The longest food chain in the world. Examples of food chains in different forests
A food chain is the transfer of energy from its source through a series of organisms. All living beings are connected, as they serve as food objects for other organisms. All food chains consist of three to five links. The first are usually producers - organisms that are able to produce themselves organic matter from inorganic. These are plants that nutrients through photosynthesis. Next come the consumers - these are heterotrophic organisms that receive ready-made organic substances. These will be animals: both herbivores and carnivores. The closing link of the food chain is usually decomposers - microorganisms that decompose organic matter.
The food chain cannot consist of six or more links, since each new link receives only 10% of the energy of the previous link, another 90% is lost in the form of heat.
What are food chains?
There are two types: pasture and detritus. The former are more common in nature. In such chains, the first link is always the producers (plants). They are followed by consumers of the first order - herbivorous animals. Further - consumers of the second order - small predators. Behind them - consumers of the third order - large predators. Further, there may also be fourth-order consumers, such long food chains are usually found in the oceans. The last link is the decomposers.
The second type of power circuits - detritus- more common in forests and savannahs. They arise due to the fact that most of the plant energy is not consumed by herbivorous organisms, but dies off, then being decomposed by decomposers and mineralized.
Food chains of this type start from detritus - organic residues of plant and animal origin. First-order consumers in such food chains are insects, such as dung beetles, or scavengers, such as hyenas, wolves, vultures. In addition, bacteria that feed on plant residues can be first-order consumers in such chains.
In biogeocenoses, everything is connected in such a way that most types of living organisms can become participants in both types of food chains.
Food chains in deciduous and mixed forests
Deciduous forests are mostly distributed in the Northern Hemisphere of the planet. They meet Western and Central Europe, in Southern Scandinavia, in the Urals, in Western Siberia, East Asia, North Florida.
Deciduous forests are divided into broad-leaved and small-leaved. The former are characterized by such trees as oak, linden, ash, maple, elm. For the second - birch, alder, aspen.
Mixed forests are those in which both coniferous and deciduous trees. Mixed forests are characteristic of the temperate climate zone. They are found in the south of Scandinavia, in the Caucasus, in the Carpathians, on Far East, in Siberia, in California, in the Appalachians, near the Great Lakes.
Mixed forests consist of trees such as spruce, pine, oak, linden, maple, elm, apple, fir, beech, hornbeam.
Very common in deciduous and mixed forests pasture food chains. The first link in the food chain in forests is usually numerous species herbs, berries such as raspberries, blueberries, strawberries. elderberry, tree bark, nuts, cones.
First-order consumers will most often be such herbivores as roe deer, elk, deer, rodents, for example, squirrels, mice, shrews, and also hares.
Second order consumers are predators. Usually it is a fox, wolf, weasel, ermine, lynx, owl and others. A vivid example of the fact that the same species participates in both pasture and detrital food chains will be the wolf: it can both hunt small mammals and eat carrion.
Second-order consumers can themselves become prey to larger predators, especially birds: for example, small owls can be eaten by hawks.
The closing link will be decomposers(decay bacteria).
Examples of food chains in a deciduous-coniferous forest:
- birch bark - hare - wolf - decomposers;
- wood - Maybug larva - woodpecker - hawk - decomposers;
- leaf litter (detritus) - worms - shrews - owl - decomposers.
Features of food chains in coniferous forests
Such forests are located in the north of Eurasia and North America. They consist of trees such as pine, spruce, fir, cedar, larch and others.
Here everything is very different from mixed and deciduous forests.
The first link in this case will not be grass, but moss, shrubs or lichens. This is due to the fact that in coniferous forests there is not enough light for a dense grass cover to exist.
Accordingly, the animals that will become consumers of the first order will be different - they should not eat grass, but moss, lichens or shrubs. It can be some types of deer.
Despite the fact that shrubs and mosses are more common, coniferous forests are still found herbaceous plants and bushes. These are nettle, celandine, strawberry, elderberry. Hares, moose, squirrels usually eat such food, which can also become first-order consumers.
The consumers of the second order will be, like mixed forests, predators. These are mink, bear, wolverine, lynx and others.
Small predators such as mink can become prey for third order consumers.
The closing link will be the microorganisms of decay.
In addition, in coniferous forests are very common detrital food chains. Here, the first link will most often be plant humus, which is fed by soil bacteria, becoming, in turn, food for unicellular animals that are eaten by fungi. Such chains are usually long and may consist of more than five links.
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The transfer of energy by eating living organisms of each other is called the food chain. These are the specific relationships of plants, fungi, animals, microorganisms that ensure the circulation of substances in nature. Also called a trophic chain.
Structure
All organisms feed, i.e. receive energy that provides life processes. The system of the trophic chain is formed by links. A link in the food chain is a group of living organisms connected with the neighboring group by the relationship "food - consumer". Some organisms are food for other organisms, which in turn are also food for a third group of organisms.
There are three types of links:
- producers - autotrophs;
- consumers - heterotrophs;
- decomposers (destructors) - saprotrophs.
Rice. 1. Links of the food chain.
One chain includes all three links. There can be several consumers (consumers of the first, second order, etc.). The basis of the chain can be producers or decomposers.
Producers include plants that convert organic substances with the help of light into organic substances that, when eaten by plants, enter the body of a first-order consumer. The main feature of the consumer is heterotrophy. At the same time, consumers can consume both living organisms and dead ones (carrion).
Examples of consumers:
- herbivores - hare, cow, mouse;
- predatory - leopard, owl, walrus;
- scavengers - vulture, Tasmanian devil, jackal.
Some consumers, including humans, occupy an intermediate position, being omnivores. Such animals can act as consumers of the first, second and even third order. For example, a bear feeds on berries and small rodents; at the same time it is a consumer of the first and second orders.
Reducers include:
- mushrooms;
- bacteria;
- protozoa;
- worms;
- insect larvae.
Rice. 2. Reducers.
Decomposers feed on the remains of living organisms and their metabolic products, returning to the soil inorganic substances consumed by producers.
Kinds
Food chains can be of two types:
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- grazing (chain of grazing);
- detrital (decomposition chain).
Pasture chains are characteristic of meadows, fields, seas, and reservoirs. The beginning of the chain of grazing are autotrophic organisms - photosynthetic plants.
Further, the links of the chain are arranged as follows:
- consumers of the first order - herbivorous animals;
- consumers of the second order - predators;
- consumers of the third order - larger predators;
- decomposers.
In marine and oceanic ecosystems, grazing chains are longer than on land. They can include up to five orders of consumers. The basis of marine chains is photosynthetic phytoplankton.
The following links form several consumers:
- zooplankton (crustaceans);
- small fish (sprats);
- large predatory fish(herring);
- large predatory mammals (seals);
- top predators (killer whales);
- decomposers.
Detrital chains are typical for forests and savannahs. The chain begins with decomposers that feed on organic remains (detritus) and are called detriophages. These include microorganisms, insects, worms. All these living organisms become food for predators. higher order eg birds, hedgehogs, lizards.
Examples of food chains of two types:
- pasture : clover - hare - fox - microorganisms;
- detritus : detritus - fly larvae - frog - snake - hawk - microorganisms.
Rice. 3. An example of a food chain.
The top of the food chain is always occupied by a predator, which is the consumer of the last order in its range. The number of top predators is not regulated by other predators and depends only on external environmental factors. Examples are killer whales, monitor lizards, large sharks.
What have we learned?
We found out what food chains are in nature and how the links are located in them. All living organisms on Earth are interconnected food chains through which energy is transferred. Autotrophs themselves produce nutrients and are food for heterotrophs, which, when dying, become a breeding ground for saprotrophs. Decomposers can also become food for consumers and produce a nutrient medium for producers without interrupting the food chain.
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Introduction
A prime example of a food chain:
Classification of living organisms regarding their role in the cycle of substances
In any food chain, 3 groups of living organisms are involved:
Producers (manufacturers) | Consumers (consumers) | decomposers (destroyers) |
Autotrophic living organisms that synthesize organic matter from mineral using energy (plants). | Heterotrophic living organisms that consume (eat, process, etc.) living organic matter and transfer the energy contained in it through food chains. | Heterotrophic living organisms that destroy (recycle) dead organic matter of any origin to mineral. |
Relationships between organisms in the food chain
The food chain, whatever it may be, creates close links between a variety of objects, both animate and inanimate. And breaking absolutely any of its links can lead to disastrous results and imbalance in nature. The most important and integral component of any food chain is solar energy. If it doesn't exist, there won't be life. When moving along the food chain, this energy is processed, and each of the organisms makes it their own, transferring only 10% to the next link.
Dying, the organism enters other similar food chains, and thus the circulation of substances continues. All organisms can safely exit one food chain and move into another.
The role of natural zones in the cycle of substances
Naturally, organisms living in the same natural area, create with each other their own special food chains that cannot be repeated in any other zone. Yes, the power supply steppe zone, for example, consists of a wide variety of herbs and animals. The food chain in the steppe practically does not include trees, since there are either very few of them or they are undersized. As for the animal world, artiodactyls, rodents, falcons (hawks and other similar birds) and various kinds of insects predominate here.
Power circuit classification
The principle of ecological pyramids
If we consider specifically the chains starting with plants, then the entire cycle of substances in them comes from photosynthesis, during which solar energy is absorbed. Plants spend most of this energy on their vital activity, and only 10% goes to the next link. As a result, each subsequent living organism needs more and more creatures (objects) of the previous link. This is well shown by ecological pyramids, which are most often used for these purposes. They are pyramids of mass, quantity and energy.
Question 28. Food chain. Types of food chains.
FOOD CHAIN(trophic chain, food chain), the relationship of organisms through the relationship of food - consumer (some serve as food for others). In this case, the transformation of matter and energy from producers(primary producers) through consumers(consumers) to decomposers(converters of dead organics into inorganic substances digestible by producers). There are 2 types of food chains - pasture and detrital. The pasture chain starts from green plants, goes to grazing herbivorous animals (consumers of the 1st order) and then to predators that prey on these animals (depending on the place in the chain - consumers of the 2nd and subsequent orders). The detrital chain starts with detritus (a product of organic decay), goes to microorganisms that feed on it, and then to detritus feeders (animals and microorganisms involved in the process of decomposition of dying organic matter).
An example of a pasture chain is its multi-channel model in the African savannah. Primary producers are herbage and trees, consumers of the 1st order are herbivorous insects and herbivores (ungulates, elephants, rhinos, etc.), 2nd order are predatory insects, 3rd order are carnivorous reptiles (snakes, etc.), 4th - predatory mammals and birds of prey. In turn, detritivores (scarab beetles, hyenas, jackals, vultures, etc.) at each stage of the pasture chain destroy the carcasses of dead animals and the remains of predators' food. The number of individuals included in the food chain consistently decreases in each of its links (the rule of the ecological pyramid), i.e., the number of victims each time significantly exceeds the number of their consumers. Food chains are not isolated from each other, but are intertwined with each other, forming food webs.
Question 29. What are ecological pyramids used for? Name them.
ecological pyramid- graphic images of the relationship between producers and consumers of all levels (herbivores, predators; species that feed on other predators) in the ecosystem.
The American zoologist Charles Elton proposed in 1927 to schematically depict these relationships.
In a schematic representation, each level is shown as a rectangle, the length or area of \u200b\u200bwhich corresponds to the numerical values \u200b\u200bof the food chain link (Elton's pyramid), their mass or energy. Rectangles arranged in a certain sequence create pyramids of various shapes.
The base of the pyramid is the first trophic level - the level of producers, the subsequent floors of the pyramid are formed by the next levels of the food chain - consumers of various orders. The height of all blocks in the pyramid is the same, and the length is proportional to the number, biomass or energy at the corresponding level.
Ecological pyramids are distinguished depending on the indicators on the basis of which the pyramid is built. At the same time, for all the pyramids, the basic rule is established, according to which in any ecosystem there are more plants than animals, herbivores than carnivores, insects than birds.
Based on the rule of the ecological pyramid, it is possible to determine or calculate the quantitative ratios of different plant and animal species in natural and artificially created ecological systems. For example, 1 kg of the mass of a sea animal (seal, dolphin) needs 10 kg of eaten fish, and these 10 kg already need 100 kg of their food - aquatic invertebrates, which, in turn, need to eat 1000 kg of algae and bacteria to form such a mass. In this case, the ecological pyramid will be stable.
However, as you know, there are exceptions to every rule, which will be considered in each type of ecological pyramids.
The first ecological schemes in the form of pyramids were built in the twenties of the XX century. Charles Elton. They were based on field observations of a number of animals of various size classes. Elton did not include primary producers in them and did not make any distinction between detritophages and decomposers. However, he noted that predators are usually larger than their prey, and realized that such a ratio is extremely specific only for certain size classes of animals. In the 1940s, the American ecologist Raymond Lindeman applied Elton's idea to trophic levels, abstracting away from the specific organisms that make them up. However, if it is easy to distribute animals into size classes, then determining which trophic level they belong to is much more difficult. In any case, this can only be done in a very simplified and generalized way. Nutritional ratios and the efficiency of energy transfer in the biotic component of an ecosystem are traditionally depicted as stepped pyramids. This provides a clear basis for comparing: 1) different ecosystems; 2) seasonal states of the same ecosystem; 3) different phases of ecosystem change. There are three types of pyramids: 1) pyramids of numbers based on counting organisms of each trophic level; 2) biomass pyramids, which use the total mass (usually dry) of organisms at each trophic level; 3) pyramids of energy, taking into account the energy intensity of organisms of each trophic level.
Types of ecological pyramids
pyramids of numbers- at each level, the number of individual organisms is postponed
The pyramid of numbers reflects a clear pattern discovered by Elton: the number of individuals that make up a sequential series of links from producers to consumers is steadily decreasing (Fig. 3).
For example, to feed one wolf, you need at least a few hares that he could hunt; to feed these hares, you need a fairly large number of various plants. In this case, the pyramid will look like a triangle with a wide base tapering upwards.
However, this form of a pyramid of numbers is not typical for all ecosystems. Sometimes they can be reversed, or inverted. This applies to forest food chains, when trees serve as producers, and insects as primary consumers. In this case, the level of primary consumers is numerically richer than the level of producers (a large number of insects feed on one tree), so the pyramids of numbers are the least informative and least indicative, i.e. the number of organisms of the same trophic level largely depends on their size.
biomass pyramids- characterizes the total dry or wet mass of organisms at a given trophic level, for example, in units of mass per unit area - g / m 2, kg / ha, t / km 2 or per volume - g / m 3 (Fig. 4)
Usually, in terrestrial biocenoses, the total mass of producers is greater than each subsequent link. In turn, the total mass of first-order consumers is greater than second-order consumers, and so on.
In this case (if the organisms do not differ too much in size), the pyramid will also look like a triangle with a wide base tapering upwards. However, there are significant exceptions to this rule. For example, in the seas, the biomass of herbivorous zooplankton is significantly (sometimes 2-3 times) greater than the biomass of phytoplankton, which is represented mainly by unicellular algae. This is explained by the fact that algae are very quickly eaten away by zooplankton, but the very high rate of division of their cells protects them from complete eating.
In general, terrestrial biogeocenoses, where producers are large and live relatively long, are characterized by relatively stable pyramids with a wide base. In aquatic ecosystems, where producers are small in size and have short life cycles, the biomass pyramid can be reversed or inverted (pointed downwards). So, in lakes and seas, the mass of plants exceeds the mass of consumers only during the flowering period (spring), and in the rest of the year the situation may be reversed.
Pyramids of numbers and biomass reflect the statics of the system, i.e., they characterize the number or biomass of organisms in a certain period of time. They do not provide complete information about the trophic structure of the ecosystem, although they allow solving a number of practical problems, especially those related to maintaining the stability of ecosystems.
The pyramid of numbers makes it possible, for example, to calculate the allowable value of catching fish or shooting animals during the hunting period without consequences for their normal reproduction.
energy pyramids- shows the magnitude of the energy flow or productivity at successive levels (Fig. 5).
In contrast to the pyramids of numbers and biomass, which reflect the statics of the system (the number of organisms at a given moment), the pyramid of energy, reflecting the picture of the speed of passage of a mass of food (amount of energy) through each trophic level of the food chain, gives the most complete picture of the functional organization of communities.
The shape of this pyramid is not affected by changes in the size and intensity of the metabolism of individuals, and if all sources of energy are taken into account, then the pyramid will always have a typical appearance with a wide base and a tapering top. When building a pyramid of energy, a rectangle is often added to its base, showing the influx of solar energy.
In 1942, the American ecologist R. Lindeman formulated the law of the pyramid of energies (the law of 10 percent), according to which, on average, about 10% of the energy received by the previous level of the ecological pyramid passes from one trophic level through food chains to another trophic level. The rest of the energy is lost in the form of thermal radiation, movement, etc. Organisms, as a result of metabolic processes, lose about 90% of all the energy that is expended to maintain their vital activity in each link of the food chain.
If a hare ate 10 kg of plant matter, then its own weight could increase by 1 kg. A fox or a wolf, eating 1 kg of hare, increases its mass by only 100 g. woody plants this proportion is much lower due to the fact that wood is poorly absorbed by organisms. For grasses and algae, this value is much higher, since they do not have hard-to-digest tissues. However, the general regularity of the process of energy transfer remains: much less energy passes through the upper trophic levels than through the lower ones.
A food chain is a complex structure of links in which each of them is interconnected with a neighboring or some other link. These components of the chain are various groups flora and fauna organisms.
In nature food chain It is a way of movement of matter and energy in a medium. All this is necessary for the development and "construction" of ecosystems. Trophic levels is a community of organisms that is located at a certain level.
Biotic cycle
The food chain is a biotic cycle that combines living organisms and components of inanimate nature. This phenomenon is also called biogeocenosis and includes three groups: 1. Producers. The group consists of organisms that produce food substances for other creatures through photosynthesis and chemosynthesis. The products of these processes are primary organic substances. Traditionally, producers are first in the food chain. 2. Consumers. The food chain places this group above the producers because they consume the nutrients produced by the producers. This group includes various heterotrophic organisms, for example, animals that eat plants. There are several subspecies of consumers: primary and secondary. Herbivores can be classified as primary consumers, and carnivores, which eat the previously described herbivores, can be classified as secondary consumers. 3. Reducers. This includes organisms that destroy all previous levels. A good example is when invertebrates and bacteria decompose plant remains or dead organisms. Thus, the food chain is completed, but the cycle of substances in nature continues, since as a result of these transformations, mineral and other useful substances are formed. In the future, the formed components are used by producers to form primary organic matter. The food chain is a complex structure, so secondary consumers can easily become food for other predators, which are classified as tertiary consumers.
Classification
thus, it is directly involved in the cycle of substances in nature. There are two types of chains: detrital and pasture. As can be seen from the names, the first group is most often found in forests, and the second - in open spaces: field, meadow, pasture.Such a chain has a more complex structure of connections, it is even possible for the appearance of predators of the fourth order there.
pyramids
one or more, existing in a particular habitat, form the paths and directions of movement of substances and energy. All this, that is, organisms and their habitats, form functional system, which is called an ecosystem (ecological system). Trophic connections are quite rarely straightforward, they usually look like a complex and intricate network in which each component is interconnected with the others. The interweaving of food chains forms food webs, which are mainly used to build and calculate ecological pyramids. At the base of each pyramid is the level of producers, on top of which all subsequent levels are adjusted. Distinguish a pyramid of numbers, energy and biomass.
