Mutually beneficial relationships of organisms - symbiosis. Types of ecological relationships Mutually beneficial cohabitation of living organisms is called

Species of any organisms living in the same territory and in contact with each other enter into different relationships with each other. The position of the species in different forms of relationships is indicated by conventional signs. The minus sign (?) denotes an adverse effect (individuals of the species are oppressed). The plus sign (+) denotes a beneficial effect (individuals of the species benefit). The zero sign (0) indicates that the relationship is indifferent (no influence).

Biotic connections? relationships between different organisms. They can be direct (direct impact) and indirect (indirect). Direct connections are carried out with the direct influence of one organism on another. Indirect links are manifested through influence on the external environment or another species.

Thus, all biotic bonds can be divided into 6 groups:

1 Neutralism - populations do not affect each other (00);

2a. Proto-cooperation - populations have mutually beneficial relationships (++) (Interaction with each other is useful for both populations, but is not mandatory);

2c. Mutualism - populations have mutually beneficial relationships (++) (Required interaction, useful for both populations);

3. Competition - relationships are harmful to both species (? ?);

5. Commensalism - one species benefits, the other does not experience harm (+0);

6. Ammensalism - one species is oppressed, the other does not benefit (? 0);

Interaction types

In nature, cohabitation of two or more species is often found, which in some cases becomes necessary for both partners. Such cohabitation is called the symbiotic relationship of organisms (from the combination of sim? together, bio? life) or symbiosis. The term "symbiosis" is general, it denotes cohabitation, a prerequisite for which is living together, a certain degree of cohabitation of organisms.

A classic example of symbiosis is lichens, which are a close mutually beneficial cohabitation of fungi and algae.

A typical symbiosis is the relationship between termites and single-celled ones living in their intestines? flagella. These protozoa produce an enzyme that breaks down fiber into sugar. Termites do not have their own cellulose-digesting enzymes and would die without symbionts. And flagellates find favorable conditions in the intestines that contribute to their survival. A well-known example of symbiosis? cohabitation of green plants (primarily trees) and fungi.

A close mutually beneficial relationship, in which the presence of each of the two partner species becomes mandatory, is called mutualism (++). Such, for example, are the relationships of highly specialized plants for pollination (figs, bathing suit, Datura, orchids) with insect species that pollinate them.

A symbiotic relationship in which one species gains some benefit without harming or benefiting the other is called commensalism (+0). The manifestations of commensalism are diverse, therefore, a number of variants are distinguished in it.

Freeloading? consumption of the host's leftover food. This, for example, is the relationship between lions and hyenas, picking up the remains of half-eaten food, or sharks with sticky fish. Companionship? consumption of different substances or parts of the same food. Example? the relationship between various types of soil bacteria-saprophytes, processing various organic substances from decayed plant residues, and higher plants, which consume the mineral salts formed in this process. Housing? the use by one species of others (their bodies, their dwellings) as shelter or dwelling. Is this type of relationship widespread in plants? an example is lianas and epiphytes (orchids, lichens, mosses) that settle directly on the trunks and branches of trees.

In nature, there are also such forms of relationships between species when coexistence is not mandatory for them. These relationships are not symbiotic, although they play an important role in the existence of organisms. An example of mutually beneficial relationships is proto-cooperation (literally: primary cooperation) (++), which can include the spread of seeds of some forest plants by ants or pollination by bees of different meadow plants.

If two or more species use similar ecological resources and live together, there may be competition between them (? ?), or a struggle for possession of the necessary resource. Competition occurs where ecological resources are in short supply, and rivalry inevitably arises between species. At the same time, each species experiences oppression, which negatively affects the growth and survival of organisms, and the number of their populations.

Competition is extremely widespread in nature. For example, plants compete for light, moisture, soil nutrients and, consequently, for the expansion of their territory. Animals fight for food resources and for shelters (if they are in short supply), that is, ultimately, also for territory. Competition weakens in areas with a sparse population, represented by a small number of species: for example, in arctic or desert areas, there is almost no competition of plants for light.

Predation (+ ?) ? a type of relationship between organisms in which representatives of one species kill and eat representatives of another. Predation? one of the forms of food relations.

If two species do not affect each other, what is it? neutralism (00). In nature, true neutralism is very rare, since indirect interactions are possible between all species, the effect of which we do not see due to the incompleteness of our knowledge.

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Question 1. Define the main forms of interactions of living organisms.
1. Symbiosis (cohabitation)- a form of relationship in which both partners or one of them benefit from the interaction without causing harm to the other.
2. Antibiosis- a form of relationship in which both interacting populations (or one of them) experience a negative impact.
3. Neutralism- a form of relationship in which organisms living in the same territory do not directly influence each other. They turn them into simple compounds.

Question 2. What forms of symbiosis do you know and what are their features?
There are several forms of symbiotic relationships, characterized by varying degrees of dependence of partners.
1. Mutualism- a form of mutually beneficial cohabitation, when the presence of a partner is a prerequisite for the existence of each of them. For example, termites and flagellate protozoa that live in their intestines. Termites themselves cannot digest the cellulose they feed on, and flagellates receive food, protection and a favorable microclimate; lichens, which 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. In a free state, lichen fungi do not occur and are able to form a symbiotic organism only with a certain type of algae.
Higher plants also enter into a mutually beneficial relationship with fungi. Many grasses and trees develop normally only when soil fungi settle on their roots. The so-called mycorrhiza is formed: root hairs do not develop on the roots of plants, and the mycelium of the fungus penetrates into the root. Plants receive water and mineral salts from the fungus, and the fungus, in turn, receives carbohydrates and other organic substances.
2. Cooperation- mutually beneficial coexistence of representatives of different we see, but which, however, is mandatory. For example, hermit crab and anemone soft coral.
3. Commensalism(companionship) - a relationship in which one species benefits, while the other is indifferent. For example, jackals and hyenas, eating up the remnants of food for large predators - lions; pilot fish.

Question 3. What is the evolutionary significance of symbiosis?
Symbiotic relationships allow organisms to master the environment most fully and efficiently; they are the most important components of natural selection involved in the process of species divergence.

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 shrubs, 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, while 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.

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.)

This term has other meanings, see Competition. Competition in biology, any antagonistic relationship associated with the struggle for existence, for dominance, for food, space and other resources between organisms or species ... Wikipedia

- (from lat. mensa meal) a type of interspecific relationship in which one species, called amensal, undergoes inhibition of growth and development, and the second, called an inhibitor, is not subject to such tests. Antibiosis and ... ... Wikipedia

- (from Latin com “with”, “together” and mensa “table”, “meal”; literally “at the table”, “at the same table”; earlier companionship) a way of coexistence (symbiosis) of two different types of living organisms, in which one population benefits ... Wikipedia

- (from other Greek ἀντι against, βίος life) antagonistic relations of species, when one organism limits the capabilities of another, the impossibility of coexistence of organisms, for example, due to intoxication by some organisms (antibiotics, ... ... Wikipedia

This term has other meanings, see Symbiosis (meanings). Clownfish and sea anemone are organisms coexisting in a mutualistic symbiosis ... Wikipedia

- (Late Lat. organismus from Late Lat. organizo I arrange, I give a slender appearance, from other Greek ὄργανον a tool) a living body that has a set of properties that distinguish it from inanimate matter. As a separate individual organism ... ... Wikipedia

"Predator" redirects here; see also other meanings. "Predators" redirects here; see also other meanings ... Wikipedia

Between two ants of the species Oecophylla longinoda. Thailand. Trophallaxis ... Wikipedia

Co-evolution of biological species interacting in an ecosystem. Changes that affect any traits of individuals of one species lead to changes in another or other species. The first to introduce the concept of co-evolution was N. V. Timofeev Resovsky ... ... Wikipedia

This article or section has a list of sources or external links, but the sources of individual statements remain unclear due to the lack of footnotes ... Wikipedia

Books

• Semiotic theory of biological life, N. A. Zarenkov. Is it possible to understand what life is, limited to the study of the flesh of organisms - the signs of life: molecules, chromosomes, cells, tissues and organs? This book substantiates the negative answer to ...

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 that pollinate 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?