Detailed solution paragraph § 76 in biology for students of grade 10, authors Kamensky A.A., Kriksunov E.A., Pasechnik V.V. 2014

• Gdz workbook in Biology for grade 10 can be found

1. What is a habitat?

Answer. Habitat (habitat) - a set of biotic, abiotic and anthropogenic (if any) environmental factors in any particular territory or water area, which is formed on the site of the primary complex of abiotic factors - an ecotope. The habitat of a species or population is an important component of his/her ecological niche. In relation to terrestrial animals, the term is considered synonymous with the concepts of station (species habitat) and biotope (community habitat).

Habitats characterized by different severity of environmental factors, but having a similar vegetation cover, are called biologically equivalent. Their existence is possible due to the partial compensation of factors by each other.

T. Southwood (1977) proposed to classify habitats according to the nature of the change in factors over time, highlighting the following:

unchanged - environmental conditions remain favorable indefinitely;

predictably seasonal - there is a regular change of favorable and unfavorable periods;

unpredictable - favorable and unfavorable periods have different durations;

ephemeral - with a short favorable period.

2. What is a food chain?

Answer. Food (trophic) chain - a series of species of plants, animals, fungi and microorganisms that are related to each other by relationships: food - consumer (a sequence of organisms in which there is a phased transfer of matter and energy from source to consumer).

The organisms of the next link eat the organisms of the previous link, and thus the chain transfer of energy and matter is carried out, which underlies the cycle of substances in nature. With each transfer from link to link, a large part (up to 80-90%) of the potential energy is lost, dissipating in the form of heat. For this reason, the number of links (species) in the food chain is limited and usually does not exceed 4-5.

3. What is interspecific struggle?

Questions after § 76

1. What is the difference between the concepts of "habitat" and "ecological niche"?

Answer. The position of the species that it occupies in the biogeocenosis, the complex of its relationships with other species and the requirements for abiotic environmental factors is called an ecological niche. The concept of "ecological niche" should be distinguished from the concept of "habitat". In the latter case, we are talking about a part of the space where the species lives and where there are the necessary abiotic conditions for its existence. The ecological niche of a species depends not only on abiotic conditions; it characterizes the entire way of life that a species can lead in a given community. According to the figurative expression of the ecologist Yu. Odum, the habitat is the address of the species, and the ecological niche is its "profession". There are fundamental (or potential) and realized niches. A fundamental ecological niche is a set of optimal conditions under which a given species can exist and reproduce. A realized niche is the conditions where a species actually occurs in a given ecosystem; it always constitutes some part of the fundamental niche.

For the reproduction and long-term existence of many species of animals, the differentiation of niches into different stages ontogeny: caterpillars and imago of Lepidoptera, larvae and beetles of the May beetle, tadpoles and adult frogs do not compete with each other, as they differ in habitat and are included in different food chains.

Interspecific competition leads to a narrowing of the ecological niche, does not allow its potential to manifest itself. Intraspecific competition, on the contrary, contributes to the expansion of the ecological niche. In connection with the increase in the number of species, the use of additional feed, the development of new habitats, the emergence of new biocoenotic relationships begins.

2. Can different species occupy the same ecological niche?

Answer. No, they can't. Lives in one place a large number of organisms different types. For example, a mixed forest is a habitat for hundreds of species of plants and animals, but each of them has its own and only one "profession" - an ecological niche.

In the forest, elk and squirrel have a similar habitat, but their niches are completely different: the squirrel lives mainly in the crowns of trees, feeds on seeds and fruits, and reproduces there. The entire life cycle of an elk is associated with the undergrowth space: feeding on green plants or their parts, reproduction and shelter in thickets.

Elements of an ecological niche:

food (species);

time and ways of eating;

breeding place;

shelter place.

Ecological niches exist according to certain rules:

the wider the requirements (tolerance limits) of a species to any or many environmental factors, the greater the space that it can occupy in nature, and hence the wider its distribution;

if the regime of any, at least one ecological factor in the habitat of individuals of one species has changed in such a way that its values ​​go beyond the niche, then this means the destruction of the niche, i.e., the restriction or impossibility of preserving the species in this habitat. Other important patterns are also associated with the concept of "ecological niche" - each species has its own, unique ecological niche, i.e. how many species on Earth, so many ecological niches (2.2 million species of living organisms, of which 1.7 million animal species). Two different species (even very close ones) cannot occupy the same ecological niche in space;

in each ecosystem there are species that claim the same niche or its elements (food, shelter). In this case, competition is inevitable, the struggle for possession of a niche. Such relationships reflect the Gause rule: if two species with similar requirements for the environment (nutrition, behavior, breeding sites) enter into competitive relations, then one of them must die or change its lifestyle and occupy a new ecological niche.

An ecological niche is a set of all the requirements of a species (population) to environmental conditions (the composition and regime of environmental factors) and the place where these requirements are met.

The ecological niches of cohabiting species may partially overlap, but never completely coincide, because. the law of competitive exclusion comes into play.

3. Can one species occupy different ecological niches? What does it depend on?

4. What is the importance of ecological niches in community life?

Answer. The concept of an ecological niche is very useful for understanding the laws of the coexistence of species. For example, any green plant, taking one or another part in the formation of biogeocenosis, ensures the existence of a number of ecological niches. Among them, there may be niches that include organisms that feed on root tissues (root beetles) or leaf tissues (leaf beetles and sap beetles), flowers (flower beetles), fruits (fruit beetles), root secretions (eccrisotrophs), etc. All together they constitute an integral system of diverse uses. plant matter of the body. At the same time, all heterotrophs that eat plant biomass almost do not compete with each other.

Each of these niches includes groups of organisms that are heterogeneous in species composition. For example, the ecological group of root beetles includes both nematodes and the larvae of some beetles (May beetle, nutcracker), and bugs and aphids enter the niche of plants sucking juices.

Ecological niches of animals feeding on plant biomass

Groups of species in a community that have similar functions and niches of the same properties are called guilds by some authors (the guild of root beetles, the guild of nocturnal predators, the guild of scavengers, etc.).

Consider Figure 122. Are herbivores occupying the same or different niches in the African savannah? Justify your answer. Consider Figure 123. Do the dragonfly and its larva occupy the same or different niches? Justify the answer.

Answer. In the savanna, animals occupy different ecological niches. An ecological niche is a place occupied by a species in a biocenosis, including a complex of its biocenotic relationships and requirements for environmental factors. The term was introduced in 1914 by J. Grinnell and 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 can be:

fundamental - determined by a combination of conditions and resources that allows the species to maintain a viable population;

realized - the properties of which are due to competing species.

This difference emphasizes that interspecific competition leads to a decrease in fertility and viability and that there may be a part of a fundamental ecological niche that a species, as a result of interspecific competition, can no longer live and reproduce successfully.

An ecological niche cannot be empty. If a niche is empty as a result of the extinction of a species, then it is immediately filled with another species.

The habitat usually consists of separate areas ("spots") with favorable and unfavorable conditions; these spots are often only temporarily available, and they occur unpredictably both in time and space.

Habitat gaps or gaps occur unpredictably in many habitats. Fires or landslides can lead to the formation of wastelands in forests; the storm can bare open area sea ​​coast, and voracious predators anywhere can exterminate potential victims. These vacant plots are invariably repopulated. However, the very first settlers will not necessarily be those species that for a long time are able to successfully compete with other species and displace them. Therefore, the coexistence of transient and competitive species is possible as long as uninhabited areas appear with suitable frequency. A transient species usually first populates a free area, develops it and reproduces. A more competitive species populates these areas slowly, but if the colonization has begun, then over time it defeats the transient species and multiplies.

The doctrine of ecological niches is of great practical importance. When introducing foreign species into the local flora and fauna, it is necessary to find out what ecological niche they occupy in their homeland, whether they will have competitors in the places of introduction. The wide distribution of the muskrat in Europe and Asia is explained precisely by the absence of rodents with a similar lifestyle in these regions.

In related species living together, there is a very fine delineation of ecological niches. So, ungulates grazing in the African savannas use pasture food in different ways: zebras mainly cut off the tops of grasses, wildebeests feed on what zebras leave them, gazelles pluck out the lowest grasses, and topi antelopes are content with dry stems left after other herbivores. Due to the division of niches, the total bioproductivity of such a herd with a complex species composition increases. The peasant herd, consisting of cows, sheep, goats, uses meadows and pastures much more efficiently, from an environmental point of view, than a single-species herd, monoculture is the least effective method agriculture.

If we compare an adult insect and dragonfly larvae, we can draw conclusions:

1) Larvae usually serve as a dispersal stage and ensure the spread of the species.

2) Larvae differ from adults both in nutritional biology, and in their habitat, and in methods of movement (a flying dragonfly and its swimming larva), and behavioral features. Thanks to this, one species can use the opportunities provided by two ecological niches throughout the entire life cycle. This increases the chances of survival of the species.

3) they can adapt to different conditions waiting for them in their second life, they have physiological endurance.

Introduction

In this work, I want to introduce you to such concepts as an ecological niche, limiting factors, and tell you more about the law of tolerance.

An ecological niche is a place occupied by a species in a biocenosis, including a complex of its biocenotic relationships and requirements for environmental factors.

The concept of an ecological niche was introduced to denote the role that a particular species plays in a community. An econiche should be understood as a way of life and, above all, a way of nourishing the body.

An ecological niche is an abstract concept, it is a set of all environmental factors within which a species can exist in nature. This term was introduced in 1927 by Charles Elton. It includes the chemical, physical, and biotic factors that an organism needs for life and is determined by its morphological fitness, physiological responses, and behavior. V different parts In the world and in different territories there are species that are systematically different, but similar in ecology - they are called ecologically equivalent.

An ecological niche is a place occupied by a species (more precisely, by its population) in a community (biocenosis). 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 ties in the biocenosis. The term "Ecological niche" was proposed by the American scientist J. Grinell (1917). The interpretation of an ecological niche as the position of a species in the food chains of 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.

The limiting factor is an environmental factor that goes beyond the endurance of the organism. The limiting factor limits any manifestation of the organism's vital activity. With the help of limiting factors, the state of organisms and ecosystems is regulated.

Shelford's law of tolerance - in ecology - the law according to which the existence of a species is determined by limiting factors that are not only at a minimum, but also at a maximum. The law of tolerance extends Liebig's law of the minimum.

J. Liebig's Law of the Minimum - in ecology - a concept according to which the existence and endurance of an organism is determined by the weakest link in the chain of its environmental needs.

According to the law of the minimum, the vital possibilities of organisms are limited by those environmental factors, the quantity and quality of which are close to the minimum required by the organism or ecosystem.

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.

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.

V different time The concept of an ecological niche has been given different meanings. 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.

Using the concept of an ecological niche, Gause's rule of competitive exclusion can be rephrased as follows: two different species cannot long time occupy one ecological niche and even enter one ecosystem; one of them must either die or 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.

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 a population that occupies this niche, differentiation continues into more private niches occupied by each individual, which determines the status of this individual in the life of this population.

Does such a differentiation occur for more low levels system hierarchy, for example, at the level of a multicellular organism? Here you can also distinguish various “types” of cells and smaller “bodies”, the structure of which determines them. 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”: bind oxygen in one place, and release it in another place. 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, the whole nature “from top to bottom” seems to be permeated with the idea of ​​differentiation, which in ecology took shape in the concept of an ecological niche, which in a certain sense is similar 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.

Despite the complexity of the structure of the population system and significant variability, any species (as well as any population) can be characterized from an ecological point of view as a whole.
The term ecological niche was introduced specifically to describe a species as an ecologically integral system. In fact, an ecological niche describes the position (including functional) that a particular species occupies in relation to other species and abiotic factors.
This term was proposed by the American ecologist Joseph Grinell in 1917 to describe the spatial and behavioral distribution of individuals of different species in relation to each other. Somewhat later, another colleague, Charles Elton, emphasized the usefulness of using the term "ecological niche" to characterize the position of a species in a community, especially in food webs. In this case, according to the figurative expression of another American scientist, Eugene Odum, the ecological niche describes the "profession" of the species, and the habitat - its "address".
Of course, attempts to describe the ecological characteristics of species were made before Grinell. Thus, it has long been well known that some species are able to exist only within very narrow limits of conditions, i.e., the zone of their tolerance is narrow. These are stenobionts (Fig. 15). Others, on the contrary, inhabit extremely diverse habitats. The latter are often called eurybionts, although it is clear that there are actually no real eurybionts in nature.
In reality, one can speak of an ecological niche as the total sum of adaptations of a species, population, or even an individual. A niche is a characteristic of an organism's ability to

(I, III) and eurybiont (II) in relation to
development environment. It should also be noted that in many species during the life cycle, in fact, there is a change in ecological niches, and the niches of the larva and adult individual can differ very sharply. For example, dragonfly larvae are typical benthic predators of water bodies, while adult dragonflies, although they are predators, live in the air layer, occasionally landing on plants. In plants, one of the most common forms of division of ecological niches within one species is the formation of so-called ecotypes, i.e., hereditarily fixed races observed in nature under peculiar conditions (Fig. 16).

Each such niche can be characterized by the limiting values ​​of the parameters that determine the possibility of the existence of the species (temperature, humidity, acidity, etc.). If many (n) factors are used to describe it, then one can imagine a niche as a kind of n-dimensional volume, where the parameters of the corresponding zone of tolerance and optimum are plotted along each of the n axes (Fig. 17). This view was developed by the Anglo-American ecologist George Evelyn Hutchinson, who believed that a niche should be defined taking into account the full range of abiotic and biotic environmental variables to which a species must be adapted and under the influence of which its populations can exist indefinitely. Hutchinson's model idealizes reality, but it is precisely this model that allows

demonstrate the uniqueness of each species (Fig. 18).

Rice. 17. Schematic representation of an ecological niche (a - in one, b - in two, c - in three dimensions; O - optimum)

Rice. Fig. 18. Two-dimensional image of ecological niches of two related species of bivalve mollusks (the distribution of animal mass per unit area is shown) (according to Zenkevich, with changes)
In this model, a niche along each individual axis can be characterized by two main parameters: the position of the niche center and its width. Of course, when discussing n-dimensional volumes, one must take into account that many environmental factors interact with each other and, as a result, should be considered interconnected. In addition, within the tolerance zone there are areas that are favorable to the species to varying degrees. In general, at least for animals, three estimates are sufficient to describe an ecological niche - habitat, food, and time of activity. Sometimes they simply talk about spatial and trophic niches. For plants and fungi, the attitude to abiotic environmental factors, the temporal nature of the development of their populations, and the passage of the life cycle are more significant.
Naturally, an n-dimensional figure can only be displayed in the corresponding n-dimensional space, along each axis
which contains the values ​​of one of the n factors. Hutchinson's concept of a multidimensional ecological niche makes it possible to describe an ecosystem as a set of ecological niches. In addition, it becomes possible to compare the ecological niches of different (including very closely related) species and identify the realized and potential (fundamental) ecological niches for each of them (Fig. 19). First
characterizes the ecological n-dimensional "space" in which the species now exists. In particular, its modern area corresponds to the realized niche in the general view. A potential niche is a "space" in which a species could exist if there were no obstacles insurmountable at the given time, important enemies or powerful competitors on its way. This is especially important for predicting the possible dispersal of one species or another.

Rice. 19. Ratios of potential and realized niches and the area of ​​possible competition of two ecologically close species (according to Solbrig, Solbrig, 1982, with simplification)
Even outwardly almost indistinguishable and cohabiting species (in particular, twin species) are often well distinguished by their ecological features. In the first half of the XX century. It was believed that one species of malarial mosquitoes was common in Europe. However, observations have shown that not all such mosquitoes are involved in the transmission of malaria. WITH

the advent of new methods (for example, cytogenetic analysis) and the accumulation of data on ecology and developmental features, it became clear that this is not one species, but a complex of very close species. Not only ecological, but even morphological differences between them were found.

If we compare the distribution of closely related species, we will see that often their ranges do not overlap, but may be similar, for example, in relation to natural areas. Such forms are called vicarious. A typical case of vicariation is the distribution of different types of larch in the Northern Hemisphere - Siberian larch in Western Siberia, Dahurian larch in Eastern Siberia and northeast Eurasia, American larch in North America.
In cases where the areas of distribution of closely related forms overlap, most often one can observe a significant divergence of their ecological niches, which often manifests itself even in a shift in morphological variability. Such differences are historical in nature and are probably in some cases related to previous isolation. various parts population system of the original species.
When ecological niches overlap with each other (especially when using a limited resource - such as food), competition can begin (see Fig. 19). Therefore, if two species coexist, then their ecological niches of competition must somehow differ. This is precisely what the law of competitive exclusion, based on the work of the Russian ecologist Georgy Frantsevich Gause, says: two species cannot occupy the same ecological niche. As a result, the ecological niches of species belonging to the same community, even if they are closely related, differ. Therefore, such an exception is very difficult to trace in nature, but can be recreated in the laboratory. Competitive exclusion can also be traced in the settlement of living organisms with the help of humans. For example, the appearance on the Hawaiian Islands of a number of continental plant species (passion flowers) and birds (house sparrow, starling) led to the disappearance of endemic forms.
The concept of an ecological niche makes it possible to identify ecological equivalents, i.e. species occupying very similar niches but in different areas. Similar forms are often not related to each other. Thus, the niche of large herbivores in the prairies of North America is occupied and occupied by bison and pronghorns, in the steppes of Eurasia - by saigas and wild horses, and in the savannahs of Australia - by large kangaroos.
An N-dimensional idea of ​​an ecological niche allows one to reveal the essence of community organization and biological diversity. In order to assess the nature of the relationship of ecological niches of different species in one habitat, the distances between niche centers and their overlap in width are used. Of course, only a few axes are compared.
It is clear that each community includes species with both completely different and very similar ecological niches. The latter are actually very close in their place and role in the ecosystem. The totality of such species in any community is called a guild. Living beings belonging to the same guild interact strongly with each other and weakly with other species.

One of the main concepts in modern ecology is the concept of an ecological niche. For the first time, zoologists started talking about an ecological niche. In 1914, the American naturalist zoologist J. Grinnell and in 1927 the English ecologist C. Elton used the term "niche" to define the smallest unit of distribution of a species, as well as the place of a given organism in the biotic environment, its position in food chains.

The generalized definition of an ecological niche is the following: this is the place of a species in nature, due to a cumulative set of environmental factors. The ecological niche includes not only the position of the species in space, but also its functional role in the community.

- this is a set of environmental factors within which one or another type of organism lives, its place in nature, within which this species can exist indefinitely.

Since when determining the ecological niche, one should take into account big number factors, then the place of the species in nature, described by these factors, is a multidimensional space. This approach allowed the American ecologist G. Hutchinson to give the following definition of an ecological niche: it is a part of an imaginary multidimensional space, the individual dimensions of which (vectors) correspond to the factors necessary for the normal existence of a species. At the same time, Hutchinson singled out a niche fundamental, which can be occupied by the population in the absence of competition (it is determined physiological characteristics organisms), and a niche implemented, those. part of the fundamental niche within which a species actually occurs in nature and which it occupies in the presence of competition with other species. It is clear that the realized niche, as a rule, is always less than the fundamental one.

Some ecologists stress that, within their ecological niche, organisms must not only occur, but also be able to reproduce. Since there is species specificity to any ecological factor, the ecological niches of species are also specific. Each species has its own ecological niche.

Most species of plants and animals can only exist in special niches that support certain physico-chemical factors, temperature, and food sources. After the destruction of bamboo began in China, for example, the panda, whose diet for 99% consists of this plant, was on the verge of extinction.

Species with common niches can easily adapt to changing habitat conditions, so the danger of their extinction is low. Typical representatives of species with common niches are mice, cockroaches, flies, rats and humans.

G. Gause's law of competitive exclusion for ecologically close species in the light of the doctrine of the ecological niche can be formulated as follows: two species cannot occupy the same ecological niche. An exit from competition is achieved by a divergence of requirements for the environment, or, in other words, by delineation of the ecological niches of species.

Competing species that live together often "share" available resources to reduce competition. A typical example is the division into animals that are active during the day and those that are active at night. Bats (every fourth mammal in the world belongs to this suborder of bats) share the airspace with other insect hunters - birds, using the change of day and night. True, bats have a few relatively weak competitors, such as owls and nightjars, which are also active at night.

A similar division of ecological niches into day and night "shifts" is observed in plants. Some plants bloom during the day (most wild-growing species), others - at night (two-leafed love, fragrant tobacco). At the same time, nocturnal species also emit an odor that attracts pollinators.

Ecological amplitudes of some species are very small. So, in tropical Africa, one of the species of worms lives under the eyelids of a hippopotamus and feeds exclusively on the tears of this animal. A narrower ecological niche is hard to imagine.

The concept of the ecological niche of a species

The position of the species that it occupies in the general system of biocenosis, including the complex of its biocenotic relationships and requirements for abiotic environmental factors, is called ecological niche of the species.

The concept of an ecological niche has proved to be very fruitful for understanding the laws of cohabitation of species. The concept of "ecological niche" should be distinguished from the concept of "habitat". In the latter case, that part of the space is meant which is inhabited by the species and which has the necessary abiotic conditions for its existence.

The ecological niche of a species depends not only on abiotic environmental conditions, but also, to no lesser extent, on its biocenotic environment. This is a characteristic of the lifestyle that a species can lead in a given community. How many species of living organisms there are on Earth - the same number of ecological niches.

Competitive exclusion rule can be expressed in such a way that two species do not get along in the same ecological niche. The way out of competition is achieved due to the divergence of requirements for the environment, a change in lifestyle, which is the delimitation of the ecological niches of species. In this case, they acquire the ability to coexist in one biocenosis.

Separation of ecological niches by cohabiting species with partial overlap one of the mechanisms of sustainability of natural biocenoses. If any of the species drastically reduces its numbers or falls out of the community, others take over its role.

The ecological niches of plants, at first glance, are less diverse than those of animals. They are clearly delineated in species that differ in nutrition. In ontogenesis, plants, like many animals, change their ecological niche. As they age, they use and transform their environment more intensively.

Plants have overlapping ecological niches. It intensifies in certain periods when environmental resources are limited, but since species use resources individually, selectively and with different intensity, competition in stable phytocenoses is weakened.

The richness of ecological niches in the biocenosis is influenced by two groups of reasons. The first is the environmental conditions provided by the biotope. The more mosaic and diverse the biotope, the more species can demarcate their ecological niches in it.

Abstract on ecology

Man is one of the representatives of the animal kingdom, a biological species of the class of mammals. Despite the fact that it has many specific properties (reason, articulate speech, labor activity, biosociality, etc.), it has not lost its biological essence and all the laws of ecology are valid for it to the same extent as for other organisms.

A person has his own, unique to him, ecological niche, i.e. a set of requirements for a variety of environmental factors, developed in the process of evolution. The space in which the human niche is localized (ie, the place where the regimes of factors do not go beyond the limits of tolerance inherited from the ancestors) is very limited. As a biological species, a person can live only within the land of the equatorial belt (tropics, subtropics), where the hominid family arose. Vertically, the niche extends approximately 3.0-3.5 km above sea level.

Due to its specific (primarily social) properties, man has expanded the boundaries of his initial range, settled in high, middle and low latitudes, mastering the depths of the ocean and space. However, its fundamental ecological niche remained practically unchanged, and outside its original range it can survive, overcoming the resistance of limiting factors not through adaptations, but with the help of specially created protective devices and devices (heated dwellings, warm clothes, oxygen devices, etc.). .), which imitate its niche in the same way as it is done for exotic animals and plants in zoos, oceanariums, botanical gardens. Nevertheless, it is not always possible to fully reproduce all the factors necessary for a person from the point of view of the law of tolerance. For example, in space flight it is impossible to reproduce such the most important factor, like gravity, and after returning to Earth from a long space expedition, astronauts need time to readapt.

In industrial environments, many factors (noise, vibration, temperature, electromagnetic fields, impurities of a number of substances in the air, etc.) are periodically or permanently beyond the tolerance of the human body. This negatively affects him: so-called occupational diseases, periodic stresses may occur. Therefore, there is a special system of technical and organizational measures aimed at ensuring safety labor activity by reducing the level of impact on the body of hazardous and harmful production factors.

It is far from always possible to provide optimal conditions for such factors, and therefore, for a number of industries, the total length of service of employees is limited, the length of the working day is reduced (for example, when working with harmful substances up to four hours).

Industrial and economic activity of a person, use (processing) natural resources inevitably lead to the formation of by-products ("waste"), dispersed in the environment. Chemical compounds entering the water, soil, atmosphere, and food are environmental factors and, consequently, elements of an ecological niche. In relation to them (especially to the upper limits), the resistance of the human body is small, and such substances turn out to be limiting factors that destroy its niche.

From the foregoing, one of the basic rules of nature protection from an ecological point of view follows: protection of nature (environment) consists in a system of measures to preserve the ecological niches of living organisms, including humans. Thus, either the human niche will be preserved for present and future generations, or the human being as a biological species is doomed to extinction.