Ecosystem capacity. Cheat sheet: Ecosystem and its properties

Ecology Considers interaction between living organisms and inanimate nature. This interaction, firstly, occurs within a certain system (ecological system, ecosystem) and, secondly, it is not chaotic, but organized in a certain way, subject to laws. An ecosystem is a set of producers, consumers and detritus feeders interacting with each other and with their environment through the exchange of matter, energy and information in such a way that this single system remains stable for a long time. Thus, a natural ecosystem is characterized by three features:

• 1) an ecosystem is necessarily a combination of living and non-living components
• 2) within the ecosystem, a full cycle is carried out, starting with the creation of organic matter and ending with its decomposition into inorganic components;
• 3) the ecosystem remains stable for some time, which is provided by a certain structure of biotic and abiotic components.

Examples of natural ecosystems are lake, forest, desert, tundra, land, ocean, biosphere. As can be seen from the examples, simpler ecosystems are included in more complex ones. At the same time, a hierarchy of organization of systems is realized, in this case, ecological ones. Thus the device of nature should be considered as a system, consisting of nested ecosystems, the highest of which is a unique global ecosystem - the biosphere. Within its framework, there is an exchange of energy and matter between all living and non-living components on a planetary scale. The catastrophe that threatens all mankind is that one of the signs that an ecosystem should have has been violated: the biosphere as an ecosystem has been brought out of a state of stability by human activity. Due to its scale and diversity of interrelations, it should not perish from this, it will pass into a new stable state, while changing its structure, first of all, inanimate, and after it, inevitably, living. Man, as a biological species, has the least chance of adapting to new rapidly changing external conditions and is likely to be the first to disappear. An instructive and illustrative example of this is the story of Easter Island. On one of the Polynesian islands, called Easter Island, as a result of complex migration processes in the 7th century, a closed civilization isolated from the whole world arose. In a favorable subtropical climate, over the hundreds of years of existence, it has reached certain heights of development, creating an original culture and writing, which to this day cannot be deciphered. And in the 17th century, it perished without a trace, first destroying the flora and fauna of the island, and then destroying itself in progressive savagery and cannibalism. The last islanders no longer had the will and material to build saving "Noah's arks" - boats or rafts. In memory of itself, the disappeared community left a semi-desert island with giant stone figures - witnesses of its former power. So, the ecosystem is the most important structural unit of the structure of the surrounding world. As can be seen, the basis of ecosystems is made up of living matter, characterized by a biotic structure, and a habitat determined by a combination of environmental factors.

Ecosystem, or ecological system(from the ancient Greek οἶκος - dwelling, residence and σύστημα - system) - a biological system consisting of a community of living organisms ( biocenosis), their habitats ( biotope), a system of connections that exchanges matter and energy between them.

Scientists differentiate ecosystems into micro-ecosystems (for example, a tree), meso-ecosystems (forest, pond) and macro-ecosystems (ocean, continent). The biosphere has become the global ecosystem.

There are properties-features that allow you to define the concept of an ecosystem that acts as an object of legal regulation. These include:

1. Closure of the ecosystem. Its independent functioning. We can say that, for example, a drop of water, a forest, a sea, etc. are ecosystems, since each of these objects has its own stable system of organisms (ciliates in a drop, fish in the sea, etc.). The closed nature of ecological systems obliges all users of natural resources to take into account the environmental consequences of their actions, even if there are no visible manifestations of the impact on nature. So, laying a road in an open area, at first glance, does not affect the environment. But under certain conditions, the road can become a source of environmental disaster, for example, if it is laid without taking into account the flow of flood waters, which, when accumulated, can destroy the ground cover.

2. Interconnection of Ecosystems. This feature necessitates an integrated approach to the use of natural objects, which in practice is called landscape. For example, when allocating land for arable land or carrying out land reclamation, it is necessary to take into account the migration routes of representatives of the wild fauna, to keep individual bushes, swamps, copses, etc. intact, that is, not to disturb the landscape that has developed in the area. The landscape approach makes it possible to ensure a general ecological priority in nature management, according to which all types of use of natural objects must be subject to the requirements of the ecological well-being of the natural environment.

3. Bioproductivity. This feature contributes to the self-reproduction of the ecosystem, the performance of a particular function, which determines as a result the different legal status of a natural object. So, lands of increased fertility should be allocated for the needs of agriculture, and for other purposes - unproductive. Productivity is also taken into account when establishing a fee for the use of a natural object, when taxing, in case of compensation for damage or the occurrence of an insured event.

Ecosystem Example - a pond with plants living in it, fish, invertebrates, microorganisms that make up the living component of the system, biocenosis. A pond as an ecosystem is characterized by bottom sediments of a certain composition, chemical composition (ionic composition, concentration of dissolved gases) and physical parameters (water transparency, trend of annual temperature changes), as well as certain indicators of biological productivity, the trophic status of the reservoir and the specific conditions of this reservoir.

Another example of an ecological system - deciduous forest in central Russia with a certain composition of forest litter, soil characteristic of this type of forest and a stable plant community, and, as a result, with strictly defined microclimate indicators (temperature, humidity, light) and a complex of animal organisms corresponding to such environmental conditions.

An important aspect that makes it possible to determine the types and boundaries of ecosystems is the trophic structure of the community and the ratio of biomass producers, its consumers, and biomass-destroying organisms, as well as indicators of productivity and metabolism of matter and energy.

An ecosystem is a complex, self-organizing, self-regulating and self-developing system. The main characteristic of an ecosystem is the presence of relatively closed, stable in space and time flows of matter and energy between the biotic and abiotic parts of an ecosystem. It follows from this that not every biological system can be called an ecosystem, for example, an aquarium or a rotten stump are not.

Such systems should be called communities of lower rank, or microcosms. Sometimes the concept of facies is used for them (for example, in geoecology), but it is not able to fully describe such systems, especially of artificial origin.

An ecosystem is an open system and is characterized by input and output flows of matter and energy. The basis for the existence of almost any ecosystem is the energy flow of sunlight, which is a consequence of the thermonuclear reaction of the Sun, either in direct (photosynthesis) or indirect (decomposition of organic matter) form. The exception is deep-sea ecosystems ("black" and "white" smokers), the source of energy in which is the internal heat of the earth and the energy of chemical reactions.

In accordance with the definitions, there is no difference between the concepts of "ecosystem" and "biogeocenosis", biogeocenosis can be considered a complete synonym for the term ecosystem. However, there is a widespread opinion that biogeocenosis can serve as an analogue of an ecosystem at the very initial level, since the term "biogeocenosis" places more emphasis on the connection of a biocenosis with a specific area of ​​\u200b\u200bland or aquatic environment, while an ecosystem implies any abstract area. Therefore, biogeocenoses are usually considered a special case of an ecosystem.

An ecosystem can be divided into two components - biotic and abiotic. Biotic is divided into autotrophic (organisms that receive primary energy for existence from photo- and chemosynthesis or producers) and heterotrophic (organisms that receive energy from the processes of oxidation of organic matter - consumers and decomposers) components that form the trophic structure of the ecosystem.

The only source of energy for the existence of an ecosystem and the maintenance of various processes in it are producers that absorb the energy of the sun (heat, chemical bonds) with an efficiency of 0.1 - 1%, rarely 3 - 4.5% of the initial amount. Autotrophs represent the first trophic level of an ecosystem. Subsequent trophic levels of the ecosystem are formed due to consumers (2nd, 3rd, 4th and subsequent levels) and are closed by decomposers that convert inanimate organic matter into a mineral form (abiotic component), which can be assimilated by an autotrophic element.

Usually the concept ecotope was defined as a habitat of organisms characterized by a certain combination of environmental conditions: soils, soils, microclimate, etc. However, in this case, this concept is actually almost identical to the concept climatetop.

For example, lava flowing into the ocean on the island of Hawaii forms a new coastal ecotope.

Currently, an ecotope, in contrast to a biotope, is understood as a certain territory or water area with the entire set and characteristics of soils, soils, microclimate and other factors in a form unchanged by organisms. Examples of an ecotope are alluvial soils, newly formed volcanic or coral islands, man-made quarries, and other newly formed territories. In this case climatetop is part of the ecotope.

Biotope- an ecotope transformed by biota or, more precisely, a piece of territory that is homogeneous in terms of living conditions for certain types of plants or animals, or for the formation of a certain biocenosis.

Topic 1.2.: Ecosystem and its properties

1. Ecosystem - the basic concept of ecology ………………………………………………4

2. Biotic structure of ecosystems…………………………………………………………5.

3. Environmental factors ………………………………………………………………….6

4. The functioning of ecosystems…………………………………………………………..12

5. Human impact on the ecosystem………………………………………………...14

Conclusion……………………………………………………………………………….16

List of references………………………………………………………………………….17

Introduction

Word "ecology" It is formed from two Greek words: "oicos", which means house, dwelling, and "logos" - science and literally translates as the science of the house, habitat. For the first time this term was used by the German zoologist Ernst Haeckel in 1886, defining ecology as a field of knowledge that studies the economics of nature - the study of the general relationship of animals with both living and non-living nature, including all both friendly and unfriendly relations, which animals and plants directly or indirectly come into contact. This understanding of ecology has become generally recognized and today the classical Ecology is the science of studying the relationship of living organisms with their environment.

Living matter is so diverse that it is studied at different levels of organization and from different points of view.

There are the following levels of organization of biosystems (See applications (Fig. 1)).

The levels of organisms, populations and ecosystems are the area of ​​interest of classical ecology.

Depending on the object of study and the angle of view from which it is studied, independent scientific directions have been formed in ecology.

By dimensions of objects The study of ecology is divided into autecology (an organism and its environment), population ecology (a population and its environment), synecology (communities and their environment), biogeocytology (the study of ecosystems) and global ecology (the study of the Earth's biosphere).

Depending on the object of study ecology is divided into the ecology of microorganisms, fungi, plants, animals, humans, agroecology, industrial (engineering), human ecology, etc.

By environments components distinguish between the ecology of land, fresh water, the sea, deserts, highlands and other environmental and geographical spaces.

Ecology often includes a large number of related branches of knowledge, mainly from the field of environmental protection.

In this paper, first of all, the basics of general ecology are considered, that is, classical laws of interaction of living organisms with the environment.

1. Ecosystem - the basic concept of ecology

Ecology considers the interaction of living organisms and inanimate nature. This interaction, firstly, occurs within a certain system (ecological system, ecosystem) and, secondly, it is not chaotic, but organized in a certain way, subject to laws.

ecosystem called a set of producers, consumers and detritus feeders interacting with each other and with their environment through the exchange of matter, energy and information in such a way that this single system remains stable for a long time.

Thus, a natural ecosystem is characterized by three features:

1) an ecosystem is necessarily a combination of living and non-living components ((see appendix (Fig. 2));

2) within the ecosystem, a full cycle is carried out, starting with the creation of organic matter and ending with its decomposition into inorganic components;

3) the ecosystem remains stable for some time, which is provided by a certain structure of biotic and abiotic components.

Examples of natural ecosystems are lake, forest, desert, tundra, land, ocean, biosphere.

As can be seen from the examples, simpler ecosystems are included in more complex ones. At the same time, a hierarchy of organization systems is realized, in this case, ecological ones.

Thus, the structure of nature should be considered as a systemic whole, consisting of nested ecosystems, the highest of which is a unique global ecosystem - the biosphere. Within its framework, there is an exchange of energy and matter between all living and non-living components on a planetary scale. The catastrophe that threatens all mankind lies in the fact that one of the signs that an ecosystem should have has been violated: the biosphere as an ecosystem has been brought out of a state of stability by human activity. By virtue of its scale and diversity of interrelations, it should not perish from this, it will pass into a new stable state, while changing its structure, first of all inanimate, and then inevitably alive. Man, as a biological species, has less chance than others to adapt to new rapidly changing external conditions and most likely will disappear first. An instructive and illustrative example of this is the history of Easter Island.

On one of the Polynesian islands, called Easter Island, as a result of complex migration processes in the 7th century, a closed civilization isolated from the whole world arose. In a favorable subtropical climate, over hundreds of years of existence, it has reached certain heights of development, creating an original culture and writing, which to this day cannot be deciphered. And in the 17th century, it perished without a trace, first destroying the flora and fauna of the island, and then destroying itself in progressive savagery and cannibalism. The last islanders did not have the will and material left to build saving "no-arks" - boats or rafts. In memory of itself, the disappeared community left a semi-desert island with giant stone figures - witnesses of its former power.

So, the ecosystem is the most important structural unit of the structure of the surrounding world. As can be seen from fig. 1 (see Appendix), the basis of ecosystems is living matter, characterized biotic structure , and habitat, determined by the totality environmental factors . Let's consider them in more detail.

2. Biotic structure of ecosystems

The ecosystem is based on the unity of living and non-living matter. The essence of this unity is shown as follows. From the elements of inanimate nature, mainly CO2 and H2O molecules, under the influence of solar energy, organic substances are synthesized that make up all life on the planet. The process of creating organic matter in nature occurs simultaneously with the opposite process - the consumption and decomposition of this substance again into the original inorganic compounds. The totality of these processes takes place within ecosystems of different levels of hierarchy. In order for these processes to be balanced, nature over billions of years has worked out a certain the structure of the living matter of the system .

The driving force in any material system is energy. It enters ecosystems mainly from the Sun. Plants, due to the pigment chlorophyll contained in them, capture the energy of the radiation of the Sun and use it to synthesize the basis of any organic substance - glucose C6H12O6.

The kinetic energy of solar radiation is thus converted into potential energy stored in glucose. From glucose, together with mineral nutrients obtained from the soil - nutrients - all tissues of the plant world are formed - proteins, carbohydrates, fats, lipids, DNA, RNA, that is, the organic matter of the planet.

In addition to plants, some bacteria can produce organic matter. They create their tissues, storing in them, like plants, potential energy from carbon dioxide without the participation of solar energy. Instead, they use the energy that is generated by the oxidation of inorganic compounds, such as ammonia, iron, and especially sulfur (in deep ocean basins, where sunlight does not penetrate, but where hydrogen sulfide accumulates in abundance, unique ecosystems have been found). This is the so-called energy of chemical synthesis, therefore organisms are called chemosynthetics .

Thus, ichemosynthetic plants create organic matter from inorganic constituents with the help of environmental energy. They are called producers or autotrophs .The release of potential energy stored by producers ensures the existence of all other types of life on the planet. Species that consume organic matter created by producers as a source of matter and energy for their life activity are called consumers or heterotrophs .

Consumers are the most diverse organisms (from microorganisms to blue whales): protozoa, insects, reptiles, fish, birds and, finally, mammals, including humans.

Consumers, in turn, are divided into a number of subgroups in accordance with differences in their food sources.

Animals that feed directly on producers are called primary consumers or first-order consumers. They themselves are eaten by secondary consumers. For example, a rabbit eating carrots is a consumer of the first order, an alice hunting a rabbit is a consumer of the second order. Some types of living organisms correspond to several such levels. For example, when a person eats vegetables - he is a consumer of the first order, beef - a consumer of the second order, and eating predatory fish, acts as a consumer of the third order.

Primary consumers that feed only on plants are called herbivores or phytophages .Consumers of the second and higher orders - carnivores . Species that eat both plants and animals are omnivores, such as humans.

Dead plant and animal remains, such as fallen leaves, animal carcasses, excretory system products, are called detritus. It's organic! There are many organisms that specialize in feeding on detritus. They're called detritivores .Vultures, jackals, worms, crayfish, termites, ants, etc. can serve as an example. As in the case of ordinary consumers, there are primary detritophages that feed directly on detritus, secondary ones, etc.

Finally, a significant part of the detritus in the ecosystem, in particular fallen leaves, dead wood, in its original form is not eaten by animals, but rots and decomposes in the process of feeding on fungi and bacteria.

Since the role of fungi and bacteria is so specific, they are usually distinguished into a special group of detritophages and are called decomposers . Reducers serve as orderlies on Earth and close the biogeochemical cycle of substances, decomposing organic matter into its original inorganic components - carbon dioxide and water.

Thus, despite the diversity of ecosystems, they all have structural similarity. In each of them, photosynthetic plants can be distinguished - producers, different levels of consumers, detritus feeders and decomposers. They constitute biotic structure of ecosystems .

3. Environmental factors

The inanimate and living nature surrounding plants, animals and humans is called habitat .The many individual components of the environment that affect organisms are called environmental factors.

According to the nature of origin, abiotic, biotic and anthropogenic factors are distinguished. Abiotic factors - These are properties of inanimate nature that directly or indirectly affect living organisms.

Biotic factors - these are all forms of influence of living organisms on each other.

Previously, human impact on living organisms was also referred to as biotic factors, but now a special category of factors generated by humans is distinguished. Anthropogenic factors - these are all forms of activity of human society that lead to a change in nature as a habitat and other species and directly affect their lives.

Thus, every living organism is influenced by inanimate nature, organisms of other species, including humans, and, in turn, affects each of these components.

Laws of the impact of environmental factors on living organisms

Despite the variety of environmental factors and the different nature of their origin, there are some general rules and patterns of their impact on living organisms.

For the life of organisms, a certain combination of conditions is necessary. If all environmental conditions are favorable, with the exception of one, then it is this condition that becomes decisive for the life of the organism in question. It limits (limits) the development of the organism, therefore it is called limiting factor .Initially, it was found that the development of living organisms is limited by the lack of any component, for example, mineral salts, moisture, light, etc. In the middle of the 19th century, the German organic chemist Eustace Liebig was the first to experimentally prove that plant growth depends on the element of nutrition that is present in a relatively minimal amount. He called this phenomenon the law of the minimum; in honor of the author, it is also called Liebig's law.

In modern formulation law of the minimum sounds like this: The endurance of an organism is determined by the weakest link in the chain of its ecological needs. However, as it turned out later, not only a deficiency, but also an excess of a factor can be limiting, for example, the death of a crop due to rains, oversaturation of the soil with fertilizers, etc. The concept that, along with a minimum, a limiting factor can also be a maximum, was introduced 70 years after Liebig by the American zoologist W. Shelford, who formulated the law of tolerance. According to the law of tolerance, the limiting factor for the prosperity of a population (organism) can be both a minimum and a maximum of environmental impact, and the range between them determines the amount of endurance (tolerance limit) or the ecological valence of the organism to this factor ((see Appendix Fig. 3).

The favorable range of the environmental factor is called optimum zone (normal activity). The more significant the deviation of the effect of the factor from the optimum, the more this factor inhibits the vital activity of the population. This range is called zone of oppression . The maximum and minimum tolerated values ​​of the factor are critical points beyond which the existence of an organism or population is no longer possible.

In accordance with the law of tolerance, any excess of matter or energy turns out to be a polluting principle. Thus, excess water, even in arid regions, is harmful and water can be regarded as a common pollutant, although it is simply necessary in optimal quantities. In particular, excess water prevents normal soil formation in the chernozem zone.

Species that require strictly defined environmental conditions for their existence are called stenobiotic, and species that adapt to the ecological environment with a wide range of parameter changes are called eurybiotic.

Among the laws that determine the interaction of an individual or an individual with its environment, we single out the rule of conformity of environmental conditions with the genetic predetermination of an organism .It claims that the species of organisms can exist until then and insofar as the natural environment surrounding it corresponds to the genetic possibilities of adapting this species to its fluctuations and changes.

Abiotic Habitat Factors

Abiotic factors are properties of inanimate nature that directly or indirectly affect living organisms. On fig. 5 (see Appendix) shows the classification of abiotic factors. Let's start with climatic factors external environment.

Temperature is the most important climatic factor. It depends on the intensity of metabolism of organisms and their geographical distribution. Any organism is able to live within a certain range of temperatures. And although for different types of organisms (eurythermal and stenothermic) these intervals are different, for most of them the zone of optimal temperatures, at which vital functions are carried out most actively and efficiently, is relatively small. The range of temperatures in which life can exist is approximately 300 C: from -200 to +100 °C. But most species and most of the activity are confined to a narrower range of temperatures. Certain organisms, especially in the dormant stage, can survive at least some of the time at very low temperatures. Certain types of microorganisms, mainly bacteria and algae, are able to live and multiply at temperatures close to the boiling point. The upper limit for hot spring bacteria is 88 C, for blue-green algae it is 80 C, and for the most resistant fish and insects it is about 50 C. Generally, the upper limits of the factor are more critical than the lower ones, although many organisms near the upper limits of the tolerance range function. more effective.

In aquatic animals, the range of temperature tolerance is usually narrower than in terrestrial animals, since the range of temperature fluctuations in water is less than on land.

Thus, temperature is an important and very often limiting factor. Temperature rhythms largely control the seasonal and diurnal activity of plants and animals.

Precipitation and humidity are the main quantities measured in the study of this factor. The amount of precipitation depends mainly on the paths and nature of large movements of air masses. For example, winds blowing from the ocean leave most of the moisture on the slopes facing the ocean, resulting in a “rain shadow” behind the mountains, contributing to the formation of the desert. Moving inland, the air accumulates a certain amount of moisture, and the amount of precipitation increases again. Deserts tend to be located behind high mountain ranges or along coasts where winds blow from large inland dry areas rather than from the ocean, such as the Nami Desert in South West Africa. The distribution of precipitation over the seasons is an extremely important limiting factor for organisms.

Humidity - a parameter characterizing the content of water vapor in the air. Absolute humidity is the amount of water vapor per unit volume of air. In connection with the dependence of the amount of vapor retained by air on temperature and pressure, the concept of relative humidity was introduced - this is the ratio of the vapor contained in the air to the saturating vapor at a given temperature and pressure. Since in nature there is a daily rhythm of humidity - an increase at night, a decrease during the day, and its fluctuation vertically and horizontally, this factor, along with light and temperature, plays an important role in regulating the activity of organisms. The supply of surface water available to living organisms depends on the amount of precipitation in a given area, but these values ​​\u200b\u200bare not always the same. So, using underground sources, where water comes from other areas, animals and plants can get more water than from its intake with precipitation. Conversely, rainwater sometimes immediately becomes inaccessible to organisms.

Sun radiation is electromagnetic waves of various lengths. It is absolutely necessary for living nature, since it is the main external source of energy. It must be borne in mind that the spectrum of the electromagnetic radiation of the Sun is very wide and its frequency ranges affect living matter in different ways.

For living matter, qualitative signs of light are important - the wavelength, intensity and duration of exposure.

ionizing radiation knocks electrons out of atoms and attaches them to other atoms to form pairs of positive and negative ions. Its source is radioactive substances contained in rocks, in addition, it comes from space.

Different types of living organisms differ greatly in their ability to withstand large doses of radiation exposure. Most studies show that rapidly dividing cells are the most sensitive to radiation.

In higher plants, sensitivity to ionizing radiation is directly proportional to the size of the cell nucleus, or rather to the volume of chromosomes or the content of DNA.

Gas composition atmosphere is also an important climatic factor. Approximately 3-3.5 billion years ago, the atmosphere contained nitrogen, ammonia, hydrogen, methane and water vapor, and there was no free oxygen in it. The composition of the atmosphere was largely determined by volcanic gases. Due to the lack of oxygen, there was no ozone screen to block the ultraviolet radiation from the sun. Over time, due to abiotic processes, oxygen began to accumulate in the atmosphere of the planet, and the formation of the ozone layer began.

Wind it is even able to change the appearance of plants, especially in those habitats, for example, in alpine zones, where other factors have a limiting effect. It has been experimentally shown that in open mountain habitats the wind limits the growth of plants: when a wall was built to protect the plants from the wind, the height of the plants increased. Storms are of great importance, although their action is purely local. Hurricanes and ordinary winds can carry animals and plants over long distances and thereby change the composition of communities.

Atmosphere pressure , apparently, is not a limiting factor of direct action, however, it is directly related to weather and climate, which have a direct limiting effect.

Water conditions create a peculiar habitat for organisms, which differs from the terrestrial one primarily in density and viscosity. Density water about 800 times, and viscosity about 55 times higher than that of air. Together with density and viscosity the most important physical and chemical properties of the aquatic environment are: temperature stratification, that is, temperature change along the depth of the water body and periodic temperature changes over time, as well as transparency water, which determines the light regime under its surface: the photosynthesis of green and purple algae, phytoplankton, and higher plants depends on transparency.

As in the atmosphere, an important role is played by gas composition aquatic environment. In aquatic habitats, the amount of oxygen, carbon dioxide, and other gases dissolved in water and therefore available to organisms varies greatly over time. In water bodies with a high content of organic matter, oxygen is the limiting factor of paramount importance.

Acidity - the concentration of hydrogen ions (pH) - is closely related to the carbonate system. The pH value varies in the range from 0 pH to 14: at pH = 7 the medium is neutral, at pH<7 - кислая, при рН>7 - alkaline. If the acidity does not approach extreme values, then the communities are able to compensate for changes in this factor - the tolerance of the community to the pH range is very significant. Waters with low pH contain few nutrients, so the productivity here is extremely low.

Salinity - content of carbonates, sulfates, chlorides, etc. - is another significant mabiotic factor in water bodies. There are few salts in fresh waters, of which about 80% are carbonates. The content of mineral substances in the oceans is on average 35 g/l. Organisms in the open ocean are usually stenohaline, while organisms in coastal brackish waters are generally euryhaline. The salt concentration in the body fluids and tissues of most marine organisms is isotonic with the salt concentration in sea water, so there are no problems with osmoregulation.

Flow not only strongly affects the concentration of gases and nutrients, but also directly acts as a limiting factor. Many river plants and animals are morphologically and physiologically adapted in a special way to maintaining their position in the stream: they have well-defined limits of tolerance to the current factor.

hydrostatic pressure in the ocean is of great importance. With immersion in water for 10 m, the pressure increases by 1 atm (105 Pa). In the deepest part of the ocean, pressure reaches 1000 atm (108 Pa). Many animals are able to tolerate sharp fluctuations in pressure, especially if they do not have free air in their body. Otherwise, a gas embolism may develop. High pressures, characteristic of great depths, as a rule, inhibit vital processes.

The soil.

Soil is a layer of matter that lies on top of the rocks of the earth's crust. Russian scientist - naturalist Vasily Vasilyevich Dokuchaev in 1870 was the first to consider the soil as a dynamic, and not an inert environment. He proved that the soil is constantly changing and developing, and chemical, physical and biological processes take place in its active zone. Soil is formed as a result of a complex interaction of climate, plants, animals and microorganisms. The composition of the soil includes four main structural components: the mineral base (usually 50-60% of the total soil composition), organic matter (up to 10%), air (15-25%) and water (25-30%).

Mineral skeleton of the soil - this is an inorganic component that was formed from the parent rock as a result of its weathering.

organic matter soil is formed by the decomposition of dead organisms, their parts and excrement. Not completely decomposed organic remains are called litter, and the end product of decomposition - an amorphous substance in which it is no longer possible to recognize the original material - is called humus. Due to its physical and chemical properties, humus improves soil structure and aeration, as well as increases the ability to retain water and nutrients.

The soil is inhabited by many species of plant and animal organisms that affect its physical and chemical characteristics: bacteria, algae, fungi or protozoa, arthropod worms. Their biomass in various soils is equal (kg/ha): bacteria 1000-7000, microscopic fungi - 100-1000, algae 100-300, arthropods - 1000, worms 350-1000.

The main topographic factor is the height above sea level. With altitude, average temperatures decrease, the daily temperature difference increases, the amount of precipitation, wind speed and radiation intensity increase, atmospheric pressure and gas concentrations decrease. All these factors affect plants and animals, causing vertical zonality.

mountain ranges can serve as climate barriers. Mountains also serve as barriers to the spread and migration of organisms and can play the role of a limiting factor in the processes of speciation.

Another topographic factor - slope exposure . In the northern hemisphere, south-facing slopes receive more sunlight, so the light intensity and temperature are higher here than at the bottom of the valleys and on the slopes of the northern exposure. In the southern hemisphere, the situation is reversed.

An important factor in the relief is also slope steepness . Steep slopes are characterized by rapid drainage and soil erosion, so here the soils are thin and drier.

For abiotic conditions, all considered laws of the impact of environmental factors on living organisms are valid. Knowledge of these laws allows us to answer the question: why different regions of the planet formed different ecosystems? The main reason is the peculiarity of the abiotic conditions of each region.

Biotic relationships and the role of species in an ecosystem

The distribution areas and the number of organisms of each species are limited not only by the conditions of the external non-living environment, but also by their relations with organisms of other species. The immediate living environment of an organism is its biotic environment , the afactors of this environment are called biotic . Representatives of each species are able to exist in an environment where connections with other organisms provide them with normal living conditions.

Consider the characteristic features of relations of various types.

Competition is the most comprehensive type of relationship in nature, in which two populations or two individuals in the struggle for the conditions necessary for life affect each other negative .

Competition may be intraspecificand interspecific.

Intraspecific struggle occurs between individuals of the same species, interspecific competition takes place between individuals of different species. Competitive interaction may involve living space, food or nutrients, light, shelter, and many other vital factors.

Interspecies competition, whatever its basis, may either bring about an equilibrium between two species, or cause the population of one species to be replaced by a population of another, or cause one species to displace the other in a different place or force it to switch to the use of other resources. Determined that two identical in ecological terms and needs of the species cannot coexist in one place, and sooner or later one competitor displaces the other. This is the so-called principle of exclusion or the Gause principle.

Since food interactions predominate in the structure of the ecosystem, the most characteristic form of interaction between species in trophic chains is predation , in which an individual of one species, called a predator, feeds on organisms (or parts of organisms) of another species, called prey, and the predator lives separately from the prey. In such cases, the two species are said to be involved in a predator-prey relationship.

Neutralism - this is a type of relationship in which none of the populations has any effect on the other: it does not affect the growth of its populations in equilibrium, and their density. In reality, however, it is quite difficult, by means of observations and experiments in natural conditions, to ascertain that two species are absolutely independent of each other.

Summarizing the consideration of formbiotic relationships, we can draw the following conclusions:

1) relations between living organisms are one of the main regulators of the abundance and spatial distribution of organisms in nature;

2) negative interactions between organisms appear at the initial stages of community development or in disturbed natural conditions; in newly formed or new associations, the probability of occurrence of strong negative interactions is greater than in old associations;

3) in the process of evolution and development of ecosystems, there is a tendency to reduce the role of negative interactions at the expense of positive ones that increase the survival of interacting species.

All these circumstances a person must take into account when carrying out measures to manage ecological systems and individual populations in order to use them in their own interests, and also to foresee the indirect consequences that may occur in this case.

4. Functioning of ecosystems

Energy in ecosystems.

Recall that an ecosystem is a collection of living organisms that continuously exchange energy, matter and information with each other and with the environment. Consider first the process of energy exchange.

energy defined as the ability to do work. The properties of energy are described by the laws of thermodynamics.

First law (beginning) of thermodynamics or law of energy conservation states that energy can change from one form to another, but it does not disappear and is not created anew.

Second law (beginning) of thermodynamics or law entropy states that in a closed system, entropy can only increase. Applied to energy in ecosystems the following formulation is convenient: the processes associated with the transformation of energy can occur spontaneously only under the condition that the energy passes from a concentrated form to a scattered one, that is, it degrades. there is entropy . The higher the order of the system, the lower its entropy.

Thus, any living system, including an ecosystem, maintains its vital activity due, firstly, to the presence in the environment of an excess of free energy (the energy of the Sun); secondly, the ability, due to the arrangement of its constituent components, to capture and concentrate this energy, and using it, to dissipate it into the environment.

Thus, first capturing and then concentrating energy with the transition from one trophic level to another provides an increase in orderliness, organization of a living system, that is, a decrease in its entropy.

Energy and productivity of ecosystems

So, life in an ecosystem is maintained due to the incessant passage through living matter of energy transmitted from one trophic level to another; while there is a constant transformation of energy from one form to another. In addition, during the transformation of energy, part of it is lost in the form of heat.

Then the question arises: in what quantitative ratios, proportions should the members of the community of different trophic levels in the ecosystem be among themselves in order to provide their need for energy?

The entire energy reserve is concentrated in the mass of organic matter - biomass, therefore the intensity of formation and destruction of organic matter at each level is determined by the passage of energy through the ecosystem (biomass can always be expressed in units of energy).

The rate of formation of organic matter is called productivity. Distinguish between primary and secondary productivity.

In any ecosystem, biomass is formed and destroyed, and these processes are entirely determined by the life of the lower trophic level - the producers. All other organisms only consume the organic matter already created by plants and, therefore, the overall productivity of the ecosystem does not depend on them.

High rates of biomass production are observed in natural and artificial ecosystems, where abiotic factors are favorable, and especially when additional energy is supplied from outside, which reduces the system's own life support costs. This additional energy can come in a variety of forms: for example, in a cultivated field, in the form of fossil fuel energy and work done by a person or animal.

Thus, to provide energy for all individuals of the community of living organisms in an ecosystem, a certain quantitative ratio is necessary between producers, consumers of different orders, detritus feeders and decomposers. However, for the life of any organisms, and hence the system as a whole, only energy is not enough, they must necessarily receive various mineral components, trace elements, organic substances necessary to build the molecules of living matter.

The cycle of elements in the ecosystem

Where do the components necessary for the construction of an organism initially come from in living matter? They are supplied to the food chain by the same producers. They extract inorganic minerals and water from the soil, CO2 from the air, and from the glucose formed during photosynthesis, with the help of biogens, they further build complex organic molecules - carbohydrates, proteins, lipids, nucleic acids, vitamins, etc.

In order for the necessary elements to be available to living organisms, they must be available all the time.

In this relationship, the law of conservation of matter is realized. It is convenient to formulate it as follows: atoms in chemical reactions never disappear, are not formed or turn into each other; they only rearrange to form different molecules and compounds (simultaneous absorption or release of energy). Because of this, atoms can be used in a wide variety of compounds and their supply is never depleted. This is what happens in natural ecosystems in the form of cycles of elements. In this case, two circulations are distinguished: large (geological) and small (biotic).

The water cycle is one of the grandiose processes on the surface of the globe. It plays a major role in linking the geological and biotic cycles. In the biosphere, water, continuously passing from one state to another, makes small and large cycles. Evaporation of water from the surface of the ocean, condensation of water vapor in the atmosphere and precipitation on the surface of the ocean form a small cycle. If water vapor is carried by air currents to land, the cycle becomes much more complicated. In this case, part of the precipitation evaporates and goes back into the atmosphere, the other part feeds rivers and reservoirs, but eventually returns to the ocean again with river and underground runoff, thereby completing a large cycle. An important property of the water cycle is that, interacting with the lithosphere, atmosphere and living matter, it links together all parts of the hydrosphere: the ocean, rivers, soil moisture, groundwater and atmospheric moisture. Water is an essential component of all living things. Groundwater, penetrating through the tissues of the plant in the process of transpiration, brings mineral salts necessary for the vital activity of the plants themselves.

Summarizing the laws of functioning of ecosystems, let us formulate once again their main provisions:

1) natural ecosystems exist at the expense of non-polluting free solar energy, the amount of which is excessive and relatively constant;

2) the transfer of energy and matter through the community of living organisms in the ecosystem occurs along the food chain; all types of living things in an ecosystem are divided according to the functions they perform in this chain into producers, consumers, detritus feeders and decomposers - this is the biotic structure of the community; the quantitative ratio of the number of living organisms between trophic levels reflects the trophic structure of the community, which determines the rate of passage of energy and matter through the community, that is, the productivity of the ecosystem;

3) due to their biotic structure, natural ecosystems maintain a stable state indefinitely without suffering from resource depletion and pollution by their own waste; obtaining resources and getting rid of waste occur within the cycle of all elements.

5. Human impact on the ecosystem.

The impact of a person on his natural environment can be considered in different aspects, depending on the purpose of studying this issue. From point of view ecology It is of interest to consider the human impact on ecological systems from the point of view of the correspondence or contradiction of human actions to the objective laws of the functioning of natural ecosystems. Based on the view of the biosphere as global ecosystem, all the variety of human activities in the biosphere leads to changes: the composition of the biosphere, the cycles and the balance of its constituent substances; energy balance of the biosphere; biota. The direction and degree of these changes are such that the man himself gave them the name ecological crisis. The modern ecological crisis is characterized by the following manifestations:

Gradual change in the planet's climate due to changes in the balance of gases in the atmosphere;

General and local (above the poles, separate areas of land) destruction of the biospheric ozone screen;

Pollution of the World Ocean with heavy metals, complex organic compounds, oil products, radioactive substances, saturation of water with carbon dioxide;

Rupture of natural ecological links between the ocean and land waters as a result of the construction of dams on rivers, leading to a change in solid runoff, spawning routes, etc.;

Atmospheric pollution with the formation of acid precipitation, highly toxic substances as a result of chemical and photochemical reactions;

Pollution of land waters, including river waters used for drinking water supply, with highly toxic substances, including dioxins, heavy metals, phenols;

Desertification of the planet;

Degradation of the soil layer, reduction of the area of ​​fertile land suitable for agriculture;

Radioactive contamination of certain territories in connection with the disposal of radioactive waste, man-made accidents, etc.;

Accumulation on the land surface of household garbage and industrial waste, in particular, practically non-degradable plastics;

Reduction of areas of tropical and boreal forests, leading to an imbalance in the gas atmosphere, including a reduction in the concentration of oxygen in the planet's atmosphere;

Pollution of underground space, including groundwater, which makes them unsuitable for water supply and threatens the still little-studied life in the lithosphere;

Massive and rapid, avalanche-like disappearance of species of living matter;

Deterioration of the living environment in populated areas, primarily urbanized areas;

General depletion and lack of natural resources for the development of mankind;

Changing the size, energy and biogeochemical role of organisms, reshaping of food chains, mass reproduction of certain types of organisms;

Violation of the hierarchy of ecosystems, an increase in systemic uniformity on the planet.

Conclusion

When, in the mid-sixties of the twentieth century, environmental problems were in the center of attention of the world community, the question arose: how much time does humanity have left? When will it begin to reap the rewards of neglect of its environment? Scientists have calculated: in 30-35 years. That time has come. We have witnessed a global environmental crisis provoked by human activities. At the same time, the past thirty years have not been in vain: a more solid scientific basis for understanding environmental problems has been created, regulatory bodies have been formed at all levels, numerous public environmental groups have been organized, useful laws and regulations have been adopted, and some international agreements have been reached.

However, it is the consequences, not the causes, that are being eliminated. attention to its own population explosion, erasing natural ecosystems from the face of the earth.

The main conclusion from the material discussed in the tutorial is quite clear: systems that contradict natural principles and laws are unstable . Attempts to preserve them are becoming increasingly costly and complex, and are doomed to fail anyway.

In order to make long-term decisions, it is necessary to pay attention to the principles that determine sustainable development, namely:

population stabilization;

transition to a more energy and resource-saving lifestyle;

development of environmentally friendly energy sources;

creation of low-waste industrial technologies;

waste recycling;

creation of a balanced agricultural production that does not deplete soil and water resources and does not pollute land and food;

conservation of biological diversity on the planet.

Bibliography

1. NebelB. Science about the environment: How the world works: In 2 volumes - M .: Mir, 1993.

2. Odum Yu. Ecology: In 2 volumes - M .: Mir, 1986.

3. ReimersN. F. Protection of nature and the human environment: Dictionary-reference book. - M.: Enlightenment, 1992. - 320 p.

4. StadnitskyG. V., Rodionov A.I. Ecology.

5. M.: Higher. school, 1988. - 272 p.

The main characteristics of ecosystems are: size, capacity, stability, reliability, self-healing, self-regulation and self-purification.

Ecosystem size- this is a space in which it is possible to carry out the processes of self-regulation and self-healing of all the components and elements that make up the ecosystem. There are microecosystems (for example, a puddle with its inhabitants, an anthill), mesoecosystems (forest, river, pond) and macroecosystems (tundra, desert, ocean).

Ecosystem capacity- this is the maximum population of one species that this ecosystem is able to maintain under certain environmental conditions for a long time. For example, the capacity of a site is the number of any wild or domestic animals that can live and breed on a unit area of ​​a site indefinitely.

Ecosystem resilience- this is the ability of an ecosystem to maintain its structure and functional features under the influence of external and internal factors, i.e. its ability to respond, proportional in magnitude to the force of the impact. Natural ecosystems are able to withstand various damaging effects and, when normal conditions are restored, return to a state close to the original. The density of one species or another decreases under unfavorable conditions, but under optimal conditions, fertility increases, the rate of growth and development, and the density of the species is restored. As a measure of the stability of ecosystems, their species diversity is often taken. Complex ecosystems are the most stable; complex trophic relationships are formed in them. Ecosystems with a simplified structure are extremely unstable; sharp fluctuations in the number of individual populations occur in them. For example, complex rainforest ecosystems are exceptionally stable, while in the Arctic the lack of species that can replace the main species as food leads to sharp fluctuations in populations.

Ecosystem Reliability- this is the ability of an ecosystem to relatively fully self-repair and self-regulate (during the successional or evolutionary period of its existence), i.e., to maintain its basic parameters in time and space. An important characteristic of reliability is the preservation of the structure, functions and direction of development of the ecosystem, without which this ecosystem is replaced by another, with a different structure, functions, and sometimes the direction of development. The simplest mechanism for maintaining the ecological reliability of an ecosystem is the replacement of a species that has retired for some reason with another, ecologically close one. If there is no such species in the ecosystem, then it is replaced by a more distant one.

Self-healing of natural ecosystems- this is an independent return of ecosystems to a state of dynamic equilibrium, from which they were brought out by the influence of any natural and anthropogenic factors.

Self-regulation of natural ecosystems- this is the ability of natural ecosystems to independently restore the balance of internal properties after any natural or anthropogenic impact using the principle of feedback between its components, i.e. an ecosystem is able to maintain its structure and functioning in a certain range of external conditions. Self-regulation is manifested, for example, in the fact that the number of individuals of each species included in the ecosystem is maintained at a certain, relatively constant level. Self-healing and self-regulation of natural ecosystems are based, in particular, on the ability of ecosystems to self-purify.

Self-purification of ecosystems- this is the natural destruction of a pollutant in the environment as a result of natural physical, chemical and biological processes occurring in it.

1. The physical factors of self-purification of water bodies are the dissolution, mixing and settling to the bottom of incoming pollution, as well as the effect of ultraviolet radiation from the Sun on bacteria and viruses. Under the influence of physical factors in zones with a temperate climate, the river clears itself already after 200-300 km from the place of pollution, and in the Far North - after 2000 km.

2. Chemical self-purification factors are the oxidation of organic and inorganic substances. To assess the chemical self-purification of a reservoir, indicators such as:

a) BOD - biological oxygen demand - is the amount of oxygen that is necessary for the oxidation of all organic matter by bacteria and protozoa (usually in 5 days BITKs) in 1 liter of contaminated water;

b) COD - chemical oxygen demand - the amount of oxygen (ml/l or g/l of water) required for the complete oxidation of pollutants with the help of chemical reagents (usually potassium bichromate).

3. Biological self-purification factors - this is the cleaning of water bodies with the help of algae, molds and yeasts, oysters, amoebas and other living organisms. For example, each mollusk filters more than 30 liters of water per day, purifying it from all kinds of impurities.

Natural ecosystems function according to three main principles:

The first principle of the functioning of natural ecosystems - obtaining resources and getting rid of waste occurs within the cycle of all elements (harmonizes with the law of conservation of mass). The cycle of biogenic elements, due to the synthesis and decay of organic substances in the ecosystem, which is based on the reaction of photosynthesis, is called biotic cycle of matter. In addition to biogenic elements, the most important mineral elements for the biota and many different compounds are involved in the biotic cycle. Therefore, the entire cyclic process of chemical transformations caused by biota is also called biogeochemical cyclevolume.

The ecosystem includes all living organisms (plants, animals, fungi and microorganisms), which, to one degree or another, interact with each other and their inanimate environment (climate, soil, sunlight, air, atmosphere, water, etc.) .).

The ecosystem has no definite size. It can be as big as a desert or a lake, or as small as a tree or a puddle. Water, temperature, plants, animals, air, light and soil all interact together.

The essence of the ecosystem

In an ecosystem, each organism has its own place or role.

Consider the ecosystem of a small lake. In it, you can find all kinds of living organisms, from microscopic to animals and plants. They depend on things like water, sunlight, air, and even the amount of nutrients in the water. (Click to learn more about the five basic needs of living organisms).

Lake ecosystem diagram

Any time an "outsider" (a living being(s) or an external factor such as rising temperatures) is introduced into an ecosystem, catastrophic consequences can occur. This is because the new organism (or factor) is capable of distorting the natural balance of interaction and causing potential harm or destruction to the non-native ecosystem.

Generally, the biotic members of an ecosystem, together with their abiotic factors, depend on each other. This means the absence of one member or one abiotic factor can affect the entire ecological system.

If there is not enough light and water, or if the soil is low in nutrients, the plants may die. If the plants die, the animals that depend on them are also at risk. If animals that depend on plants die, other animals that depend on them will also die. The ecosystem in nature works the same way. All of its parts must function together to maintain balance!

Unfortunately, ecosystems can be destroyed by natural disasters such as fires, floods, hurricanes, and volcanic eruptions. Human activity also contributes to the destruction of many ecosystems and.

Main types of ecosystems

Ecological systems have indefinite dimensions. They are able to exist in a small space, for example, under a stone, a rotting tree stump or in a small lake, and also occupy large areas (like the entire tropical forest). From a technical point of view, our planet can be called one huge ecosystem.

Diagram of a small rotting stump ecosystem

Types of ecosystems depending on the scale:

• microecosystem- a small scale ecosystem like a pond, puddle, tree stump, etc.
• mesoecosystem- an ecosystem, such as a forest or a large lake.
• Biome. A very large ecosystem or collection of ecosystems with similar biotic and abiotic factors, such as an entire rainforest with millions of animals and trees, and many different water bodies.

Ecosystem boundaries are not marked with clear lines. They are often separated by geographical barriers such as deserts, mountains, oceans, lakes, and rivers. Since boundaries are not strictly fixed, ecosystems tend to merge with each other. This is why a lake can have many smaller ecosystems with their own unique characteristics. Scientists call this mixing "Ecoton".

Types of ecosystems by type of occurrence:

In addition to the above types of ecosystems, there is also a division into natural and artificial ecological systems. A natural ecosystem is created by nature (forest, lake, steppe, etc.), and an artificial one is created by man (garden, garden plot, park, field, etc.).

Ecosystem types

There are two main types of ecosystems: aquatic and terrestrial. Every other ecosystem in the world falls into one of these two categories.

Terrestrial ecosystems

Terrestrial ecosystems can be found anywhere in the world and are subdivided into:

forest ecosystems

These are ecosystems that have an abundance of vegetation or a large number of organisms living in a relatively small space. Thus, the density of living organisms in forest ecosystems is quite high. A small change in this ecosystem can affect its entire balance. Also, in such ecosystems you can find a huge number of representatives of the fauna. In addition, forest ecosystems are divided into:

• Tropical evergreen forests or tropical rainforests: receiving an average rainfall of more than 2000 mm per year. They are characterized by dense vegetation dominated by tall trees located at different heights. These territories are a refuge for various species of animals.
• Tropical deciduous forests: Along with a huge variety of tree species, shrubs are also found here. This type of forest is found in quite a few parts of the world and is home to a wide variety of flora and fauna.
• : They have quite a few trees. It is dominated by evergreen trees that renew their foliage throughout the year.
• Broad-leaved forests: They are located in humid temperate regions that have sufficient rainfall. During the winter months, the trees shed their leaves.
• : Located directly in front, the taiga is defined by evergreen conifers, sub-zero temperatures for six months and acidic soils. In the warm season, you can meet a large number of migratory birds, insects and.

desert ecosystem

Desert ecosystems are located in desert regions and receive less than 250 mm of precipitation per year. They occupy about 17% of the entire land mass of the Earth. Due to the extremely high air temperature, poor access to and intense sunlight, and not as rich as in other ecosystems.

grassland ecosystem

Grasslands are located in the tropical and temperate regions of the world. The area of ​​the meadow mainly consists of grasses, with a small number of trees and shrubs. The meadows are inhabited by grazing animals, insectivores and herbivores. There are two main types of meadow ecosystems:

• : Tropical grasslands that have a dry season and are characterized by singly growing trees. They provide food for a large number of herbivores, and are also a hunting ground for many predators.
• Prairies (temperate grasslands): This is an area with a moderate grass cover, completely devoid of large shrubs and trees. In the prairies, forbs and tall grass are found, and arid climatic conditions are also observed.
• Steppe meadows: Territories of dry grasslands, which are located near semi-arid deserts. The vegetation of these grasslands is shorter than in the savannas and prairies. Trees are rare, and usually found on the banks of rivers and streams.

mountain ecosystems

The highlands provide a diverse range of habitats where a large number of animals and plants can be found. At altitude, harsh climatic conditions usually prevail, in which only alpine plants can survive. Animals that live high in the mountains have thick fur coats to protect them from the cold. The lower slopes are usually covered with coniferous forests.

Aquatic ecosystems

Aquatic ecosystem - an ecosystem located in an aquatic environment (for example, rivers, lakes, seas and oceans). It includes aquatic flora, fauna, and water properties, and is divided into two types: marine and freshwater ecological systems.

marine ecosystems

They are the largest ecosystems that cover about 71% of the Earth's surface and contain 97% of the planet's water. Sea water contains a large amount of dissolved minerals and salts. The marine ecological system is divided into:

• Oceanic (relatively shallow part of the ocean, which is located on the continental shelf);
• Profundal zone (deep water area not penetrated by sunlight);
• Bental region (area inhabited by benthic organisms);
• intertidal zone (a place between low and high tides);
• Estuaries;
• Coral reefs;
• Salt marshes;
• Hydrothermal vents where chemosynthetic feeders.

Many types of organisms live in marine ecosystems, namely: brown algae, corals, cephalopods, echinoderms, dinoflagellates, sharks, etc.

Freshwater ecosystems

Unlike marine ecosystems, freshwater ecosystems cover only 0.8% of the Earth's surface and contain 0.009% of the world's total water supply. There are three main types of freshwater ecosystems:

• Stagnant: Waters where there is no current, such as pools, lakes or ponds.
• Flowing: Fast moving waters such as streams and rivers.
• Wetlands: places where the soil is permanently or intermittently flooded.

Freshwater ecosystems are home to reptiles, amphibians and about 41% of the world's fish species. Fast moving waters usually contain a higher concentration of dissolved oxygen, thereby supporting more biodiversity than stagnant ponds or lakes.

Structure, components and factors of the ecosystem

An ecosystem is defined as a natural functional ecological unit consisting of living organisms (biocenosis) and their inanimate environment (abiotic or physico-chemical), which interact with each other and create a stable system. Pond, lake, desert, pasture, meadow, forest, etc. are common examples of ecosystems.

Each ecosystem consists of abiotic and biotic components:

Ecosystem structure

Abiotic components

Abiotic components are unrelated factors of life or the physical environment that influence the structure, distribution, behavior and interaction of living organisms.

Abiotic components are mainly represented by two types:

• climatic factors which include rain, temperature, light, wind, humidity, etc.
• Edaphic factors, including soil acidity, topography, mineralization, etc.

Importance of abiotic components

The atmosphere provides living organisms with carbon dioxide (for photosynthesis) and oxygen (for respiration). The processes of evaporation, transpiration and occur between the atmosphere and the surface of the Earth.

Solar radiation heats the atmosphere and evaporates water. Light is also essential for photosynthesis. provides plants with energy for growth and metabolism, as well as organic products to feed other life forms.

Most living tissue is made up of a high percentage of water, up to 90% or more. Few cells are able to survive if the water content falls below 10%, and most of them die when the water content is less than 30-50%.

Water is the medium through which mineral food products enter plants. It is also essential for photosynthesis. Plants and animals get water from the Earth's surface and soil. The main source of water is atmospheric precipitation.

Biotic Components

Living things, including plants, animals, and microorganisms (bacteria and fungi) present in an ecosystem are biotic components.

Based on their role in the ecological system, biotic components can be divided into three main groups:

• Producers produce organic substances from inorganic substances using solar energy;
• Consumers feed on ready-made organic substances produced by producers (herbivores, predators, etc.);
• Reducers. Bacteria and fungi that destroy dead organic compounds of producers (plants) and consumers (animals) for nutrition, and emit simple substances (inorganic and organic) into the environment, formed as by-products of their metabolism.

These simple substances are re-produced as a result of cyclical exchange of substances between the biotic community and the abiotic environment of the ecosystem.

Ecosystem levels

To understand the layers of an ecosystem, consider the following figure:

Ecosystem Tier Diagram

Individual

An individual is any living being or organism. Individuals do not breed with individuals from other groups. Animals, unlike plants, are usually included in this concept, since some representatives of the flora can interbreed with other species.

In the diagram above, you can see that the goldfish interacts with the environment and will breed exclusively with members of its own species.

population

A population is a group of individuals of a given species that live in a particular geographic area at a given time. (An example is the goldfish and representatives of its species). Note that a population includes individuals of the same species that may have various genetic differences such as coat/eye/skin color and body size.

Community

The community includes all living organisms in a certain area at a given time. It may contain populations of living organisms of different species. In the diagram above, notice how goldfish, salmon, crabs, and jellyfish coexist in a particular environment. A large community usually includes biodiversity.

Ecosystem

An ecosystem includes communities of living organisms interacting with the environment. At this level, living organisms depend on other abiotic factors such as rocks, water, air, and temperature.

Biome

In simple terms, it is a collection of ecosystems that have similar characteristics with their abiotic factors adapted to the environment.

Biosphere

When we look at different biomes, each of which transitions into another, a huge community of people, animals and plants is formed, living in certain habitats. is the totality of all ecosystems present on Earth.

Food chain and energy in an ecosystem

All living beings must eat to get the energy they need to grow, move, and reproduce. But what do these living organisms eat? Plants get their energy from the sun, some animals eat plants and others eat animals. This ratio of feeding in an ecosystem is called the food chain. Food chains generally represent the sequence of who feeds on whom in a biological community.

The following are some of the living organisms that can fit in the food chain:

food chain diagram

The food chain is not the same as. The trophic web is a combination of many food chains and is a complex structure.

Energy transfer

Energy is transferred along food chains from one level to another. Part of the energy is used for growth, reproduction, movement and other needs, and is not available for the next level.

Shorter food chains store more energy than long ones. The spent energy is absorbed by the environment.