Types of ecological relationships. Mutually beneficial relationships in the animal world Mutually beneficial cohabitation of organisms of different species
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 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 Bary (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?
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, 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 the 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 them as a place of attachment, 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.
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EXAMINATION TICKET No. 4 |
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Types of nutrition of living organisms. |
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Theories of the origin of life. |
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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.)
Nature is beautiful and varied. Living on the same planet, plants and animals had to learn to coexist with each other. The relationship between organisms is not an easy but interesting topic that will help you better understand the world around you.
Relationship types
There are different types of relationships. 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 an 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 during their evolutionary development. The result is a relationship 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 such a relationship between living organisms when both parties benefit. Most often, this benefit lies in the extraction of 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 of the planet.
One of them is the cooperation of hermit crab and sea anemone. Thanks to anemones, cancer finds a home and protection from other inhabitants of the water. Without a hermit crab, an anemone cannot move. But cancer allows you to expand the radius of the search for food. In addition, what the anemone does not eat will sink to the bottom and get cancer. This means that both parties benefit from this relationship.
Another example was the relationship between rhinos and bullock birds. Such relationships between organisms allow one of the parties to find food. Cowbirds eat insects that live in abundance on the huge rhinoceros. Rhinos also benefit from neighbors. Thanks to these birds, he can lead a healthy life and not 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 referred to as cheating.
Sharks are terrible marine predators. But for stick fish, they become a chance to survive and protect themselves from other aquatic predators, which are weak compared to sharks. Stick 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 the burrows of rodents you can find not only cubs, 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 hole, an insect is not afraid. In addition, here they can find enough food to lead a life without trouble. Rodents do not experience any difficulties from these types of relationships.
Negative types of relationships between organisms
Living 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
What is predation, anyone can tell without preparation. This is the relationship between organisms when one side benefits and the other suffers. In order to better understand who feeds on whom, one can compose And then it is easy to find out that many herbivores become the food of 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 don't feel safe either. They can be eaten by foxes. In addition, foxes, like wolves, feed on hares.
Despite the 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 under 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 dexterous animals win in the fight. Strong wolves get good prey, while others are left to either eat other, less satisfying animals, or die of hunger. There is a similar struggle between plants to get as much moisture or sunlight as possible.
Neutral relationship
There are also such types of relationships between organisms when both parties receive neither benefit nor harm. Despite the fact that they live in the same territory, absolutely nothing unites them. If one of the parties of these relationships disappears from the face of the planet, then this will not directly affect the other side.
So, in warm countries, different herbivores feed on the leaves of the same tree. Giraffes eat those 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 interfere with them and do not take away food. After all, low animals will not be able to reach those leaves that are eaten by high ones. And tall, it makes no sense to bend down and take food from others.
There are different forms of relationships between organisms. And learning them all is not easy. But it is important to remember that everything in nature is interconnected. Most often, animals and plants affect each other positively or negatively, less often they do not affect 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 world around us.
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 sign "zero" (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. Protocooperation - 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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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 hunts 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 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.