Types of relationships between organisms. Mutually beneficial relationships in the animal world What is mutually beneficial cohabitation of organisms called?
Question 1. Define the main forms of interactions between 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. Neutrality- a form of relationship in which organisms living in the same territory do not directly influence each other. They form 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 partners' dependencies.
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 flagellated protozoa that live in their intestines. Termites cannot themselves digest the cellulose on which they feed, but flagellates receive nutrition, protection and a favorable microclimate; lichens, which represent the inseparable cohabitation of a fungus and an algae, when the presence of a partner becomes a condition of life for each of them. The hyphae of the fungus, entwining the cells and filaments of the algae, receive substances synthesized by the algae. Algae extract water and minerals from the fungal hyphae. Lichen fungi are not found in a free state and are capable of forming a symbiotic organism only with a certain type seaweed
Higher plants also enter into mutually beneficial relationships with fungi. Many grasses and trees develop normally only when soil fungi colonize their roots. The so-called mycorrhiza is formed: root hairs on plant roots do not develop, and the fungal mycelium penetrates into the root. Water and mineral salts plants receive from the fungus, and the fungus, in turn, receives carbohydrates and other organic substances.
2. Cooperation- mutually beneficial coexistence of representatives of different species, which is, however, mandatory. For example, hermit crab and sea anemone soft coral.
3. Commensalism(companionship) - a relationship in which one species benefits, but the other is indifferent. For example, jackals and hyenas, eating leftover food from large predators - lions; fish pilots.
Question 3. What is the evolutionary significance of symbiosis?
Symbiotic relationships allow organisms to most fully and effectively master their environment and are essential components natural selection involved in the process of divergence of species.
Nature is beautiful and diverse. Existing on the same planet, plants and animals were forced to learn to coexist with each other. The relationship between organisms is complex, but interesting topic, which will help you better understand the world around you.
Types of relationships
There are different types of relationships with each other. But scientists divide them into three large groups.
The first group combines all those types of relationships between organisms that can be called positive, the result of which helps two organisms to exist without contradictions.
The second group includes those types of relationships that are called negative. As a result of the interaction of two organisms, only one benefits, while the other is oppressed. Sometimes the latter may even die as a result of such relationships. This group also includes such interaction of organisms that negatively affects both the first and second individuals.
The third group is considered the smallest. This group includes relationships between organisms that bring neither benefit nor harm to both parties.
Positive types of relationships between organisms
In order to exist in the world, you need to find allies and helpers. This is exactly what many plants and animals do throughout their lives. evolutionary development. The result is connections where both parties benefit from the relationship. Or those relationships that are beneficial only to one side, and they do not harm the other.
Positive relationships, also called symbiosis, come in many forms. Currently, cooperation, mutualism and commensalism are distinguished.
Cooperation
Cooperation is a relationship between living organisms where both parties benefit. Most often this benefit comes from obtaining food. But sometimes one of the parties receives from the other not only food, but also protection. Such relationships between organisms are very interesting. Examples can be seen in the animal kingdom in different parts planets.
One of them is the cooperation of hermit crab and sea anemone. Thanks to the sea anemone, the crayfish finds a home and protection from other inhabitants of the aquatic space. Without the hermit crab, the sea anemone cannot move. But cancer allows you to expand the radius of searching for food. In addition, what the sea anemone does not eat will sink to the bottom and go to the crayfish. This means that both parties benefit from this relationship.
Another example was the relationship between rhinoceroses and cowbirds. Such relationships between organisms allow one of the parties to find food. Cowbirds eat insects, which live in abundance on the huge rhinoceros. Rhinos also benefit from neighbors. Thanks to these birds he can lead healthy life and don't worry about insects.
Commensalism
Commensalism is those relationships between organisms in ecosystems when one of the organisms benefits, and the second does not experience inconvenience from these relationships, but does not benefit either. This type of relationship is also called freeloading.
Sharks are creepy sea predators. But for sticky fish, they become a chance to survive and protect themselves from other aquatic predators, which are weak compared to sharks. Sticky fish benefit from sharks. But they themselves do not bring them any benefit. At the same time, there is no harm. For the shark, such relationships go unnoticed.
In rodent burrows you can find not only babies, but also a huge number of different insects. The hole created by the animal becomes their home. It is here that they find not only shelter, but also protection from those animals that love to feast on them. In a rodent burrow, the insect is not afraid of this. Moreover, here they can find enough food to lead a life without troubles. Rodents do not experience any difficulties from these types of relationships.
Negative types of relationships between organisms
Existing together on the planet, animals can not only help each other, but also cause harm. It is not easy to learn these relationships between organisms. The table will help schoolchildren and students.
Predation
Anyone can tell you what predation is without preparation. This is the relationship between organisms when one side benefits and the other suffers. In order to better understand who eats whom, you can compile And then it is easy to find out that many herbivores become food for other animals. At the same time, predators can also be someone's food.
Despite the fact that hedgehogs are often depicted in pictures with apples and mushrooms, they are predators. Hedgehogs feed on small rodents. But they also cannot feel safe. They can be eaten by foxes. In addition, foxes, like wolves, feed on hares.
Despite bloodthirsty predators hunting for weaker animals day and night, competition is considered the most cruel type of relationship between organisms. After all, these include the struggle for a place in the sun among representatives of the same species. And each species has its own means of obtaining the required amount of food or better housing.
Stronger and more agile animals win the fight. Strong wolves get good prey, while others are left either to feed on other, less nourishing animals, or to die of hunger. A similar struggle is waged between plants to get as much moisture or sunlight as possible.
Neutral relationship
There are also types of relationships between organisms when both parties receive neither benefit nor harm. Despite the fact that they live in the same territory, they have absolutely nothing in common. If one of the parties to this relationship disappears from the face of the planet, then the other party will not be directly affected.
So, in warm countries different herbivores feed on the leaves of the same tree. Giraffes eat the leaves that are on top. They are the most juicy and delicious. And other herbivores are forced to feed on the remains growing below. Giraffes do not bother them and do not take away their food. After all, low animals will not be able to reach the leaves that tall animals eat. And it makes no sense for tall people to bend over and take food from others.
There are different forms of relationships between organisms. And learning them all is not so easy. But it is important to remember that everything in nature is interconnected. Most often, animals and plants influence each other positively or negatively, less often they do not influence each other at all. But even if they are not directly related, this does not mean that the disappearance of one cannot lead to the death of the other. The relationship between organisms is an important part of the surrounding world.
Species of any organisms living in the same territory and in contact with each other enter into different relationships between themselves. View position at different forms relationship is indicated conventional signs. The minus sign (?) indicates an unfavorable effect (individuals of the species are oppressed). A plus sign (+) indicates 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 (mediated). Direct connections occur through the direct influence of one organism on another. Indirect connections are manifested through influence on external environment or another type. 
Thus, all biotic connections can be divided into 6 groups:
1 Neutralism - populations do not influence each other (00);
2a. Proto-cooperation - populations have mutually beneficial relationships (++) (Interaction with each other is beneficial for both populations, but is not necessary);
2c. Mutualism - populations have mutually beneficial relationships (++) (Obligatory interaction beneficial 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);
Types of interactions
In nature, cohabitation of two or more species is often found, which in some cases becomes necessary for both partners. Such cohabitation is called a symbiotic relationship between organisms (from the combination of sym? together, bio? life) or symbiosis. The term “symbiosis” is a general one; it denotes cohabitation, the obligatory condition of which is living together, a certain degree of cohabitation of organisms.
A classic example of symbiosis are lichens, which are close mutually beneficial cohabitation mushrooms and algae.
A typical symbiosis is the relationship between termites and single-celled organisms living in their intestines? Flagellates. These protozoa produce an enzyme that breaks down fiber into sugar. Termites do not have their own enzymes to digest cellulose and would die without their symbionts. And flagellates find favorable conditions in the intestine that promote their survival. Wide famous example symbiosis? cohabitation of green plants (primarily trees) and mushrooms.
A close, mutually beneficial relationship in which the presence of each of the two partner species becomes mandatory is called mutualism (++). Such are, for example, the relationships between highly specialized plants for pollination (figs, figs, datura, orchids) with the insect species that pollinate them.
A symbiotic relationship in which one species receives some advantage without bringing any harm or benefit to the other is called commensalism (+0). The manifestations of commensalism are varied, so a number of variants are distinguished.
Freeloading? consumption of the owner's food scraps. This is, for example, the relationship between lions and hyenas picking up the remains of half-eaten food, or sharks with sticky fish. Companionship? consuming different substances or parts of the same food. Example? relationship between various types soil saprophytic bacteria that process various organic substances from rotted plant residues, and higher plants, which consume the resulting mineral salts. Tenancy? the use by one species of another (their bodies, their homes) as a shelter or home. 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 obligatory for them. These relationships are not symbiotic, although they play important role in the existence of organisms. An example of mutually beneficial connections is protocooperation (literally: primary cooperation) (++), which includes the dispersal of seeds of some forest plants by ants or the pollination of various meadow plants by bees.
If two or more species use similar ecological resources and live together, competition (? ?), or struggle for possession, may arise between them necessary resource. Competition occurs where environmental resources are scarce, and rivalry inevitably occurs between species. Each species experiences oppression, which negatively affects the growth and survival of organisms and the size of their populations.
Competition is extremely widespread in nature. For example, plants compete for light, moisture, nutrients soil and, therefore, 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. Competitive struggle weakens in areas with sparse populations represented by a small number of species: for example, in arctic or desert areas there is almost no competition between plants for light
Predation (+ ?) ? this 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 the two species do not affect each other, then this? 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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Cohabitation of algae with other organisms T.V. Sedova.[...]
Plant cohabitation can occur without intravital metabolism. In these cases, a plant living on another, using the latter only as a place of attachment, is called an epiphyte. A special case of epiphytism are epiphytism, i.e. plants that use only the leaves of another plant as support. Epiphytes and epiphylls can significantly influence their substrate, complicating gas exchange in other ways.[...]
Symbiosis (cohabitation). This is a form of relationship in which both partners or one of them benefits from the other.[...]
All forms of cohabitation that occur between organisms belonging to different species are called symbioses. Between the above types of cohabitation there are many transitional forms, which makes the connections between organisms in the biosphere extremely diverse. The more diverse the connections that support the coexistence of species, the more stable their cohabitation.[...]
Symbiosis - coexistence of organisms different types, from which both benefit.[...]
Mycorrhizal cohabitation (symbiosis) is mutually beneficial to 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 cohabitation of two organisms, is one of the most interesting and is still in many ways mysterious phenomena in biology, although the study of this issue has a history of almost a century. The phenomenon of symbiosis was first discovered by the Swiss scientist Schwendener in 1877 while studying lichens, which, as it turned out, are complex organisms consisting of an algae and a fungus. The term “symbiosis” appeared in scientific literature later. It was proposed in 1879 by De Bary.[...]
Neutrality is the cohabitation of two species on the same territory, which has neither positive nor negative consequences for them. For example, squirrels and moose.[...]
SYMBIOSIS - close cohabitation of two or more organisms of different species, in which the organisms (symbionts) benefit each other. According to the degree of partnership and food dependence on each other, several types of symbiosis are distinguished: commensalism, mutualism, etc. Thus, commensalism (from the Latin “companion”) is a form of relationship between two species, when one feeds at the expense of the other, without causing any harm to it . Hermit crabs live with sea anemones; the latter attach to the mollusk shell in which the hermit crab lives, protecting it from enemies and feeding on the remains of its prey. Commensalism is especially widespread among sea creatures leading a sedentary lifestyle.[...]
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 benefit (for example, lichen - C. fungus and algae).[...]
Mutualism is a form of cohabitation of organisms in which both partners benefit (the same as symbiosis).[...]
Symbiosis (Greek symbiosis - cohabitation) is the 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 is useful only for the other partner, adaptations in this case are one-sided. As an example, we can point out that in mites of the family Tyroglyphidae, which use various insects for dispersal, a special hypopial phase (hypopus phase) arose between the nymph and deutonymph phases.[...]
Another example of symbiosis is the cohabitation of higher plants with bacteria, the so-called bacteriotrophy. Symbiosis with nodule bacteria-nitrogen fixers are widely distributed among legumes (93% of the studied species) and mimosa (87%). Thus, bacteria from the genus Lygolisni, living in nodules on the roots of leguminous plants, are provided with food (sugars) and habitat, and the plants receive from them in return an accessible form of nitrogen (Fig. 6.13).[...]
Shilova A. I., Kurazhkovskaya T. N. Cohabitation of Glyptotendipes varipes Goetgh. and bryozoans Plumatella fungosa Pall.[...]
There are also mycorrhizal fungi that cohabit with the roots of higher plants. The mycelium of these fungi envelops the roots of plants and helps obtain nutrients from the soil. Mycorrhiza is observed mainly in woody plants that have 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 interspecific 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).[...]
Neutrality (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 do not related friend with another relationship of competition or nutrition. With neutralism, species are not directly related to each other, but can sometimes depend on the state of a given biocenosis as a whole. [...]
An example of a mutually beneficial relationship is the cohabitation of so-called nodule bacteria and leguminous plants (peas, beans, soybeans, clover, etc.). These bacteria, capable of absorbing 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. This is why legumes are introduced into 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-degrading bacteria.[...]
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-degrading bacteria. Cellulose-degrading 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 habitat with optimal temperature, humidity, etc.[...]
A typical example symbiosis can serve as close cohabitation between fungi and algae, leading to the formation of a more complex and more adapted natural conditions plant organism- lichen. To others a shining example symbiotic cohabitation in the soil is the symbiosis of fungi with higher plants, when fungi form microorganisms on the roots of plants. A clear symbiosis is observed between nodule bacteria and leguminous plants.[...]
Almost all types of trees in normal conditions cohabitate with mycorrhizal fungi. The mycelium of the fungus envelops the thin roots of the tree like a sheath, penetrating into the intercellular space. A mass of the finest mushroom threads, extending a considerable distance from this cover, successfully performs the function of root hairs, sucking up a nutrient soil solution. [...]
Mutualism is a symbiotic relationship when both cohabiting species benefit from each other. [...]
Firstly, a specific feature of lichens is the symbiotic cohabitation of two different organisms- heterotrophic fungus (mycobiont) and autotrophic algae (phycobiont). Not every cohabitation of a 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 accumulation, but this is not yet a lichen. In a true lichen, a fungus and an alga enter into close relationship, the fungal component surrounds the algae and can even penetrate their cells.[...]
Commensalism (or “freeloading”) is a form of cohabitation in which one species lives off the food reserves of another, without bringing benefit in turn. Sometimes commensalism appears as a more or less random phenomenon and is almost completely imperceptible to the partner whose food supplies are devoured. So, for example, the Malayan beetle from the genus Hustrev Nore drills into the branches of trees and feeds on the juice protruding from the wounds, and the protruding juice also attracts flies (Mie-c1 c1ae) and some other insects, which eat it together with Huygiree.[...]
Using the example of European 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 the yeasts and bacteria that inhabit their intestines (Werner, 1927; Hitz, 1927, etc.).[...]
A typical example of close symbiosis, or mutualism between plants, is the cohabitation of an algae and a 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, for example algae, fungi and microorganisms within the body of a lichen.[...]
In some cases, the body or structures of one species may serve as habitat or protection for another. For example, in coral reefs lives a large number of marine organisms. Small sea inhabitants settle in the body cavity of the echinoderm holothurian. 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 that two species, slightly different in the specifics of nutrition, behavior, lifestyle, etc., rarely coexist in the same community. Here the competition is in the nature of direct hostility. The most severe competition with unforeseen consequences occurs if a person introduces animal species into communities without taking into account already established relationships.[...]
Lichens represent a kind of group complex organisms whose body always consists of two components - a fungus and an algae. Now every schoolchild knows that the biology of lichens is based on the phenomenon of symbiosis - the cohabitation of two different organisms. But just over a hundred years ago, lichens were a great mystery to scientists, and the discovery of their essence by Simon Schwendener in 1867 was assessed as one of the most amazing discoveries of that time.[...]
Moles are not kind to their neighbors and do not tolerate any residents or other moles in their burrows. And if they are put together in a cramped box, the strong will kill and eat the weak. 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 there is a flood, he helps the mother drag the children to dry holes. But whether this is actually so is still unknown with accuracy.[...]
K. is used to study the migration routes of animals (especially birds), establish the boundaries of their habitats, the characteristics of seasonal biology, and solve other problems. COMBINED IMPACT - see art. Impact on environment. COMMENSALISM, or freeloading [from lat. sot - s 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 causing him harm. COMPENSATORY BEHAVIOR - a complex of behavioral reactions of organisms aimed at weakening (compensation) of the limiting influence environmental factor.[ ...]
Commensalism is an interspecific interaction between organisms in which one organism benefits at the expense of another without harming it, while the other organism has neither benefit nor harm from this interaction. For example, some types of marine polyps settle on the surface of the body large fish, feeding on their secretions, but for fish this cohabitation is indifferent, that is, it has no meaning.[...]
The first roots of marattiaceae are usually infected with the fungus. But mycorrhiza is facultative 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 a lichen - a fungus and an alga - physiologically complement each other. The hyphae of the fungus, entwining the cells and filaments of the algae, form special suction processes, haustoria, through which the fungus receives substances assimilated by the algae. Algae obtains its 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, minerals and organic substances from the soil into plant roots, as well as the absorption of a number of substances. In turn, they receive carbohydrates and other organic substances necessary for their existence from the roots of plants.[...]
A fairly common phenomenon in relationships between different species is symbiosis, or the coexistence of two or more species, in which none of them can live separately under given conditions. A whole class of symbiotic organisms is represented by lichens - fungi and algae living together. In this case, 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 water and minerals necessary for the algae, and the algae supplies the fungus with the products of photosynthesis. This combination of properties makes these symbiotic organisms extremely unpretentious 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 mineral substances necessary for life from dust settling 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 taking into account the number and species diversity of lichens in the controlled area, lichen indication. [...]
It is a rare animal that is so little scrupulous in choosing a home and its environment as the kuzulis. And the crowns of hundred-meter eucalyptus trees are suitable for him, and low-growing bushes, and dense rainforests, 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 male cousulis often settle in rabbit holes in Central Australia, an absurd legend was born. Farmers assure that this choice of housing was made by the old sinners for a reason: as if they were in a criminal misalliance with the rabbits. And it’s as if they saw crosses from their cohabitation. But this is a myth.[...]
A population (from the Latin populie - population) is a collection of individuals of the same species that inhabit a certain space for a long time, have a common gene pool, the ability to interbreed freely, and are to one degree or another isolated from other populations of this species. Population is the elementary form of existence of a species in nature. Populations evolve and are the units of species evolution and speciation. Having all the signs biological system, a population, however, is a collection of organisms, as if isolated from the natural system, since in nature, individuals of one species always coexist with individuals of other species. Only in artificial conditions or in a special experiment is it possible to deal with a “pure” population, for example, a culture of microorganisms, plant sowing, animal offspring, 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. The lint of almost all heathers is closely entwined with mushroom threads, supplying them with nutrients from humus. In the latter case, some simple fungi (the body of which consists of only a few cells) live entirely in the cells of the heather roots and are gradually digested by them. Mycorrhiza has a huge positive value in the life of heathers. In some cases (for example, in the strawberry tree - Arbutus, Table 13), infected roots turn into pear-shaped nodules (mycodomathia), the epidermal cells of which are transformed 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 that cohabit with them cannot tolerate alkaline soils.
Living organisms are connected to each other in a certain way. The following types of connections between species are distinguished:
- trophic,
- topical,
- phoric,
- factory
The most important are trophic and topical connections, since they are the ones that hold 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 connections can be direct or 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 one food resource.
Topical connections manifest themselves in one species changing the living conditions of another species. For example, under coniferous forest As a rule, there is no grass cover.
Phoric connections occur when one species participates in the spread 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 and neutral. In this case, different combinations of impact types are possible. There are:
Neutralism- cohabitation of two species on 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 obligatory coexistence of organisms, from which all participants benefit. For example, hermit crabs and sea anemones. Crayfish can settle on the shell coral polyp sea anemone, which has stinging cells, secreting poison. Sea anemone protects against cancer predatory fish, and the hermit crab, moving, contributes to the spread of sea anemones and an increase in 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-degrading bacteria. Cellulose-degrading 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.
Commensalism- a relationship in which one of the partners benefits from cohabitation, and the other is indifferent to the presence of the first. There are two forms of commensalism: sinoikia (lodging) And trophobiosis (freeloading). An example of synoikia is the relationship between some sea anemones and tropical fish. Tropical fish They take refuge from attacks from predators among the tentacles of sea anemones, which have stinging cells. An example of trophobiosis is the relationship between large predators and scavengers. Scavengers, such as hyenas, vultures, and jackals, feed on the remains of victims killed and partially eaten by large predators - lions.
Predation- a relationship in which one of the participants (predator) kills the other (prey) and uses him 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 size of one prey species 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 one's own kind. Occurs, for example, in rats, brown bears, person.
Competition- relationships in which organisms compete with each other for the same environmental resources when the latter are in short supply. Organisms may compete for food resources, sexual partners, shelter, light, etc. There are direct and indirect, intraspecific and interspecific competition. Indirect (passive) competition- consumption of environmental resources necessary for both types. Direct (active) competition- suppression of one type by another. Intraspecific competition- competition between individuals of the same species. Interspecific competition occurs between individuals of different but ecologically similar species. Its result can be either mutual adjustment two types, or substitution a population of one species of a population of another species that moves to another place, switches to another food, or goes extinct.
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- a relationship in which one organism influences another and suppresses its vital activity, while it itself does not experience any negative influences from the suppressed one. For example, spruce and plants lower tier. The dense crown of spruce prevents penetration sun rays under the forest canopy and suppresses the development of lower tier plants.
A special case of amensalism is allelopathy (antibiosis)- the influence of one organism on another, in which 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, and bacteria. For example, the penicillium fungus produces substances that suppress the activity of bacteria. Penicillium is used to produce penicillin, the first antibiotic discovered in medicine. IN Lately The concept of “allelopathy” also includes a positive effect.
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, increasing the survival of both species. Therefore, in mature ecosystems the proportion of strong negative interactions is less than in young ones.
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.
- (+) - a 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 can be considered "positive interactions", and types 5 and 6 can be classified as both groups.