Today, when children begin to receive environmental education in elementary school, and environmental issues are not the last in the media, ecology is still a young, complex and mysterious science. Its scientific base is not so great, and complex models are confused. Nevertheless, knowledge and understanding of the basic laws in this area is the basis of the worldview of modern man. This article will consider one of the main laws of ecology - the law of minimum, formulated long before the formation of science itself.
To the history of discovery
The law of minimum was formulated in 1840 by an outstanding chemist, professor of the University of Hesse (Germany) Eustace von Liebig. This scientist and outstanding teacher is also known for the invention of the Liebig refrigerator, which is still used in chemical laboratories for fractional separation of chemical compounds. His book “Chemistry as applied to agriculture” actually gave rise to the science of agrochemistry, and to him - the title of baron and two orders of St. Anne. Liebig studied plant survival and the role of chemical additives in increasing it. So he formulated the law of minimum or limiting factor, which turned out to be true for all biological systems. And not only for biological ones, which we demonstrate by examples.
Bit of theory
In ecology, environmental factors are those that have any effect on the body. Physical and chemical factors (abiotic) are temperature conditions, humidity, light, pressure, pH of the environment and other indicators of inanimate nature. All forms of exposure and the relationship of living organisms to each other are biotic factors. This is competition for resources, and the presence of parasites, and the intraspecific struggle for survival. In addition, there are also anthropogenic factors - the conditions created by people and their economic activities. They can also be biotic and abiotic. Environmental factors are regularly periodic, changing strength in accordance with the change of time of day, seasons of the year or tides with ebbs. In this case, the adaptation of the body is hereditary, formed over a rather long period. They can be irregular, like storms or tornadoes. And then there is a redistribution of species diversity.
Comfort zone
Most often, environmental factors are transferred by organisms within certain limits, which are limited by threshold indicators, followed by inhibition of the vital activity of the organism. These are critical points of existence. Between them are the zones of tolerance (tolerance) and the zone of optimum (comfort) - the range of beneficial influence of the factor. The points of minimum and maximum exposure to the environmental factor determine the body's response to a specific factor. Going beyond the optimum zone can lead to the following:
- elimination of the species from a specific range (for example, a shift in the population range or species migration);
- changes in fertility and mortality (for example, with sudden changes in environmental conditions);
- to adaptation (adaptation) and the emergence of new species with new phenotypic and genetic characteristics.
The essence of the law of minimum
The life of a biological system, whether it be an organism or a population, depends on the action of many factors of a biotic and abiotic nature. The wording of the law of the minimum can vary, but the essence remains constant: when any factor deviates significantly from the norm, then it becomes the most significant for the system and the most critical for life. At the same time, various indicators can act as limiting factors for the body at different time periods.
Options are possible
All living organisms live and adapt to a set of environmental factors. And the impact of the factors of this complex is always unequal. The factor may be leading (very important) or secondary. Different factors will be leading for different organisms, and at different periods of the life of one organism, certain environmental factors may be the main ones for it. In addition, the same factors can be limiting for some organisms and not limiting for others. For example, sunlight for plants is a necessary element for supporting photosynthesis processes. But for mushrooms, soil saprotrophs or deep-sea animals, it is not at all necessary. Or the presence of oxygen in water will be a limiting factor, but its presence in the soil will not.
Conditions of use
The law of the minimum is limited in application by two auxiliary principles:
- The law is applicable without clarification only to equilibrium systems, namely, only in the stationary state of the system, when the exchange of energy and substances of the system with the environment is regulated by their leakage.
- The second principle of applying the law of minimum is associated with the compensatory capabilities of organisms and systems. Under certain conditions, the limiting factor can be replaced by not limiting, but present in sufficient or high content. This will lead to a change in the need for the substance that is available in a minimal amount.
Graphic illustration
It clearly shows the effect of this law barrel, named after the scientist. In this broken barrel, the limiting factor is the height of the boards. In accordance with the ecological law of the minimum, it must be repaired with the smallest board. It is she who is the factor that is most removed from normal values that are optimal for the survival of the body. Without eliminating the impact of this factor, it makes no sense to fill the barrel - other factors do not so significantly affect the given moment in time.
Where it is thin - there it breaks
It is this proverb that conveys the essence of the law of the minimum in ecology and not only. For example, in agriculture, the indicators of the content of minerals in soils are taken into account. If in the soil only 20% of phosphorus is normal, calcium is 50%, and potassium is 95%, then fertilizers that contain phosphorus must be applied first. In the wild, for deer in summer, the amount of food will be a limiting factor, and in winter, the height of the snow cover. Or for a pine tree that grows in a shady forest, the limiting factor will be light, on dry sandy soil - water, and in marshland - the temperature in summer.
Another such example, not related to ecology. If the right-back in the team is the weakest, it is from his flank that the opponent is most likely to break through. This is true in sports, in art, in business. An underestimation of the damage caused by a weak employee even in secondary positions often becomes a significant mistake of businessmen. It is not without reason that they say that the quality of a company is determined by the quality of its worst employees. And the strength of the chain always depends on its weakest link.