A food chain is a complex structure of links in which each of them is interconnected with the neighboring or some other link. These components of the chain are various groups organisms of flora and fauna.

In nature, a food chain is a way of moving matter and energy in an environment. All this is necessary for the development and “construction” of ecosystems. Trophic levels are a community of organisms located at a certain level.

Biotic cycle

The food chain is a biotic cycle that connects living organisms and inanimate components. 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 product of these processes are primary organic substances. Traditionally, producers are the first to the food chain. 2. Consumers. The food chain places this group above producers, since they consume those nutrients, which the producers produced. This group includes various heterotrophic organisms, for example, animals that eat plants. There are several subspecies of consumers: primary and secondary. The category of primary consumers includes herbivores, and the secondary consumers include carnivores that eat the previously described herbivores. 3. Decomposers. This includes organisms that destroy all previous levels. A clear example This may be the case when invertebrates and bacteria decompose plant debris or dead organisms. Thus, the food chain ends, but the cycle of substances in nature continues, since as a result of these transformations mineral and other minerals are formed. useful material. Subsequently, the formed components are used by producers to form primary organic matter. The food chain has a complex structure, so secondary consumers can easily become food for other predators, which are classified as tertiary consumers.

Classification

Thus, it takes a direct part in the cycle of substances in nature. There are two types of chains: detritus and pasture. As the names indicate, 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 fourth-order predators to appear there.

Pyramids

one or more existing in a specific 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 rarely straightforward; they usually take the form of a complex and intricate network, in which each component is interconnected with the others. The interweaving of food chains forms food webs, which mainly serve to construct and calculate ecological pyramids. At the base of each pyramid is the level of producers, on top of which all subsequent levels are adjusted. There is a pyramid of numbers, energy and biomass.

Food chain structure

The food chain is a connected linear structure from links, each of which is connected with neighboring links by the “food-consumer” relationship. Groups of organisms, for example, specific biological species, act as links in the chain. A connection between two links is established if one group of organisms acts as food for another group. The first link of the chain has no predecessor, that is, organisms from this group do not use other organisms as food, being producers. Most often, plants, mushrooms, and algae are found in this place. Organisms in the last link in the chain do not act as food for other organisms.

Each organism has a certain amount of energy, that is, we can say that each link in the chain has its own potential energy. During the feeding process, the potential energy of food is transferred to its consumer. When transferring potential energy from link to link up to 80-90% is lost in the form of heat. This fact limits the length of the food chain, which in nature usually does not exceed 4-5 links. The longer the trophic chain, the lower the production of its last link in relation to the production of the initial one.

Trophic network

Usually, for each link in the chain, you can specify not one, but several other links connected to it by the “food-consumer” relationship. So, not only cows, but also other animals eat grass, and cows are food not only for humans. The establishment of such connections turns the food chain into a more complex structure - food web.

Trophic level

A trophic level is a set of organisms that, depending on their method of nutrition and type of food, constitute a certain link in the food chain.

In some cases, in a trophic network, it is possible to group individual links into levels in such a way that links at one level act only as food for the next level. This grouping is called a trophic level.

Types of food chains

There are 2 main types of trophic chains - pasture And detrital.

In the pasture trophic chain (grazing chain), the basis is made up of autotrophic organisms, then there are herbivorous animals consuming them (consumers) (for example, zooplankton feeding on phytoplankton), then 1st order predators (for example, fish consuming zooplankton), 2nd order predators order (for example, pike feeding on other fish). The trophic chains are especially long in the ocean, where many species (for example, tuna) occupy the place of fourth-order consumers.

In detrital trophic chains (decomposition chains), most common in forests, most plant production is not consumed directly by herbivores, but dies, then undergoes decomposition by saprotrophic organisms and mineralization. Thus, detrital trophic chains start from detritus (organic remains), go to microorganisms that feed on it, and then to detritivores and their consumers - predators. In aquatic ecosystems (especially in eutrophic reservoirs and at great depths of the ocean), part of the production of plants and animals also enters detrital food chains.

Terrestrial detrital food chains are more energy intensive because most of the organic matter created autotrophic organisms, remains unclaimed and dies, forming detritus. On a planetary scale, grazing chains account for about 10% of the energy and substances stored by autotrophs, while 90% is included in the cycle through decomposition chains.

see also

Literature

• Trophic chain / Biological encyclopedic dictionary / chapter. ed. M. S. Gilyarov. - M.: Soviet Encyclopedia, 1986. - P. 648-649.

Wikimedia Foundation.

See what “Food chain” is in other dictionaries:

- (food chain, trophic chain), relationships between organisms in which groups of individuals (bacteria, fungi, plants, animals) are connected to each other by relationships: food consumer. The food chain usually includes from 2 to 5 links: photos and... ... Modern encyclopedia

- (food chain, trophic chain), a series of organisms (plants, animals, microorganisms), in which each previous link serves as food for the next. Connected to each other by relationships: food consumer. The food chain usually includes from 2 to 5... ... Big encyclopedic Dictionary

FOOD CHAIN, a system of energy transfer from organism to organism, in which each previous organism is destroyed by the next. IN simplest form energy transfer begins with plants (PRIMARY PRODUCERS). The next link in the chain is... ... Scientific and technical encyclopedic dictionary

See Trophic chain. Ecological encyclopedic dictionary. Chisinau: Main editorial office of the Moldavian Soviet Encyclopedia. I.I. Dedu. 1989 ... Ecological dictionary

food chain- — EN food chain A sequence of organisms on successive trophic levels within a community, through which energy is transferred by feeding; energy enters the food chain during fixation… Technical Translator's Guide

- (food chain, trophic chain), a series of organisms (plants, animals, microorganisms), in which each previous link serves as food for the next. Connected to each other by relationships: food consumer. The food chain usually includes from 2 to... ... encyclopedic Dictionary

food chain- mitybos grandinė statusas T sritis ekologija ir aplinkotyra apibrėžtis Augalų, gyvūnų ir mikroorganizmų mitybos ryšiai, dėl kurių pirminė augalų energija maisto pavidalu perduodama vartotojams ir skaidytojams. Vienam organizmui pasimaitinus kitu… Ekologijos terminų aiškinamasis žodynas

- (food chain, trophic chain), a number of organisms (plants, animals, microorganisms), in which each previous link serves as food for the next one. Connected to each other by relationships: food consumer. P. c. usually includes from 2 to 5 links: photo and... ... Natural science. encyclopedic Dictionary

- (trophic chain, food chain), the relationship of organisms through food-consumer relationships (some serve as food for others). In this case, a transformation of matter and energy occurs from producers (primary producers) through consumers... ... Biological encyclopedic dictionary

See Power Circuit... Large medical dictionary

Books

• The omnivore's dilemma. A shocking study of the modern diet, Pollan Michael. Have you ever thought about how food gets to our table? Did you buy your groceries at the supermarket or farmers market? Or maybe you grew your own tomatoes or brought a goose with...

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Attention! Slide previews are for informational purposes only and may not represent all the features of the presentation. If you are interested this work, please download the full version.

The purpose of the lesson: To form knowledge about the constituent components of a biological community, about the features of the trophic structure of the community, about food connections that reflect the path of substance circulation, to form the concepts of food chain, food web.

During the classes

1. Organizational moment.

2. Checking and updating knowledge on the topic “Composition and structure of the community.”

On the board: Our world is not an accident, not chaos - there is a system in everything.

Question. What system in living nature is this statement talking about?

Working with terms.

Exercise. Fill in the missing words.

Community of organisms different types closely interconnected are called …………. . It consists of: plants, animals, …………. , …………. . A collection of living organisms and components inanimate nature, united by the exchange of matter and energy on a homogeneous area of ​​the earth's surface are called …………….. or …………….

Exercise. Select four components of the ecosystem: bacteria, animals, consumers, fungi, abiotic component, climate, decomposers, plants, producers, water.

Question. How are living organisms connected to each other in an ecosystem?

3. Studying new material. Explain using presentation.

4. Consolidation of new material.

Task No. 1. Slide No. 20.

Identify and label: producers, consumers and decomposers. Compare power circuits and establish similarities between them. (at the beginning of each chain there is plant food, then there is a herbivore, and at the end there is a predatory animal). Name the way plants and animals feed. (plants are autotrophs, i.e. they produce organic matter themselves, animals – heterotrophs – consume finished organic matter).

Conclusion: a food chain is a series of organisms sequentially feeding on each other. Food chains begin with autotrophs - green plants.

Task No. 2. Compare two food chains, identify similarities and differences.

1. Clover - rabbit - wolf
2. Plant litter – earthworm – blackbird – hawk – sparrowhawk (The first food chain begins with producers – living plants, the second from plant residues - dead organic matter).

In nature, there are two main types of food chains: pasture (grazing chains), which begin with producers, detrital (decomposition chains), which begin with plant and animal residues, animal excrement.

Conclusion: Therefore, the first food chain is pasture, because begins with producers, the second is detrital, because starts with dead organic matter.

All components of food chains are distributed into trophic levels. The trophic level is a link in the food chain.

Task No. 3. Make a food chain, including the following organisms: caterpillar, cuckoo, tree with leaves, buzzard, soil bacteria. Indicate producers, consumers, decomposers. (tree with leaves - caterpillar - cuckoo - buzzard - soil bacteria). Determine how many trophic levels this food chain contains (this chain consists of five links, therefore there are five trophic levels). Determine which organisms are located at each trophic level. Draw a conclusion.

• The first trophic level is green plants (producers),
• Second trophic level – herbivores (consumers of the 1st order)
• Third trophic level – small predators (2nd order consumers)
• Fourth trophic level – large predators (3rd order consumers)
• Fifth trophic level - organisms that consume dead organic matter - soil bacteria, fungi (decomposers)

In nature, each organism uses not one food source, but several, but in biogeocenoses food chains intertwine and form food web. For any community, you can draw up a diagram of all the food relationships of organisms, and this diagram will have the form of a network (we consider an example of a food network in Fig. 62 in the biology textbook by A.A. Kamensky and others)

5. Implementation of acquired knowledge.

Practical work in groups.

Task No. 1. Solving environmental situations

1. In one of the Canadian reserves, all wolves were destroyed in order to increase the herd of deer. Was it possible to achieve the goal in this way? Explain your answer.

2. Hares live in a certain territory. Of these, there are 100 small hares weighing 2 kg, and 20 of their parents weighing 5 kg. The weight of 1 fox is 10 kg. Find the number of foxes in this forest. How many plants must grow in the forest for hares to grow up?

3. A reservoir with rich vegetation is home to 2000 water rats, each rat consumes 80g of plants per day. How many beavers can this pond feed if a beaver consumes an average of 200 g of plant food per day?

4. Present the disorganized facts logically correct sequence(in the form of numbers).

1. Nile perch began to eat a lot of herbivorous fish.

2. Having multiplied greatly, the plants began to rot, poisoning the water.

3. Smoking Nile perch required a lot of wood.

4. In 1960, British colonists released Nile perch into the waters of Lake Victoria, which quickly multiplied and grew, reaching a weight of 40 kg and a length of 1.5 m.

5. Forests on the shores of the lake were intensively cut down - so water erosion of the soil began.

6. Dead zones with poisoned water appeared in the lake.

7. The number of herbivorous fish decreased, and the lake began to be overgrown with aquatic plants.

8. Soil erosion has led to a decrease in the fertility of fields.

9. Poor soils did not produce crops, and the peasants went bankrupt .

6. Self-test of acquired knowledge in the form of a test.

1. Producers of organic substances in the ecosystem

A) producers

B) consumers

B) decomposers

D) predators

2. To which group do microorganisms living in the soil belong?

A) producers

B) consumers of the first order

B) consumers of the second order

D) decomposers

3. Name the animal that should be included in the food chain: grass -> ... -> wolf

B) hawk

4. Identify the correct food chain

A) hedgehog -> plant -> grasshopper -> frog

B) grasshopper -> plant -> hedgehog -> frog

B) plant -> grasshopper -> frog -> hedgehog

D) hedgehog -> frog -> grasshopper -> plant

5. In a coniferous forest ecosystem, 2nd order consumers include

A) common spruce

B) forest mice

B) taiga ticks

D) soil bacteria

6. Plants produce organic matter from inorganic, therefore they play a role in food chains

A) final link

B) initial level

B) consumer organisms

D) destructive organisms

7. Bacteria and fungi play the role of:

A) producers of organic substances

B) consumers of organic substances

B) destroyers of organic substances

D) destroyers of inorganic substances

8. Identify the correct food chain

A) hawk -> tit -> insect larvae -> pine

B) pine -> tit -> insect larvae -> hawk

B) pine -> insect larvae -> tit -> hawk

D) insect larvae -> pine -> tit -> hawk

9. Determine which animal should be included in the food chain: cereals -> ? -> already -> kite

A) frog

D) lark

10. Identify the correct food chain

A) seagull -> perch -> fish fry -> algae

B) algae -> seagull -> perch -> fish fry

C) fish fry -> algae -> perch -> seagull

D) algae -> fish fry -> perch -> seagull

11. Continue the food chain: wheat -> mouse -> ...

B) gopher

B) fox

D) triton

7. General conclusions of the lesson.

Answer the questions:

1. How are organisms interconnected in biogeocenosis ( food connections)
2. What is a food chain (a series of organisms sequentially feeding on each other)
3. What types of food chains are there (pastoral and detrital chains)
4. What is the name of the link in the food chain (trophic level)
5. What is a food web (intertwined food chains)

Question 11. Living matter. Name and characterize the properties of living matter.

Question 12. Living matter. Functions of living matter.

Question 13. What function of living matter is associated with the First and Second Pasteur Points?

Question 14. Biosphere. Name and characterize the main properties of the biosphere.

Question 15. What is the essence of the Le Chatelier-Brown principle.

Question 16. Formulate Ashby's law.

Question 17. What is the basis of dynamic balance and sustainability of ecosystems. Ecosystem sustainability and self-regulation

Question 18. Cycle of substances. Types of substance cycles.

Question 19. Draw and explain the block model of an ecosystem.

Question 20. Biome. Name the largest terrestrial biomes.

Question 21. What is the essence of the “edge effect rule”.

Question 22. Species edificators, dominants.

Question 23. Trophic chain. Autotrophs, heterotrophs, decomposers.

Question 24. Ecological niche. Mr. F. Gause's rule of competitive exclusion.

Question 25. Present in the form of an equation the balance of food and energy for a living organism.

Question 26. The 10% rule, who formulated it and when.

Question 27. Products. Primary and Secondary products. Biomass of the body.

Question 28. Food chain. Types of food chains.

Question 29. What are ecological pyramids used for? Name them.

Question 30. Succession. Primary and secondary succession.

Question 31. Name the successive stages of primary succession. Climax.

Question 32. Name and characterize the stages of human impact on the biosphere.

Question 33. Biosphere resources. Classification of resources.

Question 34. Atmosphere - composition, role in the biosphere.

Question 35. The meaning of water. Classification of waters.

Classification of groundwater

Question 36. Biolithosphere. Resources of the biolithosphere.

Question 37. Soil. Fertility. Humus. Soil formation.

Question 38. Vegetation resources. Forest resources. Animal resources.

Question 39. Biocenosis. Biotope. Biogeocenosis.

Question 40. Factorial and population ecology, synecology.

Question 41. Name and characterize environmental factors.

Question 42. Biogeochemical processes. How does the nitrogen cycle work?

Question 43. Biogeochemical processes. How does the oxygen cycle work? Oxygen cycle in the biosphere

Question 44. Biogeochemical processes. How does the carbon cycle work?

Question 45. Biogeochemical processes. How does the water cycle work?

Question 46. Biogeochemical processes. How does the phosphorus cycle work?

Question 47. Biogeochemical processes. How does the sulfur cycle work?

Question 49. Energy balance of the biosphere.

Question 50. Atmosphere. Name the layers of the atmosphere.

Question 51. Types of air pollutants.

Question 52. How does natural air pollution occur?

Question 54. The main ingredients of air pollution.

Question 55. What gases cause the greenhouse effect. Consequences of increasing greenhouse gases in the atmosphere.

Question 56. Ozone. The ozone hole. What gases cause the destruction of the ozone layer. Consequences for living organisms.

Question 57. Causes of formation and precipitation of acid precipitation. What gases cause the formation of acid precipitation. Consequences.

Consequences of acid rain

Question 58. Smog, its formation and influence on humans.

Question 59. MPC, one-time MPC, average daily MPC. Pdv.

Question 60. What are dust collectors used for? Types of dust collectors.

Question 63. Name and describe methods for purifying air from steam and gaseous pollutants.

Question 64. How does the absorption method differ from the adsorption method.

Question 65. What determines the choice of gas purification method?

Question 66. Name what gases are formed during the combustion of vehicle fuel.

Question 67. Ways to purify exhaust gases from vehicles.

Question 69. Water quality. Water quality criteria. 4 water classes.

Question 70. Norms of water consumption and wastewater disposal.

Question 71. Name the physicochemical and biochemical methods of water purification. Physico-chemical method of water purification

Coagulation

Selection of coagulant

Organic coagulants

Inorganic coagulants

Question 72. Waste water. Describe hydromechanical methods for treating wastewater from solid impurities (straining, settling, filtration).

Question 73. Describe chemical methods of wastewater treatment.

Question 74. Describe biochemical methods of wastewater treatment. Advantages and disadvantages of this method.

Question 75. Aero tanks. Classification of aeration tanks.

Question 76. Land. Two types of harmful effects on the soil.

Question 77. Name measures to protect soils from pollution.

Question 78. Waste disposal and recycling.

3.1. Fire method.

3.2. Technologies of high temperature pyrolysis.

3.3. Plasmachemical technology.

3.4.Use of secondary resources.

3.5 Waste disposal

3.5.1.Polygons

3.5.2 Isolators, underground storage facilities.

3.5.3. Filling quarries.

Question 79. Name international environmental organizations. Intergovernmental environmental organizations

Question 80. Name the international environmental movements. Non-governmental international organizations

Question 81. Name the environmental organizations of the Russian Federation.

International Union for Conservation of Nature (IUCN) in Russia

Question 82. Types of environmental protection measures.

1. Environmental measures in the field of protection and rational use of water resources:

2. Environmental measures in the field of atmospheric air protection:

3. Environmental measures in the field of protection and rational use of land resources:

4. Environmental measures in the field of waste management:

5. Energy saving measures:

Question 83. Why is World Conservation Day celebrated on June 5th?

Question 85. Sustainable development. Legal protection of the biosphere.

Legal protection of the biosphere

Question 86. Financing of environmental activities.

Question 87. Environmental regulation. Environmental monitoring. Environmental assessment.

Question 88. Environmental violations. Responsibility for environmental violations.

Question 89. Rational use of natural resources.

Rational environmental management

Question 90. Global environmental problems and measures to prevent environmental threats.

Question 91. What flammable gases are components of gaseous fuel.

Question 92. Describe the following gases and their effect on humans: methane, propane, butane.

Physical properties

Chemical properties

Propane Applications

Question 93. Describe the following gases and their effect on humans: ethylene, propylene, hydrogen sulfide.

Question 94. As a result, carbon dioxide and carbon monoxide are formed, their effect on living organisms.

Question 95. As a result, nitrogen oxide, sulfur oxide and water vapor are formed, their effect on living organisms.

Question 28. Food chain. Types of food chains.

FOOD CHAIN(trophic chain, food chain), the interconnection of organisms through food-consumer relationships (some serve as food for others). In this case, a transformation of matter and energy occurs from producers(primary producers) through consumers(consumers) to decomposers(converters of dead organic matter into inorganic substances assimilated by producers). There are 2 types of food chains - pasture and detritus. The pasture chain begins with green plants, goes to grazing herbivorous animals (consumers of the 1st order) and then to the predators that prey on these animals (depending on the place in the chain - consumers of the 2nd and subsequent orders). The detrital chain begins with detritus (a product of the breakdown of organic matter), goes to microorganisms that feed on it, and then to detritivores (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 savanna. Primary producers are grass and trees, 1st order consumers are herbivorous insects and herbivores (ungulates, elephants, rhinoceroses, 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 grazing chain destroy the carcasses of dead animals and the food remains of predators. The number of individuals included in the food chain in each of its links consistently decreases (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 one another, but are intertwined with each other to form food webs.

Question 29. What are ecological pyramids used for? Name them.

Ecological pyramid- graphic representations 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 suggested schematically depicting these relationships in 1927.

In a schematic representation, each level is shown as a rectangle, the length or area of ​​which corresponds to the numerical values ​​of a link in the food chain (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; 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, a basic rule has been established for all pyramids, 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 species of plants and animals in natural and artificially created ecological systems. For example, 1 kg of mass of a sea animal (seal, dolphin) requires 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 in this case the ecological pyramid will be sustainable.

However, as you know, there are exceptions to every rule, which will be considered in each type of ecological pyramid.

The first ecological schemes in the form of pyramids were built in the twenties of the 20th century. Charles Elton. They were based on field observations of a number of animals of different size classes. Elton did not include primary producers and did not make any distinction between detritivores and decomposers. However, he noted that predators are usually larger than their prey, and realized that this ratio is extremely specific only to certain size classes of animals. In the forties, the American ecologist Raymond Lindeman applied Elton's idea to trophic levels, abstracting from the specific organisms that comprise them. However, while it is easy to distribute animals into size classes, it is much more difficult to determine which trophic level they belong to. In any case, this can only be done in a very simplified and generalized manner. Nutritional relationships and the efficiency of energy transfer in the biotic component of an ecosystem are traditionally depicted in the form of stepped pyramids. This provides a clear basis for comparing: 1) different ecosystems; 2) seasonal states of the same ecosystem; 3) different phases ecosystem changes. There are three types of pyramids: 1) pyramids of numbers, based on counting organisms at each trophic level; 2) biomass pyramids, which use the total mass (usually dry) of organisms at each trophic level; 3) energy pyramids, taking into account the energy intensity of organisms at each trophic level.

Types of ecological pyramids

pyramids of numbers- at each level the number of individual organisms is plotted

The pyramid of numbers displays a clear pattern discovered by Elton: the number of individuals constituting a sequential series of links from producers to consumers is steadily decreasing (Fig. 3).

For example, to feed one wolf, he needs at least several hares for him to hunt; To feed these hares, you need a fairly large variety of plants. In this case, the pyramid will look like a triangle with a wide base tapering upward.

However, this form of a pyramid of numbers is not typical for all ecosystems. Sometimes they can be reversed, or upside down. This applies to forest food chains, where trees serve as producers and insects serve 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), therefore 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/m2, kg/ha, t/km2 or per volume - g/m3 (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 that of second-order consumers, etc.

In this case (if the organisms do not differ too much in size) the pyramid will also have the appearance of a triangle with a wide base tapering upward. 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, represented mainly by unicellular algae. This is explained by the fact that algae are very quickly eaten by zooplankton, but they are protected from being completely eaten away by the very high rate of division of their cells.

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 pyramid of biomass can be inverted or inverted (with the tip pointing down). Thus, in lakes and seas, the mass of plants exceeds the mass of consumers only during the flowering period (spring), and during the rest of the year the opposite situation can occur.

Pyramids of numbers and biomass reflect the statics of the system, that is, 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 an ecosystem, although they allow solving a number of practical problems, especially related to maintaining the sustainability of ecosystems.

The pyramid of numbers allows, for example, to calculate the permissible amount of fish catch or shooting of animals during the hunting season without consequences for their normal reproduction.

energy pyramids- shows the amount of 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 in this moment), the energy pyramid, reflecting the rate of passage of food mass (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 metabolic rate of individuals, and if all energy sources are taken into account, the pyramid will always have a typical appearance with a wide base and a tapering apex. When constructing a pyramid of energy, a rectangle is often added to its base to show the influx of solar energy.

In 1942, the American ecologist R. Lindeman formulated the law of the energy pyramid (the law of 10 percent), according to which, on average, about 10% of the energy received at 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. As a result of metabolic processes, organisms lose about 90% of all energy in each link of the food chain, which is spent on maintaining their vital functions.

If a hare ate 10 kg of plant matter, then its own weight may increase by 1 kg. A fox or wolf, eating 1 kg of hare meat, increases its mass by only 100 g. woody plants this share is much lower due to the fact that wood is poorly absorbed by organisms. For grasses and seaweeds, this value is much greater, since they do not have difficult-to-digest tissues. However general pattern the process of energy transfer remains: much less of it passes through the upper trophic levels than through the lower ones.

For me, nature is a kind of well-oiled machine, in which every detail is provided. It’s amazing how well everything is thought out, and it’s unlikely that a person will ever be able to create something like this.

What does the term "power chain" mean?

According to the scientific definition, this concept includes the transfer of energy through a number of organisms, where the producers are the first link. This group includes plants that absorb inorganic substances, from which nutrients are synthesized organic compounds. They feed on consumers - organisms that are not capable of independent synthesis, and therefore are forced to eat ready-made organic matter. These are herbivores and insects that act as “lunch” for other consumers - predators. As a rule, the chain contains about 4-6 levels, where the closing link is represented by decomposers - organisms that decompose organic matter. In principle, there can be much more links, but there is a natural “limiter”: on average, each link receives little energy from the previous one - up to 10%.

Examples of food chains in a forest community

Forests have their own characteristics, depending on their type. Coniferous forests are not distinguished by rich herbaceous vegetation, which means that the food chain will have a certain set of animals. For example, a deer enjoys eating elderberry, but it itself becomes prey for a bear or lynx. The broad-leaved forest will have its own set. For example:

• bark - bark beetles - tit - falcon;
• fly - reptile - ferret - fox;
• seeds and fruits - squirrel - owl;
• plant - beetle - frog - snake - hawk.

It is worth mentioning scavengers who “recycle” organic remains. There are a great variety of them in forests: from the simplest single-celled ones to vertebrates. Their contribution to nature is enormous, since otherwise the planet would be covered with animal remains. They transform dead bodies into inorganic compounds that plants need, and everything starts anew. In general, nature is perfection itself!