Living organisms are interconnected in a certain way. The following types of relationships between species are distinguished:
The most important are trophic and current connections, because they are the ones that keep organisms of different species close to each other, uniting them into communities.
Trophic connections occur between species when one species eats another: living individuals, dead remains, waste products. Trophic communication can be direct or indirect. Direct connection Manifested when feeding on live lion antelopes, hyenas with zebra carcasses, manure, manure of large ungulates, etc. Indirect communication occurs when different species compete for one food resource.
Current connections are manifested in the change of one type of living conditions of another. For example, under a coniferous forest there is usually no grass cover.
Foric connections occur when one species is involved in the distribution of another species. Animal transmission of seeds, spores, plant pollen is called zoohoria and small individuals – foresia .
Factory relations It consists in the fact that one species uses for its structures products of insulation, dead remains or even living individuals of another species. For example, birds use tree branches, grass, snowflakes, and the feathers of other birds to build nests.
The impact of one species on another can be positive, negative and neutral. In this case, combinations of different types of exposure are possible. Differentiate:
Neutralism – coexistence of two species in one territory, which has no positive or 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, the benefit of which is realized by all participants. For example, hermit crabs and sea anemones. An actinium coral polyp can settle on the shell of the cancer, which has stinging cells that secrete venom. Sea anemones protect the crab from predatory fish, and hermit crabs, by moving, promote the spread of sea anemones and increase their food space.
Medualism ( obligate symbiosis ) – mutually beneficial coexistence, when either partner or both cannot exist without coexistence. For example, herbivorous ungulates and bacteria that destroy cellulose. Bacteria that destroy cellulose live in the stomach and intestines of herbivorous ungulates. They produce enzymes that break down cellulose and therefore need herbivores that do not have such enzymes. For their part, herbivorous hooves provide bacteria with nutrients and a habitat with optimal temperature, humidity, etc.
Commensalism – relationships in which one of the partners benefits from living together, and the other does not care about the presence of the first. There are two forms of commentary: sinoykia (accommodation) and trophobiosis (parasitism) . An example of sinoeukia is the relationship of some marine anemones and tropical fish. Tropical fish hide from predator attacks among the tentacles of sea anemones, which have stinging cells. An example of trophobiasis is the relationship between large predators and ponds. Scissors, such as hyenas, vultures, jackals, feed on the remains of victims killed and are partially eaten by large predators – lions.
Predation – relationships in which one of the participants (predator) kills the other (victim) and uses it as food. For example, wolves and rabbits. The state of the predator population is closely related to the state of the prey population. However, as the population of one species of predator decreases, the predator switches to another species. For example, wolves can use rabbits, mice, wild boars, deer, frogs, insects, etc. as food.
A special case of predators is cannibalism – killing and eating their own kind. It occurs, for example, in rats, brown bears, humans.
Competition – relationships in which organisms compete with each other for the same environmental resources and lack others. Organisms can compete for food, sexual partner, shelter, light, etc. Distinguish between direct and indirect, intraspecific and interspecific competition. Indirect (passive) competition – the consumption of environmental resources required of both species. Direct (active) competition – suppression of one species to another. Intraspecific competition – rivalry between individuals of the same species. Interspecific competition arises between individuals of different but ecologically close species. Its result can be any mutual adjustment of the two types, orreplacement of populations of one species population of another species that moves to another place, moves to another food, or dies out.
Competition leads to natural selection in the direction of increasing differences in the environment between competing species and their formation of different ecological niches.
Amensalism – relationships in which one organism acts on another and suppresses its vital activity, and in itself does not experience any negative influences from the repressed. For example, spruce and lower layer plants. The dense spruce canopy prevents the penetration of sunlight under the forest canopy and inhibits the development of plants in the lower layer.
A special case of amenalism is allopathy (antibiosis) – the influence of one organism on another, whereby the vital products of one organism are released into the external environment, poisoning it and making it unsuitable for another. Allolopathy is common in plants, fungi, bacteria. For example, the fungus penicillin produces substances that suppress the vital activity of bacteria. Penicillin is used to produce penicillin – the first antibiotic discovered in medicine. Lately, the term “allopathy” has included a positive effect.
During the evolution and development of ecosystems, there is a tendency to reduce the role of negative interactions due to positive interactions that increase the survival of both species. Therefore, the share of strong negative interactions is lower in mature ecosystems than in young ones.
The characteristics of the types of interaction between populations of different species are also given in the table:
- (0) – there is no significant interaction among the population.
- (+) – 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 attributed to both groups.
Throughout the history of their existence, humans have tamed about 40 species of animals. By providing them with food and providing shelter from the enemy, he in turn received food, clothing, vehicles, and labor.
However, even before the appearance of man on Earth, animals united in “friendly” alliances. In this respect, ants and termites surpassed all: they “domesticated” about 2,000 species of living beings! Two or three species are usually combined to live together, but they provide each other with such important “services” that they sometimes lose the opportunity to exist separately.