What is intraspecific competition. Types of interspear relations. Competition. Examples of competitive relationships

Competition in biology (from lat. concurrere - Faced) - interaction in which two populations (or two individuals) in the struggle for the necessary conditions affect each other negatively, i.e. Mutually oppress each other. The most satisfactory is the formulation proposed by Bigon, Harper and Townsend ( BEGON, HARPER, TOWNSEND, 1986): "Competition - interaction that reduces that one organism consumes a resource that would be available for another organism and could be consumed." It should be noted that competition can manifest itself and then when there is enough resource, but its availability is reduced due to the active opposition of individuals, which leads to a decrease in the survival of competing individuals.

Competitors Call organisms that use the same resources for their livelihoods. Plants and animals compete with each other not only for food, but also for light, moisture, food, living space, asylum, nesting - for everything, from which the well-being of the species may depend on.

Two types of competition are distinguished: intraspecific competition and interspecific. Internal competition is competition between representatives of one or several populations of some kind of resource when it is missing. Competition is extremely widespread in nature. Competition between individuals of one species living on one territory is the most acute and tough in nature, as they have the same need for environmental factors.

Internal competition In one or another stage of the existence of a specific species, it is almost always found, therefore, in the process of evolution, the organisms have developed adaptations that reduce its intensity. The most important of them is the ability to resettle the descendants and the protection of the boundaries of the individual section (territoriality), when the animal protects the place of its nesting or a certain area, a sexual partner, a place for reproduction, the ability to extract food. Thus, intraspecific competition is the struggle between individuals of one species. Intraspecific strugglethe existence is enhanced with an increase in the number of population, a reduction in the range (territory) and the strengthening of the specialization of the species.

Examples of intraspecific territorial competition in animals

Rivalry individuals of one type of food resource, when it is not enough, you can observe the population of field mice of one species. Waning out and consuming food, mouses consume energy and expose themselves to be eaten predators. Under favorable conditions, when food is sufficient, the population density increases and the need for organisms arise to spend more energy to search for food. As a result, the chances of survival are reduced.

Internal competition It can be expressed in direct aggression (active competition), which is physical, psychological or chemical. For example, males, competing for the right to have a female, can fight among themselves. To demonstrate your appearance to eclip the opponent, or with the help of the smell, keep rivals at a distance. The struggle for females, space and light often leads to active competition.

Territoriality - Territoriality. Active dispersal of individuals of one or different species in space due to competition for itself and resources available in it. ( Source: "Anglo-Russian Dictionary of Genetic Terms").

Some fish, many types of birds and other animals are characterized by the so-called territoriality - intraspecific competition for space. In birds, this competition is manifested in the particular behavior of males. For example, at the beginning of the breeding season, the male chooses a habitat (territory) and protects it from the invasion of males of the same species (birds singing in the spring - a signal on the right of ownership of the busy area). So the males of many species of birds determine the competitiveness of opponents in voting, and seriously perceive only equal to themselves by age or senior birds, American ornithologists have proved. In the protected area of \u200b\u200bcare about the nest and juveniles will not be violated by the presence of other parent couples. During the reproduction of birds, the male guards a certain territory, to which, except for his female, does not allow any individual of its species. And the louder of the male shouts the more he scares the invader, the bird strengthens its singing, and soon goes into the offensive. The couple who secured the territory has more chances to find a sufficient amount of food and it helps to do everything you need to remove the offspring.

Under the territorial behavior they understand the set of signaling means ensuring dispersing and regulating the relationship of the owners of neighboring or partially overlapping areas of habitat. In different animal species, these signals can be contact and distant (bird singing, wolves, rogging of grasshoppers, etc.). A set of visual and tactile threatening signals (up to open aggression and fights) is used in the collision of neighbors on the overall boundary and territory. With the help of sounds, many vertebrates determine their territory. The males of the monkey are guarding their huge territory, publishing an extremely loud roar, which is heard 5 km. For each type of revunov, its special sound is characteristic. For marking boundaries, some animals use a variety of odorous substances.

Animals protect their territory with the help of special signs and they are trying to cast out strangers from it. Animals will sweat their territory using sounds, light signals, smells, and frighten the non-crushed guests with claws, culbs or plumage. Such animals as sea lions and marine elephants protect their territory only during the marriage season, and the rest of the time they do not show signs of aggression to other representatives of their species. Frogs and fish are also fighting for the territory only in the marital season. Everyone heard the evening triads of frogs in a pond near the house. The barley male during the breeding period protects the territory around the nest from the invasion of other males.

Interesting chemical signals with which animals will make their territory, can be observed at roe and antelope. In the autumn period, the Siberian Rosila rides the horns of the bark of small trees and shrubs, and then rub on their head or neck. So it leaves chemical labels on the bared parts of the trees, which are allocated by special glands located on the head and neck. Trees are marked in this way indicate other features of the population of this species roeble, which the territory is busy or here passed another animal. It is possible that the intensity of chemical discharge on the label other animals determine the time of passage (applying the label) of the animal - the host. Sometimes the same roebles knock out the hooves of the plates of the Earth, leaving the remaining smell of them between their finger glands.

The antelope on the bushes and high herbs bite the top of the escape and touching the cut before the eye gland left the label. Large gerbil, as a rule, makes the signal hilly, edrebing the earth to itself, and ironing them from above the belly, where it is located that is located the pryomons (special chemicals) of the middle abdominal iron. Barsuk marks the entrance to Noura secret under the tail, rabbit - chin. Many types of lemurs leave odorless secrets on branches that move.

Some rodents use interesting marks as limiting their territory. Large gerbil, as a rule, makes the signal hilly, edrebing the earth to itself, and ironing them from above the belly, where it is located that is located the pryomons (special chemicals) of the middle abdominal iron. In the forests of Panama and Costa Rica live two types of singing mice, Scotinomys Teguina. and S. Xerampelinus.who like the birds vote label their put on. Both types of mice make special vocal sounds that a person, however, can barely disassemble. This is not just a squeak: rodents get up on the hind paws, thrust our heads and produce a series of recurring sounds like a trill.

The movement of house mice occurs according to the same routes, thanks to the steady smells of pheromones standing out with the urine. On the legs of each individual there are also special glands with which they "mark" the territory. The smell of these glands is transmitted to any subject they touch. Urine also serves as a kind of signaling device.

Scientists have established the presence of rats in the urine not only the means of metabolism, but also a number of other components - pheromones, which in rats serve as signals that determine the position and state of the individual.

Ondatra - settled and territorial animal actively protects its territory from the invasion of neighbors. The boundaries are marked with bouches of excrement on elevated places in the water. Also, animals will make the boundaries of their "possession" of glands, the strong smell of which serves as a signal of the employment of this site.

Pins and feline dilated in certain places, stating thus on some territory. Dogs will make the territory, both urine and feces, spreading, thus, information about themselves, which other representatives of their species can receive. Cats will also be scolded by urine. Cats additionally mark their territory secrets (liquid), which is distinguished between the fingers and from the glands, located in the area from the corner of the lips to the foundation of the ear. Tags left by a dog in the form of excrement, the smell of which can be enhanced by the secreted secretion from the special glands, located in the rear pass of the animal not long. This secret attaches individual smell of dog excrement. However, this substance carries short-term information, as it has the ability to quickly disappear. In addition, dogs themselves actively lick the rear pass, thus getting rid of this smell. With the help of claws and urine, the tiger marks its territory on the bark of trees. Prints of claws on the crust carry information about the size and social status of their predator who left them.

Bears will make their territory that they rub back about the trees, "hanging out" on the trunks of the shred wool. First, they make special margins: when they are suitable for the border tree, radically change the gait and leave deeper, noticeable traces. Then they jump slices of the bark from the tree, scratch it and make snacks. At the same time, they can bite the tree at different heights: standing on four and on two paws. In addition, the bear marks its territory with the smell marks, leaving the allocation of glands on trees in the jar from claws. To split the bears space, a loud signal cry is often used. Sometimes the individual is simply attacked by each other.

Territorality Development Steps:

The first stage of the development of territority is an individual space surrounding each individual. It is clearly noticeable, for example, in the rods sitting on a tree, or from the starring in a flying flock. The individual protects it from the invasion and opens for another individual only after the courtship ceremony before mating.

The second stage is a defendant place for life, rest or sleep in the middle of the non-defendant area of \u200b\u200bactivity (many predators of the hunting site). Animals standing on the second stage are practically evenly distributed. These are bears, tigers, hyenas, as well as rodents.

The third step is the rational use of space, where these territories are formed - plots from which other individuals are expelled. The owner of the plot dominates on it, he is psychologically often stronger than a stranger, who tried to penetrate its territory, and often for exile in most cases, only demonstrations, threats, persecution, the largest - pretended attacks, which stop at the boundaries of the site, labeled visually, acoustically or odor (olfactory). It is noticed that even smaller individuals were expelled from their plot larger congor. So repeatedly observed, which is much smaller in size and younger than the ondatra ran out of its plot larger and older in age. At the examples of other animals, scientists have established that almost always the owner of the site drove the foreign representative of the same species, which entered into its territory.

Output:
Territorial competition in animals is manifested in the absence of a lack of resources and contributes to the optimization of the existence of each individual of this species. Each individual holds its area of \u200b\u200bterritory and is aggressively tuned towards neighbors. This leads to a clear separation of the territory inside the population.

Territorial behavior occurs at a wide range of animals, like fish, reptiles, birds, mammals and public insects. This phenomenon is based on the congenital desire of individuals on freedom of movement on some minimal area.

For intraspecific competition, their features are characteristic. The reason for its occurrence is a typical situation when the resource for which the individual is struggling is quantitatively limited. There is a rigid competition (for the territory, feed resources, etc.), which is observed at high population density.

Another form of intraspecific competition is rivalry, when one individual does not give another to occupy an existing territory and use its resources. In this case, a form of ideal or uncompromising competition is possible, which is solved by emigration to other territories.

The acuity of competition and its influence on the population depends on the density, which determines the frequency and intensity of contacts of competitors.
Intravidaya competition not only depletes the resources and this leads to an increase in mortality, delay in the growth of individuals, it encourages self-aggression, cannibalism, reduces the implementation of a potentially possible contribution of individuals into the next generation and development of the population.
Internal competition between individuals of populations in plants can be described as a struggle for light, heat, moisture, mineral area. In this competition, the organisms are stronger than the organisms that are nearby, they displace the weak very or very much inhibit the development of them and lead to gradual die off. That is why, in agrofitsenoses to reduce competition and the creation of optimal conditions for the growth and development of cultivated plants, the density of individuals and the area of \u200b\u200btheir mineral nutrition are regulated by the corresponding type of sowing or discharge of crops, the destruction of weeds and the selection for mixed crops of biologically compatible species.

In natural populations of plants, an imposter has a decrease in the number of individuals per unit area.
Such a phenomenon is known to forests. The number of trees per unit area decreases with age of plantations. The bias of the angle occurs the faster than the larger breed and the best environmental conditions. The latter is associated with an increase in the growth rate in good terms and, accordingly, the growth of its needs, from which competition becomes tense (Fig. 9.2).

Each type of its optimal density is characteristic, i.e. Such a degree of saturation of the territory of the population by its individuals, which ensures the best reproduction and the greatest stability of the population, reduces the sharpness of competition.

In animals of different species, too, in the process of evolution, appropriate adaptive adaptations to life in an environment are amissized or densely populated by the population.
The relevant biological properties and strategy of life have been developed, allow organisms to multiply and survive in the conditions of "competitive vacuum" (absence or small competition). In the first case, small animals can multiply, their descendants will survive, although the population density will be high.

In the second case, large animals and relatively the same descendants will be perpetrated in competition. Therefore, the main energy of organisms is aimed at competitive, to increase its survival, to produce competitive descendants.

These trends and strategy of various species are reflected in the two opposing types of natural selection: R - and K - selection, which is considered in chapter 2.
Internal competition between individuals of plants of one population can be calculated using the iodine equation. Using this equation, the average area of \u200b\u200bthe area per particular (a) is inversely proportional to the population density (D).

Competition (from Late. Concurentia - Faced), the type of relationship between the organisms of the same or different species competing for the same weigh resources (sexual partners, food, territory, asylum, etc.) with the lack of latter. Internal competition is considered as the most important form of struggle for existence, since potentially the most acute competitive relations arise between more similar individuals. For example, in mammals in bright form expressed competition between males for the possession of the female during the reproduction period. During Gona, males of many species ( deer, barnes, bears) arrange fierce tournament battles.

Competition for the territory, asylum and food is most fully expressed in territorial species with a single lifestyle (some miserable rodents, choppers, predatory mammals). However, in nature there are mechanisms (environmental, behavioral, etc.), which reduce the heat of intraspecific competition. For example, many aggressive actions of animals during mutual contacts are ritualized and are designed, first of all, intimidate the enemy, without bringing contact to physical interaction.

Interwide competition is more often observed between individuals of environmentally friendly species using the same habitat and food resources. Such functionally similar groups of species that strongly interact with each other and weakly with the rest of the biocenosis are often isolated in the guild (the term is proposed by R. B. Rutom in 1967). The idea of \u200b\u200bguilds is closely related to the environmental niche model.

Competition may be passive (indirect), through the consumption of resources of the external environment necessary by both types, and active (direct), accompanied by the suppression of one species to others. The first option is often called operational competition, and the second - interference. An example of active competition can be the relationship between acclimatized American and aboriginal European minks in which the aboriginal view It turned out to be uncompetitive.

The status of competition in a long-term aspect is not energy to both competitors, therefore various mechanisms are being implemented in nature, which reduce the intensity of interspecific competitive relations, based, in particular, on the division of resources and the formation of differing environmental niches. The result of the action of intraspecific and interspecific competition is usually different (see also Speciation). The first leads to the selection of the least competitive (least adapted) individuals and, in conditions of the unchanged environment, to narrowing the norm of the reaction of the type, specialization (stabilizing selection; see Natural selection), and in a directionally changing medium - to the shift of the reaction rate in the direction determined by the changing medium, i.e., to the occurrence of a new adaptive form (driving selection; see Natural selection).

Internal competition

Interwide competition leads to further divergence of species at the expense of Morph, with similar requirements.

Natural selection), and in a directionally changing medium - to the shift of the reaction rate in the direction determined by the changing medium, i.e., to the emergence of a new adaptive form (driving selection; see Natural selection). Interwide competition leads to further divergence of species at the expense of Morph, with similar requirements.

In natural communities, animals of one and different species live together and interact with each other. In the process of evolution between animals, certain relationships are produced, reflecting the relationship between them. Each type of animal performs a certain role in the community with respect to other living organisms.

The most obvious form of relationships between animals is predation. In natural communities there are herbivores that feed on vegetation, and there are carnivorous animals that catch and eat other animals. In the relationship, herbivores are speaking victimsam.and carnivny - predatoram.. At the same time, each victim has its predators, and each predator has its own "set" of victims.

Internal competition

So, for example, lions hunt for zebras, antelope, but not on elephants and mice. Insectivore birds catch only certain types of insects.

Predators and victims in the process of evolution adapted to each other in such a way that some developed body structures developed, allowing you to catch as much as possible, while others have such a structure that allows them to run away or hide. As a result, predators catch and eat only the weakest, sick and least adapted animals.

Predators do not always eat herbivores. There are predators of the second and third order, which eat other predators. This is often found among the water inhabitants. So some types of fish are powered by Plankton, the second - these fish, and a number of aqueous mammals and birds eaten the second.

Competition - A common form of relationships in natural communities. Usually the most acute competition is manifested between animals of one species living on one territory. They have the same food, the same habitats. Between animals of different types, competition is not so acute, since their lifestyles and needs are somewhat different. So the hare and mouse - herbivores, but eating different parts of the plants and lead a different lifestyle.

Population of the relationship of individuals in the population

The population is a set of individuals of one species having a common living space and type of relationships with each other. The individuals of the population differ in themselves by age and the vitality (that is,

Competition (biology)

vital strength), which can be determined genetically, phenetically, and more often - a combination of these factors.

A number of significant differences that need to be considered in population studies have plants and animal populations. The main difference is that possessing animals can more actively respond to the emerging conditions of the external environment, avoiding unfavorable concrete concrete circumstances or dispersed on the territory to compensate for the reducing the reserve of the resource per unit area. Mobility facilitates them and protection against predators.

Due to the fact that the populations are diverse, the interactions of individuals within their composition differ.

the main type of interaction of individuals in the population is competition, i.e. Competition for the consumption of the resource that is missing. Competition may be symmetrical (competing individuals have the same effect on each other) or asymmetric (the effect of individuals is different from each other).

features of competing individuals in the population:

1. Competition reduces the speed of growth of individuals, can slow down their development, reduce fertility and eventually - reduce its contribution to the next generations. The number of descendants of a particular individual is less than the tougher conditions of competition and the less resources went to it.

2. In most cases, individuals compete for resources: each individual receives the limited number of resources that has not been consumed by its competitors. Such competition is called operational. It is less likely to compete for the physical space when the individual "mechanical" impede each other in obtaining a resource, say, protect moving animals of its territory. Such relationships are called interference.

3. Different individuals have a different competitive ability. Despite the fact that all the individuals of the population are potentially equivalent (there is a permanent alignment of their gene pool due to hybridization), in nature the equivalence of individuals is not observed. In the end of the asymmetric competition there is a decrease in the population density: weak plants are dying, and weak animals migrate in habitats with lower Competition level.

In addition to competition, other forms of individual relations in populations are also possible - neutrality (if there are so many resources and individuals so little that they practically do not interfere with each other) and positive relationships.

Mutually beneficial (or profitable individuals) relations between animals are well known: the concern of parents about the offspring, the formation of large family groups, herd lifestyle, collective defense from enemies, etc. "Caravans" of birds built into the ranks, wedges, ledges, etc. ., Allow the wings of individual individuals due to aerodynamic effects to gain large lifting force (in the team to fly easier). It is believed that hydrodynamic advantages receive and floating fish fish.

The role of mutual assistance in plants is significantly less well known. Plants awaited by the group are developing better, since in this case they are easier formed symbiosis with mushrooms and bacteria of mycorrhizia and the rhizosphere (the so-called "group effect").

Possible phenomena of mutual assistance of plants under the "collective defense" from phytophages that show excessively high activity and capable of seriously damaged by plants. In this case, after the start of active feeding, phytophages in plants occur biochemical reactions and the concentration of substances increases that reduce their eatencability (cyanides, etc.). Cases are described when individuals who are attacked by phytophages were isolated to the atmosphere. The signaling substances ("Eating me" signal), which caused an increase in the formation of cyanides from those individuals that are not yet damaged.

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Competition is a competition of organisms of one trophic level (between plants, between phytoofhagami, between predators, etc.) for the consumption of a resource available in limited quantities.

a special role is played by competition for the consumption of resources in critical periods of their deficit (for example, between plants for water during drought or predators for sacrifices in an unfavorable year).

There are no fundamental differences in interspead and intraspecific (intrapopulation) competition. It is possible as cases where intraspecific competition is more acute than interspecific and vice versa. At the same time, the intensity of competition within the population and between populations may vary in various conditions. If the conditions are unfavorable for one of the species, then the competition between its individuals can increase. In this case, it can be ousted (or more often - died) a view for which these conditions turned out to be more appropriate.

However, in the multi-axis communities of Poulalyant couples, it is most often not formed, and the competition is characterized by diffuse: many species at the same time compete for one or more environmental factors. "Duelists" can only be massive types of plants that divide the same resource (for example, trees - linden and oak, pine and fir, etc.).

Plant has competition for light, for the resources of the soil and for pollinators. On the soils rich in resources of mineral nutrition and moisture, dense closed vegetable communities are formed, where the limiting factor for which the plants compete is light.

When competing for pollinators, it wins the type that is more attractive for the insect.

In animals, competition occurs for food resources, such as herbivores compete for phytomass at the same time competitors of large units can be insects like locusts, or mathithic rodents, capable of destroying most of the mass reproduction. Predators compete for sacrifices.

Since the amount of food depends not only on environmental conditions, but also from the area where the resource is reproduced, the competition for food can be converted into competition for the occupied space.

As in the relationship between individuals of one population, competition between species (their populations) can be symmetric or asymmetric. At the same time, the situation where the conditions of the environment are equally favorable for competing species, it is quite rare, and therefore the relationship of asymmetric competition occurs more often than symmetrical.

With fluttering resources, which is usually in nature (moisturizing or elements of mineral nutrition for plants, primary biological products for different types of phytophages, the population density of victims for predators), alternately benefits the benefits of different competing species. It also does not lead to competitive exclusion, but to the coexistence of species that alternately fall into a more profitable and less profitable situation. At the same time, the deterioration of environmental conditions can be worried when a decrease in the level of metabolism or even transition to the state of rest.

It affects the outcome of competition and the fact that there is more chances to win in a competitive struggle, in which more individuals and which, accordingly, will more actively reproduce "their army" (the so-called mass effect).

23.Investment plant phytophage And the victim of the predator

Relationship "Plant-Philofag".

The relationship "Phytofag - Plant" is the first food chain link, in which the substance and energy accumulated by producers are transmitted to consultations.

For plants, equally "unprofitable" so that they are eaten to the end or did not eat at all. For this reason, in natural ecosystems, the tendency of the formation of an environmental equilibrium between plants and their phytophagami eating them is manifested. For this plant:

- they are protected from phytophages spiny, form the sockets with pressed to the ground with leaves, increasingly available for grazing animals;

- They are protected from fully remedy by biochemical by producing toxic substances that make them less attractive for phytophages (this is especially characteristic of slowly growing patients). In many species, with their eating, the formation of "tasteless" substances is enhanced;

- Mix the smells, screking phytophages.

Protection against phytophages requires significant energy costs, and therefore tradoff traced in the relationship "Philofag - Plant": the plant grows faster (and, accordingly, the better conditions for its growth), the better eaten, and vice versa, the plant is growing slower, the fact It is less attractive for phytophages.

At the same time, these means of protection do not provide complete preservation of plants from phytophages, as it would lead to a number of unwanted consequences for the plants themselves:

- The unbearable steppe grass turns into a rag - felt, which worsens the living conditions of plants. The appearance of abundant felt leads to the accumulation of snow, the delay in the start of development of plants in spring and as a result - to the destruction of the steppe ecosystem. Instead of steppe plants (nicknames, tichard), meadow species and shrubs develop. At the northern border of the steppe after this meadow stage, the forest can restore;

- In Savannah, a decrease in the consumption of trees of trees by venewed animals (antilopes, giraffes, etc.) leads to the fact that their crowns are closed. As a result, fires and trees do not have time to recover, Savannah is reborn in the thickets of shrubs. \\

In addition, with insufficient consumption of plants, phytophages are not exempt to settle the new generations of plants.

The "imperfection" of the relationship "Philofag - Plant" leads to the fact that short-term outbreaks of populations of phytophages and temporary depression of plant populations are quite often happening, followed by a decrease in the density of phytophage populations.

Relationship "Victim-Predator".

The relationship of the "predator - the victim" represents the links of the process of transmission of the substance and energy from phytophages to zoofagam or from the predators of the lower order to the predators of the highest order.

As with the relationship of the "Plants - Phytofag", the situation in which all victims will be eaten by predators, which will ultimately lead to their death, is not observed in nature.

Ecological equilibrium between predators and victims is supported by special mechanisms that exclude full extermination of victims.

So the victims can:

- To run away from the predator.

In this case, as a result of adaptation, mobility and victims increase, and predators, which is especially characteristic of steppe animals, which is not known to hide from the pursuers ("Principle of Tom and Jerry");

- acquire a protective color ("pretend to" with leaves or bitch) or, on the contrary, bright (for example, a red color warning predator about bitter taste. It is well known to change the painting of the hare at different times of the year, which allows him to disguise in the summer in foliage, and in winter on the white background snow;

- spread by groups, which makes them search and fishing for a predator more energy-intensive;

- hide in shelter;

- transition to the measures of active defense (herbivores, having a horns, spiny fish), sometimes joint (shepherds can occupy a "circular defense" from wolves, etc.).

In turn, predators are developing not only the ability to quickly persecute the victims, but also smell, allowing the smell to determine the location of the victim.

At the same time, they themselves do everything possible in order not to detect their presence. This explains the cleanness of small cats, which for eliminating the smell, spend a lot of time to the toilet and bury excrement.

With intensive exploitation of phytophage populations, a person often excludes predators from ecosystems (in the UK, for example, there are roe and deer, but there are no wolves; in artificial water bodies where carp is bred and another pond fish, there is no shock). In this case, the role of a predator is performed by a person himself, the result of a phytophaga population of individuals.

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Competition is a typical phenomenon for wildlife. It is caused by struggle for resources. But if we talk about intraspecific competition, it should be noted that this type of competition is characterized by the greatest intensity.

This is primarily due to the fact that the individuals of the same species need some kind of strictly defined resource in which there may not be the need for individuals of another species. Therefore, often with this type of competition, there is a depletion of any resource or a certain type of resources.

For example, in the grass mixture, consisting of pea and barley, the most fierce competition for soil nitrogen will go precisely between the barley plants. This is due to the fact that, due to the ability of pea, fix nitrogen from the air, the need for competition between pea sprouts for nitrogen in the soil is reduced.

Distinguish operating and interference Competition.

The first is that all individuals at the same time exploit resources, but each of them uses only what remained after a competitor. In the second case, one person does not give another to occupy existing habitat and use its resource. Another first form of competition is called rigid competition, and the second - rivalry. The first type of competition can lead to the death of the entire population. For example, in green fallen flies when overcoming the population of larvae on the source of nutrition, this type of competition may lead to the fact that at a certain age stage, the entire population of the offspring will die.

A somewhat different rivalry looks. For example, if 100 pours of birds claim 100 in some forest massif, it becomes obvious that 50 pairs will not be able to equip their nests in this area. Therefore, the only possible option for the work of the offspring can serve as the migration of these birds on another territory (i.e. emigration).

By virtue of a number of reasons, competing individuals of the same species are not equal to competing. Therefore, in nature, the strongest or the one who is more lucky due to the coincidence of circumstances is survived. So, the most ordinary sprout that climbed a little earlier than its tribesmen will continue to shade the lowest copies.

Ignorance of laws related to intraspecific competition can lead to sad consequences. For example, in agricultural production, a significant excess of seed seeding norms per unit area can lead to complete crop loss. Competition, numerous plants will simply not be able to give a harvest, but even live to reproductive age.

Competition is directly related to such a concept as an ecological niche, which is not only certain conditions of the environment to which the body is adapted, but also a way of life and a method of producing food. Often this term is used mainly to interspecific competition, but in fact the ecological niche is characteristic even for each individual organism of one species.

Another interesting factor in intraspecific competition is the body size of organisms. So, the growth of fish does not stop even after the achievement of puberty, and is determined by the reserves of feed. The American ecologist R. Whitteker leads to this such example. There are two identical ponds. The first produces 100 fry, and in the second - 50. As a result, at an equal period of time, the sizes of fish in the first pond can be twice as smaller than in the second. However, the weight of fish both in the first and in the second pond may be approximately the same.

In addition to monotonous depletion of resources, intraspecific competition can lead to intoxicating the entire population. This is due to the fact that the products of the allocation of organisms of the same species are, in fact, poison for them. For example, in the plant community, the root allocations of some plant species can be nutritional elements for other plant species. Therefore, in the wild, you can easily meet the communities represented by some one-sole species.

Another grandfather Darwin in his evolutionary theory noted that the acuteness of the struggle for existence is mostly manifested among representatives of one species. And although in the recent achievements of genetics and a number of other biological sciences on the theory of Ch. Darwin, there is an increasing number of comments and claims, however, while in biology no one has come up with anything more significant.

According to the Ukrainian ecologist V. Kucherovy: "Internal competition has many negative consequences. It not only imposes resources and leads to intoxicating the environment, but also contributes to self-aggression and cannibalism, social and reproductive inability. "

The above quotation of Will-Neils causes associations with human society. There was a time when the analogies of the laws of nature with relationships within the human society led a number of thinkers to create such a teaching as Social-Darwinism, which, according to the ecoophilosophy of M. Bon, "tied all the wild features of civilization with our genetic constitution." According to this teaching, property inequality in society is explained as interspecific competition between individual individuals of one type of one population.

And geopolitical inequality between states is explained as intraspecific competition between the populations of one species.

At first glance, everything is true. However, if you perceive Social Darwinism seriously, it turns out that a person is intelligent, in fact, is not, but is a typical biological species. Obviously, it is not. But the mainly withdrawal of this teaching is that it does not try to change something for the better, and trying not to even explain so much how much to justify the existing position of things. In Social Darvinism, the most important thing is not reflected - further perspective. Indeed, in the current environmental realities it becomes clear that both the intraspecific and interspecific competition of a person so much depletes the resources of the biosphere, which undermines the biological diversity of the entire global ecosystem, and therefore threatens the human form himself.

In modern biological science, scientists are increasingly paying attention not to competition, but mutual assistance and cooperation. But about it - in one of the following publications. In short, you can say the following. A person is a social being, therefore a number of biological laws are leveled at the expense of artificial public institutions and established behavioral norms. At the same time, it is impossible to underestimate biological laws in the vital activity of the human type. It can be said that many social mechanisms are only the means that simply pulls the reaction of biological laws. And as soon as this mechanism is destroyed due to the spontaneous, competitive or resource overload, the biological laws of survival show themselves in its entirety.

In the past two decades, fierce disputes are conducted in environmental literature about the role of competition in limiting the spread and dynamics of natural populations of different types, and, consequently, in determining the structure of the community. According to some researchers, populations included in natural communities are sufficiently strictly controlled by the system of competitive relations, sometimes, the truth is modified by the impact of predators. Others believe that competition between representatives of different species is observed in nature only episodically, and the population, for the most part, being limited by other factors, as a rule, do not reach those densities in which competitive relations become defining. There is also a compromise point of view, which involves the presence of some continuum of real natural communities, at one end of which - communities, stable in time, rich, or, more precisely, saturated with species that are rigidly controlled by biotic interactions, and in the other community unstable ( In most cases, due to the fact that abiotic conditions in their habitats are not stable), not saturated with species (T, E. allowing the introduction of new species) and controlled, as a rule, poorly predictable changes in external conditions.

To obtain direct evidence of the importance of the role of competition in determining the dynamics and distribution of populations in nature is very difficult. Usually we can judge about it only on the basis of indirect evidence, but we note that the indirect nature of certain certificates should not serve as a basis for ignoring them. In cases where a number of independently obtained indirect certificates are built into a logically substantiated and non-contrary to common sense, one should not reject this scheme on the basis that there are no direct evidence. It is also necessary to emphasize that the competition itself is not so often to observe in nature. The main mass of existing certificates of competition concerns such a distribution of species relative to each other in space or time, which can be interpreted as a result of competition. Below we present a few examples of this distribution.

Exploring changes in the species composition of birds in Peruvian Andes as raised to the mountains, Ya. Terborgh (Terborgh, 1971) found that the species of one kind are very clearly replacing each other, and the borders of the distribution are often not associated with the vertical belt of vegetation, but are probably determined Only competition between close species. In the Scheme (Fig. 57), borrowed from the work of Ya. Terborgha It is clear that the more species of the same kind on all the surveyed height range, the smaller the height interval accounts for an average of one species. So, from a height of 1000 to a height of 3,400 m there are two representatives of the same kind, then the interval of 1200 m occurs on each, and if three types of one kind in the same range are inhabited, then each species falls on average 800 m. Similar The distribution explicitly indicates competition, and it is unlikely to be explained without taking into account interspecific interactions (MacArthur, 1972). Important additional evidence of competition in the case described by Ya. Terborh, were obtained when studying the vertical distribution of birds held with the participation of the same author (Terborgh, Weske, 1975) in Andes, but not on the main ridge, but on a small insulated mountain range, Located from it 100 km. The number of types of species here was significantly less than on the ridge, but the same species met in a larger height range, indicating that it is competitive relationships, and not abiotic factors limit their distribution on the main ridge.

Many examples of interspecific competition gives the Island Fauna (Mayre, 1968), whose representatives often demonstrate a mutually exclusive distribution, although the mainland live side by side. So, M. Radovanovich (Radovanovic, 1959; quoted: Mayr, 1968), having studied the spread of lizards of the kind Lacerta. on the 46 islands of the Mediterranean Sea near the coast of Yugoslavia, found out that there were only 28 islands Lacerta Melisellensis, And on the rest - only Lacerta sicula. There is not a single island on which both types would have dwell together.

In more rare cases, researchers could directly observe the expansion of the distribution area of \u200b\u200bone species, accompanied by the disappearance or reduction of the number in this area of \u200b\u200banother species, which is its potential competitor. So, from the end of the XIX, up to the middle of the XX century. In Europe, there was a sharp reduction in the range of widespread cancer (Astacus Astacus) and the corresponding extension to the north-west of the area of \u200b\u200ba relative species - long-shaped cancer (Astacus Lepiodactylus), Capturing the entire Volga pool, and then penetrated the Neva and Seversk Donets (Birstein, Vinogradov, 1934) into the pool. Currently, both species are found in the Baltic States and Belarus, however, cases of their location in one reservoir are very rare (Zucerzis, 1970). The displacement mechanism of one species is not clear to others, with the exception of those few cases when the long-shaped cancer was specifically launched into those reservoirs, where widespread died in the epizootia of the "rach of the plague" - a fungal disease capable of completely destroying the population of river cancers. It is likely that the successful extension of the range A. Lepiodactylus. contributed to the fact that compared to A. Astacus. It grows faster, it is more fruitfulness and the ability to eat around the clock, and not only at night, like widespread cancer.

On the territory of the British Islands there was a sharp reduction in the range of ordinary proteins (Sciurus vulgaris) After being conjugable from North America close to it, the type of Caroline proteins (Sciurus Carolinensis), Although the nature of competitive displacement remained unknown. Types living on the islands are especially suffering from universal universities, which, as a rule, are more competitive. As E. Mair notes (1968), most of the bird species disappeared over the past 200 years were island.

It is obvious that the increase in the distribution area of \u200b\u200bone species, which coincides with the simultaneous reduction in the distribution area of \u200b\u200banother environmentally friendly species, does not necessarily be due to the consequence of competition. Other biotic factors can also affect a similar shift of habitats of habitats, such as predators, availability of feed objects or a change in abiotic conditions. So, as an example of competitive displacement was considered before the change in the distribution on Newfoundland of two types of hares: a polar hare Lepus Arcticus) n American hare-beyak Lepus Americanus). More than a hundred years ago, only the polar hare died on the island, which inhabited the most various biotopes, both in the mountains and in the forest valleys. Drawn on the island at the end of the last century, Zayac Besak spread through forest valleys, and the polar hare began to meet only in mountain flameshedral areas. There was a simple hypothesis of competitive displacement of one species to others, but then it turned out (Bergerud, 1967), then in the disappearance of the polar habit of forest areas is the predator - Lynx (Lynx Lynx), the number of which has sharply increased after the instill on the island of Zaitz-Belyak. An indirect argument in favor of the fact that the press of predators played in this case a decisive role, serves the disappearance of the polar hare from the areas where the bias-whisk penetrated, but which by the nature of vegetation are convenient for the persecution of Zaitsev's trot. Thus, the hypothesis of competitive exception in this case, although it was not fully rejected, should have yielded a hypothesis that takes into account the relationship between three species: two potential competitors and one predator.

Coexistence of competing species. Models of dynamics determined by the concentration of resources

If there is significantly proven cases of competitive outstanding one species to others in natural conditions, and on the value of competition as a factor determining the dynamics of populations and communities, endless discussions are underway, the numerous facts of coexistence are environmentally friendly and therefore most likely competing doubts do not cause . So, we have already mentioned the "plankton paradox", but with no less reason you can talk about the "meadow paradox", since a number of types of grassy plants, limited by light, moisture and the same set of mineral nutrition elements, grow side by side In one place, although they are in competitive relationships.

In principle, the coexistence of competing species (T, E. Failure to comply with the Law of the GAUZ) can be explained by the following circumstances: 1) the population of different types is limited to different resources; 2) the predator mainly eats a stronger competitor; 3) the competitive advantage of species varies depending on the impermanence of external conditions (i.e., competitive displacement does not reach the end, replacing a period favorable for the form previously displaced); 4) The populations of different species are in fact divided in space - time, and what is represented by an observer by one habitat, from the point of view of the studied organisms contains a whole set of different habitats.

To explain the coexistence of species competing for a limited number of resources, it is necessary to at least briefly consider the model dynamics of populations limited in its development of the amount of available resource. The basis of this model lies already mentioned above the idea of \u200b\u200bthe so-called threshold concentration of the resource R * i.e., the minimum concentration at which the birth rate is precisely balanced mortality (see Fig. 44), and the population retains a stationary number. Obviously, in different types depending on one resource, the values \u200b\u200bof threshold concentrations may not coincide, but if there is a lot of resource in the environment, then both types are growing with maximum speeds, and faster increasing its number that has more fertility in this concentration. and mortality (i.e. value b - D). Obviously, however, that in the natural situation as the number of organisms that consume this resource increases, its concentration is reduced in the medium, and when it reaches the threshold for this type of organisms of the magnitude, the population is beginning to fall. As a result of competition of two types, one resource wins the one for which the threshold concentration of the resource.

Now consider a model with two resources, the values \u200b\u200bof the concentrations of which in the environment R 1. and R 2. We postpone on two orthogonal axes (Fig. 58). In the coordinate space of these resources, we carry out a line corresponding to the values \u200b\u200bof the concentrations of the first and second resources, in which the population retains its number of constant ( dN / NDT \u003d 0). This line, called the isoclinic zero increase, actually corresponds to the threshold for this type by combinations of concentrations of the first and second resources. If the points corresponding to the resource-observed resource concentrations lie from this line closer to the beginning of the coordinates, then the population of these concentration values \u200b\u200bwill fall. If they lie for isoklin, then the population will grow.

Note that straight isocline on the considered graph is carried out only for simplicity. This case corresponds to the interchangeability of resources, so on. The possibilities of the species successfully exist, consuming only one of the resources or content with some combination thereof. In fact, the isocline may be concave (resource complementarity) in cases where, feeding with a mixture of different components, the body consumes them in an amount less than when powered by each of these components separately, and convex, for example, in synergies of the effects of toxic substances consumed with different food components. Note that to maintain a constant number in one type (Fig. 58, but) It takes a much larger second resource than the first, but another type (Fig. 58, b.) It may be a more effective consumer of the second resource that requires it, respectively, less than the first one.

Let us now try on the same schedule to spend the zero increase for the second type. Obviously, if the isocline of the type in will be closer to the beginning of the coordinates than isocline of the type A (Fig. 58, b), then the winner in competition will be the view of both the concentration of both resources to such a low level in which the stationary population will be Views can not exist. If the isocline of the type in will be further from the start of coordinates than isocline of the species A, then the winner in competition is precisely A (Fig. 58, d). If the isoclines of two species intersect, then with a certain ratio of resources in the medium, species can coexist, and with a friend - one type of one species can be observed. So, for example, in the situation shown in Fig. 58, d, With a high concentration of the second resource and low concentration of the first, the competitive advantage affects the form A, and at high concentration of the first resource and low concentration of the second advantage turns out to be at V. V.

The example above corresponded to the resources, completely interchangeable. However, for most organisms there is a number of resources of irreplaceable. So, for example, no matter how well a plant with nitrogen is well provided, it will not be able to grow and develop if there is no phosphorus in its nutrient medium. In the coordinate axes of the two resources of the zero increase in the population, limited to such "two resources, will be depicted with a line bent at a right angle, i.e. so that it is consisting of two branches parallel to the string axes (Fig. 59, but). The position of each branch corresponds to the threshold concentration of the first or second resource. If two species compete in two indispensable resources, then in the same way as in the case of interchangeable resources, various options for each other are the zero growth of these species relative to each other. Obviously, in the situation shown in Fig. 59, b, The winner will be the view A, and in the figure shown in Fig. 59, b - species V. When crossing isoclin (Fig. 59, g.) Both species can be achieved, since various resources are limiting for each of them.

The latter occasion is experimental confirmation. So, David Tilman (Tilman, 1982), which made a great contribution to the development of modern ideas about competition for resources,. spent a series of experiments with two types of diatom planktonal algae Asterionella Formosa. and Cyclotella meneghinia And on the basis of the data obtained, it was built for them with zero increase, depending on the concentration of two essential resources - phosphorus and silicon (Fig. 60).

As part of this model, it is relatively easy to explain the coexistence of different types if they are limited to different resources. However, the concept of "different resources" needs to be clarified. So, probably, everyone will agree that various types of plants for fitofophages can be considered as different resources. With slightly smaller grounds, but, apparently, we can say that different parts of one plants can be interpreted as different resources. However, the number of elements of mineral nutrition required by plants along with light and moisture is very limited. In any case, it is significantly less than the number of types of plankton algae, living within a small volume of water (remember the "plankton paradox"), or the number of types of grassy plants growing on one meadow. An attempt to explain the coexistence of many species competing for a small number of shared resources was undertaken by D. Tilman (Tilman, 1982). To clarify the essence of its reasoning, it is necessary to make some complications in the model described above.

Let's start with the fact that all previous arguments were based on the assumption of stable concentrations of resources. It is clear, however, that in fact, resources, as well as their populations, are in the constant dynamics of PLI, in any case, in a state of dynamic equilibrium, in which the resource consumption is balanced by the influx of it on Wednesday. If we imagine that consumers can withdraw from the environment, it is obvious that there are some higher concentrations of limiting resources. The point corresponding to the concentrations of resources in the absence of consumption, D. Tilman suggested calling the supply point (eng. Supply Point). In fact, in an implicit form, we have already used this concept when we discussed the models depicted in Fig. 58-59, and spoke about one or another observable concentration of resources. In fig. 61 In the space of two indispensable resources, the supply point is applied (its coordinates S 1, S 2) And the isocline of zero increase for one species. At each point on this isoblin, the fertility, by definition, is equal to mortality, but this does not mean that the ratio in the consumption of two resources is necessarily exactly equal to their relation when entering Wednesday. From each point we can conduct vector consumption FROMshowing the direction in which the population seeks to move the threshold concentration and the supply vector U, Directional to the supply point and showing the ratio of resources that would be established in the medium with some weakening of its consumption by this population. Vector consumption and supply vector can be directed in strictly opposite sides (at an angle of 180 °): In this case, the corresponding point on the isoclin will be called the equilibrium point (point E. In fig. 61). At other points of isoblin, vector consumption and supply vector may be at an angle less than 180 °: such a ratio of resources will be nonequilibrium.

Fig. 61. Izoklin zero population growth in coordinates of indispensable resources (by Tilman, 1982)

Fig. 62. Isoclines of two species limited to two indispensable resources: C A and C B - consumption vectors (by Tilman, 1982)

Fig. 63. Isoclines of four types (A, B, C, D), limited to two resources. Each of the circles shows a certain variability in a quantitative ratio of resource data in the medium (by Tilman, 1982)

In the case of intersection of the isocline of two species competing for two independent resources, the equilibrium point of resources is just an intersection point of isoclin. In fig. 62 shows the consumption vectors (and continuing their supply vectors) emanating from the equilibrium point. The coexistence of species in this case is steadily, since each of the competing species consumes the resource that limits the growth of its own population. In particular, in fig. 62 View and more consumes the second resource, and the view is first. If the situation was reverse, then the coexistence of species would be unstable. If you refer to the diagram shown in Fig. 62, where the numbers are indicated by separate areas, limited by isoclins and vectors, then in the region 1 none of the way but can not exist in the region 2 And may exist, and can not; And the area 6 The opposite position is observed - in may exist, and not; in area 4 both species successfully coexist; in area 3 A. competitively displaces in, and in the area 5 In Competence, A.

Instead of two species in the space of two resources, we can depict the isoclines of a number of species and from the intersection points of these isoclins to carry out the supply vectors that limit areas in which the coexistence of each pair of species is possible (Fig. 63). At different points of this space, one species, two views or any one can dwell. In other words, with a precisely defined quantitative ratio of two resources in each particular case, the principle of competitive exception is carried out: the number of coexisting species does not exceed the number of limiting resources. But if we turn to nature from an idealized model, we will find that even closely located points in any real space of any habitat (both ground and water) differ quite strongly on the quantitative ratio of limiting resources. In addition, a ratio defined for any point may vary in time. For example, by D. Tiliman, a very detailed study of the distribution of nitrogen content in the soil of a section of 12 × 12 m was shown by a variation of 42%, and the variation in the magnesium content on the same site reached 100%. Spatio-temporal variability in the receipt of resources on Wednesday in Fig. 63 can be depicted with a circle of a certain diameter. As can be seen from the scheme, if this circle is placed in the area of \u200b\u200bhigh concentrations, then no more than two types can coexist with such variations, but if the same circle is placed in the field of low values, it can cover the coexistence region at once a number of species. In other words, at very low concentrations of limiting resources, even very small variability of them from one point of space to another or from one point in time to another, it is enough to ensure the real possibility of coexistence at once a large number of species (in any case, much more than the number of limiting resources ). From this follows another curious conclusion: when enriching the environment of resources, we have the right to expect a decrease in species diversity. Such a reduction in the number of species and strengthening the numerical predominance of a few species are indeed observed both in the aquatic environment (eutrophing phenomenon) and in the ground (depletion of the species composition of the meadows with long-term fertilizer).

Conclusion

In nature, any population of the form of organisms enters into a network of relationships with other types of populations: relationship type predator - the victim (or resource - consumer) and competitive relationships are one of the most important in the lives of any organisms and at the same time some of the most studied. Under the increase in the number of victims, it is observed as a functional reaction of a predator (i.e., an increase in the number of victims consumed per unit of time by one person of the predator) and numerical (i.e., an increase in the number of predator population). Due to the ability of predators to the functional and numerical reaction, the press on the victims population acts as a factor depending on the density and therefore possessing regulatory effects.

According to the theory developed by mathematicians, the system of interrelated populations of the predator and the victim, most likely should demonstrate the oscillatory regime, but even in the laboratory conditions to obtain sustainable fluctuations in the predator - the victim is almost very difficult. In the same cases, when it succeeds, researchers, as a rule, limit the amount of food for the victim or create complex heterogeneous habitats, in which the victim and predator can migrate, and the speed of the victim's resettlement is somewhat larger than the predator resettlement rate. In natural conditions, we are usually visible only to follow the number of predator for vibrations of the victim, determined by other factors not directly related to the impact of this predator.

The evolution of the predator and the evolution of the victim is always intertwined closely. One of the possible victims of predators from the press of predators in the evolution is an increase in fertility (compensating for the corresponding increase in mortality from the predator). Other possible ways: this is an avoidance strategy with a predator or a strategy for developing morphological, physiological and biochemical means of protection against it. Both of these strategies aimed at direct decline in the predator mortality are conjugate to the victim with certain spending, which are eventually expressed in reducing the birth rate. The evolution of a predator is aimed at increasing its own fertility and (or) a decrease in mortality, which is almost always associated with an increase in the efficiency of the use of victims.

Competitive relations between populations of different species occur when they are in dire need of one resource existing in insufficient quantities. Competition can flow by type of operation, i.e., a simple use of a scarce resource, or by the type of interference, in which individuals one species creates interference to the individuals of the other in the use of shared resources.

In ecology there is a long tradition of a theoretical research of competition. According to the mathematical model of Volterry trays, later developed and confirmed experimentally, the city of F. Gause, two species competing for one resource, as a rule, cannot sustainably coexist in a homogeneous medium, and the outcome of competition is determined by the ratio of the intensity of self-restraint each of the populations and their constructions. . This rule, also known as the GAUZ law, or the principle of competitive exception, as a result of a comprehensive study of theorists and experimenters has undergone a certain development. In modern formulation, it states that the number of species that are unlimitedly coexistent in constant homogeneous habitat conditions cannot exceed the number of density-dependent factors limiting the development of their populations.

The Gause law continues to maintain heuristic importance for naturalists studying competition in nature. Direct evidence of the importance of the role of interspecific competition in nature is immeasurably harder than in the laboratory. Therefore, as a rule, the value of competition as a factor determining the dynamics and distribution of natural populations is judged by the aggregate of indirect evidence.

In some cases, the number of coexistent species competing for general, the resources limiting their development is clearly more than the number of such resources (an example is the plankton algae community or community of meadow plants), which contradicts the law of Gause. This contradiction is removed, however, the theory that takes into account the spatial and temporary variability in the provision of competing species with limiting resources.

In Russian, the word "ecology" was first mentioned, apparently, in a brief sentence of "general morphology", E. Geckel - a small book, published in 1868, edited by I. I. Mechnikov.

Now we are, however, we begin to realize that, perhaps, and for nothing to strive to develop ecology and biology in general by sample physics. It is possible that the biology of the future will be closer to the humanitarian sciences. In any case, the "fitness" is one of the central concepts in Darvinism (and this is the only fairly common eco-evolutionary theory) - refers to the field of semantic information (Zarengkov, 1984).

The richest group of organisms on earth - insects. Insect species are much larger than all other types of animals and plants combined. The total number of them remains unknown, since most inhabitants in the tropics are not yet described. Until recently, it was believed that insects 3-5 million species, but in recent years they have appeared (May, 1988), indicating that this figure should be increased, perhaps an order of magnitude, that is, the number of insect species on Earth At least 30 million grounds for this revaluation were, in particular, the results of the survey of the crowns of tropical trees. So, by applying the method of fumigation to exile insects from the crown, it was possible to show that at 19 copies. one type of tropical evergreen trees Geuhea Seemanni. In Panama, 1100 species lived in Panama.

The reduced definition, as indicated by the author, is a somewhat modified definition of the ecology proposed by the Australian researcher in Andrevartha (AndrewArtha. 1961), which in turn proceeded from ideas developed in the 20th centuries. C. Elton (1934; ELTON, 1927).

This situation was observed, however, in physics. As Waiskopf (1977) noted, the progress made by this science in a new time is associated with the refusal of attempts to establish all the truth and explain entirely the entire universe. Instead of setting general questions and receive private answers, scientists began to ask more private questions, but, no matter how surprisingly, they received more general answers.

Note that the expressions are "sufficiently perfect" or "sufficiently adapted" does not at all mean that this type is adapted in the best possible way, and continue to improve him. From the said it should not also be that each species lives in nature in the most optimal conditions. It often happens that the most optimal (in abiotic conditions) sections of its potential range is displaced by competitors or predators. It is enough to refer to at least the above example with an atrociety under a strong press of the listogryza Chrysolina.

In the English-language literature dedicated to the evolutionary aspects of ecology, the English saying "Jack of All Trades Is A Master of None" is very often quoted, which can be roughly translated into Russian: "The one who takes to do any job does not make one of them "

Systematics specialists are noticed (Skvortsov, 1988) that certain names of taxonomic categories are rather names of their own, not nine. For example, saying "Class of Monocoons" or "Class of Required", we first imagine one-bedroom and reptiles, and not a certain "class in general" is a conditional unit of systematics that agreed that classes are divided into units, but are combined into types.

Among the domestic scientists, such a point was defended by S. S. Schwartz (1969). Currently adheres to A. V. Yablov (1987), which in his book "Population Biology" determines the population as "... a minimal self-reproducing group of individuals of one species, throughout an evolutionary long time inhabiting a certain space forms an independent genetic system and forming its own ecological space "(p. 150). Explaining its definition, A. V. Appleov emphasizes that "... population is always a fairly numerous group of individuals, for a large number of generations to a high degree isolated from other similar groups of individuals" (p. 151).

Clons are usually called groups of individuals that occurred from one ancestral form through vegetative or parthenogenetic reproduction of h because being very close relatives. Environmentalists are very often used in their experiments clones of algae, simplest, travmatics and other organisms.

A similar point of view, phytocenologists are often particularly strictly adhered. Instead of the term "population", they prefer to use the term "priceopopulation", thus emphasizing that it is not just a set of plants of a certain species, but a totality, which is included in specific centencies (\u003d community).

N. P. Naumov in the 1960s. Consistently defended the "soft" definition of the population, rightly stressing that the disputes themselves about the possibility or inability to consider one or another grouping by the population are objective, since they reflect the natural hierarchical structure of the population. In our opinion, it is completely fair to N. P. Naumov (1965, p. 626) believed that the dynamics of the number is "a phenomenon that deployed not only in time, but also in space."

Assessment of the total population is especially important for disappearing, listed in the Red Book of species of animals and plants. The question of how the minimum permissible size of these populations may be acquired already purely practical.

Experts that study the methods of spatial distribution opens are recommended to use the indicator σ 2 / t. Only in cases where with an increase in the average (which is achieved by the use of larger platforms) dispersion increases according to a linear law. In other cases, other indicators of spatial aggregation (Romanovsky, 1979) are used.

We emphasize that in this example there is a dry mass of food (raw mass can be 10 times more). All figures are borrowed from the generalizing work B. D. Abaturova and V.N. Lopatina (1987).

The world of wildlife is amazingly diverse. The same can be said about the relationship between all kinds inhabiting the planet. Like people, animals can exploit, interfere in the affairs of each other or at all in no way interact with each other. Examples of competition in nature are quite frequent and natural phenomenon. Which of them are the most stronnight and interesting?

Examples of competitive relations in nature

Intervida competition has always been difficult to demonstrate in the field, and therefore you can not observe many specific examples. If two types use the same resource, it does not mean that they compete. Animals just no need to join the struggle where everything you need for survival is available in unlimited quantities. Such examples can be found in natural systems.

To say that the types compete, they must occupy the same ecosystem and use the overall resource, and as a result, this should lead to a decrease in the number of one of the populations or even to its complete destruction or exile. As a rule, it is much easier to demonstrate interference competition. This is when one species directly prevents access to a different type to a limited resource, and this leads to a decrease in survival.

One example of competition of organisms in nature is the Argentine ant. His homeland is South America, and this is one of the worst species of invasive ants around the world. When a colony finds a food resource, they are physically and chemically protect it, not allowing indigenous ants to access the food resource. They often attack and displace other colonies of fellow in the area. This leads to a decrease in the number of populations of ants. Since they physically interact with other colonies of ants, this is a classic example of interspecific competition in nature.

Invisible competition

It is much more difficult to detect examples of competition in nature in animals that do not directly interact with each other. Turtles eat only shrubs that they can reach, pulling the neck. Goats also eat bushes, but their choice is sewn than in the turtles. As a result, the second gets less vegetation, which is needed for survival and prosperity. This example of interspecific competition in nature proves the fact that some animals can reduce the number of others even without direct physical interaction.

Operation and intervention (interference)

Interwide competition occurs when different types of species in the ecosystem compete for the same resources: food, shelter, light, water and other important needs. Such a struggle can reduce the number of concrete species, moreover, the increase in the population of competitors also tends to limit the growth of a particular type. Thus, competition can be carried out in two ways at the level of individual organisms, namely: operational competition and interference competition.

Examples of competition in the nature of the first type include often invisible struggle for limited resources. As a result of using their specific species, they become insufficient for others. Intervention or interference means direct interaction to obtain resources.

Examples of intraspecific competition in nature, as well as interspecific, may include the struggle between prey predators. Thus, a cruel confrontation may occur inside the type (between two tigers) and between several species (between the lion and hyenas).

Possible effects

• As a result, there may be restrictions in the size of the population, as well as changes in communities and evolution of species.
• According to the principle of competitive exception, none of two species using the same limited resources in the same way in the same space can not exist together.
• Although local extinction is rarely found compared to the competitive exception and differentiation of niches, it also occurs.

Examples of competitive relationships

In a dense forest between tree plants, interspecific competition may occur. This is due to the fact that when there are mixed types of trees, access to resources for some of them can be easier than for others. For example, higher trees are able to absorb more sunlight, which makes it less affordable for lower trees.

Wild animals, such as lions and tigers, are also bright examples of competition in nature. They hunt for the same prey that can cause less availability of food resources for one of them. In addition, spotted hyenas compete with African lion for food. The same thing happens with brown bears and tigers. Zebra and Gazelles are fighting for the grass.

Competitive relations can be observed in the oceans, for example, it may be sponges and corals, rival for space. In the desert areas of Coyote and the rattle snake fiercely fighting for food and water. Intervida competition is also observed in small animals, such as proteins and chipmunks that tend to compete for nuts and other products.

Where both organism live in one niche and are in competition for resources or space, the negative result will inevitably be inevitably for each body, since the available resource will decrease for both sides.

Intraspecific struggle for existence

This competition is the most fierce and especially stubborn. This confrontation implies oppression and violent displacement, expulsion or destruction of less adapted individuals. Nature does not like weak in the struggle for resources and living space. One of the most bloodshed is the fights for female in the marriage.

Examples of competition in nature can be a variety of, including competition when choosing a sexual partner to continue the kind (deer), the struggle for living space and food (a stronger corona will be weak) and so on.

Interspear struggle for existence

If there is something directly or indirectly, individuals of various species are fighting, then here it is about interspecific competition. Especially persistent confrontation is observed between nearby creatures, for example:

1. Gray rat huses black from its living space.
2. Dremat's Drozd causes a decrease in the population of a singing thrush.
3. The cockroach Prusak successfully surpasses and infringe on black relatives.

Competition and struggle for existence are important driving forces of evolution. An important role is played by natural selection and hereditary variability. It is difficult to imagine how diverse and complex are the relationship between living beings inhabiting our planet. Intravidaya and interspecific competition are huge, if not crucial in the formation of biological diversity and regulating the numerical composition of populations.

Types of interaction between two species

The essence of interspecific competition is that the individuals of one species decreases fertility, survival, or growth rate as a result of the use of a resource or interference from individual species. However, this simple formulation lies a large number of the most diverse nuances. The influence of interspecific competition on the dynamics of the population of competing species of Multico. The dynamics in turn can influence the distribution of species and their evolution.

All these types of interactions are shown in Table 1.

Table 1 Analysis of interactions of populations of two species

• 1. 0 means the absence of significant interactions; + means improving growth, survival and other benefits for a population (a positive dick is added to the growth equation); - means slowing down growth and deterioration of other characteristics (negative member is added to the growth equation).
• 2. Types 2-4 can be considered "negative relationships", types 7-9 - "positive relationships", and Types 5 and 6 can be related to both these groups.

Three principles based on these categories should be emphasized:

• · Negative interactions are manifested in the initial stages of the community development or in disturbed natural conditions, where high mortality is neutralized by R-selection.
• · In the process of evolution and development of ecosystems, a tendency to reduce the role of negative interactions at the expense of positive, increasing survival of interacting species
• · In recently formed or new associations, the likelihood of strong negative interactions is larger than in old associations.

Effect on growth rate or mortality

One population often affects the growth rate or mortality of the other. Thus, members of one population can eat members of another population, compete with them for food, to allocate harmful substances or interact with them in a different way. In the same way, the populations can be useful for each other, and the benefits in some cases turn out to be mutual, and in others - one-sided. As shown in Table 1, the interactions of this kind are divided into several categories.

To clarify the actions of various factors in complex natural situations, as well as to more accurately determine the concepts and greater clarity of reasoning, it is useful to use "models" in the form of equations. If the growth of one population can be described using the equation, the influence of another population can be expressed by a member that changes the growth of the first population. Depending on the type of interaction in the equation, different members can be substituted. For example, if there is a competition, the growth rate of each population is equal to the speed of non-limited growth minus the effect of own number (which grows with an increase in the population number) and minus the value characterizing the negative effect of another species, N2 (which also grows as the numbers of both types of N1 and N2 ), or

Growth rate;

Non-limited growth;

The effect of own numbers;

Negative influence of another species.

When the types of two interacting populations have a favorable, and not damaging effect, a positive term is introduced into the equation. In such cases, both populations grow and thrive, reaching equilibrium levels, which is favorable for both species. If they need their mutual influence on each of the populations to grow and survive each other, then such relationships are called mutualism. If, on the other hand, these favorable influences only cause an increase in the size of the population or its growth rate, but are not necessary for its growth and survival, then such interaction corresponds to cooperation or protoco operation. (Since such cooperation is not a consequence of conscious or "reasonable" activities, it is preferable to use the last term). And mutualism and protocooperation lead to a similar result: the growth of the population in the absence of the other is either slow or is equal to zero. To achieve equilibrium, both populations continue to coexist, usually keeping a certain relation.

Competition and coexistence of species

In the broadest sense, competition is the interaction of two organisms seeking to get the same resource. Intervidal competition is any interaction between populations of two or more species, which adversely affects their growth and survival. As shown in Table 1, it can manifest itself in two forms. The tendency to the environmental separation, observed in the competition of closely related or similar species in other relations, is known as the principle of competitive exception. At the same time, competition contributes to the emergence of many adaptation in the selection process, which leads to an increase in the diversity of species coexisting in this space or community.

Competitive interaction can concern spaces, food or biogenic elements, lights, unused substances, depending on predators, disease exposure, etc. and many other types of interactions. Competition results are of great interest; They were repeatedly investigated as one of the mechanisms of natural selection.

Interspecific competition, regardless of what undergoes it, can lead either to establish an equilibrium between two species, or, with more fierce competition, to replacing the population of one type of another population, or to the fact that one species will turn out another to another place Or will make it go to the use of other food. It was repeatedly noted that nearby organisms, the leading similar lifestyles and possessing similar morphology, do not live in the same places. If they live in one place, they often use different resources or active at different times.

An explanation of the environmental separation of close-friendly (or similar in other respects) of species received fame as the GAUZ principle named Russian biologist, who in 1932 first confirmed its existence experimentally or as a principle of competitive exception (Harden, 1940).

To understand the causes of competition, it is necessary to consider not only the features of populations and conditions that determine the competitive exception, but also situations in which similar species coexist, since in open natural systems a large number of species actually uses common resources. The table shows the situation that could be called the TRIBOLIUM model (Khushcheki) - trifolium (tribal); This model clearly demonstrates a competitive exception in a pair of types of beetles (Tribolium) and coexistence of two types of clover (trifolium).

One of the most careful and long experimental studies of interspecific competition was held in the Laboratory of Dr. Thomas Park in the University of Chicago. Park, his students and employees worked with a flour Khrushchek, in particular with the species of the genus Tribolium. These minor beetles can complete the entire life cycle in a very simple and homogeneous environment - in a can with flour or wheat bran. In this case, the medium serves simultaneously with food, and habitat larvae and imago. If you regularly add a fresh medium, then the population of beetles can be maintained for a long time. From the point of view of the ideas about the energy flow, such an experimental system can be described as a stabilized heterotrophic ecosystem, in which the import of food energy is equalized by respiratory costs.

Table 2. The case of competitive exception in the populations of a flour wheelchair (Tribolium). (By PARK, 1954).

1. Each of the 6 experiments were carried out in 20 - 30 repairs. In a clean culture, each species survives with any combination of conditions, however, with joint cultivation of two species, only one survives. The percentage expressed the relative number of repetitions in which only one species was preserved, and the other disappears.

Using the data obtained in the model experiments on Tribolium, it is easy to create conditions in which the types would not exclude each other, and coexisted. If cultures alternately put in hot and wet, then in dry and cold conditions (to simulate seasonal weather changes), the advantage of one species before the other will be not sufficiently long for the destruction of the other. If the cultivation system was "open" and the individuals of the dominant species forced emigrate (or they would have been removed, as predator does) quickly, then the competition would be so weak that both types could coexist. Many other conditions could convene the existence.

Interesting experts on competition in plants held J. L. Harper and his colleagues from the University College of Northern Wales. Due to differences in the nature of growth, two types of clover can coexist in the same environment (under the same light conditions, temperature, on the same soil, etc.). Of these two types of TRIFOLIUM REPENS grow faster and rather reaches maximum leaning. However, T. Fragiferum has longer stuffs and above planted leaves, so it can go to the upper tier earlier than a rapidly growing look (especially after the growth rate of T. RepenS decreases), and thus avoid shading. In mixed herbs because of these features, each species inhibits the development of another, but both are able to complete the life cycle and give seeds, although the density of each species is lowered (however, the total density in mixed herbs of two species was about equal to the density in pure herbs) . In this case, both types, despite the strong competition for light, can coexist, and this coexistence is due to the peculiarities of morphology and differences in the time of maximum growth. Harper (heated, 1961) came to the conclusion that two types of plants can coexist for a long time if their populations are independently regulated by one or more of the following mechanisms: 1) differences in nutritional needs (for example, legumes and non-timber); 2) differences in causes of mortality (for example, different sensitivity to diverting spending); 3) sensitivity to various toxins and 4) sensitivity to the same regulatory factor (light, water, etc.) at different times (as in the case of the example described with clover).

When studying the literature on competition, the overall impression is that in systems where immigration and emigration are missing or lowered, there is more severe competition and a more likely competitive exception. Such systems include laboratory cultures, islands or other natural situations with difficult obstinate barriers to input and output. In conventional natural open systems, the probability of coexistence is higher.

An example of a competing with direct suppression is described Cruby (1947). He found that the joint cultivation in Tribolium and Oryzaephilus flour (another genus Khrushchekov) ends with the destruction of ORAZAEPHILUS, because Tribolium exterminates the imperfect stages of ORAZAEPHILUS.

However, if we put glass tubes in the flour, in which unheated individuals can hide in the sizes of ORAZAEPHILUS, both populations will survive. Thus, if there are asylums in the environment, allowing to hide from direct impact (in this case of predatoryness), the competition decreases so much that both types are preserved.

But rather laboratory examples. It is absolutely obvious that the crowded in laboratory experiments can be quite significant, which leads to excessive competition. In field studies, interspecific competition was studied in detail in plants; The results of these studies have made it possible to conclude (at present this conclusion is generally accepted) that competition is an important factor that causes the change of species. Keever (Keever, 1955) described the case when the first year's deposit was almost entirely occupied by a pure High Weed Herbage, in the future it gradually displaced another type of previously known in these places. These two kinds, although belong to different kinds, have very similar life cycles (the time of flowering and ripening seeds) and life forms, fell into conditions of intensive competition. Careful subsequent studies of these departments showed that the new algered did not displace the appearance growing here; It turned out that both types coexist, but their numerical ratio depends on the soil, time and degree of violations.

The following example relates to two types of land Salamander Plethodon Glutinosus and P. JoRdani, in the southern part of the Appalachian mountains in the United States.

Usually P. JoRDani is found at large altitudes than P. glutinosus, but in some areas the zone of their habitat is overlapped. Haraston (Hairston, 1980) conducted an experiment on two sites, one of which was in the Great Smuki mountains, where the overlapping was observed only in a small range of heights, and the other in the balsamic mountains, where species coexisted in a much wider zone. At both sites, the population of the other species and, in general, Fauna Salamander was similar; The populations were at one height and were subjected to the same effects. On each site

Heierston laid seven experimental sites: the individuals of P. jordani were removed on two of them, and two other individuals P. glutinosus, and the remaining three served as control. This work was started in 1974 and in the next 5 years at all sites 6 times a year, the number of individuals of each species was calculated; All individuals were divided into three groups: a yearunic, two years old, all others.

In the control sites, as expected, from the two species under consideration was much more numerous P. jordani; And on the venues from which it was removed, a statistically significant increase in the number of P. glutinosus was observed. At the venues from which P. glutinosus was removed, the corresponding significant increase in the number of P. JORDANI was not marked. However, at both sites, a statistically significant increase in the share of P. jordani among the Godovikov and two-year-olds was observed. Apparently, this was due to the increased fecundity and (or) increased survival of the juvenile; Both of these factor are the main reasons that determine the reproduction rate.

An important point is that the unfavorable impact on the part of another species initially experienced individuals from both species; After removing one of their species, the remaining has observed a significant increase in the number and (or) of fertility and (or) survival. It follows from this that these species usually competed with each other at check vessels and in other places of joint habitat, but they still coexisted.

As another example, I will give an experiment made by one of the most famous "founding fathers" ecology of plants A.G. Tensley, who studied the competition between the two types of Podmarnik (Tansley, 1917). Galium Hercinicum is a kind of growing in the UK on acidic soils, while the distribution of Galium Pumilum is limited to more alkaline soils.

Growing views separately, Tensley found that each of them grew well both on the acidic soil from habitat Galium Hercinicum and on alkaline soil from habitat Galium Pumilum. However, with joint cultivation on acidic soil, only Galium Hercinicum successfully increased, and on alkaline ground - Galium Pumilum. Apparently, these results indicate competition between species in their joint cultivation. In a competitive struggle, one species wins, while the other loses so much that his displacement from the biotype occurs. The outcome of competition depends on the conditions in which it occurs.