Food chain: examples. How is the food chain formed?

In living nature, there are practically no living organisms that would not eat other creatures or would not be food for anyone. So, many insects feed on plants. Insects themselves are prey to larger creatures. These or other organisms are the links from which the food chain is formed. Examples of this "dependence" can be found everywhere. However, in any such structure, there is a first initial level. As a rule, these are green plants. What are some examples of food chains? What organisms can be links? How is the interaction between them? About this later in the article.

general information

The food chain, examples of which will be given below, is a certain set of microorganisms, fungi, plants, animals. Each link is at its own level. This "dependence" is built on the principle of "food-consumer". At the top of many food chains is a man. The higher the population density in a particular country, the fewer links it will contain in natural sequence, since people are forced to eat plants more often in such conditions.

Number of levels

How long can the food chain be? Examples of multi-level sequences exist different. The most revealing is the following: inside the body of the caterpillar there are parasitic fly larvae, in them - nematodes (worms), in worms, respectively, bacteria, but in them - a variety of viruses. But there can not be an infinite number of links. At each next level, biomass is reduced by several dozen times. So, for example, elk from 1000 kg of plants can "form" one hundred kilograms of its body. But a tiger for weight gain of 10 kg will require 100 kg of elk. The number of links depends on the conditions under which a particular animal food chain is formed. Examples of these systems can be seen in nature. So, frogs are the favorite food of some kinds of snakes, which, in turn, feed on predators. As a rule, in such a "sequence" no more than three or four links. This "construction" is also called an ecological pyramid. In it, each next step is much smaller than the previous one.

How is the interaction within the ecological pyramids?

How does the food chain work? The examples given above show that each next link should be at a higher level of development than the previous one. As already mentioned, the relationship in any ecological pyramid is built on the principle of "food-consumer". Due to eating by some other organisms, energy is transferred from the lower levels to the higher ones. As a result, there is a cycle of substances in nature.

Food chain. Examples

Conventionally, several types of ecological pyramids can be distinguished. There is, in particular, a pasturable food chain. Examples that can be seen in nature are sequences where the transfer of energy is from the lower (simplest) organisms to the higher (predators). To such pyramids, in particular, the following sequences can be assigned: "caterpillars-mice-vipers-hedgehogs-foxes", "rodents-predators". Another, detrital food chain, examples of which will be given below, is a sequence in which biomass is not used by predators, but a decay process involving microorganisms takes place. It is believed that this ecological pyramid begins with plants. So, in particular, the food chain of the forest looks like. Examples include the following: "fallen leaves-rotting with the participation of microorganisms", "dead plant tissues-fungi-centipedes-feces-mushrooms- nail-twigs-pincers-predators-centipedes-bacteria".

Producers and consumers

In a large body of water (ocean, sea), planktonic unicellular algae are food for the branching crustaceans (animal filterers). They, in turn, represent prey for predatory larvae of mosquitoes. These organisms feed on a certain type of fish. They are eaten by larger predators. This ecological pyramid is an example of the food chain of the sea. All organisms acting as links are at different trophic levels. At the first stage are producers, on the next - consumers of the first order (consumers). The third trophic level includes consumers of the second order (primary carnivores). They, in turn, serve as food for secondary predators - consumers of the third order, and so on. As a rule, ecological pyramids of land include three or five links.

Outdoor pond

Over the shelf sea, in the place where the slope of the continent is more or less abruptly cut off towards the deep-water plain, the open sea begins. In this zone, mostly blue and transparent water. This is due to the lack of inorganic suspended compounds and a smaller volume of microscopic planktonic plants and animals (phytoplankton and zooplankton). In some areas the surface of the water is distinguished by a particularly bright blue coloration. For example, the Sargasso Sea. In such cases, talk about the so-called ocean deserts. In these zones, even at a depth of thousands of meters with the help of sensitive equipment, you can find traces of light (in the blue-green spectrum). The open sea is characterized by a complete absence in the zooplankton composition of various larvae of benthic organisms (echinoderms, mollusks, crustaceans), the number of which decreases sharply with distance from the shore. As in shallow water, and in wide open spaces, sunlight is the only source of energy. As a result of photosynthesis, phytoplankton with chlorophyll forms organic compounds from carbon dioxide and water. This is how the so-called primary products are formed.

Chains of the food chain of the sea

Algae-synthesized organic compounds are transmitted indirectly or directly to all organisms. The second link in the food chain in the sea is the animal filter. The organisms that make up the phytoplankton have microscopically small dimensions (0.002-1mm). Often they form colonies, but their size does not exceed five millimeters. The third link is carnivorous animals. They feed on filters. In the shelf, as in the open seas, there are many such organisms. These include, in particular, siphonophores, ctenophores, jellyfish, copepods, bristle-jaw, carinarids. Among the fish to the filter feeders should be included herring. Their main food is copepods, forming large concentrations in the northern waters. The fourth link is predatory large fish. Some species are of commercial importance. Cephalopods, toothed whales and seabirds should also be referred to the final link.

Transport of nutrients

The transfer of organic compounds within food chains is accompanied by significant energy losses. This is mainly due to the fact that most of it is spent on metabolic processes. About 10% of energy is converted into a substance in the body. Therefore, for example, anchovy, feeding on plankton algae and entering into the structure of an exceptionally short food chain, can develop in such huge quantities as it occurs in the Peruvian current. The transfer of food to the twilight and deep zones from the light is due to active vertical migrations of zooplankton and certain species of fish. Moving up and down animals at different times of the day are at different depths.

Conclusion

It should be said that linear food chains are quite rare. Most often, ecological pyramids include populations belonging to several levels at once. The same species can eat both plants and animals; Carnivores can be fed as consumers of the first, and second and the following orders; Many animals consume living and dead organisms. Due to the complexity of link links, the loss of a species often has little impact on the state of the ecosystem. Those organisms that took the fallen link in their food can quite find another source of food, and other organisms start eating the food of the disappeared link. So in general, the community maintains its balance. The ecological system will be more stable, in which there are more complex feeding chains, consisting of a large number of links, including many different types.