ecological pyramid is a graphic representation of energy losses in power circuits.

Food chains are stable chains of interconnected species that sequentially extract materials and energy from the source food substance formed during the evolution of living organisms and the biosphere as a whole. They make up the trophic structure of any biocenosis, through which energy transfer and substance cycling are carried out. The food chain consists of a series of trophic levels, the sequence of which corresponds to the flow of energy.

The primary source of energy in food chains is solar energy. The first trophic level- producers (green plants) - use solar energy in the process of photosynthesis, creating the primary production of any biocenosis. At the same time, only 0.1% of solar energy is used in the process of photosynthesis. The efficiency with which green plants assimilate solar energy is estimated by the value of primary productivity. More than half of the energy associated with photosynthesis is immediately consumed by plants in the process of respiration, the rest of the energy is transferred further along the food chains.

At the same time, there is an important regularity associated with the efficiency of the use and conversion of energy in the process of nutrition. Its essence is as follows: the amount of energy spent on maintaining one's own life activity in food chains grows from one trophic level to another, while productivity decreases.

Phytobiomass is used as a source of energy and material to create the biomass of organisms of the second

trophic level consumers of the first order - herbivores. Usually the productivity of the second trophic level is no more than 5 - 20% (10%) of the previous level. This is reflected in the ratio of plant and animal biomass on the planet. The amount of energy needed to ensure the vital activity of the body increases with an increase in the level morphofunctional organization. Accordingly, the amount of biomass created at higher trophic levels is reduced.

Ecosystems are highly variable in the relative rates of creation and expenditure of both net primary production and net secondary production at each trophic level. However, all ecosystems, without exception, are characterized by certain ratios of primary and secondary production. The amount of plant matter that serves as the basis of the food chain is always several times (about 10 times) greater than the total mass of herbivorous animals, and the mass of each subsequent link in the food chain, accordingly, changes proportionally.

The progressive decline of assimilated energy in a series of trophic levels is reflected in the structure of ecological pyramids.

A decrease in the amount of available energy at each subsequent trophic level is accompanied by a decrease in biomass and the number of individuals. Pyramids of biomass and abundance of organisms for a given biocenosis are repeated in in general terms productivity pyramid configuration.

Graphically, the ecological pyramid is depicted as several rectangles of the same height but different lengths. The length of the rectangle decreases from the bottom to the top, corresponding to a decrease in productivity at subsequent trophic levels. The lower triangle is the largest in length and corresponds to the first trophic level - producers, the second is approximately 10 times smaller and corresponds to the second trophic level - herbivorous animals, first-order consumers, etc.

Creation speed organic matter does not determine its total reserves, i.e. the total mass of organisms at each trophic level. The available biomass of producers and consumers in specific ecosystems depends on how the rates of accumulation of organic matter at a certain trophic level and its transfer to a higher one, i.e., correlate with each other. how strong the consumption of the formed reserves is. An important role is played by the speed of reproduction of the main generations of producers and consumers.

In most terrestrial ecosystems, as already mentioned, the biomass rule also applies, i.e. the total mass of plants turns out to be greater than the biomass of all herbivores, and the mass of herbivores exceeds the mass of all predators.

It is necessary to distinguish quantitatively between productivity - namely, the annual growth of vegetation - and biomass. The difference between the primary production of the biocenosis and the biomass determines the extent of the grazing of the plant mass. Even for communities with a predominance of herbaceous forms, whose biomass reproduction rate is quite high, animals use up to 70% of the annual plant growth.

In those trophic chains where energy transfer is carried out through “predator-prey” connections, pyramids of the number of individuals are often observed: total number individuals participating in food chains decreases with each link. This is also due to the fact that predators, as a rule, are larger than their victims. An exception to the rules of the pyramid of numbers are cases when small predators live by group hunting for large animals.

All three rules of the pyramid - productivity, biomass and abundance - express energy relationships in ecosystems. At the same time, the productivity pyramid has a universal character, while the pyramids of biomass and abundance appear in communities with a certain trophic structure.

Knowledge of the laws of ecosystem productivity, the ability to quantify the flow of energy are of great practical importance. The primary production of agrocenoses and human exploitation of natural communities is the main source of food for humans. The secondary production of biocenoses, obtained from industrial and agricultural animals, is also important as a source of animal protein. Knowledge of the laws of distribution of energy, flows of energy and matter in biocenoses, the laws of productivity of plants and animals, understanding the limits of permissible withdrawal of plant and animal biomass from natural systems allow us to correctly build relationships in the "society - nature" system.

Relationships in which some organisms eat other organisms or their remains or secretions (excrement) are called trophic (trophe - nutrition, food, gr.). At the same time, nutritional relationships between members of the ecosystem are expressed through trophic (food) chains . Examples of such circuits are:

Moss moss → deer → wolf (tundra ecosystem);

Grass → cow → human (anthropogenic ecosystem);

microscopic algae (phytoplankton) → bugs and daphnia (zooplankton) → roach → pike → gulls (aquatic ecosystem).

Influencing food chains with the aim of optimizing them and obtaining more or better products in quality is not always successful. So widely known from the literature is the example of the importation of cows to Australia. Prior to this, natural pastures were used mainly by kangaroos, whose excrement was successfully developed and processed by the Australian dung beetle. Cow dung was not used by the Australian beetle, as a result of which the gradual degradation of pastures began. To stop this process, the European dung beetle had to be brought to Australia.

Trophic or food chains can be represented in the form pyramids. The numerical value of each step of such a pyramid can be expressed by the number of individuals, their biomass or the energy accumulated in it.

In accordance with energy pyramid law R. Lindemann and ten percent rule , approximately 10% (from 7 to 17%) of energy or matter in energy terms passes from each stage to the next stage (Fig. 3.7). Note that at each subsequent level, with a decrease in the amount of energy, its quality increases, i.e. the ability to do the work of a unit of animal biomass is a corresponding number of times higher than the same plant biomass.

A prime example is a food chain of the open sea, represented by plankton and whales. The mass of plankton is dispersed in ocean water and, if the bioproductivity of the open sea is less than 0.5 g/m2 day-1, the amount of potential energy in cubic meter ocean water is infinitely small compared to the energy of a whale, whose mass can reach several hundred tons. As you know, whale oil is a high-calorie product that was even used for lighting.

Fig.3.7. Pyramid of energy transfer along the food chain (according to Y. Odum)

In the destruction of organics, a corresponding sequence is also observed: for example, about 90% of the energy of pure primary production is released by microorganisms and fungi, less than 10% by invertebrates, and less than 1% by vertebrates, which are final cosuments. In accordance with the last digit, one percent rule : for the stability of the biosphere as a whole, the share of possible final consumption of net primary production in energy terms should not exceed 1%.

Based on the food chain as the basis for the functioning of the ecosystem, it is also possible to explain the cases of accumulation in the tissues of certain substances (for example, synthetic poisons), which, as they move along the trophic chain, do not participate in the normal metabolism of organisms. According to biological amplification rules there is an approximately tenfold increase in the concentration of the pollutant when moving to a higher level of the ecological pyramid.

In particular, a seemingly insignificant increase in the content of radionuclides in river water at the first level of the trophic chain is assimilated by microorganisms and plankton, then it is concentrated in fish tissues and reaches maximum values at the seagulls. Their eggs have a level of radionuclides 5000 times higher than background pollution.

The species composition of organisms is usually studied at the level populations .

Recall that a population is a set of individuals of the same species inhabiting the same territory, having a common gene pool and the ability to interbreed freely. In general, one or another population can be within a certain ecosystem, but it can also spread beyond the borders. For example, the population of the black-capped marmot of the Tuora-Sis ridge, listed in the Red Book, is known and protected. This population is not limited to this range, but also extends further south to the Verkhoyansk mountains in Yakutia.

The environment in which the species under study usually occurs is called its habitat.

As a rule, an ecological niche is occupied by one species or its population. With the same requirements for environment and food resources, two species invariably enter into a competitive struggle, which usually ends in the displacement of one of them. This situation is known in systems ecology as G.F. principle Gause , which states that two species cannot exist in the same locality if their ecological needs are identical, i.e. if they occupy the same niche. Accordingly, the system of interacting populations, differentiated by ecological niches, complementing each other to a greater extent than competing with each other for the use of space, time and resources, is called a community (coenosis).

The polar bear cannot live in taiga ecosystems, just like the brown bear in the polar regions.

Speciation is always adaptive, so Ch. Darwin's axiom each species is adapted to a strictly defined set of conditions of existence specific to it. At the same time, organisms reproduce with an intensity that provides the maximum possible number of them ( rule of maximum "life pressure"" ).

For example, organisms of oceanic plankton quite quickly cover an area of thousands of square kilometers in the form of a film. V.I.Vernadsky calculated that the speed of advancement of a Fisher bacterium with a size of 10-12 cm3 by reproduction in a straight line would be equal to about 397,200 m/h - the speed of an airplane! However, excessive reproduction of organisms is limited by limiting factors and correlates with the amount of food resources of their habitat.

When species disappear, primarily composed of large individuals, as a result, the material-energy structure of qualifications changes. If the energy flow passing through the ecosystem does not change, then the mechanisms ecological duplication according to the principle: an endangered or destroyed species within one level of the ecological pyramid replaces another functional-coenotic, similar one. The replacement of a species follows the scheme: a small one replaces a large one, evolutionarily lower organized, more highly organized, more genetically labile, less genetically variable. Because ecological niche cannot be empty in the biocenosis, then ecological duplication occurs necessarily.

A successive change of biocenoses, successively arising in the same territory under the influence of natural factors or human impact is called succession (succession - continuity, lat.). For example, after a forest fire, for many years the burnt area is first populated with grasses, then with shrubs, then with deciduous trees, and finally with coniferous forests. In this case, successive communities that replace each other are called series or stages. end result succession will be the state of a stabilized ecosystem - menopause (climax - stairs, "mature step", gr.).

A succession that begins in a previously unoccupied area is called primary . These include lichen settlements on stones, which will later replace mosses, grasses and shrubs (Fig. 3.8). If a community develops on the site of an already existing one (for example, after a fire or uprooting, a pond or reservoir device), then they talk about secondary successions. Of course, succession rates will vary. Primary successions may take hundreds or thousands of years, while secondary successions are faster.

All populations of producers, consumers and heterotrophs closely interact through trophic chains and thus maintain the structure and integrity of biocenoses, coordinate energy and substance flows, and determine the regulation of their environment. The whole set of bodies of living organisms inhabiting the Earth is physically and chemically one, regardless of their systematic affiliation, and is called living matter ( the law of physico-chemical unity of living matter by V.I. Vernadsky). The mass of living matter is relatively small and is estimated at 2.4-3.6 * 1012 tons (in dry weight). If it is distributed over the entire surface of the planet, you get a layer of only one and a half centimeters. According to VI Vernadsky, this "film of life", which is less than 10-6 masses of other shells of the Earth, is "one of the most powerful geochemical forces of our planet."

The trophic structure of an ecosystem can be depicted graphically as an ecological pyramid, which is based on the first level. These pyramids reflect the laws of biomass and energy expenditure in food chains. The numerical value of each step of such a pyramid can be expressed by the number of individuals, their biomass or the energy accumulated in it.

Food webs that emerge in an ecosystem have a structure that is characterized by a certain number of organisms at each trophic level. It is noticed that the number of organisms decreases in direct proportion when moving from one trophic level to another. This pattern is called "Rule of the Ecological Pyramid". AT this case considered pyramid of numbers . It can be broken if small predators live due to group hunting for large animals.

Each trophic level has its own biomass - the total mass of organisms of any group. In food chains, the biomass of organisms at different trophic levels is different: the biomass of producers (the first trophic level) is much higher than the biomass of consumers - herbivorous animals (the second trophic level). The biomass of each of the subsequent trophic levels of the food chain also progressively decreases. This pattern has been named biomass pyramids .

A similar pattern can be identified when considering the transfer of energy through trophic levels, that is, in pyramid of energy (production ) . The amount of energy spent on maintaining one's own life activity in the chain of trophic levels is growing, while productivity is falling. Plants absorb only a small part of solar energy during photosynthesis. Herbivorous animals, which make up the second trophic level, assimilate only a certain part (20-60%) of the absorbed food. Digested food is used to support the vital processes of animal organisms and growth (for example, to build tissues, reserves in the form of fat deposition).

Organisms of the third trophic level (carnivorous animals) when eating herbivorous animals again lose most of the energy contained in food. The amount of energy at subsequent trophic levels again progressively decreases. The result of these energy losses is a small number (three to five) of trophic levels in the food chain.

The energy lost in the supply chains can only be replenished by the supply of new portions of it. Therefore, in an ecosystem there cannot be a cycle of energy, similar to the cycle of substances. Ecosystems are open systems that need an influx of solar energy or ready-made reserves of organic matter, thus. energy transfer in ecosystems occurs according to known the laws of thermodynamics:

1. Energy can change from one form to another, but it is never created again or disappears.

2. There cannot be a single process associated with the transformation of energy without losing some of it in the form of heat, i.e. there are no energy conversions with 100% efficiency.

It is estimated that only about 10% of energy is transferred from one trophic level to another. This pattern has been named ten percent rule.

In this way, most of energy in the power supply chain is lost when moving from one level to another. The next link in the food chain receives only the energy that is contained in the mass of the previous eaten link. Energy losses are about 90% with each transition through the food chain. For example, if the energy of a plant organism is 1000 J, then when it is completely eaten by a herbivore, only 100 J is assimilated in the body of the latter, 10 J in the body of a predator, and if this predator is eaten by another, then only 1 J of energy is assimilated in its body, then there is 0.1%.

As a result, the energy accumulated by green plants in food chains is rapidly running out. Therefore, the food chain cannot include more than 4 - 5 links. The energy lost in the supply chains can only be replenished through the receipt of new portions of it. In ecosystems there can be no cycle of energy, like the cycle of substances. The life and functioning of any ecological system is possible only with a one-way directed flow of energy in the form of solar radiation or with an influx of ready-made organic matter.

Thus, the pyramid of numbers reflects the number of individuals in each link in the food chain. The biomass pyramid reflects the amount of organic matter formed at each link - its biomass. The energy pyramid shows the amount of energy at each trophic level.

A decrease in the amount of available energy at each subsequent trophic level is accompanied by a decrease in biomass and the number of individuals. Pyramids of biomass and abundance of organisms for a given biocenosis repeat in general terms the configuration of the productivity pyramid.

All three rules of the pyramid - productivity, biomass and abundance - express energy relations in ecosystems. At the same time, the productivity pyramid has a universal character, while the pyramids of biomass and abundance appear in communities with a certain trophic structure.

It can be depicted graphically, in the form of the so-called ecological pyramids. The base of the pyramid is the level of producers, and the subsequent levels of nutrition form the floors and top of the pyramid. There are three main types of ecological pyramids:

A pyramid of numbers reflecting the number of organisms at each level;
Biomass pyramidcharacterizing the mass of living matter - total dry weight, calorie content, etc.;
Pyramid of production (energy), which has a universal character, showing the change in primary production (or energy) at successive trophic levels.

Ordinary pyramids of numbers for pasture chains have a very wide base and a sharp narrowing towards the final consumers. At the same time, the number of "steps" differ by at least 1-3 orders of magnitude. But this is true only for grass communities - meadow or steppe biocenoses.

The picture changes dramatically if we consider the forest community (thousands of phytophages can feed on one tree) or if such different phytophages as aphids and elephants are at the same trophic level. This distortion can be overcome with biomass pyramids.

In terrestrial ecosystems, plant biomass is always significantly greater than animal biomass, and phytophage biomass is always greater than zoophagous biomass.

Biomass pyramids for aquatic, especially marine ecosystems look different: animal biomass is usually much larger than plant biomass. This "irregularity" is due to the fact that biomass pyramids do not take into account the duration of the existence of generations of individuals at different trophic levels, the rate of formation and consumption of biomass. The main producer of marine ecosystems is phytoplankton, which has a great reproductive potential and rapid generational change. During the time that predatory fish (especially walruses and whales) accumulate their biomass, many generations of phytoplankton will change, the total biomass of which is much greater. That is why the universal way of expressing the trophic structure of ecosystems is the pyramids of the rates of formation of living matter, in other words, the pyramids of energies.

A more perfect reflection of the influence of trophic relations on an ecosystem is the rule pyramids of products (energy): at each previous trophic level, the amount of biomass created per unit of time (or energy) is greater than at the next. The product pyramid reflects the laws of energy expenditure on trophic chains.

Ultimately, all three rules of the pyramids reflect the energy relations in the ecosystem, and the pyramid of production (energy) has a universal character.

In nature, in stable systems, biomass changes insignificantly; nature tends to use fully the gross output. Knowledge of the energy of the ecosystem and its quantitative indicators make it possible to accurately take into account the possibility of withdrawal from natural ecosystem of this or that amount of plant and animal biomass without undermining its productivity.

A person receives a lot of products from natural systems, however, the main source of food for him is Agriculture. Having created agroecosystems, a person seeks to get as much pure vegetation production as possible, but he needs to spend half of the plant mass on feeding herbivores, birds, etc., a significant part of the production goes to industry and is lost in waste, i.e. and here about 90% of pure production is lost and only about 10% is directly used for human consumption.

One of the types of relationships between organisms in ecosystems are trophic relationships. They show how energy moves through food chains in ecosystems. A model that demonstrates the change in the amount of energy in the links of food chains is the ecological pyramid.

The structure of the pyramid

The pyramid is a graphic model. Her image is divided into horizontal levels. The number of levels corresponds to the number of links in the food chains.

All food chains begin with producers - autotrophic organisms that form organic substances. The totality of ecosystem autotrophs is what is at the base of the ecological pyramid.

Rice. 1. Ecological pyramid of population

Usually the food pyramid contains from 3 to 5 levels.

The last links in the food chain are always large predators or humans. Thus, the number of individuals and biomass at the last level of the pyramid are the lowest.

Model conditionality

It should be understood that the model shows the reality in a generalized way. Everything is more difficult in life. Any large organism, including humans, can be eaten and its energy will be used in the ecological pyramid in an atypical way.

Part of the biomass of an ecosystem is always accounted for by decomposers - organisms that decompose dead organic matter. Reducers are eaten by consumers, partially returning energy to the ecosystem.

Omnivorous animals such as the brown bear act both as a consumer of the first order (eats plants), and as a decomposer (eats carrion), and as a large predator.

Kinds

Depending on what quantitative characteristic levels are used, There are three types of ecological pyramids:

numbers;
biomass;
energy.

10% rule

According to ecologists' calculations, 10% of the biomass or energy of the previous level goes to each subsequent level of the ecological pyramid. The remaining 90% is spent on the vital processes of organisms and dissipated in the form of thermal radiation.

This pattern is called the rule of the ecological pyramid of energy and biomass.

Consider examples. About 100 kg of body weight of herbivores is formed from one ton of green plants. When herbivores are consumed by small predators, their weight increases by 10 kg. If small predators are eaten by large ones, then the body weight of the latter increases by 1 kg.

Rice. 2. Ecological pyramid of biomass

Food chain: phytoplankton - zooplankton - small fish - big fish- human. There are already 5 levels here, and in order for a person's mass to increase by 1 kg, it is necessary that there are 10 tons of phytoplankton on the first level.

Rice. 3. Ecological pyramid of energy

Apex Benefits

Species at the top of the ecological pyramid are much more likely to evolve. In ancient times, it was the animals that occupied the highest level in trophic relationships that developed faster.

In the Mesozoic, mammals occupied the middle levels of the ecological pyramid and were actively exterminated by predatory reptiles. It was only thanks to the extinction of the dinosaurs that they were able to rise to the top level and take a dominant position in all ecosystems.

Lindemann's rule (10%)

The through flow of energy, passing through the trophic levels of the biocenosis, is gradually extinguished. In 1942, R. Lindemann formulated the law of the pyramid of energies, or the law (rule) of 10%, according to which from one trophic level of the ecological pyramid it moves to another, higher level (along the "ladder": producer - consumer - decomposer) on average about 10% of the energy received at the previous level of the ecological pyramid. The reverse flow associated with the consumption of substances and the energy produced by the upper level of the ecological pyramid of energy by its lower levels, for example, from animals to plants, is much weaker - no more than 0.5% (even 0.25%) of its total flow, and therefore we can say about the cycle of energy in the biocenosis is not necessary.

If energy is lost tenfold during the transition to a higher level of the ecological pyramid, then the accumulation of a number of substances, including toxic and radioactive ones, increases in approximately the same proportion. This fact is fixed in the biological amplification rule. It is true for all cenoses. In aquatic biocenoses, the accumulation of many toxic substances, including organochlorine pesticides, correlates with the mass of fats (lipids), i.e. clearly has an energy background.

Ecological pyramids

To illustrate the relationship between organisms various kinds in the biocenosis, it is customary to use ecological pyramids, distinguishing between the pyramids of abundance, biomass and energy.

Among the ecological pyramids, the most famous and frequently used are:

§ Pyramid of numbers

§ Pyramid of biomass

Pyramid of numbers. To build a pyramid of abundance, the number of organisms in a certain territory is counted, grouping them according to trophic levels:

§ producers - green plants;

§ primary consumers - herbivores;

§ secondary consumers - carnivores;

§ tertiary consumers - carnivores;

§ ha-e consumers ("ultimate predators") - carnivores;

§ decomposers - destructors.

Each level is conventionally depicted as a rectangle, the length or area of which corresponds to the numerical value of the number of individuals. By placing these rectangles in a subordinate sequence, they get an ecological pyramid of abundance (Fig. 3), the basic principle of which was first formulated by the American ecologist Ch. Elton Nikolaikin N. I. Ecology: Proc. for universities / N. I. Nikolaykin, N. E. Nikolaykina, O. P. Melekhova. - 3rd ed., stereotype. - M .: Bustard, 2004 ..

Rice. Fig. 3. Ecological pyramid of abundance for a meadow overgrown with cereals: numbers - number of individuals

Data for population pyramids are easily obtained by direct sampling, but there are some difficulties:

§ Producers vary greatly in size, although one cereal or algae has the same status as one tree. This sometimes violates the correct pyramidal shape, sometimes even giving inverted pyramids (Fig. 4) Ibid .;

Rice.

§ the range of abundance of different species is so wide that graphic image makes it difficult to scale, but in such cases a logarithmic scale can be used.

Biomass pyramid. The ecological pyramid of biomass is built similarly to the pyramid of abundance. Its main meaning is to show the amount of living matter (biomass - the total mass of organisms) at each trophic level. This avoids the inconveniences typical of population pyramids. In this case, the size of the rectangles is proportional to the mass of living matter of the corresponding level, per unit area or volume (Fig. 5, a, b) Nikolaykin N. I. Ecology: Proc. for universities / N. I. Nikolaykin, N. E. Nikolaykina, O. P. Melekhova. - 3rd ed., stereotype. - M.: Bustard, 2004 .. The term "biomass pyramid" arose due to the fact that in the vast majority of cases the mass of primary consumers living at the expense of producers is much less than the mass of these producers, and the mass of secondary consumers is much less than the mass of primary consumers. It is customary to show the biomass of destructors separately.

Rice. Fig. 5. Pyramids of biomass of biocenoses of the coral reef (a) and the English Channel (b): numbers - biomass in grams of dry matter per 1 m 2

Sampling determines standing biomass or standing yield (ie, at a given point in time), which does not contain any information about the rate of production or consumption of biomass.

The rate of creation of organic matter does not determine its total reserves, i.e. the total biomass of all organisms at each trophic level. Therefore, errors may occur in further analysis if the following are not taken into account:

* Firstly, if the rate of biomass consumption (loss due to eating) and the rate of its formation are equal, the standing crop does not indicate productivity, i.e. about the amount of energy and matter passing from one trophic level to another, higher one, for a certain period of time (for example, for a year). So, on a fertile, intensively used pasture, the yield of grasses on the vine may be lower, and the productivity is higher than on a less fertile, but little used for grazing;

* secondly, small-sized producers, such as algae, are characterized by a high growth and reproduction rate, balanced by their intensive consumption by other organisms and natural death. Therefore, their productivity can be no less than that of large producers (for example, trees), although the biomass on the vine can be small. In other words, phytoplankton with the same productivity as a tree will have a much lower biomass, although it could support the life of animals of the same mass.

One of the consequences of what has been described is "inverted pyramids" (Fig. 3, b). Zooplankton of biocenoses of lakes and seas most often has a greater biomass than its food - phytoplankton, however, the rate of reproduction of green algae is so high that during the day they restore all the biomass eaten by zooplankton. Nevertheless, in certain periods of the year (during spring flowering), the usual ratio of their biomasses is observed (Fig. 6) Nikolaikin NI Ecology: Proc. for universities / N. I. Nikolaykin, N. E. Nikolaykina, O. P. Melekhova. - 3rd ed., stereotype. - M .: Bustard, 2004 ..

Rice. Fig. 6. Seasonal changes in the lake biomass pyramids (on the example of one of the Italian lakes): numbers - biomass in grams of dry matter per 1 m 3

Seeming anomalies are devoid of pyramids of energies, which are considered below.

Energy Pyramid. The most fundamental way to reflect the relationships between organisms of different trophic levels and the functional organization of biocenoses is the energy pyramid, in which the size of the rectangles is proportional to the energy equivalent per unit time, i.e. the amount of energy (per unit area or volume) that has passed through a certain trophic level during the accepted period (Fig. 7) Ibid.. One more rectangle can be reasonably added from below to the base of the pyramid of energy, reflecting the flow of solar energy.

The pyramid of energies reflects the dynamics of the passage of a mass of food through the food (trophic) chain, which fundamentally distinguishes it from the pyramids of abundance and biomass, which reflect the statics of the system (the number of organisms at a given moment). The shape of this pyramid is not affected by changes in the size and intensity of the metabolism of individuals. If all sources of energy are taken into account, then the pyramid will always have a typical shape (in the form of a pyramid with the top up), according to the second law of thermodynamics.

Rice. 7. Pyramid of energy: numbers - the amount of energy, kJ * m -2 * r -1

Energy pyramids allow not only to compare different biocenoses, but also to identify the relative importance of populations within the same community. They are the most useful of the three types of ecological pyramids, but the data to build them is the most difficult to obtain.

One of the most successful and illustrative examples of classical ecological pyramids are the pyramids depicted in Fig. 8 Nikolaikin N. I. Ecology: Proc. for universities / N. I. Nikolaykin, N. E. Nikolaykina, O. P. Melekhova. - 3rd ed., stereotype. - M.: Bustard, 2004 .. They illustrate the conditional biocenosis proposed by the American ecologist Y. Odum. The "biocenosis" consists of a boy who eats only veal and calves who eat only alfalfa.

Rice.

rule 1% Ecology. Lecture course. Compiled by: Candidate of Technical Sciences, Associate Professor Tikhonov AI, 2002. Pasteur's points, as well as the law of the pyramid of energies by R. Lindemann, gave rise to the formulation of the rules of one and ten percent. Of course, 1 and 10 are approximate numbers: about 1 and about 10.

"Magic Number" 1% arises from the ratio of energy consumption possibilities and the "capacities" needed to stabilize the environment. For the biosphere, the share of possible consumption of total primary production does not exceed 1% (which also follows from R. Lindemann's law: about 1% of net primary production in energy terms is consumed by vertebrates as consumers of higher orders, about 10% by invertebrates as consumers of lower orders and the remaining some are bacteria and saprophage fungi). As soon as humanity, on the verge of the past and our centuries, began to use a greater amount of biosphere production (now at least 10%), the Le Chatelier-Brown principle ceased to be satisfied (apparently, from about 0.5% of the total energy of the biosphere): vegetation did not give biomass growth in accordance with the increase in CO 2 concentration, etc. (an increase in the amount of carbon bound by plants was observed only in the last century).

Empirically, the consumption threshold of 5 - 10% of the amount of a substance, which, when passing through it, leads to noticeable changes in the systems of nature, is quite recognized. It was adopted mainly on an empirical-intuitive level, without distinguishing between the forms and nature of control in these systems. Approximately, it is possible to divide the emerging transitions for natural systems with an organismic and consortium type of control, on the one hand, and population systems, on the other. For the former, the quantities of interest to us are the threshold for exiting the stationary state up to 1% of the energy flow (the "norm" of consumption) and the self-destruction threshold - about 10% of this "norm". For population systems, exceeding on average 10% of the withdrawal volume leads to the exit of these systems from the stationary state.