The factor limiting the vital activity of organisms: light, water, temperature

For sure, each of us noticed how plants of the same species develop beautifully in the forest, but in the open spaces they feel bad. Or, for example, some species of mammals have a large population, while others are more limited under seemingly identical conditions. All living things on Earth somehow obey their own laws and rules. They study ecology. One of the fundamental statements is the law of the Liebig minimum (limiting factor).

The limiting environmental factor: what is it?

German chemist and founder of agrochemistry, Professor Justus von Liebig, made many discoveries. One of the most famous and recognized is the discovery of a fundamental law of ecology: a limiting factor. It was formulated in 1840, and later supplemented and generalized by Shelford. The law says that for any living organism, the most significant factor is the one that deviates more from its optimal value. In other words, the existence of an animal or plant depends on the degree of expression (minimum or maximum) of a particular condition. Individuals occur throughout their lives with a wide variety of limiting factors.

"Barrel of Liebig"

The factor limiting the vital activity of organisms can be different. The formulated law to this day is actively used in agriculture. Yu Libich established that the productivity of plants depends primarily on the mineral substance (nutrient), the most weakly expressed in the soil. For example, if nitrogen in soil is only 10% of the required norm, and phosphorus is 20%, then the factor limiting normal development is the lack of the first element. Therefore, nitrogen fertilizers should be initially introduced into the soil. The meaning of the law was most clearly and graphically described in the so-called "barrel of Liebig" (pictured above). Its essence lies in the fact that when the vessel is filled, the water begins to pour over the edge where there is the shortest board, and the length of the remaining ones no longer matters.

Water

This factor is the most stringent and significant in comparison with the rest. Water - the basis of life, as it plays an important role in the life of an individual cell and the whole organism as a whole. Maintaining its quantity at the proper level is one of the main physiological functions of any plant or animal. Water as a factor limiting life activity is due to the uneven distribution of moisture over the surface of the Earth during the year. In the process of evolution, many organisms have adapted to the economical use of moisture, the experience of a dry period in a state of hibernation or rest. This factor is most strongly expressed in deserts and semi-deserts, where very scarce and peculiar flora and fauna.

Shine

Coming in the form of solar radiation, light provides all life processes on the planet. To organisms its wave length, duration of action, intensity of radiation is important. Depending on these indicators, the organism adapts itself to environmental conditions. As a limiting factor, it is particularly pronounced in large marine depths. For example, plants at a depth of 200 m no longer occur. Together with the lighting here, "work", at least two more limiting factors: pressure and oxygen concentration. This can be contrasted with the humid tropical forests of South America, as the most favorable territory for life.

Ambient temperature

It's not a secret for anyone that all the physiological processes taking place in the body depend on the external and internal temperature. And most of the species is adapted to a rather narrow range (15-30 ° C). Particularly pronounced dependence in organisms that are not able to independently maintain a constant body temperature, for example, reptiles (reptiles). In the process of evolution, a variety of adaptations have been formed that allow one to overcome this limited factor. Thus, the evaporation of water in hot weather in order to avoid overheating in plants is strengthened through the stomata, in animals - through the skin and respiratory system, as well as behavioral features (hiding in shadows, burrows, etc.).

Pollutants

The importance of the anthropogenic factor can not be underestimated. The last few centuries for man have been marked by rapid technical progress, the rapid development of industry. This led to the fact that harmful emissions in water bodies, soil and in the atmosphere increased several times. To understand, what factor restricts this or that kind, it is possible only after researches. This state of affairs explains the fact that the species diversity of individual regions or regions has changed beyond recognition. Organisms are changing and adapting, some are replaced by others.

All this - the main factors that limit life. In addition to them, there are many others, which are simply impossible to enumerate. Each species and even an individual is individual, therefore the limiting factors will be very diverse. For example, for trout, the percentage of oxygen dissolved in water is important, for plants - the quantitative and qualitative composition of insect pollinators, etc.

All living organisms have certain limits of endurance for this or that limiting factor. Some of them are quite wide, others have narrow ones. Depending on this indicator distinguish between eurybionts and stenobionts. The former are able to tolerate a large amplitude of oscillation of various limiting factors. For example, an ordinary fox, inhabiting everywhere from steppes to forest-tundra, wolves, etc. Stenobionts, on the contrary, are able to withstand very narrow fluctuations, they include almost all the plants of rain forests.