Biotic bonds in nature. Examples, types of biotic bonds

The biotic factors of nature are the relationships of all living organisms with each other and with the environment. Biotic relationships arise in the biogeocenosis between different species. The most important and important form of such connections is food relations, which form food cycles and complex chains.

Neutralism

Biotic bonds, in which the vital activity of one organism does not have any effect on the life of another, is called neutralism. Examples of this relationship are the hare and ribbonworm, the urticaria and flea, and also an endless number of others.

Scientists have noticed that during their life, all living organisms release into the environment solid, liquid and gaseous substances that can affect other plants, animals and microorganisms.

Allelopathy

Biotic bonds, which are realized due to specific active metabolic products released into the external environment, are called allelopathy.

This phenomenon is known for a long time, but only in 1937 the German scientist Molish gave him a certain name.

In more detail, this phenomenon has been studied in plant organisms. Allocation of many plants can exert both toxic and stimulating effects on their neighbors. Examples of biotic bonds in plants can be:

• Absintine leaves of bitter wormwood can inhibit the growth and development of many other plants;
• Beans retard the growth of spring wheat;
• Allocation of roots of wheatgrass badly affects not only other herbs and shrubs, but also trees.

Animals also release substances - pheromones, which can influence the behavior and development of individuals of a particular species. With their help, information is also transmitted to other species.

The isolation of biologically active substances is also characteristic of microorganisms. For example, antibiotics such as penicillin and streptomycin are widely known.

Effect group

The group effect is the optimization of all processes, which leads to the maximum increase in the viability of individuals in their cohabitation. This feature is manifested in a large number of species that can normally multiply and develop only if they are combined into small or large groups.

The types of biotic bonds depend on the habitat of individuals and the methods of their existence. For example, in order to survive a herd of African elephants, it must be at least thirty individuals.

Competition

Biotic relationships, during which there are relationships between individuals of one or different species, under which the same resources are used, with their significant shortage, are called competition. Intraspecific competition can significantly increase the intensity of natural selection. The most popular example of this process is the self-thinning of the fir trees.

But the interspecific type of competition is most often characteristic of ecologically close individuals or populations of different species. Can be both passive and active. The first implies the use of natural resources needed by both species. And during the second, one species is suppressed by another.

Competition is one of the main reasons that several species, characterized by a similar way of life, behavior and specific food, can not cohabit in one community. Such competition can turn into enmity.

Predation

Biotic bonds in nature, which are characterized by such a way of food production, as catching, killing and eating of caught individuals, are called predation. The basis of such relationships are food links and food chains. Predator first kills prey, but only then it eats. But before that, you need to catch it. For these purposes, each predator has special adaptations. Historically, the victims have protective elements. For example, carapace, spines, thorns, poisonous glands and protective paint.

Thanks to such mutual adaptations, groups of organisms - predators and prey - were formed. In such relationships, the principles of regulating the size of both components are formed.

Until recently, scientists thought that all predators - harmful inhabitants of the planet, so they need to exterminate. However, this opinion was erroneous. Such actions will have negative global consequences. There is a risk of damaging not only the wild nature, but the whole economy.

Symbiosis

Biotic connections in nature, during which one of the partners (or both at once) benefits from relationships with each other, are called symbiosis.

There are a lot of examples of mutually beneficial symbiosis in the world. For example, gastric and intestinal bacteria, without which the digestive process is impossible. Or pollination of some orchids, whose pollen can tolerate only a certain type of insect. Such relationships are successful when they increase the likelihood of both partners to survive.

In other words, it is absolutely any form of interrelations between organisms of different species (this includes parasitism - a special kind of relationship that is beneficial to one partner, but harmful to another).

Symbiosis, which will be beneficial for both representatives, is called mutualism. But commensalism is a relationship that is useful to one, but indifferent to another. Endosymbiosis is the ability of one partner to live within the cell of another.

Mutualism

Mutualism is considered the most common form of cohabitation. Biotic connections in nature (the 9th grade of the school curriculum describes this topic in detail) in the form of mutualism are a prerequisite - the existence of both partners. During this communication, each of the partners receives their benefits. For example, one partner uses the other as a power source, and the other is protected from enemies or under favorable conditions for development and reproduction.

Every participant in a mutualistic couple is selfish, and mutual benefit only arises from the fact that the benefits obtained outweigh all the costs that are required to maintain a relationship.

Mutually beneficial links are also formed due to behavioral reactions. Examples of biotic links mutualizma - birds combine their own food, and at the same time are seed spreaders. Sometimes physical relationships arise.

The close contact of species with mutualism promotes their joint evolution. Such an example is the adaptations that were formed in flowers and their pollinators.

Commensalism

Biotic bonds (grade 9) distinguish three types of commensalism:

1. Use food of other kinds.
2. They are attached to another organism, which becomes a "master".
3. They settle in the internal organs of the host.

Relations of this type are very important for nature, as they enable each species of the Earth to cohabit a large number of species, as well as to maximally master the environment and use food resources.

However, very often this type of communication goes into other relationships. When eating food starts to harm the owner, the relationship goes to a new level and becomes parasitism or competition.

Parasitism

Parasitism is a kind of relationship in which a parasite uses the master as the main residence and food source. Biotic links (the table is presented in the article) describe this kind of coexistence of individuals: the parasite settles inside the host or on its surface. Parasitism can occur among various groups of organisms (in plants, animals, fungi and humans).

The physiology of the parasite is subject to the host's life processes. Therefore, for productive existence it is necessary to use biological resources. The longer coexistence takes place, the better this type of parasite adapts to its owner and does less harm to it.