Mutually beneficial cohabitation of two organisms is called. Mutually beneficial relationships of organisms - symbiosis. What does ecology study

Detailed solution paragraph § 77 in biology for students of grade 10, authors Kamensky A.A., Kriksunov E.A., Pasechnik V.V. 2014

Gdz workbook in Biology for grade 10 can be found

1. What biotic environmental factors do you know?

2. What types of competition do you know?

Answer. Competition - in biology, any antagonistic relationship associated with the struggle for existence, for dominance, for food, space and other resources between organisms, species or populations of species that need the same resources.

Intraspecific competition is competition between members of one or more populations of a species. Goes for resources, intra-group dominance, females/males, etc.

Interspecific competition is competition between populations of different species of non-adjacent trophic levels in a biocenosis. It is due to the fact that representatives of different species jointly use the same resources, which are usually limited. Resources can be both food (for example, the same types of prey for predators or plants - for phytophages), and of another kind, for example, the availability of places for breeding, shelters for protection from enemies, etc. Species can also compete for dominance in the ecosystem. There are two forms of competitive relationships: direct competition (interference) and indirect (exploitation). With direct competition between populations of species in a biocenosis, antagonistic relationships (antibiosis) develop evolutionarily, expressed by various types of mutual oppression (fights, blocking access to a resource, allelopathy, etc.). With indirect competition, one of the species monopolizes a resource or habitat, while worsening the conditions for the existence of a competitive species in a similar ecological niche.

Both evolutionarily (taxonomically) close species and representatives of very distant groups can compete in nature. For example, ground squirrels in the dry steppe eat up to 40% of plant growth. This means that pastures can support fewer saigas or sheep. And during the years of mass reproduction of locusts, neither gophers nor sheep have enough food.

3. What is symbiosis?

Usually, symbiosis is mutualistic, that is, the cohabitation of both organisms (symbionts) is mutually beneficial and arises in the process of evolution as one of the forms of adaptation to the conditions of existence. Symbiosis can be carried out both at the level of multicellular organisms and at the level of individual cells (intracellular symbiosis). Plants with plants, plants with animals, animals with animals, plants and animals with microorganisms, microorganisms with microorganisms can enter into symbiotic relationships. The term "symbiosis" was first introduced by the German botanist A. de Bari (1879) as applied to lichens. A vivid example of symbiosis among plants is mycorrhiza - the cohabitation of the mycelium of a fungus with the roots of a higher plant (hyphae braid the roots and contribute to the flow of water and minerals from the soil into them); some orchids cannot grow without mycorrhiza.

Nature knows numerous examples of symbiotic relationships from which both partners benefit. For example, the symbiosis between leguminous plants and soil bacteria Rhizobium is extremely important for the nitrogen cycle in nature. These bacteria - they are also called nitrogen-fixing - settle on the roots of plants and have the ability to "fix" nitrogen, that is, to break down strong bonds between the atoms of atmospheric free nitrogen, making it possible to incorporate nitrogen into plant-available compounds, such as ammonia. In this case, the mutual benefit is obvious: the roots are the habitat of bacteria, and the bacteria supply the plant with the necessary nutrients.

There are also numerous examples of symbiosis that is beneficial to one species and does not bring any benefit or harm to another species. For example, the human intestine is inhabited by many types of bacteria, the presence of which is harmless to humans. Similarly, plants called bromeliads (which include, for example, pineapple) live on the branches of trees, but get their nutrients from the air. These plants use the tree for support without depriving it of nutrients.

A type of symbiosis is endosymbiosis, when one of the partners lives inside the cell of the other.

The science of symbiosis is symbiology.

Questions after § 77

1. What examples of positive and negative interactions do you know between organisms of different species?

2. What is the essence of the "predator-prey" relationship?

Answer. Predation (+ -) is a type of relationship between populations in which representatives of one species eat (destroy) representatives of another, i.e., the organisms of one population serve as food for the organisms of another. The predator usually catches and kills its prey itself, after which it eats it in whole or in part. Such predators are characterized by hunting behavior. But besides hunter-predators, there is also a large group of predator-gatherers whose way of feeding is simply to search for and collect prey. Such, for example, are many insectivorous birds that gather food on the ground, in grass or on trees.

Predation is a widespread form of communication, not only between animals, but also between plants and animals. So, herbivory (eating plants by animals), in essence, is also predation; on the other hand, a number of insectivorous plants (dew, nepenthes) can also be classified as predators.

However, in a narrow, ecological sense, it is customary to consider only the eating of animals by animals as predation.

4. What are the most famous examples of symbiotic relationships that you know of?

Answer. A symbiotic relationship in which there is a stable mutually beneficial cohabitation of two organisms of different species is called mutualism. Such, for example, are the relationships between the hermit crab and sea anemones or highly specialized plants for pollination with insect species pollinating them (clover and bumblebee). The nutcracker, feeding only on the seeds (nuts) of the cedar pine, is the only distributor of its seeds. Mutualism is very widely developed in nature.

5. How do you understand mutualism and symbiosis?

Algae cohabitation with other organisms T. V. Sedova.[ ...]

Cohabitation of plants can be without intravital metabolism. In these cases, a plant living on another, using the latter only as an attachment site, is called an epiphyte. A special case of epiphytism are epiphytism, i.e. plants that use only the leaves of another plant as a support. Epiphytes and epiphylls can significantly affect their substrate, hindering gas exchange in other ways.[ ...]

Symbiosis (cohabitation). This is a form of relationship in which both partners or one of them benefit from the other.[ ...]

All forms of cohabitation that occur between organisms belonging to different species are called symbioses. There are many transitional forms between the above types of cohabitation, which makes the connections between organisms in the biosphere extremely diverse. The more diverse the bonds that support the coexistence of species, the more stable their cohabitation.[ ...]

Symbiosis is the cohabitation of organisms of different species, from which both benefit.[ ...]

Mycorrhizal cohabitation (symbiosis) is mutually beneficial for both symbionts: the fungus extracts additional, inaccessible nutrients and water from the soil for the tree, and the tree supplies the fungus with the products of its photosynthesis - carbohydrates.[ ...]

Symbiosis, or the cohabitation of two organisms, is one of the most interesting and still largely mysterious phenomena in biology, although the study of this issue has been going on for almost a century. The phenomenon of symbiosis was first discovered by the Swiss scientist Schwendener in 1877 when studying lichens, which, as it turned out, are complex organisms consisting of algae and fungus. The term "symbiosis" appeared in the scientific literature later. It was proposed in 1879 by De Bari.[ ...]

Neutralism is the cohabitation of two species in the same territory, which has neither positive nor negative consequences for them. For example, squirrels and moose.[ ...]

SYMBIOSIS - a close cohabitation of two or more organisms of different species, in which organisms (symbionts) benefit each other. According to the degree of partnership and food dependence, several types of symbiosis are distinguished from each other: commensalism, mutualism, etc. Thus, commensalism (from Latin “companion”) is a form of relationship between two types, when one feeds on the other without causing him any harm . Hermit crabs live with sea anemones; the latter attach themselves to the shell of the mollusk in which the hermit crab lives, protecting it from enemies and feeding on the remnants of its prey. Commensalism is especially widespread among sedentary marine life.[ ...]

Symbiosis is a close cohabitation of two or more species, beneficial for partners.[ ...]

SYMBIOSIS [gr. symbiosis cohabitation] - long-term cohabitation of organisms of different species (symbionts), usually bringing them mutual benefits (for example, lichen - C. fungus and algae).[ ...]

Mutualism is a form of cohabitation of organisms in which both partners benefit (same as symbiosis).[ ...]

Symbiosis (Greek symbiosis - cohabitation) - cohabitation of individuals of two species, when both partners enter into direct mutually beneficial interaction with the external environment, which manifests itself for them in the form of one of the forms of adaptation to the conditions of existence.[ ...]

Since in synoikia cohabitation is indifferent for one of the partners and useful only for the other partner, adaptations in this case are one-sided. As an example, it can be pointed out that in ticks of the family Tyroglyphidae, which use various insects for settling, a special r and pial phase (the hypopus phase) arose between the phases of the nymph and the deutonymph.[ ...]

Another example of symbiosis is the cohabitation of higher plants with bacteria, the so-called bacteriotrophy. Symbiosis with nodule nitrogen-fixing bacteria is widespread among legumes (93% of the studied species) and mimosa (87%). For example, bacteria from the genus Ligouminus, living in nodules on the roots of leguminous plants, are provided with food (sugar) and habitat, and plants receive from them an accessible form of nitrogen in return (Fig. 6.13).[ ...]

Shilova A.I., Kurazhkovskaya T.N. Cohabitation of Glyptotendipes varipes Goetgh. and bryozoans Plumatella fungosa Pall.[ ...]

There are also mycorrhizal fungi cohabiting with the roots of higher plants. The mycelium of these fungi envelops the roots of plants and helps to obtain nutrients from the soil. Mycorrhiza is observed mainly in woody plants with short sucking roots (oak, pine, larch, spruce).[ ...]

Mutualism is a mutually beneficial cohabitation, when the presence of a partner becomes a prerequisite for the existence of each of them. An example is the cohabitation of nodule bacteria and leguminous plants, which can live together on soils poor in nitrogen and enrich the soil with it.[ ...]

Commensalism is a type of interspecies relationship, cohabitation, in which, in a joint environment, organisms of one species unilaterally benefit from the presence of organisms of another species (for example, “housing”, “transportation”, freeloading).[ ...]

Neutralism (from Latin - neither one nor the other) is the cohabitation of two populations of living organisms, when neither of them is influenced by the other. For example, species of herbivorous and predatory insects living in the same biocenosis, not related to each other by the relationship of competition or nutrition. With neutralism, species are not directly related to each other, but sometimes they can depend on the state of a given biocenosis as a whole.[ ...]

An example of a mutually beneficial relationship is the cohabitation of the so-called nodule bacteria and legumes (peas, beans, soybeans, clover, etc.). These bacteria, capable of taking nitrogen from the air and converting it into amino acids, settle in the roots of plants. The presence of bacteria causes the growth of root tissues and the formation of thickenings - nodules. Plants in symbiosis with nitrogen-fixing bacteria can grow on soils poor in nitrogen and enrich the soil with it. That is why legumes are introduced into the agricultural crop rotation.[ ...]

Mutualism (obligate symbiosis) is a mutually beneficial cohabitation, when either one of the partners, or both, cannot exist without a cohabitant. For example, herbivorous ungulates and cellulose-destroying bacteria. Cellulose-destroying bacteria live in the stomach and intestines of herbivorous ungulates. They produce enzymes that break down cellulose, so they are essential for herbivores who do not have such enzymes. Herbivorous ungulates, for their part, provide bacteria with nutrients and a habitat with optimal temperature, humidity, etc.[ ...]

A typical example of symbiosis is the close cohabitation between fungi and algae, leading to the formation of a more complex and more adapted plant organism - a lichen. Another striking example of symbiotic cohabitation in the soil is the symbiosis of fungi with higher plants, when the fungi form fungi on the roots of plants. A pronounced symbiosis is observed between nodule bacteria and leguminous plants.[ ...]

Almost all types of trees under normal conditions cohabit with mycorrhizal fungi. The mycelium of the fungus wraps around the thin roots of the tree with a sheath, penetrating into the intercellular space. The mass of the finest fungal filaments extending a considerable distance from this sheath successfully performs the function of root hairs, absorbing the nutrient soil solution.[ ...]

Mutualism is a symbiotic relationship where both cohabiting species benefit mutually.[ ...]

First, a specific feature of lichens is the symbiotic cohabitation of two different organisms - a heterotrophic fungus (mycobiont) and an autotrophic algae (phycobiont). Not every cohabitation of fungus and algae forms a lichen. Lichen cohabitation should be permanent and historically developed, and not random, short-term. In nature, there are cases when a fungus and an alga form a temporary mixed cluster, but this is not yet a lichen. In a real lichen, the fungus and algae enter into a close relationship, the fungal component surrounds the algae and can even penetrate into their cells.[ ...]

Commensalism (or “freeloading”) is a form of cohabitation in which one species lives at the expense of the food reserves of another, without bringing benefits in turn. Sometimes commensalism appears as a more or less random phenomenon and is almost completely imperceptible to the partner whose food supply is being devoured. Thus, for example, the Malayan beetle of the genus Khystrev Nore bores through the branches of trees and feeds on the juice protruding from the wounds, and the protruding juice also attracts flies (Mie-clay claye) and some other insects that eat it together with Huygiree.[ ...]

On the example of eugropous and partly allotropic insects, we see their mutually beneficial cohabitation in biocenoses with plants. Even closer symbiotic relationships have been noted between some insects and yeast fungi and bacteria inhabiting their intestines (Werner, 1927; Hitz, 1927, etc.).[ ...]

A characteristic example of close symbiosis, or mutualism between plants, is the cohabitation of algae and fungus, which form a special integral lichen organism (Fig. 6.11).[ ...]

SYMBIOSIS - a type of relationship between organisms of different systematic groups - mutually beneficial cohabitation of individuals of two or more species, such as algae, fungi and microorganisms in the body of a lichen.[ ...]

In some cases, the body or buildings of one species may serve as a habitat or means of protection for another. For example, coral reefs are home to a large number of marine organisms. In the body cavity of the echinoderm holothurian, small inhabitants of the sea settle. Epiphytic plants (mosses, lichens, some flowering plants) settle on trees, using them only as a place of attachment, and feed by photosynthesis.[ ...]

Competition is one of the reasons why two species that differ slightly in the specifics of nutrition, behavior, lifestyle, etc., rarely cohabit in the same community. Here the competition is in the nature of direct hostility. The fiercest competition with unforeseen consequences occurs when a person introduces animal species into communities without taking into account already established relationships.[ ...]

Lichens represent a peculiar group of complex organisms, the body of which always consists of two components - a fungus and an algae. Now every student knows that the biology of lichens is based on the phenomenon of symbiosis - the cohabitation of two different organisms. But a little more than a hundred years ago, lichens were a great mystery to scientists, and the discovery by Simon Schwendener in 1867 of their essence was assessed as one of the most amazing discoveries of that time.[ ...]

Moles are unkind to their neighbors and do not tolerate any tenants or other moles in their burrows. And if they are planted together in a cramped box, the strong will kill the weak and eat them. Only when it is time to breed, usually in March - May, do the male and female cohabit for a short time. It is possible that the male stays with the children until they grow up, and even allegedly brings them worms and other food. And if it floods with floods, it helps the mother to drag the kids into dry otnor-ki. But is it really so, it is still unknown with accuracy.[ ...]

K. is used to study the migration routes of animals (especially birds), to establish the boundaries of their ranges, the characteristics of seasonal biology, and to solve other problems. COMBINED IMPACT - see Art. Environmental impact. COMMENSALISM, or freeloading [from lat. honeycomb - with and mensa - table, meal] - a type of cohabitation of organisms, when one of them (commensal) constantly or temporarily exists at the expense of the other, without harming it. COMPENSATORY BEHAVIOR - a complex of behavioral reactions of organisms aimed at weakening (compensating) the limiting influence of an environmental factor.[ ...]

Commensalism is an interspecies interaction between organisms in which one organism benefits at the expense of another without damaging it, while the other organism does not benefit or suffer from this interaction. For example, some types of marine polyps settle on the surface of the body of large fish, feeding on their secretions, but for fish this cohabitation is indifferent, that is, it does not matter.[ ...]

The first roots of Marattiaceae are usually infected with the fungus. But mycorrhiza is optional here, since the fern can develop normally without interaction with the fungus, and this cohabitation is not vital for them.[ ...]

Mutualism is a widespread form of mutually beneficial relationships between species. Lichens are a classic example of mutualism. Symbionts in lichen - fungus and algae - physiologically complement each other. The hyphae of the fungus, braiding the cells and threads of algae, form special suction processes, haustoria, through which the fungus receives substances assimilated by algae. Algae get minerals from water. Many grasses and trees normally exist only in cohabitation with soil fungi that settle on their roots. Mycorrhizal fungi promote the penetration of water, mineral and organic substances from the soil into the roots of plants, as well as the absorption of a number of substances. In turn, they receive from the roots of plants carbohydrates and other organic substances necessary for their existence.[ ...]

A fairly common phenomenon in the relationship of different species is symbiosis, or the coexistence of two or more species, in which none of them individually can live under given conditions. A whole class of symbiotic organisms are lichens - fungi and algae living together. With this, the lichen fungus, as a rule, does not live at all in the absence of algae, while most of the algae that make up lichens are also found in free form. In this mutually beneficial cohabitation, the fungus supplies the necessary water and minerals to the algae, and the algae supplies the fungus with the products of photosynthesis. This combination of properties makes these symbiotic organisms extremely undemanding to living conditions. They are able to settle on bare stones, on the bark of trees, etc. At the same time, the fact that lichens obtain a significant part of the minerals necessary for life from dust deposited on their surface makes them very sensitive to the content of toxic substances in the air. One of the most reliable methods for determining the level of toxicity of impurities contained in the air is to take into account the number and species diversity of lichens in a controlled area, lichen indication.[ ...]

A rare animal is so little scrupulous in choosing a dwelling and its environment as a kuzulis. And the crowns of hundred-meter eucalyptus trees suit him, and undersized bushes, and dense tropical forests, and rare groves along river valleys, and crevices in bare rocks, and holes in river cliffs, and rabbit holes in the open steppe, and even attics. Because in Central Australia, male kuzulis often settle in rabbit holes, an absurd legend was born. Farmers assure that such a choice of housing was made by old sinners for a reason: as if they were in a criminal misalliance with rabbits. And as if they saw crossbreeds from their cohabitation. But this is a myth.[ ...]

A population (from lat. poppy - population) is a collection of individuals of the same species that inhabit a certain space for a long time, having a common gene pool, the ability to freely interbreed and, to one degree or another, isolated from other populations of this species. A population is an elementary form of existence of a species in nature. Populations evolve and are the units of species evolution and speciation. Possessing all the features of a biological system, a population, nevertheless, is a collection of organisms, as if separated from the natural system, since in nature individuals of one species always cohabit with individuals of other species. Only under artificial conditions or in a special experiment can one deal with a “pure” population, for example, a culture of microorganisms, sowing plants, offspring of animals, etc.[ ...]

Life on poor soils has developed a number of adaptations in heathers, the most important of which is symbiosis with fungi in the form of mycorrhiza. Korpi of almost all heathers are closely braided with fungal threads, supplying them with nutrients from humus. In the latter case, some of the simplest fungi (whose body consists of only a few cells) live entirely in the cells of the heather root and are gradually digested by them. Mycorrhiza is of great positive importance in the life of heathers. In some cases (for example, in the strawberry tree - Arbutus, Table 13), infected roots turn into pear-shaped nodules (mi-kodomatia), the epidermal cells of which are converted into root hairs. It has been established that heather seeds, for example, germinate only with the help of mycorrhiza. Some researchers believe that heathers live on acidic soils because the fungi cohabiting with them cannot stand alkaline soils.

Living organisms are related to each other in a certain way. There are the following types of relationships between species:

trophic,
topical,
phoric,
factory.

The most important are trophic and topical connections, since it is they that keep organisms of different species near each other, uniting them into communities.

Trophic connections arise between species when one species feeds on another: living individuals, dead remains, waste products. Trophic communication can be direct and indirect. direct connection manifests itself when lions feed on live antelopes, hyenas on the corpses of zebras, dung beetles on the droppings of large ungulates, etc. Indirect connection occurs when different species compete for the same food resource.

Topical connections are manifested in the change by one species of the living conditions of another species. For example, under a coniferous forest, as a rule, there is no grass cover.

Foric connections occur when one species participates in the distribution of another species. The transfer of seeds, spores, and pollen by animals is called zoochory, and small individuals - phoresia.

factory connections consist in the fact that one species uses excretory products, dead remains, or even living individuals of another species for its structures. For example, when building nests, birds use tree branches, grass, down and feathers of other birds.

Types of relationships between organisms

The impact of one species on another can be positive, negative or neutral. In this case, different combinations of types of influence are possible. Distinguish:

Neutralism- the cohabitation of two species in the same territory, which has neither positive nor negative consequences for them. For example, squirrels and moose do not have significant effects on each other.

Protocooperation- mutually beneficial, but not mandatory, coexistence of organisms, from which all participants benefit. For example, hermit crabs and sea anemones. A coral anemone polyp can settle on the crayfish shell, which has stinging cells that secrete poison. Anemones protect the crayfish from predatory fish, and the hermit crab, moving, contributes to the spread of anemones and increase their feeding space.

Mutualism (obligate symbiosis) - mutually beneficial cohabitation, when either one of the partners, or both cannot exist without a cohabitant. For example, herbivorous ungulates and cellulose-destroying bacteria. Cellulose-destroying bacteria live in the stomach and intestines of herbivorous ungulates. They produce enzymes that break down cellulose, so herbivores who do not have such enzymes are required. Herbivorous ungulates, for their part, provide bacteria with nutrients and a habitat with optimal temperature, humidity, etc.

Commensalism- a relationship in which one of the partners benefits from cohabitation, and the presence of the first is indifferent to the other. There are two forms of commensalism: synoikia (lodging) and trophobiosis (freeloading). An example of synoikia is the relationship between some sea anemones and tropical fish. Tropical fish hide from predators among the tentacles of anemones, which have stinging cells. An example of trophobiosis is the relationship between large predators and scavengers. Scavengers, such as hyenas, vultures, jackals, feed on the remains of victims killed and partially eaten by large predators - lions.

Predation- a relationship in which one of the participants (the predator) kills the other (the victim) and uses it as food. For example, wolves and hares. The state of the predator population is closely related to the state of the prey population. However, when the population of one species of prey decreases, the predator switches to another species. For example, wolves can use hares, mice, wild boars, roe deer, frogs, insects, etc. as food.

A special case of predation is cannibalism- killing and eating their own kind. It occurs, for example, in rats, brown bears, humans.

Competition- relationships in which organisms compete with each other for the same resources of the external environment with a lack of the latter. Organisms can compete for food resources, sexual partners, shelter, light, and so on. There are direct and indirect, intraspecific and interspecific competition. Indirect (passive) competition—consumption of environmental resources required by both species. Direct (active) competition- the suppression of one species by another. intraspecific competition- rivalry between individuals of the same species. Interspecific competition occurs between individuals of different, but ecologically close species. Its result can be either mutual accommodation two types, or substitution a population of one species a population of another species that moves to another place, switches to another food or dies out.

Competition leads to natural selection in the direction of increasing ecological differences between competing species and the formation of different ecological niches by them.

Amensalism- relationships in which one organism affects another and suppresses its vital activity, and itself does not experience any negative influences from the suppressed. For example, spruce and plants of the lower tier. The dense crown of spruce prevents the penetration of sunlight under the forest canopy and inhibits the development of plants of the lower tier.

A special case of amensalism is allelopathy (antibiosis)- the influence of one organism on another, in which the waste products of one organism are released into the external environment, poisoning it and making it unsuitable for the life of another. Allelopathy is common in plants, fungi, bacteria. For example, a penicillium fungus produces substances that suppress the vital activity of bacteria. Penicillium is used to produce penicillin, the first antibiotic discovered in medicine. Recently, the concept of "allelopathy" includes a positive impact.

In the course of evolution and development of ecosystems, there is a tendency to reduce the role of negative interactions at the expense of positive ones, which increase the survival of both species. Therefore, in mature ecosystems, the proportion of strong negative interactions is less than in young ones.

The characteristics of the types of interaction between populations of different species are also given in the table:

Notes:

(0) - there is no significant interaction between populations.
(+) - beneficial effect on growth, survival or other characteristics of the population.
(-) - inhibitory effect on growth or other characteristics of the population.
Types 2-4 can be considered "negative interactions", 7-9 "positive interactions", and types 5 and 6 can be classified as both.

Types of relationships between organisms

Animals and plants, fungi and bacteria do not exist in isolation from each other, but enter into complex relationships. There are several forms of interaction between populations.

Neutralism

The cohabitation of two species in the same territory, which has neither positive nor negative consequences for them.

In neutralism, cohabiting populations of different species do not affect each other. For example, it can be said that a squirrel and a bear, a wolf and a cockchafer do not directly interact, although live in the same forest.

Antibiosis

When both interacting populations or one of them experience a harmful, overwhelming influence.

Antagonistic relationships can manifest themselves as follows:

1. Competition.

A form of antibiotic relationship in which organisms compete with each other for food resources, a sexual partner, shelter, light, etc.

In competition for food, the species that reproduces the fastest wins. Under natural conditions, competition between closely related species weakens if one of them moves to a new food source (that is, they occupy a different ecological niche). For example, in winter, insectivorous birds avoid competition due to different places for searching for food: on the trunk of trees, in bushes, on stumps, on large or small branches.

Displacement of one population by another: In mixed crops of different types of clover, they coexist, but competition for light leads to a decrease in the density of each of them. Thus, competition arising between close species can have two consequences: either the displacement of one species by another, or different ecological specialization of species, which makes it possible to coexist.

Suppression of one population by another: Thus, fungi that produce antibiotics inhibit the growth of microorganisms. Some plants that can grow in nitrogen-poor soils secrete substances that inhibit the activity of free-living nitrogen-fixing bacteria, as well as the formation of nodules in legumes. In this way, they prevent the accumulation of nitrogen in the soil and the colonization of it by species that need a large amount of it.

3. Amensalism

A form of antibiotic relationship in which one organism interacts with another and suppresses its vital activity, while itself does not experience any negative influences from the suppressed one (for example, spruce and plants of the lower tier). A special case is allelopathy - the influence of one organism on another, in which the waste products of one organism are released into the external environment, poisoning it and making the other unsuitable for life (common in plants).

5 Predation

This is a form of relationship in which an organism of one species uses members of another species as a food source once (by killing them).

Cannibalism - a special case of predation - killing and eating their own kind (found in rats, brown bears, humans).

Symbiosis

A form of relationship in which the participants benefit or at least do not harm each other from cohabitation. Symbiotic relationships also come in a variety of forms.

1. Protocooperation - mutually beneficial, but optional coexistence of organisms, from which all participants benefit (for example, hermit crab and sea anemone).

2. Mutualism is a form of symbiotic relationship in which either one of the partners or both cannot exist without a cohabitant (for example, herbivorous ungulates and cellulose-destroying microorganisms).

Lichens are an inseparable cohabitation of a fungus and algae, when the presence of a partner becomes a condition for the life of each of them. Hyphae of the fungus, braiding the cells and threads of algae, receive substances synthesized by algae. Algae extract water and minerals from fungal hyphae.

Many grasses and trees develop normally only when soil fungi (mycorrhiza) settle on their roots: root hairs do not develop, and the mycelium of the fungus penetrates into the root. Plants receive water and mineral salts from the fungus, and it, in turn, receives organic substances.

3. Commensalism - a form of symbiotic relationship in which one of the partners benefits from cohabitation, and the other is indifferent to the presence of the first. There are two types of cohabitation:

Lodging (some sea anemones and tropical fish). The fish stuck, sticking to large fish (sharks), uses them as a means of transportation and, in addition, feeds on their garbage.

The use of structures and body cavities of other species as shelters is widespread. In tropical waters, some fish hide in the cavity of the respiratory organs (water lungs) of holothurians (or sea cucumbers, a detachment of echinoderms). The fry of some fish find shelter under the umbrella of jellyfish and are protected by their stinging threads. As protection for developing offspring, fish use a strong shell of crabs or bivalve mollusks. The eggs laid on the gills of a crab develop under conditions of an ideal supply of clean water passed through the gills of the host. Plants also use other species as habitats. These are the so-called epiphytes - plants that settle on trees. It can be algae, lichens, mosses, ferns, flowering plants. Woody plants serve as a place of attachment for them, but not a source of nutrients.

Freeloading (large predators and scavengers). For example, hyenas follow lions, picking up the remains of prey that they have not eaten. There can be various spatial relationships between partners. If one partner is outside the cells of the other, they talk about ectosymbiosis, and if inside the cells - endosymbiosis.

EXAMINATION TICKET No. 4
	Types of nutrition of living organisms.
	Theories of the origin of life.

Types of nutrition of living organisms:

There are two types of nutrition of living organisms: autotrophic and heterotrophic.

Autotrophs (autotrophic organisms) - organisms that use carbon dioxide as a source of carbon (plants and some bacteria). In other words, these are organisms capable of creating organic substances from inorganic ones - carbon dioxide, water, mineral salts.

Heterotrophs (heterotrophic organisms) - organisms that use organic compounds (animals, fungi and most bacteria) as a carbon source. In other words, these are organisms that are not able to create organic substances from inorganic ones, but need ready-made organic substances.

Some living beings, depending on the habitat conditions, are capable of both autotrophic and heterotrophic nutrition. Organisms with a mixed type of nutrition are called mixotrophs. Mixotrophs - organisms that can both synthesize organic substances from inorganic ones and feed on ready-made organic compounds (insectivorous plants, representatives of the Euglena algae department, etc.)

Over the entire history of its existence, man has tamed about 40 species of animals. Having provided them with food and shelter from enemies, he received in return food, clothing, vehicles, and labor.

However, even before the appearance of man on Earth, animals united among themselves in "friendly" unions. Ants and termites have excelled in this respect: they have "domesticated" about 2,000 species of living creatures! For joint life, usually two or three species are usually combined, but they provide each other with such important “services” that sometimes they lose the opportunity to exist separately.

TEMPORARY BUT IMPORTANT COOPERATION

Everyone knows that wolves hunt moose in packs, and dolphins hunt fish in herds. Such mutual assistance is natural for animals of the same species. But sometimes "outsiders" come together to hunt. This happens, for example, in the steppes of Central Asia, where the corsac fox and a small animal, similar to a ferret, live.

Both of them are interested in a large gerbil, which is quite difficult to catch: the fox is too fat to climb into the hole of a rodent, and a bandage that can do this cannot catch the animal at the exit from the hole: while it makes its way underground, the gerbil leaves through emergency passages.

But when two hunters cooperate, luck invariably accompanies them: the bandage drives the gerbils to the surface, and the fox is on duty outside, at the exit from the hole, not allowing the animal to leave. As a result, the booty goes to the one who gets to it first. Sometimes it's a fox, sometimes it's a bandage. It happens that they run from hole to hole until both are sated. And in a few days they are waiting for each other in their hunting area and start a new raid.

SINGLE BENEFITS

Sometimes only one side benefits from cohabitation. Such relationships can be considered “on-bread”. An example here is the union of a coot (a waterfowl the size of a duck) and carp, whose shoals follow the birds.

The reason for this “affection” is obvious: diving for algae, their main food, coots stir up silt, in which many small organisms that are tasty for fish are hiding. This attracts carp, seeking to profit without making any effort.

Often, small animals feed on the remnants of a meal of a stronger animal or bird, turning into their companions. Polar bears, for example, are accompanied by Arctic foxes and white gulls during difficult winter times.

Gray partridges do not fly far from hares, which are better at shoveling snow. Hyenas with jackals strive to be closer to the king of beasts, the lion. An animal-producer from such a "union" is neither benefit nor harm, but the "freeloaders" are extremely interested in it.

ENEMIES CAN BECOME DEFENDERS

A person who finds himself in the tundra for the first time will probably be surprised to see that geese and peregrine falcons (classic models of “predator” and “prey”!) nest in the same territory. It's like meeting a hare walking fearlessly near a wolf's hole.

The key to such good neighborliness is that the peregrine falcon never trades near the nest: its hunting and nesting areas do not coincide. In addition, he hunts only in the air, which geese are well aware of.

They even developed a habit of taking off and landing away from their nests and reaching them by land. Proximity to the falcon gives the geese considerable advantages: protecting their offspring from uninvited guests, he unwittingly becomes a formidable protector of the goose family. Whether the peregrine falcon receives any benefits from such “cohabitation” is still unknown.

MUTUAL SERVICES

Impressed by his trip to Ceylon, Ivan Bunin wrote the following lines at the beginning of the last century:

Lagoon near Ranna
like a sapphire.
Roses all around
flamingo,
Dozing through the puddles
buffaloes. On them
Herons are standing, whitening,
and with a buzz
Flies are sparkling...

They not only feed, but also breed on their body in unimaginable quantities. It is sometimes possible to comb out so many insects, their larvae and testicles from the wool of some domestic cattle that this is enough for a whole collection. But the animals themselves, especially large ones, are not able to get rid of the "evil spirits". Bathing does not help here, and they do not know how to rob each other like monkeys. And how many insects can you pull out with the help of a zebra's hoof or a hippopotamus mouth - a "suitcase"?

Herons with an elephant and a hippopotamus

Birds provide their wards with another service: they notify them of danger. Seeing the enemy on the horizon, they take off and, screaming loudly, begin to circle over their "masters", giving them a chance to escape. Such alliances are vitally beneficial to both parties.

COMMONWEALTH OF WATER DIVISIONS

Among the marine inhabitants there are real lovebirds, unable to exist without each other. A classic example of such a pair is hermit crab and adamsia anemone.

Cancer, having settled in the shell of a mollusk, immediately begins to take care of its protection. He finds an anemone of the right size, separates it from the substrate, carefully transfers it in a claw to his house and seats it there.

At the same time, anemone, burning with poisonous tentacles of everyone who approaches it, does not offer cancer the slightest resistance! She seems to know that in a new place she will be much more satisfying: small pieces of prey that have slipped out of the cancer's mouth will fall into her mouth. In addition, by “saddling” a hermit crab, she will be able to move around, which means she can quickly renew the water in her womb, which is vital for her. Cancer, from now on, will be protected from predators who want to profit from them.

And so they live together until death. If you remove an anemone from a cancer house, he will immediately plant it back. If, however, the cancer itself is removed from the shell, the sea anemone will soon die, no matter how well it is fed.

CHAINED BY ONE CHAIN

The mystery of such “gravity” has not been fully solved, but it is probably known that it is based on “profit”: it is easier for animals of different species to save their lives by uniting in a kind of “commonwealth”. As well as people.

In nature, everything is interconnected, and it is impossible to painlessly affect a single link of the biological system. I would like to hope that, mastering natural resources, people will take this into account.