Types and examples of biogeocenosis. Biogeocoenosis and ecosystem

The notion of "ecosystem" was introduced in 1935 by A. Tensley, an English botanist. By this term he designated any set of organisms living together, as well as their environment. Its definition emphasizes the existence of interdependence, relationships, cause and effect relationships existing between the abiotic environment and the biological community, uniting them into a certain functional whole. Ecosystem, according to biologists - is the totality of all kinds of populations of different species that inhabit the common territory, as well as the surrounding inanimate environment.

Biogeocenosis is a natural formation with clear boundaries. It consists of a set of biocenoses (living beings) that occupy a certain place. For example, for aquatic organisms this place is water, for those who live on land, the atmosphere and the soil. Below we will consider examples of biogeocenosis that will help you understand what it is. We describe these systems in detail. You will learn about what their structure is, what kinds of species exist and how they change.

Biogeocenosis and ecosystem: differences

To some extent, the concepts of "ecosystem" and "biogeocoenosis" are unambiguous. Nevertheless, they do not always coincide in volume. The biogeocoenosis and ecosystem are correlated as a less broad and broader concept. Ecosystem is not associated with a certain limited area of the earth's surface. This concept can be applied to all stable systems of inanimate and living components in which internal and external circulation of energy and substances takes place. To ecosystems, for example, can be attributed a drop of water with microorganisms contained in it, a flower pot, an aquarium, a biofilter, an aerotank, a spaceship. But they can not be called biogeocenoses. The ecosystem can have several biogeocenoses in its composition. Let us turn to examples. One can single out biogeocenoses of the ocean and the biosphere as a whole, the continent, the belt, the soil-climatic region, the zone, the province, and the okrug. Thus, not every ecosystem can be considered a biogeocoenosis. We found this out by looking at the examples. But any biogeocenosis can be called an ecological system. We hope, now you understand the specifics of these concepts. "Biogeocenosis" and "ecosystem" are often used as synonyms, but there is still a difference between them.

Features of biogeocenosis

A lot of species usually live in any of the restricted spaces. Between them, a complex and permanent relationship is established. In other words, different kinds of organisms that exist in a certain space characterized by a complex of special physicochemical conditions represent a complex system that persists for a more or less long time in nature. Clarifying the definition, we note that biogeocenosis is a community of organisms of various species (historically formed) that are closely related to each other and to the inanimate nature surrounding them, the exchange of energy and substances. A specific characteristic of the biogeocoenosis is that it is spatially limited and fairly homogeneous in the species composition of the living beings included in it, as well as in the complex of various abiotic factors. The existence of a complete system ensures a constant supply of this solar energy. As a rule, the boundary of the biogeocoenosis is established along the border of the phytocenosis (plant community), which is its most important component. These are its main features. The role of biogeocenosis is great. At its level, all the processes of energy flow and the cycle of substances in the biosphere take place.

Three groups of biocenosis

The main role in the interaction between its various components belongs to the biocenosis, that is, to living beings. They are subdivided according to their functions into 3 groups - decomposers, consumers and producers - and closely interact with the biotope (inanimate nature) and with each other. These living beings are united by existing food links between them.

Producers are a group of autotrophic living organisms. Consuming the energy of sunlight and minerals from the biotope, they thereby create primary organic substances. This group includes some bacteria, as well as plants.

Consumers are heterotrophic organisms that use ready-made organic substances in the form of food, which serve them as a source of energy, as well as substances that consumers need for their livelihoods. We can refer to them almost all animals, plant parasites, predator plants, as well as some (parasitic) bacteria and fungi.

The decomposers decompose the remains of dead organisms, and also break down organic substances into inorganic substances, thereby returning to the biotope the mineral substances "withdrawn" by the producers. These are, for example, some types of unicellular fungi and bacteria.

Food relations between groups of biocenosis

The food relations existing between these three components of the biogeocenosis determine the circulation of substances and the energy flows in it. Capturing the energy of the sun and absorbing minerals, producers create organic substances. Of them, their body is built. Thus, solar energy is converted into energy of chemical bonds. Eating each other and producers, consuments (herbivorous, parasitic and carnivorous organisms) thereby break down organic substances. They use them, as well as the energy released as a result of this, to ensure their vital activity and build their own body. Reedents, feeding on dead organisms, decompose their organic substances. They thus extract the energy and materials they need, and also ensure the return to the biotope of inorganic substances. So in the biogeocoenosis a cycle of substances is carried out. Its permanence is the key to the long-term existence of the ecological system, despite the fact that the mineral reserve is limited in it.

Dynamic equilibrium of the system

Dynamic equilibrium characterizes the relationship of organisms with each other and with the surrounding inanimate nature. For example, in a year when the weather conditions are favorable (a lot of sunny days, the values of humidity and temperature are optimal), plants produce an increased amount of primary organic substances. Such an abundance of food leads to the fact that rodents begin to multiply multiply. This, in turn, causes an increase in parasites and predators, which reduce the number of rodents. In the end, this leads to a decrease in the number of predators, since some part of them perishes from lack of food. Thus, the initial state of the ecosystem is restored.

Types of biogeocenosis

Biogeocenosis can be natural and artificial. The latter include agrobiocenoses and urban biogeocenoses. Let us dwell in more detail on each of them.

Natural biogeocenosis

Note that every natural natural biogeocenosis is a system that has developed over a long period of time - thousands and millions of years. Therefore, all its elements are "ground" to each other. This leads to the fact that the stability of the biogeocoenosis to various changes occurring in the environment is very high. The "strength" of ecosystems is not unlimited. Deep and abrupt changes in conditions of existence, reduction in the number of species of organisms (for example, as a result of large-scale catch of commercial species) lead to the fact that the equilibrium can be violated and it can be destroyed. In this case, biogeocenosis changes.

Agrobiocenoses

Agrobiocenoses are special communities of organisms that form on the territories used by people for agricultural purposes (planting, planting of cultivated plants). Producers (plants), in contrast to natural biogeocenosis, are represented here by a single species of culture grown by man, as well as by a certain number of species of weeds. The variety of herbivorous animals (rodents, birds, insects, etc.) determines the vegetation cover. These are species that can feed on plants growing on the territory of agrobiocenoses, and also be in the conditions of their cultivation. These conditions determine the presence of other species of animals, plants, microorganisms and fungi.

Agrobiocenosis depends, first of all, on human activity (fertilization, mechanical tillage, irrigation, treatment with poisonous chemicals, etc.). The stability of the biogeocenosis of this species is weak - it will collapse very quickly without human intervention. This is partly due to the fact that cultural plants are much more whimsical than wild plants. Therefore, they can not withstand competition with them.

Urban biogeocenoses

Urban biogeocenoses are of particular interest. This is another kind of anthropogenic ecosystem. Examples include parks. The main environmental factors, as in the case of agrobiocenoses, are anthropogenic in them. The species composition of plants is determined by man. He plants them, and also cares for them and their processing. The most pronounced changes in the external environment are expressed precisely in the cities: a rise in temperature (from 2 to 7 ° C), specific features of soil and atmospheric composition, a special regime of humidity, illumination, and wind action. All these factors form urban biogeocenoses. These are very interesting and specific systems.

Examples of biogeocenosis are numerous. Different systems differ from each other in the species composition of organisms, as well as in the properties of the environment in which they inhabit. Examples of biogeocenosis, on which we will dwell in detail, is a deciduous forest and a pond.

Deciduous forest as an example of biogeocenosis

Deciduous forest is a complex ecological system. The biogeocoenosis in our example includes such species of plants as oaks, beeches, limes, hornbeams, birches, maples, mountain ash, aspen and other trees, whose leaves fall in autumn. Several of their tiers stand out in the forest: low and tall wood, mossy soil cover, grasses, shrubs. Plants inhabiting the upper tiers are more photophilous. They are better able to withstand fluctuations in humidity and temperature than representatives of the lower tiers. Mosses, grasses and shrubs are shade-tolerant. They exist in the summer in the twilight, formed after the unfolding of the foliage of trees. The litter lies on the surface of the soil. It is formed from half-decomposed remains, twigs of bushes and trees, fallen leaves, dead grasses.

Forest biogeocenoses, including deciduous forests, are characterized by a rich fauna. They are inhabited by a lot of nordic rodents, predators (bear, badger, fox), earthling insectivores. There are also living on trees mammals (chipmunk, squirrel, lynx). Roe deer, moose, deer are a part of a group of large herbivores. Wild boars are widespread. In different tiers of the forest birds nest: on trunks, in bushes, on land or on tops of trees and in hollows. There are many insects feeding on leaves (for example, caterpillars), as well as wood (bark beetles). In the upper layers of the soil, as well as in the litter, there is a large number of other vertebrates (mites, earthworms, insect larvae), and a host of bacteria and fungi besides insects.

Pond as a biogeocoenosis

Consider now the pond. This is an example of biogeocenosis, the environment of life of organisms in which water is. Large floating or rooted plants (pondyas, water lilies, reeds) settle in the shallow water of ponds. Small floating plants are distributed throughout the thickness of the water, to the depth at which light penetrates. This is mainly algae, which is called phytoplankton. They are sometimes abundant, as a result of which the water becomes green, "blooms." A lot of blue-green, green and diatom algae is contained in the phytoplankton. Tadpoles, insect larvae, herbivorous fish, crustaceans feed on plant remains or living plants. Pisces and predatory insects eat small animals. And for herbivorous and smaller predatory fish, large predators prey. Organisms that decompose organic substances (fungi, flagella, bacteria) are widely distributed throughout the pond. In particular, there are many of them on the bottom, as the remains of dead animals and plants accumulate here.

Comparison of two examples

Comparing examples of biogeocenosis, we see how unlike the species composition and the external appearance of the pond and forest ecosystem. This is due to the fact that the organisms inhabiting them have different habitats. In the pond is water and air, in the forest - soil and air. Nevertheless, functional groups of organisms are of the same type. In the forest, producers are mosses, grasses, bushes, trees; In the pond - algae and floating plants. In the forest, confusates include insects, birds, animals and other invertebrates that inhabit the litter and soil. Among the consumers in the pond are various amphibians, insects, crustaceans, predatory and herbivorous fish. In the forest, the decomposers (bacteria and fungi) are represented by terrestrial forms, and in the pond - by water. We also note that both the pond and the deciduous forest are a natural biogeocenosis. Examples of artificial we cited above.

Why do biogeocenoses replace each other?

Biogeocenosis can not exist forever. It inevitably sooner or later is replaced by another. This occurs as a result of a change in the environment by living organisms, under the influence of man, in the process of evolution, under changing climatic conditions.

Example of biogeocenosis change

Consider, as an example, the case where the living organisms themselves are the cause of the change of ecosystems. It is the colonization of rock by vegetation. Great importance in the first stages of this process is the weathering of rocks: partial dissolution of minerals and change in their chemical properties, destruction. At the initial stages a very large role is played by the first settlers: algae, bacteria, scale lichens, blue-green. Producers are blue-green, algae in the composition of lichens and algae free-living. They create organic matter. Blue-green from the air take nitrogen and enrich them with a medium that is not of much use for habitat. Lichens dissolve secretions of organic acids in rock. They contribute to the fact that elements of mineral nutrition gradually accumulate. Mushrooms and bacteria destroy organic substances created by producers. The latter are not completely mineralized. Gradually accumulates a mixture consisting of mineral and organic compounds and nitrogen-rich plant residues. Conditions are created for the existence of bushy lichens and mosses. Accelerates the process of accumulation of nitrogen and organic matter, a thin layer of soil is formed.

A primitive community is formed that can exist in this unfavorable situation. To the severe conditions of the rocks, the first settlers are well adapted - they withstand both frost, heat, and land. Gradually they change the habitat, creating conditions for the formation of new populations. After there are herbaceous plants (clover, grasses, sedges, bell, etc.), the competition for nutrients, light, water becomes tougher. In this struggle, pioneer settlers are replaced by new species. Shrubs settle for grasses. They bind their roots to the emerging soil. Forest communities are replaced by herbaceous shrubs.

During the long process of development and change of the biogeocenosis, the number of species of living organisms entering into it gradually increases. The community becomes more complex, its food web becomes more and more ramified. The variety of connections existing between organisms increases. The community uses the resources of the environment more fully. So it turns into a mature one, which is well adapted to environmental conditions and has a self-regulation. In it, populations of species are well reproduced and other species are not replaced. For thousands of years the described change of biogeocenoses lasts. However, there are shifts that occur in front of just one generation of people. For example, this is the overgrowth of shallow water bodies.

So, we talked about what a biogeocenosis is. The examples with the description presented above give a clear idea of it. All that we have described is important for understanding this topic. The types of biogeocenosis, their structure, features, examples - all this should be studied in order to have a complete picture of them.