The concept of "ecosystem" was introduced in 1935 by A. Tensley, an English botanist. By this term, he designated any set of organisms that live together, as well as their environment. Its definition emphasizes the presence of interdependence, relationships, causal relationships that exist between the abiotic environment and the biological community, combining them into a kind of functional whole. An ecosystem, according to biologists, is a collection of various populations of various species that live on a common territory, as well as the inanimate environment surrounding them.
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, it is the atmosphere and soil. Below we will considerexamples of biogeocenosis that will help you understand what it is. We will describe these systems in detail. You will learn about their structure, what types of them exist and how they change.
Biogeocenosis and ecosystem: differences
To some extent, the concepts of "ecosystem" and "biogeocenosis" are unambiguous. However, they do not always coincide in volume. Biogeocenosis and ecosystem are related as a less broad and broader concept. The ecosystem is not associated with a certain limited area of the earth's surface. This concept can be applied to all stable systems of non-living and living components in which there is an internal and external circulation of energy and substances. Ecosystems, for example, include a drop of water with microorganisms in it, a flower pot, an aquarium, a biofilter, an aeration tank, a spaceship. But they cannot be called biogeocenoses. An ecosystem may include several biogeocenoses. Let's turn to examples. It is possible to distinguish the biogeocenoses of the ocean and the biosphere as a whole, the mainland, belt, soil-climatic region, zone, province, district. Thus, not every ecosystem can be considered a biogeocenosis. We figured it out by looking at examples. But any biogeocenosis can be called an ecological system. We hope you now 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
Many species commonly found inany of the limited spaces. A complex and constant relationship is established between them. In other words, different types of organisms that exist in a certain space, characterized by a complex of special physico-chemical 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 established), which are closely related to each other and to the inanimate nature surrounding them, the exchange of energy and substances. A specific characteristic of biogeocenosis is that it is spatially limited and rather homogeneous in terms of the species composition of living beings included in it, as well as in terms of a complex of various abiotic factors. Existence as an integral system provides a constant supply of solar energy to this complex. As a rule, the boundary of the biogeocenosis is established along the boundary 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 circulation of substances in the biosphere take place.
Three groups of biocenosis
The main role in the implementation of the interaction between its various components belongs to the biocenosis, that is, living beings. They are divided 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 unitedfood links that exist between them.
Producers are a group of autotrophic living organisms. Consuming the energy of sunlight and minerals from the biotope, they create primary organic substances. This group includes some bacteria, as well as plants.
Consumers are heterotrophic organisms that use ready-made organic substances as food, serving as a source of energy, as well as substances necessary for consumers for their life. We can classify almost all animals, parasitic plants, predatory plants, as well as some (parasitic) bacteria and fungi.
Decomposers decompose the remains of dead organisms, and also break down organic substances into inorganic ones, thereby returning mineral substances "withdrawn" by producers to the biotope. 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 cycle of substances and the energy flows in it. Capturing the energy of the Sun and absorbing minerals, producers create organic substances. Their body is built from them. Thus, solar energy is converted into the energy of chemical bonds. Eating each other and producers, consumers (herbivorous, parasitic and predatory organisms) thereby break down organic matter. They use them, as well as the energy released as a result of this, to ensure their livelihoods and build their own body. Decomposers, feeding on dead organisms, decompose their organic matter. They thus extract the energy and materials they need, and also ensure the return of inorganic substances to the biotope. So in the biogeocenosis, the circulation of substances is carried out. Its constancy is the key to the long existence of the ecological system, despite the fact that the supply of minerals is limited in it.
Dynamic equilibrium of the system
Dynamic balance characterizes the relationship of organisms with each other and with the inanimate nature surrounding them. For example, in a year when weather conditions are favorable (many sunny days, humidity and temperature are optimal), plants produce an increased amount of primary organic matter. Such an abundance of food leads to the fact that rodents begin to multiply en masse. This, in turn, causes an increase in parasites and predators, which reduce the number of rodents. As a result, this leads to a decrease in the number of predators, since some of them die from a lack of food. Thus, the original state of the ecosystem is restored.
Types of biogeocenosis
Biogeocenosis can be natural and artificial. The species of the latter include agrobiocenoses and urban biogeocenoses. Let's take a closer look at each of them.
Biogeocenosis natural
Note that every natural natural biogeocenosis is a system that has developed over a long time - thousands and millions of years. Therefore, all its elements are "lapped" to each other. This leads tothat the resistance of biogeocenosis to various changes occurring in the environment is very high. The "strength" of ecosystems is not unlimited. Deep and abrupt changes in the conditions of existence, a reduction in the number of species of organisms (for example, as a result of a large-scale catch of commercial species) lead to the fact that the balance can be disturbed and it can be destroyed. In this case, there is a change of biogeocenoses.
Agrobiocenoses
Agrobiocenoses are special communities of organisms that develop in areas used by people for agricultural purposes (planting, sowing cultivated plants). Producers (plants), in contrast to biogeocenoses of a natural species, are represented here by one type of crop grown by man, as well as a certain number of weed species. 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, as well as 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 activities (fertilization, tillage, irrigation, pesticide treatment, 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 cultivated plants are much more whimsical than wild ones. That's why they can't standcompetition with them.
Urban biogeocenoses
Urban biogeocenoses are of particular interest. This is another type of anthropogenic ecosystems. Parks are an example. 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 takes care of them and their processing. The most pronounced changes in the external environment are expressed precisely in cities - an increase in temperature (from 2 to 7 ° C), specific features of the 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 live. Examples of biogeocenosis, which we will dwell on in detail, are a deciduous forest and a pond.
Deciduous forest as an example of biogeocenosis
The deciduous forest is a complex ecological system. The composition of the biogeocenosis in our example includes plant species such as oaks, beeches, lindens, hornbeams, birches, maples, mountain ash, aspens and other trees whose foliage falls in autumn. Several of their tiers stand out in the forest: low and high woody, moss ground cover, grasses, shrubs. Plants inhabiting the upper tiers are more photophilous. They are better able to withstand vibrations.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 foliage of the trees unfolds. The litter lies on the surface of the soil. It is formed from semi-decomposed remains, twigs of shrubs and trees, fallen leaves, dead grasses.
Forest biogeocenoses, including deciduous forests, are characterized by rich fauna. They are inhabited by many burrowing rodents, predators (bear, badger, fox), and burrowing insectivores. There are also mammals living on trees (chipmunk, squirrel, lynx). Roe deer, elk, deer are part of the group of large herbivores. Boars are widespread. Birds nest in different tiers of the forest: on trunks, in bushes, on the ground or on the tops of trees and in hollows. There are many insects that feed on leaves (for example, caterpillars), as well as wood (bark beetles). In the upper layers of the soil, as well as in the litter, in addition to insects, a huge number of other vertebrates (ticks, earthworms, insect larvae), many bacteria and fungi live.
Pond as biogeocenosis
Now consider the pond. This is an example of biogeocenosis, in which the living environment of organisms is water. Large floating or rooting plants (weeds, water lilies, reeds) settle in the shallow water of ponds. Small floating plants are distributed throughout the water column, to the depth where light penetrates. These are mainly algae, which are called phytoplankton. There are sometimes a lot of them, as a result of which the water turns green,"blooms". Many blue-green, green and diatom algae are found in phytoplankton. Tadpoles, insect larvae, herbivorous fish, crustaceans feed on plant debris or living plants. Fish and predatory insects eat small animals. And herbivorous and smaller predatory fish are hunted by large predatory ones. Organisms that decompose organic matter (fungi, flagellates, bacteria) are widespread throughout the pond. There are especially many of them at the bottom, as the remains of dead animals and plants accumulate here.
Comparison of two examples
Comparing examples of biogeocenosis, we see how dissimilar both in terms of species composition and appearance of the pond and forest ecosystems. This is due to the fact that the organisms inhabiting them have a different habitat. In a pond it is water and air, in a forest it is soil and air. Nevertheless, the functional groups of organisms are of the same type. In the forest, producers are mosses, herbs, shrubs, trees; in the pond - algae and floating plants. In the forest, consumers include insects, birds, animals and other invertebrates that inhabit the litter and soil. The consumers in the pond include various amphibians, insects, crustaceans, predatory and herbivorous fish. In the forest, decomposers (bacteria and fungi) are represented by terrestrial forms, and in the pond - by aquatic ones. We also note that both the pond and the deciduous forest are natural biogeocenosis. We gave examples of artificial ones above.
Why do biogeocenoses replace each other?
Biogeocenosis cannot exist forever. He inevitably sooner orreplaced late. This happens as a result of changes in the environment by living organisms, under the influence of man, in the process of evolution, with changing climatic conditions.
An example of a change in biogeocenosis
Let's consider as an example the case when living organisms themselves are the cause of ecosystem change. This is the settlement of rocks with vegetation. Of great importance in the first stages of this process is the weathering of rocks: partial dissolution of minerals and a change in their chemical properties, destruction. At the initial stages, the first settlers play a very important role: algae, bacteria, scale lichens, blue-green. The producers are blue-green, algae in the composition of lichens and free-living algae. They create organic matter. Blue-greens take nitrogen from the air and enrich it with an environment that is still unsuitable for habitation. Lichens dissolve rock with secretions of organic acids. They contribute to the fact that the elements of mineral nutrition are gradually accumulated. Fungi and bacteria destroy the organic substances created by the producers. The latter are not fully mineralized. Gradually, a mixture of mineral and organic compounds and plant residues enriched with nitrogen accumulates. Conditions are created for the existence of bushy lichens and mosses. The process of accumulation of nitrogen and organic matter accelerates, a thin layer of soil is formed.
A primitive community is being formed that can exist in this unfavorable environment. The first settlers are well adapted to the harsh conditions of the rocks - they withstand andfrost, and heat, and dryness. Gradually, they change their habitat, creating conditions for the formation of new populations. After the appearance of herbaceous plants (clover, cereals, sedges, bluebell, etc.), competition for nutrients, light, and water intensifies. In this struggle, the pioneer settlers are displaced by new species. Shrubs settle for herbs. They hold the soil in place with their roots. Forest communities are replaced by grass and shrub communities.
In the course of a long process of development and change of biogeocenosis, the number of species of living organisms included in it is gradually growing. The community becomes more complex, its food web becomes more and more ramified. The variety of relationships that exist between organisms is increasing. More and more community uses the resources of the environment. So it turns into a mature one, which is well adapted to environmental conditions and has self-regulation. In it, species populations reproduce well and are not replaced by other species. The described change of biogeocenoses lasts for thousands of years. However, there are changes that take place before the eyes of just one generation of people. For example, this is the overgrowing of shallow reservoirs.
So, we talked about what biogeocenosis is. The examples with descriptions presented above give a visual representation of it. Everything we have talked about is important for understanding this topic. Types of biogeocenoses, their structure, features, examples - all this should be studied in order to have a complete picture of them.
