Examples of biotic factors. Biotic factors, their characteristics, biotic factors examples, biotic environmental factors, biotic factors abstract, abstract on the topic biotic factors, biotic environmental factors examples, biotic factors

Biotic factors

Indirect interactions consist in the fact that some organisms are environment-formers in relation to others, and the priority importance here belongs, of course, to photosynthetic plants. For example, the local and global environment-forming function of forests, including their soil- and field-protective and water-protective roles, is well known. A unique microclimate is created directly in the forest, which depends on the morphological characteristics of the trees and allows specific forest animals to live here, herbaceous plants, mosses, etc. The conditions of feather grass steppes represent completely different regimes of abiotic factors. In reservoirs and watercourses, plants are the main source of such an important abiotic component of the environment as oxygen.

At the same time, plants serve as a direct habitat for other organisms. For example, many fungi develop in the tissues of a tree (wood, bast, bark), the fruiting bodies of which (tinder fungi) can be seen on the surface of the trunk; Many insects and other invertebrates live inside the leaves, fruits, and stems of herbaceous and woody plants, and tree hollows are the usual habitat for a number of mammals and birds. For many species of secretive animals, their feeding place is combined with their habitat.

Interactions between living organisms in terrestrial and aquatic environment

Interactions between living organisms (mainly animals) are classified in terms of their mutual reactions.

There are homotypic (from Greek. homos- identical) reactions, i.e. interactions between individuals and groups of individuals of the same species, and heterotypic (from the Greek. heteros- different, different) - interactions between representatives of different species. Among animals, there are species that are capable of feeding on only one type of food (monophages), on a more or less limited range of food sources (narrow or broad oligophages), or on many species, using not only plant but also animal tissues for food (polyphags). The latter include, for example, many birds that are capable of eating both insects and plant seeds, or such known species, like a bear, is a predator by nature, but willingly eats berries and honey.

The most common type of heterotypic interactions between animals is predation, i.e. the direct pursuit and consumption of some species by others, for example, insects - birds, herbivorous ungulates - carnivorous predators, small fish- larger ones, etc. Predation is widespread among invertebrate animals - insects, arachnids, worms, etc.

Other forms of interactions between organisms include the well-known pollination of plants by animals (insects); phoresia, i.e. transfer by one species to another (for example, plant seeds by birds and mammals); commensalism (common eating), when some organisms feed on the leftover food or secretions of others, an example of which are hyenas and vultures devouring the leftover food of lions; synoikia (cohabitation), for example, the use by some animals of the habitats (burrows, nests) of other animals; neutralism, i.e. mutual independence of different species living in a common territory.

One of the important types of interaction between organisms is competition, which is defined as the desire of two species (or individuals of the same species) to possess the same resource. Thus, intraspecific and interspecific competition are distinguished. Interspecific competition is also considered as the desire of one species to displace another species (competitor) from a given habitat.

However, real evidence of competition in natural (rather than experimental) conditions is difficult to find. Of course, two different individuals of the same species may try to take pieces of meat or other food from each other, but such phenomena are explained by the different quality of the individuals themselves, their different adaptability to the same environmental factors. Any type of organism is adapted not to one particular factor, but to their complex, and the requirements of two different (even close) species do not coincide. Therefore, one of the two will be forced out in the natural environment not due to the competitive aspirations of the other, but simply because it is less well adapted to other factors. A typical example is the “competition” for light between coniferous and deciduous trees tree species in young animals.

Deciduous trees (aspen, birch) outstrip pine or spruce in growth, but this cannot be considered competition between them: the former are simply better adapted to the conditions of clearings and burnt areas than the latter. Many years of work on the destruction of deciduous “weeds” with the help of herbicides and arboricides (chemical preparations for the destruction of herbaceous and shrubby plants), as a rule, did not lead to the “victory” of conifers, since not only light supply, but also many other factors (such as biotic , and abiotic) did not meet their requirements.

A person must take all these circumstances into account when managing wildlife, when exploiting animals and plants, that is, when fishing or carrying out such economic activities as plant protection in agriculture.

Soil biotic factors

As mentioned above, soil is a bioinert body. Living organisms play a vital role in the processes of its formation and functioning. These include, first of all, green plants that extract nutrients from the soil. chemical substances and returning them back along with dying tissues.

But in soil formation processes decisive role play living organisms (pedobionts) inhabiting the soil: microbes, invertebrates, etc. Microorganisms play a leading role in the transformation of chemical compounds and migration chemical elements, plant nutrition.

The primary destruction of dead organic matter is carried out by invertebrate animals (worms, mollusks, insects, etc.) in the process of feeding and excreting digestive products into the soil. Photosynthetic carbon sequestration in soil is carried out in some types of soil by microscopic green and blue-green algae.

Soil microorganisms carry out the main destruction of minerals and lead to the formation of organic and mineral acids, alkalis, and release enzymes, polysaccharides, and phenolic compounds synthesized by them.

The most important link in the biogeochemical nitrogen cycle is nitrogen fixation, which is carried out by nitrogen-fixing bacteria. It is known that the total production of nitrogen fixation by microbes is 160-170 million tons/year. It is also necessary to mention that nitrogen fixation, as a rule, is symbiotic (joint with plants), carried out by nodule bacteria located on the roots of plants.

Biologically active substances living organisms

To the number environmental factors biotic nature refers to chemical compounds that are active and produced by living organisms. These are, in particular, phytoncides - predominantly volatile substances produced by organisms by plants that kill microorganisms or suppress their growth. These include glycosides, terpenoids, phenols, tannins and many other substances. For example, 1 hectare of deciduous forest releases about 2 kg of volatile substances per day, coniferous forest - up to 5 kg, juniper forest - about 30 kg. Therefore, the air of forest ecosystems is of critical sanitary and hygienic importance, killing microorganisms that cause dangerous human diseases. For the plant, phytoncides serve as protection against bacterial, fungal infections, and protozoa. Plants are able to produce protective substances in response to infection by pathogenic fungi.

Volatile substances from some plants can serve as a means of displacing other plants. The mutual influence of plants through the release of physiologically active substances into the environment is called allelopathy (from the Greek. allelon- mutually, pathos- suffering).

Organic substances produced by microorganisms that have the ability to kill microbes (or inhibit their growth) are called antibiotics; typical example is penicillin. Antibiotics also include antibacterial substances contained in plant and animal cells.

Dangerous alkaloids that have toxic and psychotropic effects are found in many mushrooms, higher plants. The strongest headache, nausea up to loss of consciousness can occur as a result of a person’s long stay in a wild rosemary swamp.

Vertebrate and invertebrate animals have the ability to produce and secrete repellent, attractive, signaling, and killing substances. Among them are many arachnids (scorpion, karakurt, tarantula, etc.), and reptiles. Man widely uses animal and plant poisons for medicinal purposes.

The joint evolution of animals and plants has developed in them the most complex information-chemical relationships. Let us give just one example: many insects distinguish their food species by smell; bark beetles, in particular, fly only to a dying tree, recognizing it by the composition of the volatile terpenes of the resin.

Anthropogenic environmental factors

The entire history of scientific and technological progress is a combination of man’s transformation of natural environmental factors for his own purposes and the creation of new ones that previously did not exist in nature.

The smelting of metals from ores and the production of equipment are impossible without the creation high temperatures, pressure, powerful electromagnetic fields. Receive and store high yields agricultural crops requires the production of fertilizers and chemical plant protection products from pests and pathogens. Modern healthcare is unthinkable without chemotherapy and physiotherapy. These examples can be multiplied.

Achievements of scientific and technological progress began to be used for political and economic purposes, which was extremely manifested in the creation of special affecting humans and its property environmental factors: from firearms to means of mass physical, chemical and biological influence. In this case, we can speak directly about the totality of anthropotropic (i.e., aimed at the human body) and, in particular, anthropocidal environmental factors that cause pollution environment.

On the other hand, in addition to such purposeful factors, during the exploitation and processing of natural resources, by-product chemical compounds and zones of high levels of physical factors are inevitably formed. In some cases, these processes can be of an abrupt nature (in conditions of accidents and disasters) with severe environmental and material consequences. Hence it was necessary to create ways and means of protecting people from dangerous and harmful factors, which has now been implemented into the above-mentioned system - life safety.

In a simplified form, an approximate classification of anthropogenic environmental factors is presented in Fig. 1.

Rice. 1. Classification of anthropogenic environmental factors

Biotic factors are a set of influences of the life activity of some organisms on the life activity of others, as well as on inanimate nature.

Classification of biotic interactions:

1. Neutralism- neither population influences the other.

2. Competition- this is the use of resources (food, water, light, space) by one organism, which thereby reduces the availability of this resource for another organism.

Competition can be intraspecific and interspecific.

If the population size is small, then intraspecific competition is weakly expressed and resources are abundant. At high population densities, intensive intraspecific competition reduces the availability of resources to a level that inhibits further growth, thereby regulating population size.

Interspecific competition- interactions between populations that adversely affect their growth and survival. When imported into Britain from North America Carolina squirrel, the number of common squirrels has decreased, because. the Carolina squirrel turned out to be more competitive.

Competition can be direct and indirect.

Straight- this is intraspecific competition associated with the struggle for habitat, in particular the protection of individual areas in birds or animals, expressed in direct collisions. If there is a lack of resources, it is possible to eat animals of their own species (wolves, lynxes, predatory bugs, spiders, rats, pike, perch, etc.)

Indirect- between shrubs and herbaceous plants in California. The type that settles first excludes the other type. Fast-growing, deep-rooted grasses reduced the soil moisture content to levels unsuitable for shrubs. And the tall bushes shaded the grasses, preventing them from growing due to lack of light.

Inside the owner. Viruses, bacteria, primitive fungi - plants. Worms are animals. High fertility. Does not lead to the death of the owner, but inhibits vital processes

4. Predation- eating of one organism (prey) by another organism (predator).

Predators can eat herbivores and also weak predators. Predators have a wide range of food and easily switch from one prey to another more accessible one.

Predators often attack weak prey. The mink destroys sick and old muskrats, but does not attack adult individuals.

Ecological balance is maintained between prey-predator populations.

5. Symbiosis- cohabitation of two organisms of different species in which the organisms benefit each other. According to the degree of partnership, symbiosis is:

Commensalism- one organism feeds at the expense of another without harming it. Crayfish - sea anemone. The sea anemone attaches to the shell, protecting it from enemies, and feeds on leftover food.

Mutualism- both organisms benefit, but they cannot exist without each other. Lichen - mushroom + algae. The fungus protects the algae, and the algae feeds it.

Under natural conditions, one species will not lead to the destruction of another species.

Biotic factors

What are biotic factors?

Describe intraspecific factors (homotypic reactions).

Describe interspecific factors (heterotypic reactions).

Under biotic factors understand the forms of interaction between individuals and populations. Biotic factors are divided into two groups: intraspecific (homotypic from Greek. homoios- the same) and interspecific (heterotypic from Greek. heteros- different) interactions.

Homotypic reactions.
Homotypic reactions are interactions between individuals of the same species. Ecological significance have phenomena associated with group and mass effects, as well as intraspecific competition.

Group effect- this is the influence of the group as such and the number of individuals in the group on the behavior, physiology, development and reproduction of individuals, caused by the perception of the presence of individuals of their own species through the senses.

Wildebeest crossing the river

Many insects (crickets, cockroaches, locusts, etc.) in a group have a more intense metabolism than when living alone, grow and mature faster.

Many animal species develop normally only when they are united in fairly large groups. For example, cormorants can exist in a colony of at least 10,000 individuals, where there are at least 3 nests per 1 m2. It is known that for African elephants to survive, a herd must contain at least 25 individuals, and the most productive herds reindeer include 300-400 individuals.

Living in groups makes it easier for animals to find and obtain food and protect themselves from enemies. Wolves united in a pack attack large animals, while single individuals are unable to do this. It is easier for flocks of pelicans to catch fish by driving them into shallow water. Optimization of physiological processes leading to increased vitality during coexistence is called"group effect" . It manifests itself as a psychophysiological reaction of an individual to the presence of other individuals of its species. Sheep outside the herd increase their pulse and breathing, and when they see an approaching herd, these processes normalize. Solitary winterers the bats

have a higher level of metabolism than in the colony. This leads to increased energy consumption, exhaustion and often ends in their death. The group effect is manifested in accelerated growth rates of animals, increased fertility, faster formation conditioned reflexes , increase average duration life of the individual, etc. In a group, animals are often able to maintain optimal temperature

The group effect does not appear in solitary species. If such animals are forced to artificially live together, their irritability increases, collisions become more frequent, and many physiological indicators deviate greatly from the norm. So, eared hedgehogs in a group they increase oxygen consumption up to 134% compared to those kept alone.

Mass effect caused by changes in the environment that occur with an excessive increase in the number of individuals and population density. As a rule, the mass effect negatively affects the fertility, growth rate, and lifespan of animals. For example, with the development of a mealy beetle population, excrement and molting skins constantly accumulate in the flour, which leads to the deterioration of the flour as a habitat. This causes a drop in fertility and an increase in mortality in the beetle population. In overpopulated groups of house mice, fertility decreases, and sometimes reproduction stops altogether.

In nature, group and mass effects most often occur simultaneously. Exclusively important role group and mass effects play in the dynamics of population numbers, acting as one of the density-dependent environmental factors that regulate population numbers according to the feedback principle. This pattern is formulated as follows:

For each animal species there is optimal size groups and optimal population density (Allee's principle).

Homotypic reactions, in addition to the effect of group and mass, include another form of interaction between individuals
one type - intraspecific competition. The rule applies to all types of competition: the more the needs of competitors coincide, the more intense the competition.

Heterotypic reactions.
Heterotypic reactions- These are interactions between individuals belonging to different species. Different kinds interactions of similar populations (for example, A and B) are presented in Table 1.

Table 1.

Types of heterotypic reactions

Heterotypic reactions

View A

View B Legend: 0 - no influence on this type, (+) - favorable influence, (-) - unfavorable (negative) influence. Competition. Interspecific relationships in which populations, in the struggle for food, habitat and other conditions necessary for life, negatively affect each other. Intense competition often explains the incompatibility of broad-clawed and narrow-clawed crayfish in the same reservoir. Usually the winner is the narrow-clawed crayfish as the most prolific and adapted to changing environmental conditions. An example of plant competition is the relationship between meadow foxtail and fescue. Experiments have shown that fescue can grow in moist soil, but does not grow in the meadow foxtail community. Here it is suppressed by the shadow A hardy and fast-growing foxtail, in drier areas fescue suppresses foxtail. Example interspecific competition between a lynx and a wolverine is shown in the figure. Interspecific competition between lynx and wolverine There are two forms of competition: Straight- carried out through the direct influence of individuals on each other, for example, during aggressive clashes between animals or the release of toxins from plants and microorganisms. Indirect- does not involve direct interaction between individuals. It occurs indirectly - through the consumption of different animals of the same resource, which is a limiting factor. Therefore, indirect competition is also called exploitative competition. It was discovered that in the process of life, some plants secrete external environment various substances ( phytoncides - Phytoncides (from Greek phyton - plant and Lat. caedo - kill) - biologically active substances secreted by plants and killing or suppressing the growth and development of other organisms) which, having a certain biological activity, influence other organisms. This phenomenon has been known since ancient times, but only in 1937 did the German botanist H. Molisch give it a name allelopathy (from Greek allelon- mutual, pathos- suffering, impact) - interaction of organisms through specifically acting chemical metabolic products. Most often, allelopathy manifests itself in the suppression of one species by another, for example, wheatgrass and weeds displace cultivated plants, walnut and oak, with their secretions, suppress herbaceous vegetation under the crown, etc. Symbiosis. Mutually beneficial cohabitation of individuals of different species. A classic example of symbiosis in animals is the cohabitation of a hermit crab and an anemone, which attaches to clam shell, masking and protecting it (coelenterates have stinging cells). In turn, the sea anemone feeds on pieces of food left over from the crayfish’s meal and uses it as a means of transportation. The relationship between many ants and aphids takes the form of a symbiosis: the ants protect the aphids from their enemies, and they themselves feed on their sugary secretions. Symbiosis is observed in termites, whose digestive tract serves as a shelter for flagellates. Termites are known for their ability to feed on wood, despite their lack of enzymes that hydrolyze cellulose. Flagellates do this for them. The resulting sugar is used by termites. Termites cannot exist without this intestinal fauna. Symbiosis is represented in widespread lichens - a symbiosis of algae and fungi. Example of commensalism - big fish and the fish stuck Amensalism (from lat. mensa - table, meal). Relationships in which negative conditions arise for one from populations: inhibition of growth, reproduction, etc., and the second is not subject to such inconveniences. Amensalism can be considered an extreme form of allelopathy, i.e. the impossibility of the existence of one or another species in the presence of another as a result of environmental intoxication. These are, for example, the relationships between mold fungi and bacteria (mold fungi produce antibiotics, in the presence of which the vital activity of bacteria is suppressed or significantly limited). Predation. An interaction between populations in which one of them, while adversely affecting the other, benefits from it. Usually the prey is killed by the predator and eaten in whole or in part. The predator-prey relationship is based on food connections. Until recently, it was a common belief that all predators were harmful animals and should be destroyed. This is a misconception, since the destruction of predators often leads to undesirable consequences and causes great damage to both nature and economic activity

person. After all, the victims of predators are usually sick and weakened individuals, the destruction of which curbs the spread of diseases and makes this or that population healthier. Today there is no longer any doubt that wolves, for example, help increase the viability of the reindeer population in the forest-tundra and tundra; pike in pond farms, if their quantity does not exceed a certain limit, stimulate the productivity of carp, etc.

Every day, rushing about business, you walk down the street, shivering from the cold or sweating from the heat. And after a working day, you go to the store and buy food. Leaving the store, you hastily stop a passing minibus and helplessly sit down on the nearest free seat. For many, this is a familiar way of life, isn't it? Have you ever thought about how life works from an environmental point of view? The existence of humans, plants and animals is possible only through their interaction. It does not do without influence inanimate nature. Each of these types of impact has its own designation. So, there are only three types of impact on the environment. These are anthropogenic, biotic and abiotic factors. Let's look at each of them and its impact on nature.

1. Anthropogenic factors - influence on the nature of all forms of human activity

When this term is mentioned, not a single positive thought comes to mind. Even when people do something good for animals and plants, it happens because of the consequences of previously doing something bad (for example, poaching).

Anthropogenic factors (examples):

• Drying swamps.
• Fertilizing fields with pesticides.
• Poaching.
• Industrial waste (photo).

Conclusion

As you can see, basically humans only cause harm to the environment. And due to the increase in economic and industrial production, even environmental measures established by rare volunteers (the creation of nature reserves, environmental rallies) are no longer helping.

2. Biotic factors - the influence of living nature on various organisms

Simply put, it is the interaction of plants and animals with each other. It can be both positive and negative. There are several types of such interaction:

1. Competition - such relationships between individuals of the same or different species in which the use of a certain resource by one of them reduces its availability for others. In general, in competition, animals or plants fight among themselves for their piece of bread

2. Mutualism is a relationship in which each species receives a certain benefit. Simply put, when plants and/or animals complement each other harmoniously.

3. Commensalism is a form of symbiosis between organisms of different species, in which one of them uses the host’s home or organism as a place of settlement and can feed on food remains or products of its vital activity. At the same time, it brings neither harm nor benefit to the owner. All in all, a small, unnoticeable addition.

Biotic factors (examples):

Coexistence of fish and coral polyps, flagellated protozoans and insects, trees and birds (eg woodpeckers), mynah starlings and rhinoceroses.

Conclusion

Despite the fact that biotic factors can be harmful to animals, plants and humans, they also have great benefits.

3. Abiotic factors - the impact of inanimate nature on a variety of organisms

Yes, and inanimate nature also plays an important role in the life processes of animals, plants and humans. Perhaps the most important abiotic factor is weather.

Abiotic factors: examples

Abiotic factors are temperature, humidity, light, salinity of water and soil, as well as the air and its gas composition.

Conclusion

Abiotic factors can be harmful to animals, plants and humans, but they still generally benefit them

Bottom line

The only factor that does not benefit anyone is anthropogenic. Yes, it also does not bring anything good to a person, although he is sure that he is changing nature for his own good, and does not think about what this “good” will turn into for him and his descendants in ten years. Humans have already completely destroyed many species of animals and plants that had their place in the world ecosystem. The Earth's biosphere is like a film in which there are no minor roles, all of them are the main ones. Now imagine that some of them were removed. What will happen in the film? This is how it is in nature: if the smallest grain of sand disappears, the great building of Life will collapse.

Biotic factors- all forms of influence on the body from surrounding living beings (microorganisms, the influence of animals on plants and vice versa, the influence of humans on the environment).

Every living organism on Earth is influenced not only by factors of inanimate nature, but also by other living organisms (biotic factors). Animals and plants are not distributed chaotically, but necessarily form certain spatial groupings. The organisms included in them, of course, must have common or similar requirements for the given conditions of existence, on the basis of which corresponding dependencies and relationships are formed between them. This relationship arises primarily on the basis of nutritional needs (connections) and methods of obtaining energy necessary for life processes.

The group of biotic factors is divided into intraspecific and interspecific.

These include factors operating within a species, at the population level.

First of all, this is the population size and its density - the number of individuals of a species per certain area or in volume. Biotic factors of population rank also include the life expectancy of organisms, their fertility, sex ratio, etc., which to one degree or another influence and create environmental situation both in the population and in the biocenosis. In addition, this group of factors includes behavioral features of many animals (ethological factors), primarily the concept of group effect, used to designate morphological behavioral changes observed in animals of the same species during group living.

Competition as a form of biotic communication between organisms is most clearly manifested at the population level. As the population grows, when its size approaches the saturating environment, internal physiological mechanisms for regulating the size of this population come into play: the mortality of individuals increases, fertility decreases, and stressful situations, fights, etc. Space and food become the subject of competition.

• competition is a form of relationship between organisms that develops in the struggle for the same environmental conditions.

  In addition to intraspecific competition, interspecific, direct and indirect competition are distinguished. The more similar the needs of competitors are, the more intense competition becomes. Plants compete for light and moisture; ungulates, rodents, locusts - for the same food sources (plants); predator birds forests and foxes - for mouse-like rodents.

The effect exerted by one species on another is usually carried out through direct contact between individuals, which is preceded or accompanied by changes in the environment caused by the vital activity of organisms (chemical and physical changes in the environment caused by plants, earthworms, unicellular organisms, fungi, etc.).

The interaction of populations of two or more species has various forms of manifestation, both on a positive and negative basis.

Negative interspecies interactions

• Interspecific competition for space, food, light, shelter, etc., i.e., any interaction between two or more populations that is detrimental to their growth and survival. If two species compete for common conditions, one of them displaces the other. On the other hand, two species can exist if their ecological requirements are different.

With interspecific competition, representatives of two or more species actively search for the same food resources of the environment. (More broadly, it is any interaction between two or more populations that is detrimental to their growth and survival.)

Competitive relationships between organisms are observed when they share factors, the amount of which is minimal or insufficient for all consumers.

• Predation- a form of relationship between organisms in which some hunt, kill and eat others. Predators are insectivorous plants (sundews, Venus flytraps), as well as representatives of animals of all types. For example, in the phylum arthropods, predators are spiders, dragonflies, ladybugs; in the phylum chordates, predators are found in the classes of fish (sharks, pike, perches, ruffes), reptiles (crocodiles, snakes), birds (owls, eagles, hawks), and mammals (wolves, jackals, lions, tigers).

  A type of predation is cannibalism, or intraspecific predation (eating by individuals of other individuals of their own species). For example, female karakurt spiders eat males after mating, Balkhash perch eats its young, etc. By eliminating the weakest and sickest animals from the population, predators help increase the viability of the species.

From an ecological point of view, such a relationship between the two different types favorable for one of them and unfavorable for the other. The destructive effect is much less if the population has developed together in an environment that is stable for a long period. Moreover, both species adopt such a way of life and such numerical ratios that, instead of the gradual disappearance of the prey or predator, ensure their existence, i.e., biological regulation of populations is carried out.

• Antibiosis- a form of antagonistic relationships between organisms, when one of them inhibits the vital activity of others, most often by releasing special substances, so-called antibiotics and phytoncides. Antibiotics are secreted by lower plants (fungi, lichens), phytoncides - by higher ones. Thus, the penicillium fungus secretes the antibiotic penicillium, which suppresses the vital activity of many bacteria; lactic acid bacteria that live in the human intestine suppress putrefactive bacteria. Phytoncides that have a bactericidal effect are released by pine, cedar, onions, garlic and other plants. Phytoncides are used in folk medicine and medical practice.

There are different forms of antibiosis:

1. Amensalism is a relationship in which one species creates negative conditions for another, but does not itself experience opposition. This is the relationship between molds, producing antibiotics, and bacteria, the vital activity of which is suppressed or significantly limited.
2. Allelopathy is the interaction of plant organisms in phytocenoses - the chemical mutual influence of some plant species on others through specifically acting root secretions, metabolic products of the aerial parts ( essential oils, glycosides, phytoncides, which are combined under a single term - viburnum). Most often, allelopathy manifests itself in the displacement of one species by another. For example, wheatgrass or other weeds displace or oppress cultivated plants, walnut or oak suppress herbaceous vegetation under the crown with their secretions, etc.

   Occasionally, mutual assistance or a beneficial effect from joint growth is observed (vegetable-oat mixture, corn and soybean crops, etc.).

Positive Interspecies Interactions

• Symbiosis (mutualism) is a form of relationship between organisms of different systematic groups, in which coexistence is mutually beneficial for individuals of two or more species. Symbionts can be only plants, plants and animals, or only animals. Symbiosis is distinguished by the degree of connection of partners and by their food dependence on each other.

Symbiosis of nodule bacteria with legumes, mycorrhiza of some fungi with tree roots, lichens, termites and flagellated protozoa of their intestines, destroying their cellulose plant food, are examples of food-dependent symbionts.

Some coral polyps, freshwater sponges form communities with unicellular algae. Such a connection, not for the purpose of feeding one at the expense of the other, but only to obtain protection or mechanical support, is observed in climbing and climbing plants.

An interesting form of cooperation, reminiscent of symbiosis, is the relationship between hermit crabs and sea anemones (the sea anemone uses the crab for movement and at the same time serves as protection for it thanks to its stinging cells), often complicated by the presence of other animals (for example, polychaetnereids) feeding on the leftover food of the crayfish and sea anemone. Bird nests and rodent burrows are inhabited by permanent cohabitants who use the microclimate of the shelters and find food there.

A variety of epiphytic plants (algae, lichens) settle on the bark of tree trunks. This form of relationship between two species, when the activity of one of them provides food or shelter to the other, is called commensalism. This is the unilateral use of one species by another without causing harm to it.

Many marine animals have commensals (small fish in the cavity of sea cucumbers, fry of horse mackerel under the bell of jellyfish and in the mantle cavity of cuttlefish). Commensals of another type live in large burrows sea ​​worms, in anthills, termite mounds, rodent burrows, bird nests, etc., using them as a habitat with a more stable and favorable microclimate.

Other types of chemical interactions

Animals of various taxonomic groups produce pheromones (telergons) - unique biologically active substances that influence the development, behavior and biocommunication of individuals of one species, as well as providing signal information to other species. These include sexual attractants (for example, in moths), substances for marking territory or for laying odorous trails (“ant trails”), as well as “alarm pheromones” causing reactions fear and flight (freshwater herbivorous fish) or increased aggressiveness (bees, wasps, ants) in individuals of the same species. These short-acting signal pheromones are distinguished from triggering pheromones, which are capable of long-term physiological changes and chemical signaling (royal jelly of bees, which inhibits the development of ovaries in worker bee colonies).

Biotic factors influencing plant organisms as primary producers organic matter , classified into

1. zoogenic factors - phytophagy, entomophily, zoochory, zoogamy, ornithophily, myrmecochory, i.e. diverse forms of influence of animal organisms on the lifestyle, reproduction and properties of plants.
2. phytogenic factors - plants usually included in plant communities, experience the diverse influences of neighboring plants and at the same time themselves influence their co-inhabitants. The forms of relationships are varied and depend on the method and degree of contact between plant organisms, associated factors, etc.
3. anthropogenic factors - environmental factors associated with human activity and influencing living organisms. These factors are the most significant in their scale and nature

   Anthropogenic factors can be both positive and negative.

   The positive impact is manifested in the reasonable transformation of nature - planting forests, parks, gardens, creating and breeding varieties of plants and animal breeds, creating artificial reservoirs, nature reserves, sanctuaries, etc. However, with the growth of the population on Earth, the areas of transformed surface areas are continuously increasing, Many landscapes disappear or change their former appearance. Yes, they pass out forested areas, centuries-old swamps are drying up, deep rivers (Volga, Dnieper, Angara, etc.) are turning into a cascade of reservoirs, and the exploitation of the natural resources of the World Ocean and land is intensifying. Humans release huge quantities of industrial and household waste. More than 4 billion tons of oil are produced annually in the world and natural gas, over 2 billion tons of coal, almost 20 billion tons of rock mass in the form of ore and related rocks. The products of their processing end up in the air, soil, and water. About 22 billion tons of carbon dioxide are emitted into the atmosphere alone.

   Thus, anthropogenic factors actively influence the environment, changing it.

   Anthropogenic systems are formed as a result of industrialization, chemicalization, urbanization, transport development, and space exploration. Currently, humanity is thinking about the problem of wise use natural environment which is getting poorer natural resources and more dangerous to human health.

Consort connections

Typically, a consortium is formed on the basis of populations of autotrophic plants (spruce, aspen, birch, feather grass, etc.). They are called determinants, and the species united around them are called consorts. Among the consorts there are species that receive nutrition and energy from the determinant, i.e., are associated with it trophically (food connections) and topically (finding shelter and housing on it).

In general, any organism not only of autotrophic, but also of heterotrophic mode of nutrition serves as a source of energy for other organisms associated with it by consortium.

The importance of ecological relationships

Any form of relationship serves as a regulator of the ecological structure of the population and is determined by the nature of the distribution of the population in the territory (density), age and sex composition, and population dynamics.

Knowing the patterns of ecological relationships between populations, one can intelligently control certain parameters of the ecological structure of the population. One of these activities is the scientifically based management of hunting and fishing (establishment certain places, timing, volumes and methods of hunting and fishing), ensuring the reproduction of populations. For example, streamlining the hunt for fur seal allowed to restore its population.

Currently, recommendations have been developed for rational deforestation and harvesting of medicinal plants, providing for the preservation of seed and vegetative reproduction of populations. For example, it has been established that in order to maintain the viability of the creeping thyme population, the volume of its harvest per 1 m2 should not exceed 50%.