Define an ecological niche. How do you understand the term “human ecological niche”? Ecological niche. Interaction of environmental factors Divergence of ecological niches

Ecological niche called the position of the species that oi occupies in the general system of biocenosis, a complex of its biocenotic connections and requirements for abiotic environmental factors. An ecological niche reflects the participation of a species in a biocenosis. In this case, what is meant is not its territorial location, but the functional manifestation of the organism in the community. According to Ch. Elton (1934), an ecological niche is “a place in a living environment, the relationship of a species to food and to enemies.” The concept of an ecological niche has proven to be very fruitful for understanding the laws of joint life of species. In addition to C. Elton, many ecologists worked on its development, among them D. Grinnell, G. Hutchinson, Y. Odum and others.

The existence of a species in a community is determined by the combination and action of many factors, but in determining whether organisms belong to a particular niche, they proceed from the nature of the nutrition of these organisms, from their ability to obtain or supply food. Thus, a green plant, taking part in the formation of a biocenosis, ensures the existence of a number of ecological niches. These may be niches that include organisms that feed on root tissue or leaf tissue, flowers, fruits, root secretions, etc. (Fig. 11).

Rice. eleven

1 - root beetles; 2 - eating root secretions; 3 - leaf beetles; 4 - stem eaters, 5 - fruit eaters; 6 - seed eaters; 7 - flower beetles; 8 - pollen eaters; 9 - juice eaters; 10 - bud eaters (according to I.N. Ponomareva, 1975)

Each of these niches includes groups of organisms that are heterogeneous in species composition. Thus, the ecological group of root beetles includes nematodes and the larvae of some beetles (nutcrackers, May beetles), and the niche of plants sucking plant juices includes bugs and aphids. The ecological niches of “stem beetles” or “stem beetles” cover a large group of animals, among which insects (carpenter beetles, wood beetles, bark beetles, longhorned beetles, etc.) are especially numerous.

It should be noted that among them there are also those that feed only on the wood of living plants or only on the bark - both belong to different ecological niches. Specialization of species in relation to food resources reduces competition and increases the stability of community structure.

There are different types of resource sharing.

• 1. Specialization of morphology and behavior in accordance with the type of food: for example, the beak of birds can be adapted for catching insects, chiseling holes, cracking nuts, tearing meat, etc.
• 2. Vertical separation, for example between canopy and forest floor inhabitants.
• 3. Horizontal separation, for example, between inhabitants of different microhabitats. Each of these types or their combination leads to the division of organisms into groups that compete less with each other, since each of them occupies its own niche. For example, there is a division of birds into ecological groups based on where they feed: air, foliage, trunk, soil. Further division of these groups depending on the main type of food is shown in Fig. 12.

Rice. 12. Division of birds into ecological groups based on the place of their feeding: air, foliage, trunk, ground (according to N. Green et al., 1993)

Specialization of a species in nutrition, use of space, time of activity and other conditions is characterized as a narrowing of its ecological niche, and reverse processes are characterized as its expansion.

The narrowing or expansion of the ecological niche of a species in a community is greatly influenced by competitors. Formulated by G.F. Gause's rule of competitive exclusion for ecologically similar species can be expressed in such a way that two species do not coexist in the same ecological niche. Exit from competition is achieved by diverging requirements for the environment, changing lifestyles, or, in other words, is the delimitation of ecological niches of species. In this case, they acquire the ability to coexist in the same biocenosis. Thus, in the mangroves of the coast of South Florida, a wide variety of herons live and often feed on up to nine different species of fish on the same shallows. At the same time, they practically do not interfere with each other, since in their behavior - in what hunting areas they prefer and how they catch fish - adaptations have been developed that allow them to occupy different niches within the same shallows. A green night heron passively waits for fish, sitting on the roots of mangrove trees protruding from the water. The Louisiana heron makes sudden movements, stirring up the water and scaring away hidden fish. The snowy egret moves slowly from place to place in search of prey.

The most sophisticated method of fishing is used by the red heron, which first stirs up the water and then opens its wings wide to create shade. At the same time, firstly, she herself clearly sees everything that is happening in the water, and, secondly, the frightened fish take the shadow for cover, rush towards it, falling straight into the enemy’s beak. The size of the great blue heron allows it to hunt in places inaccessible to its smaller and shorter-legged relatives. Insectivorous birds in the winter forests of Russia, feeding on trees, also avoid competition with each other due to the different nature of their search for food. Nuthatches and pikas collect food on tree trunks. Nuthatches quickly explore the trees, quickly grabbing insects and seeds caught in large cracks in the bark, and small pikas carefully search the surface of the trunk for the slightest cracks into which their thin awl-shaped beak penetrates. In the European part of Russia there are closely related species of tits, the isolation of which from each other is due to differences in habitats, feeding areas and prey sizes. Ecological differences are also reflected in a number of small details of the external structure, including changes in the length and thickness of the beak (Fig. 13).

In winter, in mixed flocks, great tits conduct a wide search for food in trees, bushes, stumps, and often in the snow. Chickadees mostly inspect large branches. Long-tailed tits search for food at the ends of branches, and small tits carefully examine the upper parts of coniferous crowns.

Numerous orders of grass-eating animals include steppe biocenoses. Among them are many large and small mammals, such as ungulates (horses, sheep, goats, saigas) and rodents (gophers, marmots, mice). All of them constitute one large functional group of biocenosis (ecosystem) - herbivores. At the same time, research shows that the role of these animals in consuming plant matter is not the same, since they use different components of the grass cover in their diet.

Rice. 13.

Thus, large ungulates (currently these are domestic animals and saigas, and before human development of the steppes - only wild species) only partially, selectively eat food, mainly tall, most nutritious grasses, biting them at a considerable height (4-7 cm) from the soil surface. Marmots living here choose food among the grass, thinned out and modified by ungulates, eating it, which was inaccessible to them. Marmots settle and feed only where there is no tall grass. Smaller animals - gophers - prefer to collect food where the grass stand is even more disturbed. Here they collect what is left from feeding ungulates and marmots. Between these three groups of herbivores that form the zoocenosis, there is a division of functions in the use of herbaceous biomass. The relationships that have developed between these groups of animals are not competitive in nature. All these animal species use different components of the vegetation cover, “eating” what is not available to other herbivores. Different-quality participation in eating grass or the placement of organisms in different ecological niches provides a more complex structure of the biocenosis in a given territory, ensuring a more complete use of living conditions in natural ecosystems and maximum consumption of its products. The coexistence of these animals is characterized not only by the absence of competitive relationships, but, on the contrary, ensures their high numbers. Thus, the increase in gophers and their settlement observed in recent decades is the result of increased grazing of domestic animals in the steppe regions due to an increase in the number of livestock. In places deprived of grazing (for example, protected lands), a decrease in the number of marmots and gophers is observed. In areas with rapid grass growth (especially in tall grass areas), marmots leave completely, and ground squirrels remain in small numbers.

Plants living in the same layer have similar ecological niches, which helps to weaken competition between plants of different layers and causes them to develop different ecological niches. In a biocenosis, different plant species occupy different ecological niches, which weakens interspecific competitive tension. The same plant species in different natural zones can occupy different ecological niches. Thus, pine and blueberry in the blueberry forest, aquatic plants (pondweed, egg capsule, waterweed, duckweed) settle together, but are distributed in different niches. Sedmichnik and blueberry in temperate forests are typical shady forms, and in the forest-tundra and tundra they grow in open spaces and become light. The ecological niche of a species is influenced by interspecific and intraspecific competition.

In the presence of competition with closely related or ecologically similar species, the habitat zone is reduced to optimal boundaries (Fig. 14), i.e. the species spreads in the zones most favorable for it, where it has an advantage over its competitors. If interspecific competition narrows the ecological niche of a species, preventing it from manifesting itself in full, then intraspecific competition, on the contrary, contributes to the expansion of ecological niches. With an increased number of species, the use of additional food begins, the development of new habitats, and the emergence of new biocenotic connections.

Its ecological niche is called. The ecological niche of a species is characterized by the limits of its endurance in relation to various factors, the nature of its connection with other species, its way of life, and its distribution in space.

Often the concept of “ecological niche” is considered as a synonym for the concept of “habitat”, but the concept of a niche is much broader and more meaningful. The American ecologist Odum figuratively called the habitat the “address” of an organism (species), and the ecological niche its “profession.”

A large number of organisms of different species live in one habitat. 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 similar habitats, 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 subcanopy space: feeding on green plants or their parts, reproduction and shelter in thickets.

Elements and rules of an ecological niche

Elements of an ecological niche:

• food (types);
• time and methods of nutrition;
• breeding place;
• place of shelter.

Ecological niches exist according to certain rules:

• the wider the requirements (limits of tolerance) of a species to any or many environmental factors, the larger the space that it can occupy in nature, and therefore the wider its distribution;
• if the regime of any, at least one, environmental factor in the habitat of individuals of one species has changed in such a way that its values ​​go beyond the limits of the niche, then this means the destruction of the niche, that is, the limitation or impossibility of preserving the species in a given habitat. Other important patterns are also associated with the concept of “ecological niche” - each species has its own, unique ecological niche, i.e., as many species on Earth, so many ecological niches (2.2 million species of living organisms, of which 1.7 million species of animals). Two different species (even very close ones) cannot occupy the same ecological niche in space;
• in every ecosystem there are species that claim the same niche or its elements (food, shelter). In this case, competition is inevitable, the struggle to own a niche. Such relationships are reflected by Gause's rule: if two species with similar requirements for the environment (nutrition, behavior, breeding sites) enter into a competitive relationship, then one of them must die or change its lifestyle and occupy a new ecological niche.

An ecological niche is the totality of all requirements of a species (

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

The concept of ecological niche has proven to be very fruitful for understanding the laws of coexistence between species. Many ecologists worked on its development: J. Grinnell, C. Elton, G. Hutchinson, Y. Odum and others.

The concept of “ecological niche” should be distinguished from the concept of “habitat”. In the latter case, we mean that part of the space that 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, no less, on its biocenotic environment. The nature of the ecological niche occupied is determined both by the ecological capabilities of the species and by the extent to which these capabilities can be realized in specific biocenoses. This is a characteristic of the lifestyle that a species can lead in a given community.

G. Hutchinson put forward the concepts of a fundamental and realized ecological niche. Under fundamental refers to the entire set of conditions under which a species can successfully exist and reproduce. In natural biocenoses, however, species do not develop all the resources suitable for them due, first of all, to competitive relations. Realized ecological niche - this is the position of a species in a specific community, where it is limited by complex biocenotic relationships. In other words, the fundamental ecological niche characterizes the potential capabilities of a species, and the realized one characterizes that part of them that can be realized under given conditions, given the availability of the resource. Thus, the realized niche is always smaller than the fundamental one.

In ecology, the question of how many ecological niches a biocenosis can accommodate and how many species of any particular group that have similar environmental requirements can live together is widely discussed.

Specialization of a species in nutrition, use of space, time of activity and other conditions is characterized as a narrowing of its ecological niche, and reverse processes are characterized as its expansion. The expansion or narrowing of the ecological niche of a species in a community is greatly influenced by competitors. Competitive exclusion rule formulated by G.F. Gause for species that are similar in ecology, can be expressed in such a way that two species do not coexist in the same ecological niche.

Experiments and observations in nature show that in all cases where species cannot avoid competition for basic resources, weaker competitors are gradually driven out of the community. However, in biocenoses there are many opportunities for at least partial delimitation of the ecological niches of species that are similar in ecology.

Exit from competition is achieved due to divergence of requirements for the environment, changes in lifestyle, which, in other words, is the delimitation of the ecological niches of species. In this case, they acquire the ability to coexist in the same biocenosis. Each of the species living together is capable of more complete use of resources in the absence of a competitor. This phenomenon is easy to observe in nature. Thus, herbaceous plants in a spruce forest are able to be content with a small amount of soil nitrogen, which remains from being intercepted by tree roots. However, if the roots of these spruce trees are cut off in a limited area, the nitrogen nutrition conditions for the grasses improve and they grow rapidly, taking on a dense green color. Improving living conditions and increasing the number of a species as a result of removing from the biocenosis another, similar in environmental requirements, is called competitive release.

The division of ecological niches by co-living species with their partial overlap is one of the mechanisms of stability of natural biocenoses. If any of the species sharply reduces its numbers or drops out of the community, others take on its role. The more species there are in a biocenosis, the lower the number of each of them, the more pronounced their ecological specialization. In this case, they speak of “a denser packing of ecological niches in the biocenosis.”

Closely related species living together usually have very fine delineations of ecological niches. Thus, ungulates grazing in African savannas use pasture food in different ways: zebras pluck mainly the tops of grasses, wildebeests feed on what zebras leave for them, choosing certain types of plants, gazelles pluck the shortest grasses, and topi antelopes are content with tall dry ones. stems left behind by other herbivores. The same “division of labor” in the southern European steppes was once carried out by wild horses, marmots and ground squirrels (Fig. 92).

Rice. 92. Different types of herbivores eat grass at different heights in African savannas (top rows) and in the Eurasian steppes (bottom rows) (according to F. R. Fuente, 1972; B. D. Abaturov, G. V. Kuznetsov, 1973)

In our winter forests, insectivorous tree-feeding birds also avoid competition with each other due to their different search patterns. For example, nuthatches and pikas collect food on tree trunks. At the same time, nuthatches quickly examine the tree, quickly grabbing insects or seeds caught in large cracks in the bark, while small pikas carefully search the surface of the trunk for the smallest cracks into which their thin awl-shaped beak penetrates. In winter, in mixed flocks, great tits conduct a wide search in trees, bushes, stumps, and often in the snow; Chickadees inspect mainly large branches; long-tailed tits search for food at the ends of branches; small kinglets carefully search the upper parts of coniferous crowns.

Ants exist in natural conditions in multi-species associations, the members of which differ in lifestyle. In the forests of the Moscow region, the following association of species is most often found: the dominant species (Formica rufa, F. aquilonia or Lasius fuliginosus) occupies several layers, L. flavus is active in the soil, Myrmica rubra is active in the forest litter, the ground layer is colonized by L. niger and F. fusca, trees – Camponotus herculeanus. Specialization for life in different tiers is reflected in the life form of species. In addition to separation in space, ants also differ in the nature of obtaining food and in the time of daily activity.

In deserts, the most developed complex of ants collect food on the soil surface (herpetobionts). Among them, representatives of three trophic groups stand out: 1) diurnal zoonecrophages - active in the hottest time, feeding on the corpses of insects and small living insects active during the day; 2) nocturnal zoophages - they hunt sedentary insects with soft covers that appear on the surface only at night, and molting arthropods; 3) carpophages (day and night) - eat plant seeds.

Several species from the same trophic group can live together. The mechanisms for exiting competition and delineating ecological niches are as follows.

1. Size differentiation (Fig. 93). For example, the average weights of working individuals of the three most common diurnal zoonecrophages in the Kyzylkum sands are in the ratio 1:8:120. Approximately the same ratio of weights is found in a medium-sized cat, lynx and tiger.

Rice. 93. Comparative sizes of four species of ants from the group of diurnal zoonecrophages in the sandy desert of the Central Karakum and distribution of prey of three species by weight class (according to G. M. Dlussky, 1981): 1 – medium and large workers of Cataglyphis setipes; 2 – S. pallida; 3 – Acantholepis semenovi; 4 – Plagiolepis pallescens

2. Behavioral differences consist of different foraging strategies. Ants that create roads and use the mobilization of carriers to carry discovered food to the nest feed primarily on the seeds of plants that form clumps. Ants, whose foragers work as solitary foragers, collect mainly seeds of plants that are dispersedly distributed.

3. Spatial differentiation. Within the same tier, food collection by different species can be confined to different areas, for example, in open areas or under wormwood bushes, on sandy or clayey areas, etc.

4. Differences in activity time relate mainly to the time of day, but in some species there are discrepancies in activity between seasons (mainly spring or autumn activity).

The ecological niches of species vary in space and time. They can be sharply differentiated in individual development depending on the stage of ontogenesis, as, for example, in caterpillars and adults of lepidoptera, larvae and May beetles, tadpoles and adult frogs. In this case, both the habitat and the entire biocenotic environment change. In other species, the ecological niches occupied by young and adult forms are closer, but nevertheless there are always differences between them. Thus, adult perches and their fry living in the same lake use different energy sources for their existence and are part of different food chains. The fry live off small plankton, while the adults are typical predators.

The weakening of interspecific competition leads to the expansion of the ecological niche of the species. On oceanic islands with a poor fauna, a number of birds, compared to their relatives on the mainland, inhabit more diverse habitats and expand the range of food, since they do not encounter competing species. Among island inhabitants, there is even increased variability in the shape of the beak as an indicator of the expansion of the nature of food connections.

If interspecific competition narrows the ecological niche of a species, preventing all its potential from being manifested, then intraspecific competition, on the contrary, contributes to the expansion of ecological niches. With an increased number of species, the use of additional food begins, the development of new habitats, and the emergence of new biocenotic connections.

In reservoirs, plants that are completely immersed in water (elodea, hornwort, urut) find themselves in different conditions of temperature, illumination, and gas conditions than those floating on the surface (telores, watercolor, duckweed) or rooting at the bottom and bringing leaves to the surface (water lily, egg capsule, Victoria). They also differ in their relationships with the environment. Epiphytes of tropical forests occupy similar, but still not identical niches, since they belong to different ecological groups in relation to light and water (heliophytes and sciophytes, hygrophytes, mesophytes and xerophytes). Different epiphytic orchids have highly specialized pollinators.

In a mature broad-leaved forest, the trees of the first tier - common oak, smooth elm, sycamore maple, heart-leaved linden, and common ash - have similar life forms. The tree canopy formed by their crowns ends up in the same horizon, under similar environmental conditions. But a careful analysis shows that they participate in the life of the community in different ways and, therefore, occupy different ecological niches. These trees differ in the degree of light and shade tolerance, timing of flowering and fruiting, methods of pollination and distribution of fruits, composition of consorts, etc. Oak, elm and ash are anemophilous plants, but the saturation of the environment with their pollen occurs at different times. Maple and linden are entomophiles, good honey plants, but they bloom at different times. Oak has zoochory, while other broad-leaved trees have anemochory. The composition of consorts is different for everyone.

If in a broad-leaved forest the tree crowns are located in the same horizon, then the active root endings are located at different depths. The roots of oak penetrate most deeply, the roots of maple are located higher and the roots of ash are even more superficial. The litter of different tree species is utilized at different rates. The leaves of linden, maple, elm, and ash almost completely decompose by spring, and the leaves of oak still form loose forest litter in the spring.

In accordance with the ideas of L. G. Ramensky about the ecological individuality of species and taking into account the fact that plant species in a community participate in the development and transformation of the environment and energy transformation in different ways, we can assume that in the existing phytocenoses each plant species has its own ecological niche .

During ontogenesis, plants, like many animals, change their ecological niche. As they age, they use and transform their environment more intensively. The transition of a plant into the generative period significantly expands the range of consorts and changes the size and intensity of the phytogenic field. The environment-forming role of aging, senile plants decreases. They are losing many consorts, but the role of the destructors associated with them is increasing. Production processes are weakened.

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 intensities, competition in stable phytocenoses is weakened.

Rice. 94. Correlation between foliage layer diversity and bird species diversity (Shannon MacArthur indices from E. Pianka, 1981)

Bibliography

Shilov I. A. Ecology. M.: Higher School, 1997.

Khristoforova N.K. Fundamentals of ecology. Vladivostok: Dalnauka, 1999.

Gilyarov A. M. Population ecology. M.: Moscow State University Publishing House, 1990.

In this lesson you will learn about the most important concept of modern biology and ecology - the “ecological niche”. Get acquainted with the spatial, behavioral (phenological) and temporal characteristics of the ecological niche of a living organism, consider the rule of competitive exclusion of species with the same ecological niche, discovered by the Russian scientist G.F. Gause. Find out what factors influence the diversity of ecological niches in biogeocenosis. Understand the difference between a fundamental and a realized ecological niche.

It includes three main characteristics:

Behavioral characteristic describes the nature of food production, methods of protection from enemies, methods of combating unfavorable abiotic factors. It includes requirements for the quantitative and qualitative composition of food, as well as the presence of natural enemies and competitors.

Spatial characteristics describes the habitats of species. Includes characteristics of species necessary directly for living or providing building material, symbionts and commensals.

Time characteristic describes the daily, annual and seasonal activity of the species.

For clover, the ecological niche would include:

Temperate climate

Moderate hydration

Slightly acidic or neutral-alkaline soil pH

Herbaceous layer

Good lighting (more than 17,000 lux)

Lack of shading forms of vegetation

Presence of arthropod pollinators

Presence of nitrogen-fixing nodule bacteria

Growing season spring-summer

For the lynx, the ecological niche would include:

Temperate cold climate

Coniferous forest condition

Placement in woody and herbaceous layers

Main diet: medium-sized ungulates (roe deer, musk deer), as well as hares and grouse birds

Type of hunting: sneaking, providing shelter among trees and terrain elements

Lifestyle: daytime, all-season

Natural enemies and competitors - wolves

In the process of evolution occurs specialization or universalization species by type of nutrition, use of space, time of activity. Accordingly it happens narrowing or extension ecological niche.

The narrowing of the ecological niche in the process of evolution occurs, as a rule, under the influence of competitors.

Russian scientist G. F. Gause formulated competitive exclusion rule , Whereby onean ecological niche in a biocenosis cannot be occupied by two species.

The more the ecological niches of species overlap, the more pronounced the competition. As a result, one of the species disappears. A way out of the situation is achieved by diverging requirements for the environment and changing lifestyles, that is, dividing ecological niches.

For example, in a mature broad-leaved forest, the trees of the first tier (common oak, smooth elm, sycamore maple, cordate linden) have similar life forms (Fig. 1).

Rice. 1. Plants with a similar ecological niche, growing in the first layer of deciduous forests

The tree canopy is formed by their crowns, and they find themselves in the same horizon under similar environmental conditions. But they participate in plant communities in different ways and occupy different ecological niches. These trees differ in light-loving and shade-tolerant, flowering and fruiting periods, methods of pollination and distribution of fruits.

Thanks to the delimitation of ecological niches, species have the opportunity to exist in the same biogeocenosis. If one of the competitors in the biocenosis is absent, then the other, as a rule, can fully use all the necessary environmental resources that previously went to the lost competitor.

Different biogeocenoses provide living organisms with different numbers of ecological niches.

On wealth of ecological niches influenced by two groups of factors:

Mosaic and diversity biotope

Number of species or biodiversity

A new species, entering the biocenosis, gradually becomes part of it. Its representatives create new habitats, join food chains, and find new symbionts and antibionts.

Separation of food types of ungulates

Closely related species living together usually have very fine delineation of ecological niches.

Thus, ungulates in African shrouds use pasture food in different ways. Zebras pick off the tops of grasses, wildebeests feed on what zebras leave for them, taking in a certain type of plant, gazelles pluck out the shortest grasses, topi antelopes are content with tall dry stems (Fig. 2).

Rice. 2. Food differentiation of ungulates in the savanna

Fundamental and realized ecological niches

There are concepts fundamental And realized ecological niche .

Usually, in real conditions of biogeocenosis, due to competitive relations, a species cannot take advantage of all favorable environmental conditions.

In other words, the fundamental ecological niche describes the potential capabilities of a species, and the realized ecological niche describes the actual distribution of the species in the conditions of a given community.

Thus, the fundamental ecological niche is always much wider than the realized niche.

Ecological niche for several species

In addition to the ecological niche of each individual species, an ecological niche is distinguished for a group of species that have a certain “profession” in the biogeocenosis.

Thus, we can identify an ecological niche nocturnal predators, granivorous rodents, water filters and etc.

The same ecological niche on different continents can be occupied by different species (see video)

Bibliography

1. A.A. Kamensky, E.A. Kriksunov, V.V. Beekeeper. General biology, grades 10-11. - M.: Bustard, 2005. Download the textbook from the link: ()
2. D.K. Belyaev. Biology 10-11 grade. General biology. A basic level of. - 11th edition, stereotypical. - M.: Education, 2012. - 304 p. ()
3. V.B. Zakharov, S.G. Mamontov, N.I. Sonin, E.T. Zakharova. Biology 11th grade. General biology. Profile level. - 5th edition, stereotypical. - M.: Bustard, 2010. - 388 p. ()
4. IN AND. Sivoglazov, I.B. Agafonova, E.T. Zakharova. Biology 10-11 grade. General biology. A basic level of. - 6th edition, expanded. - M.: Bustard, 2010. - 384 p. ()

1. Bioword.narod.ru ().
2. Sbio.info().
3. Bio.fizteh.ru ().
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5. Biologiya-uroki.ru ().

Homework

1. What is an ecological niche?
2. What types of ecological niche do you know?
3. How is the ecological niche of representatives of a particular species formed?
4. What is the essence of the biological phenomenon of competition? What are its consequences?
5. Using the diagram proposed in the lesson, describe the ecological niche of an animal or plant common in your area.
6. How is the realized ecological niche related to the fundamental one? What about the fundamental niche of pets?
7. How can you practically use knowledge about an ecological niche?
8. Discuss with friends and family what ecological niche is typical for our species.

Each organism is influenced by various environmental conditions during its existence. These can be factors of living or inanimate nature. Under their influence, through adaptation, each species takes its place - its own ecological niche.

general characteristics

A general characteristic of the cell occupied by an animal or plant consists of defining and describing its model.

An ecological niche is a place occupied by a species or individual organism in a biocenosis. It is determined taking into account a complex of biocenotic connections, abiotic and biotic factors of the habitat. There are many interpretations of this term. According to the definitions of various scientists, the ecological niche is also called spatial or trophic. This is because, settling in his cell, the individual occupies the territory he needs and creates his own food chains.

The hypervolume model created by J. E. Hutchence is currently dominant. It is a cube, on its axes there are environmental factors that have their own range (valency). The scientist divided the niches into 2 groups:

• Fundamental ones are those that create optimal conditions and are equipped with the necessary resources to support the life of the population.
• Realized. They have a number of properties that are determined by competing species.

Characteristics of ecological niches

The characteristics of ecological niches include three main components:

• Behavioral characteristic is the way a particular type reacts to stimuli. And also how it gets food, the features of its shelter from enemies, its adaptability to abiotic factors (for example, the ability to withstand cold or heat).
• Spatial characteristics. These are the coordinates of the population location. For example, penguins live in Antarctica, New Zealand, and South America.
• Temporary. It describes the activity of species in a certain period of time: day, year, season.

The principle of competitive exclusion

The principle of competitive exclusion states that there are as many ecological niches as there are species of different organisms. Its author is the famous scientist Gause. He discovered patterns while working with different species of ciliates. The scientist first grew the organisms in monoculture, studying their density and feeding method, and later combined the species for breeding in one container. It was noticed that each species significantly decreased in number, and as a result of the struggle for food, each organism occupied its own ecological niche.

It cannot be that two different species occupy the same cell in a biocenosis. To become a winner in this competition, one of the species must have some advantage over the other, be more adapted to environmental factors, since even very similar species always have some differences.

Law of Constancy

The law of constancy is based on the theory that the biomass of all organisms on the planet should remain unchanged. This statement was confirmed by V.I. Vernadsky. He, the founder of the doctrine of the biosphere and noosphere, was able to prove that with an increase or decrease in the number of organisms in one niche, it is necessarily compensated for in another.

This means that an extinct species is replaced by any other that can easily and quickly adapt to environmental conditions and increase its numbers. Or, conversely, with a significant increase in the number of some organisms, the number of others decreases.

Mandatory Completion Rule

The mandatory filling rule states that an ecological niche never remains empty. When a species goes extinct for any reason, another immediately takes its place. The organism that occupies the cell enters into competition. If he turns out to be weaker, he is forced out of the territory and is forced to look for another place to settle.

Ways of coexistence of organisms

Methods of coexistence of organisms can be divided into positive ones - those that benefit all organisms, and negative ones, which benefit only one species. The former are called “symbiosis”, the latter – “mutualism”.

Commensalism is a relationship in which organisms do not harm each other, but also do not help. Can be intraspecific and interspecific.

Amensalism is an interspecific mode of coexistence in which one species is oppressed by another. At the same time, one of them does not receive the required amount of nutrients, which is why its growth and development slow down.

Predation - predator species with this method of coexistence feed on the body of the victims.

Competition can be within the same species or between different ones. It appears when organisms need the same food or territory with optimal climatic conditions for them.

Evolution of human ecological niches

The evolution of human ecological niches began with the period of the existence of archanthropes. They led a collective way of life, using only those abundances of nature that were maximally accessible to them. The consumption of animal food during this period of existence was reduced to a minimum. To search for food, archanthropes had to develop a large amount of feeding territory.

After man mastered the tools of labor, people began to hunt, thereby having a significant impact on the environment. As soon as a person obtained fire, he made the transition to the next stage of development. After the increase in population, agriculture arose as one of the ways to adapt to food shortages in places where natural resources were almost depleted by intense hunting and gathering. During the same period, cattle breeding emerged. This led to a sedentary way of life.

Then nomadic cattle breeding arose. As a result of human nomadic activity, a huge amount of pastures is depleted, this forces nomads to move and develop more and more new lands.

Human ecological niche

The ecological niche of a person changes along with changes in the way people live. Homo sapiens differs from other living organisms in its ability to articulate speech, abstract thinking, and a high level of development of material and intangible culture.

Man as a biological species was distributed in the tropics and subtropics, in places where the altitude above sea level was up to 3-3.5 km. Due to certain features endowed with man, his habitat has greatly increased in size. But as far as the fundamental ecological niche is concerned, it has remained virtually unchanged. Human existence becomes more complicated outside the original space; he has to confront various unfavorable factors. This is possible not only through the adaptation process, but also through the invention of various protective mechanisms and devices. For example, man invented different types of heating systems to combat such an abiotic factor as cold.

Thus, we can conclude that the ecological niche is occupied by each organism after competition and adheres to certain rules. It must have an optimal area of ​​territory, suitable climatic conditions and be provided with living organisms that are part of the food chain of the dominant species. All living beings that are within a niche necessarily interact.