restrictive.
It has upper and lower limits. So, for fish, the limiting factor is water. Outside the aquatic environment, their life is impossible. Lowering the water temperature below 0 ° C is the lower limit, and increasing above 45 ° C is the upper limit of endurance.
Fig. 94.Scheme of the environmental factor on the body
Thus, the optimum reflects the characteristics of the living conditions of various species. In accordance with the level of the most favorable factors, organisms are divided into heat- and cold-loving, moisture-loving and drought-resistant, light-loving and shade-tolerant, adapted to life in salt and fresh water, etc. The wider the endurance limit, the more plastic the organism. Moreover, the endurance limit in relation to various environmental factors in organisms varies. For example, hygrophilous plants can tolerate large temperature changes, while the lack of moisture is detrimental to them. Narrowly adapted species are less plastic and have a small endurance limit, widely adapted species are more plastic and have a wide range of fluctuation of environmental factors.
For fish living in the cold seas of Antarctica and the Arctic Ocean, the tolerated temperature range is 4–8 ° C. As the temperature rises (above 10 ° C), they stop moving and fall into a thermal stupor. On the other hand, fish of equatorial and temperate latitudes tolerate temperature fluctuations from 10 to 40 ° C. A wider range of endurance possess warm-blooded animals. So, Arctic foxes in the tundra can tolerate temperature drops from -50 to 30 ° C.
Plants of temperate latitudes withstand temperature fluctuations within 60–80 ° C, while in tropical plants the temperature range is much narrower: 30–40 ° C.
The interaction of environmental factorslies in the fact that a change in the intensity of one of them can narrow the endurance limit to another factor or, conversely, increase it. For example, optimal temperature increases stamina for lack of moisture and food. High humidity significantly reduces the body's resistance to high temperatures. The intensity of exposure to environmental factors is directly dependent on the duration of this exposure. The prolonged action of high or low temperatures is detrimental to many plants, while short-term drops in the plant tolerate normally. The limiting factors for plants are the composition of the soil, the presence of nitrogen and other nutrients in it. So, clover grows better on soils that are poor in nitrogen, and nettles - on the contrary. A decrease in the nitrogen content in the soil leads to a decrease in the drought tolerance of cereals. On salty soils, plants grow worse; many species do not take root at all. Thus, the body’s adaptability to individual environmental factors is individual and can have both a wide and a narrow range of endurance. But if a quantitative change in at least one of the factors goes beyond the limits of endurance, then, despite the fact that other conditions are favorable, the body dies.
The set of environmental factors (abiotic and biotic) that are necessary for the existence of a species are called ecological niche.
The ecological niche characterizes the lifestyle of the organism, the conditions of its habitat and nutrition. In contrast to a niche, the term habitat denotes the territory where the organism lives, that is, its “address”. For example, the herbivorous inhabitants of the steppes cow and kangaroos occupy the same ecological niche, but have different habitats. On the contrary, the inhabitants of the forest - squirrel and elk, also related to herbivores, occupy different ecological niches. An ecological niche always determines the distribution of an organism and its role in a community.
The law of optimum.Environmental environmental factors are quantified. Each factor has certain limits of a positive effect on organisms (Fig. 2). Both insufficient and excessive action of the factor negatively affects the life of individuals.
In relation to each factor, one can distinguish an optimum zone (a zone of normal life), a pessimum zone (a zone of oppression), and upper and lower limits of an organism’s endurance.
Optimum Zone, or Optimum (from lat. optimum - the noblest, the best), is the amount of environmental factor at which the intensity of the vital activity of organisms is maximum.
Zone of pessimum, or pessimum (from lat. pessimum - cause harm, endure damage) is the amount of environmental factor in which the intensity of the vital activity of organisms is inhibited.
Upper endurance limit - the maximum amount of environmental factor in which the existence of an organism is possible.
Fig. 2.
Lower fatigue limit - the minimum amount of environmental factor in which the existence of the body is possible.
Beyond stamina, the existence of an organism is impossible.
The curve can be wide or narrow, symmetric or asymmetric. Its shape depends on the species affiliation of the organism, on the nature of the factor and on which of the reactions of the organism is chosen as the response and at what stage of development.
The ability of living organisms to tolerate quantitative fluctuations in the action of the environmental factor to one degree or another is called ecological valency (tolerance, stability, plasticity).
The values \u200b\u200bof the environmental factor between the upper and lower limits of endurance is called zone of tolerance.
Species with a wide tolerance zone are called eurybiontic (from Greek euris - wide), with a narrow - stenobiontic (from Greek stems - narrow) (Fig. 3 and 4).
Organisms that undergo significant temperature fluctuations are called eurythermic , and adapted to a narrow temperature range - stenothermal. In the same way, with respect to pressure, heury- and stenobath organisms in relation to humidity - heury and stenohydric, in relation to the degree of
Fig. 3.1 - eurybiontic: 2 - stenobiont
Fig. 4.
salting medium - heury and stenohaline, in relation to the oxygen content in water - hevras and stenoxybionts, in relation to the write - heury and stenophage, in relation to the habitat - heury and wall-resistant etc.
Thus, the direction and intensity of the environmental factor depends on how much it is taken in combination with what other factors. There are no absolutely useful or harmful environmental factors: it is all about quantity. For example, if the ambient temperature is too low or too high, that is, it goes beyond the endurance of living organisms, this is bad for them. Only optimal values \u200b\u200bare favorable. Moreover, environmental factors cannot be considered in isolation from each other. For example, if the body is deficient in water, then it is more difficult for it to tolerate high temperature.
The phenomenon of acclimatization.The position of the optimum and endurance limits on the gradient of the factor can shift within certain limits. For example, a person can tolerate a lower ambient temperature in winter than in summer, and a higher one - on the contrary. This phenomenon is called acclimatization (or acclimation). Acclimatization occurs when the seasons change or when entering a territory with a different climate.
The ambiguity of the effect of the factor on different functions of the body.
The same amount of factor unequally affects different functions of the body. The optimum for some processes may be a pessimum for others. For example, in plants, the maximum intensity of photosynthesis is observed at an air temperature of +25 ... + 35 ° С, and respiration - +55 ° С (Fig. 5). Accordingly, an increase in plant biomass will occur at lower temperatures, and a loss of biomass at higher temperatures. In cold-blooded animals, an increase in temperature to +40 ° C and more strongly increases the rate of metabolic processes in the body, but inhibits motor activity, and the animals fall into a thermal numbness. In humans, the testes are carried outside the pelvis, since spermatogenesis requires lower temperatures. For many fish, the water temperature optimal for gamete maturation is unfavorable for spawning, which occurs at a different temperature.
The life cycle, in which, at certain periods, the body performs primarily certain functions (nutrition, growth, reproduction, resettlement, etc.), is always consistent with seasonal changes in the complex of environmental factors. Motile organisms can
Fig. 5.t MUH, t onm, t MaKC - temperature minimum, optimum and maximum for plant growth (shaded area)
also change habitats for the successful implementation of all their life functions.
Ecological valency of the species.The ecological valencies of individual individuals do not coincide. They depend on the hereditary and ontogenetic characteristics of individual individuals: sexual, age, morphological, physiological, etc. Therefore, the ecological valency of the species is wider than the ecological valency of each individual. For example, a butterfly of a mill ognevka, one of the pests of flour and grain products, has a critical minimum temperature for caterpillars of -7 ° С, for adult forms - 22 ° С,
and for eggs - 27 ° C. Frost at -10 ° C destroys caterpillars, but is not dangerous for
adults and eggs of this pest.
The ecological spectrum of the species.The set of ecological valencies of a species with respect to different environmental factors is ecological spectrum of the species. Ecological spectra of different species differ from each other. This allows different species to occupy different habitats. Knowledge of the ecological spectrum of the species allows the successful introduction of plants and animals.
The interaction of factors.In nature, environmental factors act together, that is, comprehensively. The combined effect on the body of several environmental factors is called constellation. The optimum zone and the endurance limits of organisms with respect to any environmental factor can shift depending on how strong and in what combination other factors act simultaneously. For example, heat is harder to tolerate when water is scarce, strong winds increase the effects of cold, heat is easier to tolerate in dry air, etc. Thus, the same factor in combination with others has a different environmental impact (Fig. 6). Accordingly, the same environmental result can be obtained in different ways. For example, compensation for lack of moisture can be carried out by watering or lowering the temperature. The effect of partial substitution of factors is created. However, the mutual compensation of the action of environmental factors has certain limits, and it is impossible to completely replace one of them with another.
Fig.6. Mortality of pine silkworm eggs Dendrolimuspiniwith different combinations of temperature and humidity (according to N.M. Chernova, A.M. Bylova, 2004)
Thus, the absolute absence of any of the mandatory living conditions cannot be replaced by other environmental factors, but a deficiency or excess of some environmental factors can be compensated for by other environmental factors. For example, the complete (absolute) lack of water cannot be compensated for by other environmental factors. However, if other environmental factors are in optimum, then it is easier to transfer the lack of water than when other factors are in shortage or excess.
The law of the limiting factor.The possibility of the existence of organisms is primarily limited by those environmental factors that are most removed from the optimum. The environmental factor, the quantitative value of which goes beyond the endurance of the species, is called limiting (limiting) factor. Such a factor will limit the existence (distribution) of the species even if all other factors are favorable (Fig. 7).
Fig.
Limiting factors determine the geographical area of \u200b\u200bthe species. For example, the progress of a species toward the poles may be limited by a lack of heat, and in arid areas by a lack of moisture or too high temperatures.
A person’s knowledge of the limiting factors for a particular kind of organisms allows, by changing environmental conditions, either to suppress or stimulate its development.
Living conditions and living conditions.The complex of factors under the influence of which all the basic life processes of organisms are carried out, including normal development and reproduction, is called living conditions. The conditions under which breeding does not occur are called living conditions.
Despite the wide variety of environmental factors, a number of general patterns can be revealed in the nature of their effects on organisms and in the responses of living things.
The law of tolerance (the law of optimum or the law of W. Shelford) -each factor has certain limits on the positive effects on organisms. Both inadequate and excessive effect of the factor negatively affects the life of individuals (a lot of “good” - also “not good”).
Environmental factors are quantified. In relation to each factor, we can distinguish optimum zone (zone of normal life), pessimum zone (zone of oppression) and endurance limits organism. The optimum is such an amount of environmental factor at which the intensity of the vital activity of organisms is maximum. In the pessimum zone, the vital activity of organisms is inhibited. Beyond stamina, the existence of an organism is impossible. There are lower and upper endurance limits.
The ability of living organisms to tolerate quantitative fluctuations in the action of the environmental factor to one degree or another is called ecological valency (tolerance, stability, plasticity).
The values \u200b\u200bof the environmental factor between the upper and lower limits of endurance is called zone of tolerance. Species with a wide tolerance zone are called eurybiontic with narrow - stenobiontic . Organisms that undergo significant temperature fluctuations are called eurythermic, and adapted to a narrow temperature range - stenothermal. In the same way, with respect to pressure, evry- and stenobathic organisms, in relation to the degree of salinization of the medium - evry- and stenohalinein relation to nutrition evry- and stenotrophs (as applied to animals, the terms evry- and stenophages) etc.
The environmental valencies of individual individuals do not match. Therefore, the ecological valency of the species is wider than the ecological valency of each individual.
Ecological valencies of the species to different environmental factors can vary significantly. The set of ecological valencies in relation to various environmental factors is ecological spectrum of the species.
The environmental factor, the quantitative value of which goes beyond the endurance of the species, is called limiting (limiting) factor.
2. The ambiguity of the effect of the factor on different functions -each factor differently affects different functions of the body. Optimum for some processes may be a pessimum for others. So, for many fish, the water temperature optimal for the maturation of reproductive products is unfavorable for spawning.
3. A variety of individual reactions to environmental factors -degree of endurance, critical points, optimal and pessimal zones of individual individuals of the same species do not coincide. This variability is determined both by the hereditary qualities of individuals, and by gender, age and physiological differences. For example, a butterfly of a mill ognevka, one of the pests of flour and grain products, has a critical minimum temperature of -7 ° С for caterpillars, -22 ° С for adults, and -27 ° С for eggs. Frost at -10 ° C destroys caterpillars, but is not dangerous for adults and eggs of this pest. Consequently, the ecological valency of a species is always wider than the ecological valency of each individual.
4. The relative independence of the adaptation of organisms to various factors - the degree of endurance to any factor does not mean the corresponding ecological valency of the species in relation to other factors. For example, species that tolerate wide temperature changes do not necessarily have to be adapted to wide fluctuations in humidity or salt regime. Eurythermic species can be stenohaline, stenobath or vice versa.
5. Mismatch of ecological spectra of individual species - each species is specific in its environmental capabilities. Even species that are close in their ways of adapting to the environment have differences in attitudes toward any particular factors.
6. Interaction of factors - the optimal zone and endurance limits of organisms with respect to any environmental factor can shift depending on how strong and in what combination other factors act simultaneously. For example, heat is easier to carry in dry rather than humid air. The threat of freezing is much higher in frost with a strong wind than in calm weather.
7. The law of the minimum (the law of J. Liebig or the rule of limiting factors) -the possibility of the existence of organisms is primarily limited by those environmental factors that are most removed from the optimum. If at least one of the environmental factors approaches or exceeds critical limits, then, despite the optimal combination of other conditions, individuals are at risk of death. So, the advance of the species to the north can be limited (limited) by a lack of heat, in arid areas - by a lack of moisture or too high temperatures. Identification of limiting factors is very important in agricultural practice.
8. The hypothesis of the indispensability of fundamental factors (V. R. Williamson) - the complete absence in the environment of the complete absence in the environment of fundamental environmental factors (physiologically necessary; for example, light, water, carbon dioxide, nutrients) cannot be compensated (replaced) by other factors. Thus, according to the Guinness Book of Records, a person can live up to 10 minutes without air, 10-15 days without water, and up to 100 days without food.
In nature, environmental factors act together, that is, comprehensively. The complex of factors under the influence of which all the basic life processes of organisms are carried out, including normal development and reproduction, are called living conditions. The conditions under which breeding does not occur are called living conditions.
