Ecological valency is an important indicator that demonstrates the level of adaptability of organisms to changing environmental conditions. It allows you to find out whether a particular species will survive in a particular area or not. Environmental plasticity (the same as valency) is a range of values within which the existence of living organisms is possible.
Ecological valency and adaptation
What it is? The most important concept of evolutionary ecology, inextricably linked with valency, is adaptation. Without it, development would have been impossible. The ability to adapt or adapt is the most important property of wildlife. It manifests itself at all structural levels, from the molecular to the biosphere.
Any adaptation is relative, because it is associated only with a specific environmental situation. Any environment is constantly changing, which means it deteriorates, as it becomes different from the one to which the body is already used. Therefore, adaptation is ongoing.
Migration and wintering
When the degree of ecological valency shows that the limits of tolerance of organisms have been reached (that is, specific individuals are not able to survive in a given area or at a given temperature), they can migrate to a more suitable climate. Some species switch to wintering mode. This becomes possible due to the specific properties of organisms, such as:
- variability;
- self-regulation;
- chemical composition;
- rhythm.
Migration is an active transition to an area with a more favorable temperature. Wintering is a slowdown in the cold period of metabolic rate in the body. An extreme case is a fall into diapause. This concept refers to a period of rest when all processes are suspended. Body temperature during diapause usually decreases.
Humidity is an important factor affecting valency
Without water, existence becomes impossible. Humidity is of the utmost importance to all organisms. The normal life of any creature is possible only when it receives from the external environment a sufficient amount of moisture.
More than half the weight of any living organism falls on the water contained in it. Therefore, in the driest regions of the Earth there is almost no life. Maintaining the required water balance is one of the foundations of biochemical processes in cells.
Hygrophytes, xerophytes, mesophytes
Individuals, depending on the properties of organisms and water requirements, are divided into groups. Known aquatic (otherwise called hygrophytes) and amphibians, living in very humid environments. This, for example, includes all kinds of algae. Hygrophytes live on earth in conditions of high humidity. Most of the plants known to us, which form the basis of forests of the middle zone, belong to the so-called mesophytes, which have a moderate need for water.
Arid plants are called xerophytes. They are divided into two groups. The first is succulents, succulent plants that accumulate a store of moisture in themselves (for example, cacti). Sclerophytes, on the contrary, have a morphology and exchange pattern, in which the basic life processes can take place, experiencing a lack of moisture. Their wood is dry, dense, and the roots are very deep, reaching aquifers (for example, saxaul).
Hygrophytes, xerophytes, mesophytes are vivid examples of the adaptability of organisms to the environment. Due to changes in nature, many species have to learn not to survive in the most suitable conditions.
Environmental valency is an indicator that demonstrates that plants are in a less favorable position than animals. If the former receive moisture only from the external environment, then the latter have more diverse ways of absorbing water:
- through drinking;
- through liquid food;
- in the course of reactions in their body of the breakdown of substances into low molecular weight.
Animals are divided into hygrophilous, hygrophilous (for example, amphibians), xerophiles living in arid areas (snakes, lizards), and intermediate - mesophylls, to which most known animals belong.
Degree of illumination
Ecological valency is an indicator that also takes into account the visible part of electromagnetic radiation. Light is one of the most important factors. It provides the primary energy necessary for photosynthesis - the process of formation of basic organic substances on the planet. However, the direct effect of visible light and wavelengths close to it (infrared, ultraviolet) can have a negative value. Light is a limiting factor, both in the case of its excess and lack.
Nature has created many organs that perceive light. These are the sensitive stigmas of protozoa, and such a complex organ as the eye of higher animals.
Zones of different lighting
According to the reaction to light, the following categories of animals are distinguished: photophilous, shade-loving, tolerating wide and narrow ranges of illumination. Plants are divided into:
- photophilous (hemophytes) living in open, illuminated places;
- sunophytes are shade-loving.
In direct light, the excess flux is not perceived by the eye, but is reflected. The eyes of some insects see the ultraviolet part of the spectrum. For example, in the life of bees, the ability to navigate the sun is of great importance. They take full advantage of this feature when the sun is hidden by clouds, since ultraviolet rays pass through them.
Light also matters in the life of aquatic organisms. Zones of different illumination are distinguished in water: polyphotic (to a depth of 100 m), mesophotic (from 100 to 500 m) and aphotous (deeper than 500 m), where there is practically no light. A large number of organisms that emit their own light, which arises due to chemical reactions taking place in their bodies, live here. This light is used to orientate in space and attract prey.
So, we can draw the following conclusion that ecological valency is an indicator without which it is impossible to calculate the probability of survival of a particular species under certain conditions.