Abstract ecological niches

ecological niche - the place of the species in the biogeocenosis, determined by its biotic potential and the totality of environmental factors to which it is adapted. This is not only the physical space occupied by the organism, but also its functional role in the community (position in the food chain), and its place relative to external factors.

There are 3 components in the structure of the ecological niche:

1. Spatial niche (habitat) - "address" of the organism;
2. Trophic niche - the characteristic features of nutrition and the role of the species in the community - "profession";
3. A multidimensional (hyperspace) ecological niche is the range of all conditions under which an individual or population lives and reproduces itself.

Distinguish fundamental (potential) niche, which the organism or species could occupy in the absence of competition, predators, in which abiotic conditions are optimal; and realized niche- the actual range of conditions for the existence of an organism, which is less than or equal to the fundamental niche.

The rule of obligation to fill the ecological niche.
An empty ecological niche is always and necessarily naturally filled. In saturated biogeocenoses, life resources are used most fully - in them all ecological niches are occupied. In unsaturated biogeocenoses, vital resources are partially utilized; they are characterized by the presence of free ecological niches.

Environmental duplication- occupation of the vacated ecological niche by another species capable of performing the same functions in the community as the extinct species. It follows from this that knowing the distribution of species according to the ecological niche in the community and the parameters of each ecological niche, it is possible to describe in advance the species that can occupy one or another niche if it is released.

Ecological diversification- the phenomenon of division of the ecological niche as a result of interspecific competition. It is carried out according to three parameters:
- by spatial arrangement
- by diet
- according to the distribution of activity over time.
As a result of diversification, a shift in characters occurs - individuals of two closely related species are more similar to each other in those parts of the ranges where they occur separately than in areas of joint residence.

Characteristics of an ecological niche:
1. Width
2. Overlapping this niche with neighboring

Ecological niche width- a relative parameter, which is estimated by comparison with the width of the ecological niche of other species. Eurybionts generally have wider ecological niches than stenobionts. However, the same ecological niche can have a different width in different directions: for example, in terms of spatial distribution, food connections, etc.

Covering the ecological niche occurs when different species cohabitate using the same resources. The overlap can be total or partial, according to one or more parameters of the ecological niche.

If the ecological niches of organisms of two species are very different from each other, then these species that have the same habitat do not compete with each other (Fig. 3).

If ecological niches partially overlap (Fig. 2), then their coexistence will be possible due to the presence of specific adaptations for each species.

If the ecological niche of one species includes the ecological niche of another (Fig. 1), then intense competition arises, the dominant competitor will push its rival to the periphery of the fitness zone.

Competition has important environmental consequences. In nature, individuals of each species are simultaneously subjected to interspecific and intraspecific competition. Interspecific in its consequences is opposite to intraspecific, since it narrows the area of ​​habitats and the quantity and quality of the necessary environmental resources.

Intraspecific competition promotes the territorial distribution of species, that is, the expansion of the spatial ecological niche. The end result is the ratio of interspecific and intraspecific competition. If interspecific competition is greater, then the range of a given species decreases to a territory with optimal conditions and, at the same time, the specialization of the species increases.

Any living organism is adapted (adapted) to certain environmental conditions. Changing its parameters, their going beyond certain boundaries suppresses the vital activity of organisms and can cause their death. The requirements of one or another organism to the environmental factors determine the range (distribution boundaries) of the species to which the organism belongs, and within the range - specific habitats.

habitat- a spatially limited set of environmental conditions (abiotic and biotic), providing the entire cycle of development and reproduction of individuals (or groups of individuals) of the same species. This, for example, is a hedge, a pond, a grove, a rocky shore, etc. At the same time, within the habitat, places with special conditions can be distinguished (for example, under the bark of a rotting tree trunk in a grove), in some cases called microhabitats.

For the overall characterization of the physical space occupied by organisms of a species, their functional role in the biotic habitat, including the mode of nutrition (trophic status), lifestyle and relationships with other species, the American scientist J. Grinnell in 1928. the term "ecological niche" was introduced. Its modern definition is as follows.

An ecological niche is a set

· All the requirements of the organism to the conditions of the environment (composition and modes of environmental factors) and the place where these requirements are met;

· The whole set of biological characteristics and physical parameters of the environment that determine the conditions for the existence of a particular species, its transformation of energy, the exchange of information with the environment and their own kind.

Thus, the ecological niche characterizes the degree of biological specialization of a species. It can be argued that the habitat of an organism is its “address”, while the ecological niche is its “occupation”, or “lifestyle”, or “profession”. For example, the thrush's habitat includes forests, parks, meadows, orchards, kitchen gardens, and yards. Its ecological niche includes such factors as nesting and incubation of chicks on trees, feeding on insects, earthworms and fruits, transferring fruit and berry seeds with their excrement.

Ecological specificity of species is emphasized axiom of ecological adaptability: each species is adapted to a strictly defined, specific set of conditions of existence for it - an ecological niche.

Since the species of organisms are ecologically individual, they also have specific ecological niches.

Thus, there are as many species of living organisms on Earth as there are ecological niches.

Organisms that lead a similar way of life, as a rule, do not live in the same places due to interspecific competition. According to the established in 1934. Soviet biologist G.F. Gause (1910-1986) principle of competitive mutual exclusion: two species do not occupy the same ecological niche.

It also works in nature rule of obligatory filling of ecological niches: The empty ecological niche will always and will definitely be filled.

Folk wisdom formulated these two postulates as follows: “Two bears cannot get along in one lair” and “Nature does not tolerate emptiness.”

These systematic observations are realized in the formation of biotic communities and biocenoses. Ecological niches are always filled, although this sometimes takes a considerable amount of time. The common expression “free ecological niche” means that in a certain place there is little competition for any type of food and there is an insufficiently used amount of other conditions for a certain species that is included in similar natural systems, but is absent in the one under consideration.

It is especially important to take into account natural patterns when trying to intervene in an existing (or prevailing in a certain place) situation in order to create more favorable conditions for a person. So, biologists have proved the following: in cities, with an increase in the contamination of the territory with food waste, the number of crows increases. When trying to improve the situation, for example, by physically destroying them, the population may face the fact that the ecological niche in the urban environment, vacated by ravens, will be quickly occupied by a species that has a close ecological niche, namely, rats. Such a result can hardly be considered a victory.

Each biological species plays a specific role in its ecosystem. Ecologists have proven that some species, called key species, drastically affect many other organisms in the ecosystem. The disappearance of a key species from an ecosystem can provoke a whole cascade of sharp drops in population size and even the extinction of those species that depended on it in one form or another.

An example of a key species is the earth turtle. The earth turtle lives on sandy uplands in Florida and other southern regions of the United States. This slow, dinner plate-sized animal digs a hole up to 9 meters deep. In the hot, inhospitable ecosystems of the US South, these burrows provide shelter from the heat for nearly 40 other animal species such as the gray fox, opossum, indigo snake and many insects. Where the earth tortoise has been extirpated or driven to the brink of extinction by numerous hunters for its exquisite meat, many species dependent on the tortoise have ceased to exist.

Ecological niches of all living organisms are divided into specialized and general. This division depends on the main food sources of the respective species, the size of the habitat, and sensitivity to abiotic environmental factors.

Specialized niches. Most species of plants and animals are adapted to exist only in a narrow range of climatic conditions and other environmental characteristics, they feed on a limited set of plants or animals. Such species have a specialized niche that determines their habitat in the natural environment.

So, the giant panda has a highly specialized niche, because it feeds on 99% of leaves and bamboo shoots. The mass destruction of certain types of bamboo in areas of China where the panda lived led this animal to extinction.

The variety of species and forms of flora and fauna that exists in tropical rainforests is associated with the presence of a number of specialized ecological niches in each of the clearly defined tiers of forest vegetation. Therefore, the intensive deforestation of these forests has caused the extinction of millions of specialized plant and animal species.

General niches. Species with common niches are characterized by easy adaptability to changes in environmental environmental factors. They can successfully exist in a variety of places, eat a variety of foods and withstand sharp fluctuations in natural conditions. Flies, cockroaches, mice, rats, humans, etc. have common ecological niches.

For species that have common ecological niches, there is a significantly lower threat of extinction than for those with specialized niches.

As long as an ecosystem has enough common resources, different species consume them together. However, if two or more species in the same ecosystem begin to consume the same scarce resource, they will find themselves in a relationship interspecies competition.

A species gains an advantage in interspecific competition if it is characterized by

More intensive reproduction;

Adaptation to a wider range of temperature, light, water salinity or

concentrations of certain harmful substances;

Depriving a competitor of access to a resource.

Ways to reduce interspecific competition:

Relocation to another area;

Switching to more inaccessible or difficult to digest food;

Change in time and place of foraging.

The most characteristic form of species interaction in food chains and networks is predation, in which an individual of one species (predator) feeds on organisms (or parts of organisms) of another species (prey), and the predator lives separately from the prey. These two organisms are involved in a predator-prey relationship.

Prey species use a range of defense mechanisms to avoid becoming easy prey for predators:

The ability to run or fly fast;

Possession of thick skin or shell;

Possession of a protective coloration or a way to change color;

The ability to release chemicals with an odor or taste that repels or even poisons a predator.

Predators also have several ways to prey:

The ability to run fast (for example, a cheetah);

Hunting in packs (eg spotted hyenas, lions, wolves);

Capturing as victims predominantly sick, wounded and other inferior individuals;

The fourth way to provide yourself with animal food is the way that a reasonable person went, the way of inventing hunting tools and traps, as well as domesticating animals.

It often happens that two different kinds of organisms directly interact in such a way that they bring mutual benefit to each other. Such mutually beneficial interspecies interactions are called mutualism. For example, flowers and pollinating insects.

Commensalism is characterized by the fact that one of the two species benefits from interspecies interaction, while the other is practically not reflected in any way (neither positively nor negatively). For example, crustaceans in the jaws of a whale.

The concept of the so-called saturated and unsaturated biocenoses is closely related to the concept of an ecological niche. The former are ecosystems in which life resources at each stage of biomass and energy conversion are used to the fullest extent. When vital resources are partially utilized, biocenoses can be called unsaturated. They are characterized by the presence of free ecological niches. However, this is highly arbitrary, since ecological niches cannot exist on their own, regardless of the species occupying them.

Unused reserves, unrealized opportunities for intensifying the flow of substances and energy are available in almost any biogeocenosis (otherwise their constant development in time and space could not be carried out!), All biocenoses can conditionally be considered unsaturated. The lower the saturation of the biocenosis, the easier it is to introduce new species into its composition and more successfully acclimatize.

A very important property of biogeocenoses, as biological systems, is their self-regulation - the ability to withstand high loads of adverse external influences, the ability to return to a conditionally initial state after significant violations of their structure (Le Chatelier's principle). But above a certain threshold of influence, the self-healing mechanisms do not work, and the biogeocenosis is irreversibly destroyed.

In the course of the evolutionary process, the global ecological niche of the biosphere expanded. When a species exhausted the genetically conditioned potential for the development of the ecological niche where it was born, it either forced out other species, conquering their ecological niches, or mastered a previously lifeless niche, genetically reorganizing itself under it, possibly generating the new kind organisms.

At some stage in the development of the biosphere, a species of Homo sapiens arose, the representatives of which are all mankind, despite all the diversity of races, peoples, nationalities, tribes.

The potential for the development of adults of each biological species for all the qualities of an individual is genetically determined, although it may not be revealed, not filled with real content if the environmental conditions do not favor it. In relation to the population, genetic conditioning and the potential for its development are subject to probabilistic predeterminations, reflected in the statistical patterns of what happened. This fully applies to humans - a biological species that carries the largest absolute and relative volume (compared to other types of living organisms of the Earth's biosphere) of non-genetically determined behavioral information, providing the greatest flexibility of behavior in a rapidly changing environment.

1. General provisions. Living beings, both plants and animals, are many and varied. There is no doubt that this diversity and abundance of organisms is determined by environmental factors. Thus, each species occupies a strictly assigned place in the geographic space with a specific set of physical and chemical parameters. However, the position of a species depends not only on abiotic environmental factors, but also on the relationships of a given organism with other organisms, both within its own species and with representatives of other species. The wolf will not live in those geographic areas, even if the set of abiotic factors is quite acceptable for him, if there is no food resource for him here. Therefore, the place that a species occupies in a particular habitat must be determined not only by the territory, but also be associated with the need for food and the function of reproduction. Each of the species, as well as a specific organism, in a community (biocenosis) has its own time of stay and its place, which distinguish it from other species.

Thus, we meet with different concepts. First, this range species - the distribution of the species in geographic space (the geographical aspect of the species), secondly, species habitat(habitat or biotope) is the type of geographic space in terms of a set of physical and chemical parameters and (or) biotic characteristics where the species lives and, thirdly, ecological niche, implying something more than just the place where this species lives. A species can occupy a number of different habitats in different parts of its range.

The best and most accurate comparative definition of the ecological niche and environment was given by the French ecologists R. Wiebert and C. Lagler: Wednesday is the address where the given organism resides, while niche additionally indicates the type of his occupation in this place, his profession.

Some ecologists are more willing to use the term "habitat," which is almost synonymous with "habitat," and the two terms often overlap, but remember that "habitat" refers only to the space in which a species occurs. In this sense, this term is very close to the concept of the range of a species.

2. habitat. This is a piece of land or a reservoir occupied by a population of one species or part of it and having all the necessary conditions for its existence (climate, topography, soil, nutrients). The habitat of a species is a set of sites that meet its ecological requirements within the species range. Thus, a habitat is nothing but a component of an ecological niche. According to the breadth of the use of habitats, they distinguish stenotopic and eurytopic organisms, i.e. organisms that occupy specific spaces with a specific set of environmental factors, and organisms that exist in a wide range of environmental factors (cosmopolitans). If we are talking about the habitat of a community of organisms or the place of a biocenosis, then the term "biotope" is more often used. Location has another synonym ecotope– geographical space characterized by a specific set of environmental parameters. In this case, the population of any species living in a given space is called ecotype.

The term "habitat" can be applied both to specific organisms and to communities as a whole. We can point to a meadow as a single habitat for various herbs and animals, although both herbs and animals occupy different ecological niches. But this term should never replace the concept of "ecological niche".

Habitat can refer to a complex of interconnected some living and non-living characteristics of a geographic space. For example, the habitat of aquatic insects of the smooth bug and the float is shallow areas of lakes covered with vegetation. These insects occupy the same habitat, but have different trophic chains (smooth is an active predator, while float feeds on decaying vegetation), which distinguishes the ecological niches of these two species.

Habitat can also refer only to the biotic environment. This is how bacilli and bacteria live inside other organisms. Lice live in the hairline of the host. Some mushrooms are associated with a particular type of forest (boletus). But the habitat can also be represented by a purely physical-geographical environment. You can point to the tidal coast of the sea, where such a variety of organisms live. It can be a desert, and a separate mountain, dunes, a stream and a river, a lake, etc.

3. ecological niche concept, according to Y. Oduma, more capacious. Ecological niche, as shown by an English scientist C. Elton(1927), includes not only the physical space occupied by the organism, but also the functional role of the organism in the community. Elton distinguished niches as the position of a species in relation to other species in a community. Ch. Elton's idea that a niche is not a synonym for a habitat has received wide recognition and distribution. The trophic position, way of life, connections with other organisms, etc. are very important for the organism. and its position relative to the gradients of external factors as conditions of existence (temperature, humidity, pH, soil composition and type, etc.).

These three aspects of the ecological niche (space, the functional role of the organism, external factors) can be conveniently referred to as spatial niche(niche place) trophic niche(functional niche), in the understanding of Ch. Elton, and multidimensional niche(the whole volume and set of biotic and abiotic characteristics are taken into account, hypervolume). The ecological niche of an organism depends not only on where it lives, but also includes the total amount of its environmental requirements. The body not only experiences the action of environmental factors, but also makes its own demands on them.

4. The modern concept of ecological niche formed on the basis of the model proposed J. Hutchinson(1957). According to this model, an ecological niche is a part of an imaginary multidimensional space (hypervolume), individual dimensions of which correspond to the factors necessary for the normal existence and reproduction of an organism. Hutchinson's niche, which we will call multidimensional (hyperspace), can be described using quantitative characteristics and operated with it using mathematical calculations and models. R. Whittaker(1980) defines an ecological niche as the position of a species in a community, implying that the community is already associated with a specific biotope, i.e. with a certain set of physical and chemical parameters. Therefore, an ecological niche is a term used to denote the specialization of a population of a species within a community. Groups of species in a biocenosis with similar functions and niches of the same size are called guilds. Species that occupy the same niche in different geographical areas are called environmental equivalents.

5. Individuality and originality of ecological niches. No matter how close in habitat organisms (or species in general) are, no matter how close their functional characteristics in biocenoses are, they will never occupy the same ecological niche. Thus, the number of ecological niches on our planet is uncountable. Figuratively, one can imagine a human population, all individuals of which have only their own unique niche. It is impossible to imagine two absolutely identical people with absolutely identical morphophysiological and functional characteristics, including such as mental, attitude towards their own kind, an absolute need for the type and quality of food, sexual relations, norms of behavior, etc. But the individual niches of different people can overlap in certain ecological parameters. For example, students can be linked by one university, specific teachers, and at the same time, they can differ in their behavior in society, in the choice of food, biological activity, etc.

6. Measuring ecological niches. To characterize a niche, two standard measurements are usually used - niche width and niche overlap with neighboring niches.

Niche width refers to gradients or the range of some environmental factor, but only within a given hyperspace. The width of a niche can be determined by the intensity of illumination, by the length of the trophic chain, by the intensity of the action of some abiotic factor. The overlapping of ecological niches means overlapping along the width of niches and overlapping of hypervolumes.

7. Types of ecological niches. There are two main types of ecological niches. First, this fundamental(formal) niche - the largest "abstract inhabited hypervolume”, where the action of environmental factors without the influence of competition ensures the maximum abundance and functioning of the species. However, the species experiences constant changes in environmental factors within its range. In addition, as we already know, an increase in the action of one factor can change the relation of a species to another factor (a consequence of Liebig's law), and its range can change. The action of two factors at the same time can change the attitude of the species to each of them specifically. There are always biotic restrictions (predation, competition) within ecological niches. All these actions lead to the fact that in reality the species occupies an ecological space that is much smaller than the hyperspace of the fundamental niche. In this case, we are talking about implemented niche, i.e. real niche.

8 . Principle VanderMeer and Gause. J.H. Vandermeer (1972) greatly expanded the concept of Hutchinson's realized niche. He came to the conclusion that if N interacting species coexist in this particular habitat, then they will occupy completely different realized ecological niches, the number of which will be equal to N. This observation is called the Vandermeer principle.

Competitive interaction can concern both space, nutrients, the use of light (trees in the forest), and the process of fighting for a female, for food, as well as dependence on a predator, susceptibility to disease, etc. Usually, the toughest competition is observed at the interspecific level. It can lead to the replacement of a population of one species by a population of another species, but it can also lead to an equilibrium between two species (usually this the balance of nature is established in the predator-prey system). Extreme cases are the displacement of one species by another outside the given habitat. There are cases when one species displaces another in the trophic chain and forces it to switch to the use of other food. Observation of the behavior of closely related organisms with a similar way of life and similar morphology shows that such organisms try never to live in the same place. This observation was made Joseph Grinell in 1917-1928, who studied the life of California mockingbirds. Grinell actually introduced the concept "niche", but did not introduce into this concept the distinction between niche and habitat.

If closely related organisms live in the same water and in the same place, then they will either use different food resources or lead an active lifestyle at different times (night, day). This ecological separation of closely related species is called principle of competitive exclusion or Gause principle named after the Russian biologist who experimentally demonstrated the operation of this principle in 1932. In his conclusions, Gause used Elton's concept of the position of a species in a community depending on other species.

9. niche space. The ecological niches of species are more than the relation of a species to a single environmental gradient. Many signs or axes of multidimensional space (hypervolume) are very difficult to measure or cannot be expressed by linear vectors (for example, behavior, addiction, etc.). Therefore, it is necessary, as rightly noted by R. Whittaker (1980), to move from the concept of the niche axis (remember the width of the niche in terms of one or more parameters) to the concept of its multidimensional definition, which will reveal the nature of species relationships with their full range of adaptive relationships .

If a niche is a "place" or "position" of a species in a community according to Elton's concept, then it is right to give it some measurements. According to Hutchinson, a niche can be defined by a number of environmental variables within a community to which a species must be adapted. These variables include both biological indicators (for example, food size) and non-biological ones (climatic, orographic, hydrographic, etc.). These variables can serve as axes along which a multidimensional space is recreated, which is called ecological space or niche space. Each of the species can adapt or be resistant to some range of values ​​of each variable. The upper and lower limits of all these variables delineate the ecological space that a species can occupy. This is the fundamental niche in Hutchinson's understanding. In a simplified form, this can be imagined as an "n-sided box" with sides corresponding to the stability limits of the view on the axes of the niche.

By applying a multidimensional approach to the space of a community niche, we can find out the position of species in space, the nature of the response of a species to exposure to more than one variable, the relative sizes of niches.

Ministry of Education and Science Russian Federation

Federal State Budgetary Educational Institution

higher professional education

"Siberian State Industrial University"

Department of Ecology

discipline: Social ecology

on the topic: "Ecological niche"

Completed:

Student gr. ERM-12

Belichenko Ya.V.

Checked:

Assoc. Dugin

Novokuznetsk

Introduction………………………………………………………..……………….…. 3

1. Ecological niche…………………………….…………………………........... 4

1.1. The concept of ecological niche……………….…………………………. four

1.2. Width and overlap of niches…………………….……………………. 5

1.3. Niche Evolution……………………………………….……………….…10

2. Aspects of ecological niche…………………………….……………….….….12

3. The modern concept of ecological niche……………..………...................... 13

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

List of used literature………………………………….………...... 19

Introduction

In this paper, the topic "Ecological niches" is considered. An ecological niche is a place occupied by a species (more precisely, its population) in a community, a complex of its biocenotic relationships and requirements for abiotic environmental factors. This term was introduced in 1927 by Charles Elton. The ecological niche is the sum of factors for the existence of a given species, the main of which is its place in the food chain.

An ecological niche is a place occupied by a species in a community. The interaction of a given species (population) with partners in the community to which it belongs as a member determines its place in the cycle of substances due to food and competitive links in the biocenosis. The term "Ecological niche" was proposed by the American scientist J. Grinnell (1917). The interpretation of an ecological niche as the position of a species for the purpose of feeding one or more biocenoses was given by the English ecologist C. Elton (1927). Such an interpretation of the concept of ecological niche makes it possible to give a quantitative description of the ecological niche for each species or for its individual populations. To do this, the abundance of the species (number of individuals or biomass) is compared in the coordinate system with indicators of temperature, humidity, or any other environmental factor.

In this way, it is possible to single out the optimum zone and the limits of the deviations tolerated by the species - the maximum and minimum of each factor or set of factors. As a rule, each species occupies a certain ecological niche, for the existence in which it is adapted by the entire course of evolutionary development. The place occupied by a species (its population) in space (spatial ecological niche) is more often called a habitat.

Let's take a closer look at ecological niches.

1. ecological niche

Any kind of organisms is adapted for certain conditions of existence and cannot arbitrarily change the habitat, diet, feeding time, breeding place, shelter, etc. The whole complex of relations to such factors determines the place that nature has allocated to a given organism, and the role that it must play in the general life process. All this is combined in the concept of an ecological niche.

1.1. The concept of an ecological niche

An ecological niche is understood as the place of an organism in nature and the whole way of its life activity, its life status, fixed in its organization and adaptations.

At different times, different meanings were attributed to the concept of an ecological niche. At first, the word "niche" denoted the basic unit of distribution of a species within the space of an ecosystem, dictated by the structural and instinctive limitations of a given species. For example, squirrels live in trees, moose live on the ground, some bird species nest on branches, others in hollows, etc. Here the concept of an ecological niche is interpreted mainly as a habitat, or a spatial niche. Later, the term "niche" was given the meaning of "the functional status of an organism in a community." This mainly concerned the place of a given species in the trophic structure of the ecosystem: the type of food, the time and place of feeding, who is the predator for this organism, etc. This is now called a trophic niche. Then it was shown that a niche can be considered as a kind of hypervolume in a multidimensional space built on the basis of environmental factors. This hypervolume limited the range of factors in which a given species could exist (the hyperspace niche).

That is, in the modern understanding of the ecological niche, at least three aspects can be distinguished: the physical space occupied by an organism in nature (habitat), its relationship to environmental factors and living organisms adjacent to it (connections), as well as its functional role in the ecosystem. All these aspects are manifested through the structure of the organism, its adaptations, instincts, life cycles, life “interests”, etc. The right of an organism to choose its ecological niche is limited by rather narrow limits assigned to it from birth. However, its descendants can claim other ecological niches if they have undergone appropriate genetic changes.

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Introduction.
In this paper, the topic "Ecological niches" is considered. An ecological niche is a place occupied by a species (more precisely, its population) in a community, a complex of its biocenotic relationships and requirements for abiotic environmental factors. This term was introduced in 1927 by Charles Elton.
The ecological niche is the sum of factors for the existence of a given species, the main of which is its place in the food chain.
The purpose of the work is to reveal the essence of the concept of "ecological niche".
The objectives of the study follow from the goal:
- to give the concept of an ecological niche;
- analyze the features of ecological niches;
- consider the ecological niches of species in communities.
An ecological niche is a place occupied by a species in a community. The interaction of a given species (population) with partners in the community to which it belongs as a member determines its place in the cycle of substances due to food and competitive links in the biocenosis. The term "Ecological niche" was proposed by the American scientist J. Grinnell (1917). The interpretation of an ecological niche as the position of a species for the purpose of feeding one or more biocenoses was given by the English ecologist C. Elton (1927). Such an interpretation of the concept of ecological niche makes it possible to give a quantitative description of the ecological niche for each species or for its individual populations. To do this, in the coordinate system, the abundance of the species (number of individuals or biomass) is compared with
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indicators of temperature, humidity or any other environmental factor. In this way, it is possible to single out the optimum zone and the limits of the deviations tolerated by the species - the maximum and minimum of each factor or set of factors. As a rule, each species occupies a certain ecological niche, for the existence in which it is adapted by the entire course of evolutionary development. The place occupied by a species (its population) in space (spatial ecological niche) is more often called a habitat.
Let's take a closer look at ecological niches.

1. Ecological niche
Any kind of organisms is adapted for certain conditions of existence and cannot arbitrarily change the habitat, diet, feeding time, breeding place, shelter, etc. The whole complex of relations to such factors determines the place that nature has allocated to a given organism, and the role that it must play in the general life process. All this is combined in the concept ecological niche.
1.1. The concept of an ecological niche.
An ecological niche is understood as the place of an organism in nature and the whole way of its life activity, its life status, fixed in its organization and adaptations.
At different times, different meanings were attributed to the concept of an ecological niche. At first, the word "niche" denoted the basic unit of distribution of a species within the space of an ecosystem, dictated by the structural and
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instinctive limitations of this kind. For example, squirrels live in trees, moose live on the ground, some bird species nest on branches, others in hollows, etc. Here the concept of an ecological niche is interpreted mainly as a habitat, or a spatial niche. Later, the term "niche" was given the meaning of "the functional status of an organism in a community." This mainly concerned the place of a given species in the trophic structure of the ecosystem: the type of food, the time and place of feeding, who is the predator for this organism, etc. This is now called a trophic niche. Then it was shown that a niche can be considered as a kind of hypervolume in a multidimensional space built on the basis of environmental factors. This hypervolume limited the range of factors in which a given species could exist (the hyperspace niche).
That is, in the modern understanding of the ecological niche, at least three aspects can be distinguished: the physical space occupied by an organism in nature (habitat), its relationship to environmental factors and living organisms adjacent to it (connections), as well as its functional role in the ecosystem. All these aspects are manifested through the structure of the organism, its adaptations, instincts, life cycles, life “interests”, etc. The right of an organism to choose its ecological niche is limited by rather narrow limits assigned to it from birth. However, its descendants can claim other ecological niches if they have undergone appropriate genetic changes.
1.2. Niche width and overlap.
Using the concept of an ecological niche, Gause's rule of competitive exclusion can be rephrased as follows: two different species cannot occupy the same ecological niche for a long time and even enter the same ecosystem; one of them must either die or
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change and occupy a new ecological niche. By the way, intraspecific competition is often greatly reduced, precisely because at different stages of the life cycle, many organisms occupy different ecological niches. For example, a tadpole is a herbivore, while adult frogs that live in the same pond are predators. Another example: insects in the larval and adult stages.
A large number of organisms of different species can live in one area in an ecosystem. These may be closely related species, but each of them must occupy its own unique ecological niche. In this case, these species do not enter into competitive relations and, in a certain sense, become neutral to each other. However, often the ecological niches of different species may overlap in at least one of the aspects, such as habitat or diet. This leads to interspecific competition, which is usually not tough and contributes to the clear delineation of ecological niches. To characterize a niche, two standard measurements are usually used - the width of the niche and the overlap of the niche with neighboring niches.
Niche width refers to gradients or the range of some environmental factor, but only within a given hyperspace. The width of a niche can be determined by the intensity of illumination, by the length of the trophic chain, by the intensity of the action of some abiotic factor. The overlapping of ecological niches means overlapping along the width of niches and overlapping of hypervolumes.The width of the ecological niche is a relative parameter, which is estimated by comparison with the width of the ecological niche of other species. Eurybionts generally have wider ecological niches than stenobionts. However, the same ecological niche can have different widths according to different
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directions: for example, by spatial distribution, food relationships, etc.
Ecological niche overlapping occurs when different species cohabitate using the same resources. The overlap can be total or partial, according to one or more parameters of the ecological niche.

If the ecological niches of organisms of two species are very different from each other, then these species that have the same habitat do not compete with each other (Fig. 3).

If ecological niches partially overlap (Fig. 2), then their coexistence will be possible due to the presence of specific adaptations for each species.

If the ecological niche of one species includes the ecological niche of another (Fig. 1), then intense competition arises, the dominant competitor will push its rival to the periphery of the fitness zone.
Competition has important environmental consequences. In nature, individuals of each species are simultaneously subjected to interspecific and intraspecific competition. Interspecies in its consequences
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it is opposite to intraspecific, since it narrows the area of ​​habitats and the quantity and quality of the necessary environmental resources. Intraspecific competition promotes the territorial distribution of species, that is, the expansion of the spatial ecological niche. The end result is the ratio of interspecific and intraspecific competition. If interspecific competition is greater, then the range of a given species decreases to a territory with optimal conditions and, at the same time, the specialization of the species increases.

1.3. Niche differentiation.
Thus, ecosystems implement a law similar to the Pauli exclusion principle in quantum physics: in a given quantum system, more than one fermion (particles with half-integer spin, such as electrons, protons, neutrons, etc.) cannot be in the same quantum state. ). In ecosystems, the quantization of ecological niches also takes place, which tend to be clearly localized in relation to other ecological niches. Within a given ecological niche, that is, within the population that occupies this niche, differentiation continues into more particular
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niches occupied by each specific individual, which determines the status of this individual in the life of this population.
Does such differentiation occur at lower levels of the systemic hierarchy, for example, at the level of a multicellular organism? Here, one can also distinguish various “types” of cells and smaller “bodies”, the structure of which determines their functional purpose inside the body. Some of them are immobile, their colonies form organs, the purpose of which makes sense only in relation to the organism as a whole. There are also mobile simple organisms that seem to live their own “personal” life, which nevertheless fully satisfies the needs of the entire multicellular organism. For example, red blood cells do only what they “can”: they bind oxygen in one place and released elsewhere. This is their “ecological niche”. The vital activity of each cell of the body is built in such a way that, “living for itself”, it simultaneously works for the benefit of the whole organism. Such work does not tire us at all, just as the process of eating food, or doing what we love does not tire us (unless, of course, all this is in moderation). Cells are arranged in such a way that they simply cannot live in any other way, just as a bee cannot live without collecting nectar and pollen from flowers (probably, this brings her some kind of pleasure).
Thus, all nature “from top to bottom” seems to be permeated with the idea of ​​differentiation, which in ecology has taken shape in the concept of an ecological niche, which in a certain sense is analogous to an organ or subsystem of a living organism. These “organs” themselves are formed under the influence of the external environment, that is, their formation is subject to the requirements of the supersystem, in our case, the biosphere.

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1.4. Niche evolution.
So it is known that under similar conditions similar ecosystems are formed with the same set of ecological niches, even if these ecosystems are located in different geographical areas separated by insurmountable obstacles. The most striking example in this regard is the living world of Australia, which for a long time developed separately from the rest of the land world. In the ecosystems of Australia, functional niches can be identified that are equivalent to the corresponding niches of ecosystems on other continents. These niches are occupied by those biological groups that are present in the fauna and flora of a given area, but are similarly specialized for the same functions in the ecosystem that are characteristic of this ecological niche. Such types of organisms are called ecologically equivalent. For example, the large kangaroos of Australia are equivalent to the bison and antelopes of North America (on both continents, these animals are now replaced mainly by cows and sheep). Similar phenomena in the theory of evolution are called parallelism. Very often, parallelism is accompanied by convergence (convergence) of many morphological (from the Greek word morphe - form) features. So, despite the fact that the whole world was conquered by plantentals, in Australia, for some reason, almost all mammals are marsupials, with the exception of a few species of animals brought much later than the living world of Australia finally took shape. However, marsupial mole, and marsupial squirrel, and marsupial wolf, etc. are also found here. All these animals are not only functionally, but also morphologically similar to the corresponding animals of our ecosystems, although there is no relationship between them. All this testifies in favor of the presence of a certain “program” for the formation of ecosystems in these specific
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conditions. All matter, each particle of which gallogram stores information about the entire Universe, can act as “genes” that store this program. This information is realized in the actual world in the form of laws of nature, which contribute to the fact that various natural elements canfold into ordered structures not at all in an arbitrary way, but in the only possible way, or at least in several possible ways. So, for example, a water molecule, obtained from one oxygen atom and two hydrogen atoms, has the same spatial shape, regardless of whether the reaction took place in our country or in Australia, although according to Isaac Asimov's calculations, only one chance is realized. out of 60 million. Probably, something similar happens in the case of the formation of ecosystems.
Thus, in any ecosystem there is a certain set of potentially possible (virtual) ecological niches strictly linked to each other, designed to ensure the integrity and sustainability of the ecosystem. This virtual structure is a kind of "biofield" of this ecosystem, containing the "standard" of its actual (real) structure. And by and large, it doesn’t even matter what the nature of this biofield is: electromagnetic, informational, ideal or some other. The very fact of its existence is important. In any naturally formed ecosystem that has not experienced human impact, all ecological niches are filled. This is called the rule of obligation to fill ecological niches. Its mechanism is based on the property of life to densely fill all the space available to it (by space, in this case, we mean the hypervolume of environmental factors). One of the main conditions ensuring the implementation of this rule is the presence of sufficient species diversity. The number of ecological niches and their interconnection is subject to a single goal
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the functioning of the ecosystem as a whole, having the mechanisms of homeostasis (stability), binding and releasing energy and the circulation of substances. In fact, the subsystems of any living organism are focused on the same goals, which once again indicates the need to revise the traditional understanding of the term “living being”. Just as a living organism cannot exist normally without one or another organ, so an ecosystem cannot be stable if all its ecological niches are not filled.
2. Aspects of ecological niche.

E ecological niche - a concept, according to Y. Odum , more capacious. The ecological niche, as shown by the English scientist C. Elton (1927), includes not only the physical space occupied by the organism, but also the functional role of the organism in the community. Elton distinguished niches as the position of a species in relation to other species in a community. Ch. Elton's idea that a niche is not a synonym for a habitat has received wide recognition and distribution. The trophic position, way of life, connections with other organisms, etc. are very important for the organism. and its position relative to the gradients of external factors as conditions of existence (temperature, humidity, pH, soil composition and type, etc.).
These three aspects of the ecological niche (space, the functional role of the organism, external factors) can be conveniently designated as a spatial niche (niche of a place), a trophic niche (a functional niche), in the understanding of Ch. Elton, and a multidimensional niche (the entire volume and set of biotic and abiotic characteristics are taken into account). , hypervolume). The ecological niche of an organism depends not only on where it lives, but also includes the total amount of its environmental requirements.
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The body not only experiences the action of environmental factors, but also makes its own demands on them.

3. The modern concept of an ecological niche.

It was formed on the basis of the model proposed by J. Hutchinson (1957). According to this model, an ecological niche is a part of an imaginary multidimensional space (hypervolume), individual dimensions of which correspond to the factors necessary for the normal existence and reproduction of an organism. Hutchinson's niche, which we will call multidimensional (hyperspace), can be described using quantitative characteristics and operated with it using mathematical calculations and models. R. Whittaker (1980) defines an ecological niche as the position of a species in a community, implying that the community is already associated with a particular biotope, i.e. with a certain set of physical and chemical parameters. Therefore, an ecological niche is a term used to denote the specialization of a population of a species within a community.
Groups of species in a biocenosis with similar functions and niches of the same size are called guilds. Species that occupy the same niches in different geographical areas are called ecological equivalents.

4. Individuality and originality of ecological niches.

No matter how close in habitat organisms (or species in general) are, no matter how close their functional characteristics in biocenoses are, they will never occupy the same ecological niche. Thus, the number of ecological niches on our planet is uncountable.
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Figuratively, one can imagine a human population, all individuals of which have only their own unique niche. It is impossible to imagine two absolutely identical people with absolutely identical morphophysiological and functional characteristics, including such as mental, attitude towards their own kind, an absolute need for the type and quality of food, sexual relations, norms of behavior, etc. But the individual niches of different people can overlap in certain ecological parameters. For example, students can be linked by one university, specific teachers, and at the same time, they can differ in their behavior in society, in the choice of food, biological activity, etc.

5. Types of ecological niches.

There are two main types of ecological niches. First, this
fundamental (formal) niche - the largest "abstractly populated
hypervolume”, where the action of environmental factors without the influence of competition ensures the maximum abundance and functioning of the species. However, the species experiences constant changes in environmental factors within its range. In addition, as we already know, an increase in the action of one factor can change the relation of a species to another factor (a consequence of Liebig's law), and its range can change. The action of two factors at the same time can change the attitude of the species to each of them specifically. There are always biotic restrictions (predation, competition) within ecological niches. All these actions lead to the fact that in reality the species occupies an ecological space that is much smaller than the hyperspace of the fundamental niche. In this case, we are talking about a realized niche, i.e. real niche.

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6. niche space.

The ecological niches of species are more than the relation of a species to a single environmental gradient. Many signs or axes of multidimensional space (hypervolume) are very difficult to measure or cannot be expressed by linear vectors (for example, behavior, addiction, etc.). Therefore, it is necessary, as rightly noted by R. Whittaker (1980), to move from the concept of the niche axis (remember the width of the niche in terms of one or more parameters) to the concept of its multidimensional definition, which will reveal the nature of species relationships with their full range of adaptive relationships .
If a niche is a "place" or "position" of a species in a community according to Elton's concept, then it is right to give it some measurements. According to Hutchinson, a niche can be defined by a number of environmental variables within a community to which a species must be adapted. These variables include both biological indicators (for example, food size) and non-biological ones (climatic, orographic, hydrographic, etc.). These variables can serve as axes along which a multidimensional space is recreated, which is called ecological space or niche space. Each of the species can adapt or be resistant to some range of values ​​of each variable. The upper and lower limits of all these variables delineate the ecological space that a species can occupy. This is the fundamental niche in Hutchinson's understanding. In a simplified form, this can be imagined as an "n-sided box" with sides corresponding to the stability limits
view on the axes of the niche. By applying a multidimensional approach to community niche space, we can find out the position of species in space, the nature of the response of a species to exposure to more than one variable, relative
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niche sizes.
Conclusion.

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Bibliography:

Chernova N.M., Bylova A.M. Ecology.- M.: Education, 1988.
Brodsky A.K. A short course in general ecology, Textbook for universities. - St. Petersburg: "Dean", 2000. - 224 p.
etc.................