Dubrava as a natural community (biogeocenosis), characterized by integrity and sustainability.
Ecological systems
- Biogeocenosis
- A pond and an oak forest as examples of biogeocenoses
- Changes in biogeocenoses
- Biogeocenoses created by man
- Food connections
- Energy losses in power circuits
Biogeocenosis.
Biogeocenosis is a stable community of plants, animals and microorganisms that are in constant interaction with the components of the atmosphere, hydrosphere and lithosphere. This community receives the energy of the Sun, minerals soil and atmospheric gases, water, and heat, oxygen, carbon dioxide, and waste products of organisms are released from it. The main functions of biogeocenosis are the accumulation and redistribution of energy and the circulation of substances. Biogeocenosis is an integral self-regulating and self-sustaining system. It includes the following mandatory components: inorganic (carbon, nitrogen, carbon dioxide, water, mineral salts) and organic substances (proteins, carbohydrates, lipids, etc.); autotrophic organisms - producers of organic substances; heterotrophic organisms - consumers of ready-made organic substances of plant origin - consumers (consumers of the first order) and animals (consumers of the second and subsequent orders). Heterotrophic organisms include decomposers - decomposers, or destructors, which decompose the remains of dead plants and animals, turning them into simple mineral compounds.
When talking about biocenoses, we consider only interconnected living organisms living in a given area. Biocenoses are characterized by species diversity, i.e. the number of species of living organisms that form it; population density, i.e. the number of individuals of a given species per unit area or per unit volume (for aquatic and soil organisms); biomass - the total amount of animal organic matter expressed in units of mass.
Biomass is formed as a result of the capture of solar energy. The efficiency with which plants assimilate solar energy, varies in different biocenoses. The total production of photosynthesis is called primary production. Plant biomass is used by first-order consumers - herbivores - as a source of energy and material for creating biomass; moreover, it is used extremely selectively (Fig. 17.7), which reduces the intensity of interspecific struggle for existence and contributes to the conservation natural resources. Herbivorous animals, in turn, serve as a source of energy and material for second-order consumers - predators, etc. Figure 17.8 shows comparative data on the productivity of various biogeocenoses. Largest quantity biomass is formed in the tropics and in temperate zone, very little - in the tundra and ocean.
Organisms that are part of biogeocenoses are influenced inanimate nature - abiotic factors, as well as from living nature - biotic influences.
Biocenoses are integral, self-regulating biological systems, which include living organisms living in the same territory.
The energy from sunlight is assimilated by plants, which are subsequently used by animals as food.
Food connections .
Energy losses in power circuits
All species that form the food chain exist on organic matter created by green plants. In this case, there is an important pattern associated with the efficiency of use and conversion of energy in the nutrition process. Its essence is as follows.
In total, only about 1% of the radiant energy of the Sun falling on a plant is converted into potential energy of chemical bonds of synthesized organic substances and can be further used by heterotrophic organisms for nutrition. When an animal eats a plant, most of the energy contained in the food is spent on various processes vital activity, turning into heat and dissipating. Only 5-20% of food energy passes into the newly built substance of the animal’s body. If a predator eats a herbivore, then again most of the energy contained in the food is lost. Due to such large losses of useful energy, food chains cannot be very long: they usually consist of no more than 3-5 links (food levels).
The amount of plant matter that serves as the basis of the food chain is always several times greater than total weight herbivorous animals, and the mass of each of the subsequent links in the food chain also decreases HH o This very important pattern is called the rule of the ecological pyramid.
A pond and an oak forest as examples of biogeocenoses
1. Biogeocenosis of a fresh water body.
Any natural body of water, such as a lake or pond, with its plant and animal population is a separate biogeocenosis. This natural system, like other biogeocenoses, has the ability for self-regulation and continuous self-renewal.
Plants and animals inhabiting a reservoir are distributed unevenly in it. Each species lives in the conditions to which it is adapted. The most diverse and favorable conditions for life are created in the coastal zone. Here the water is warmer as it warms up sun rays. It is quite saturated with oxygen. The abundance of light penetrating to the bottom ensures the development of many higher plants. Small algae are also numerous. Most animals also live in the coastal zone. Some are adapted to life on aquatic plants, others actively swim in the water column (fish, predatory swimming beetles and water bugs). Many are found at the bottom (barley beetles, toothless beetles, larvae of some insects - caddis flies, dragonflies, mayflies, a number of worms, etc.). Even the surface film of water serves as a habitat for species specially adapted to it. In quiet pools you can see predatory water strider bugs running on the surface of the water and whirligig beetles swimming quickly in circles. The abundance of food and other favorable conditions attract fish to the coastal zone.
In the deep bottom areas of the reservoir, where it weakly penetrates sunlight, life is poorer and more monotonous. Photosynthetic plants cannot exist here. Due to weak mixing, the lower layers of water remain cold. Here the water contains little oxygen.
Special conditions are also created in the thickness of the water in open areas of the reservoir. It is populated by a mass of tiny plant and animal organisms, which are concentrated in the upper, warmer and well-lit layers of water. Various microscopic algae develop here; Numerous protozoa - ciliates, as well as rotifers and crustaceans - feed on algae and bacteria. This entire complex of small organisms suspended in water is called plankton. Plankton plays a very important role in the cycle of substances and in the life of a reservoir.
2. Food connections and stability of the pond biogeocenosis.
Let's consider why the system of reservoir inhabitants exists and how it is maintained. Power supply chains consist of several consecutive links. For example, protozoa, which are eaten by small crustaceans, feed on plant debris and the bacteria that develop on them. The crustaceans, in turn, serve as food for fish, and the latter can be eaten by predatory fish. Almost all species do not feed on one type of food, but use different food objects. Food chains intricately intertwined. An important general conclusion follows from this: if any member of the biogeocenosis falls out, then the system is not disrupted, since other food sources are used. The greater the species diversity, the more stable the system.
The primary source of energy in aquatic biogeocenosis, as in most ecological systems, is sunlight, thanks to which plants synthesize organic matter. Obviously, the biomass of all animals existing in a reservoir completely depends on the biological productivity of plants.
Often the reason for the low productivity of natural reservoirs is a lack of minerals (especially nitrogen and phosphorus) necessary for the growth of autotrophic plants, or unfavorable acidity of the water. The application of mineral fertilizers, and in the case of an acidic environment, liming of reservoirs, contributes to the proliferation of plant plankton, which feeds animals that serve as food for fish. In this way, the productivity of fishery ponds is increased.
3.Biogeocenosis widely deciduous forest.
Biogeocenosis of broad-leaved forest
Among terrestrial biogeocenoses, one of the most complex is a broad-leaved forest, such as an oak forest. Oak grove is a perfect and stable ecological system, capable of existing for centuries under constant external conditions. The oak forest biogeocenosis consists of more than a hundred plant species and several thousand animal species.
Oak forest plants. The main biological products are created by higher plants. In the forest they are predominantly perennial tree species.
A characteristic feature of a deciduous forest is the species diversity of vegetation. There is intense competition between plants for the basic living conditions: space, light, water with minerals dissolved in it. As a result of long natural selection Plants have developed adaptations that allow different species to exist together. This is clearly manifested in the layering characteristic of oak forests.
The upper tier is formed by the most light-loving tree species. Below are the accompanying less light-loving trees. Even lower is a layer of undergrowth formed by various shrubs. Finally, a layer of herbaceous plants grows on the soil. The lower the tier, the more shade-tolerant the plants that form it.
The oak forest is characterized by high biological productivity. Due to its complex multi-tiered nature, the total area of plant leaves growing on each hectare reaches 4-6 hectares. Such a powerful photosynthetic apparatus captures and transforms about 1% of the annual influx of organic matter into potential energy solar radiation. biogeocenosis deciduous oak forest fauna
Food chains in oak forests. The richness and diversity of plants, which produce enormous amounts of organic matter that can be used as food, cause the development in oak forests of numerous consumers from the animal world, from protozoa to higher vertebrates - birds and mammals.
Food chains in the forest are intertwined into a very complex food web, so the loss of one species of animal usually does not significantly disrupt the entire system. Meaning different groups animals in the biocenosis are different.
Self-regulation in forest biocenosis. The process of self-regulation in an oak forest is manifested in the fact that the entire diverse population of the forest exists together, without completely destroying each other, but only limiting the number of individuals of each species to a certain level.
In the forest biogeocenosis, the circulation of substances and the movement of energy are clearly visible.
Part deciduous forests includes beech, oak, hornbeam, linden, maple, birch, aspen, rowan and other trees whose foliage falls in autumn. There are several tiers of plants in the forest: high and low woody, shrubs, grasses and moss ground cover. Plants upper tiers more light-loving and better adapted to fluctuations in temperature and humidity than plants in the lower tiers. Shrubs, grasses and mosses in the forest are shade-tolerant; in summer they exist in twilight, which forms after the leaves of the trees have fully expanded. On the surface of the soil lies a litter consisting of semi-decomposed remains, fallen leaves, twigs of trees and shrubs, and dead grasses (Fig. 2).
The fauna of deciduous forests is rich. There are many burrowing rodents, burrowing insectivores, and predators (fox, badger, bear). There are mammals that live in trees (lynx, squirrel, chipmunk). The group of large herbivores includes deer, elk, and roe deer. Wild boars are widespread. Birds nest in different layers of the forest: on the ground, in bushes, on trunks or in hollows and on the tops of trees. There are many insects that feed on leaves (for example, caterpillars) and wood (bark beetles). In addition to insects, the litter and upper soil horizons are home to a huge number of other vertebrates ( earthworms, mites, insect larvae), a mass of fungi and bacteria.
Broad-leaved forests occupy vast areas from the British Isles in the west to the Urals in the east. Eastern Urals they are replaced by small-leaved forests. Broad-leaved forests reappear already in Far East, on the coast Pacific Ocean. As you know, the further a given territory is from the ocean, the less moisture it receives. Therefore, in the deep parts of the continents of Eurasia and North America, the annual amount of precipitation is significantly less than in the oceanic regions. Vegetation is distributed depending on this deciduous forests. IN Western Europe Moisture-loving beech forests are widespread, which are replaced to the east by drier oak forests. Along with oak, hornbeam, maple, ash, linden, elm, and elm grow here.
IN deciduous forests temperate latitudes There are vines: hops, wild grapes, ivy, clematis. Very interesting feature of these forests is the presence of a group of ephemeroids. Ephemeroids are called perennials, developing only in the spring, before the leaves bloom on the trees. By the time the leaves bloom on the trees of the first tier and a green twilight reigns in the forest, the ephemeroids have already completely completed their development cycle. At the end of May - beginning of June, they disappear from the composition of the grass stand and remain in the soil until next spring in the form of bulbs, tubers, rhizomes, etc. Ephemeroids are well known to everyone. As soon as the snow melts, the first spring flowers appear in the thawed areas - azure snowdrops, yellow anemones, chistyaks, purple corydalis, pink catfish, etc., which in some places cover the ground with a continuous multi-colored carpet. But after two to three weeks, when the leaves bloom on the trees, they completely fade and disappear from the grass stand.
Studying the structure
oak forest biogeocenosis and
human influence on him.
Work is done
11th grade student
Municipal educational institution secondary school No. 49
Golovanov Vadim
Art. Smolensk
Supervisor:
Biology teacher
Art. Smolenskaya, 2011
Introduction…………………………………………………………………………………..3
Biogeocenosis of the oak forest……………………………………………………………..6
The main components of biogeocenosis and the connections between them……………………6
Diversity of species in the biogeocenosis, their adaptability to living together………………………………………………………………………………….7
Factors causing change in numbers; self-regulation in biogeocenosis………………………………………………………………………………...9
Study of local biogeocenosis and the influence of human activities………. 10
Structure of the local biocenosis……………………………………………………………10
The influence of human activity on the biocenosis………………………………….12
Applications………………………………………………………………………………...16
Introduction
The planet's green outfit is beautiful, poetic and absolutely necessary. It is to this green decoration that not only all the numerous animal world earth, but also humanity.
Forests not only decorate the Earth - they soften the climate, feed rivers with water, serve as housing for animals and birds, and provide humans with many valuable materials and products. Without food, clothing, shelter, as we know, there is no life. And plants give people, in addition to all these benefits, also essential oxygen, clean the air from carbon dioxide.
Almost a quarter of our country is covered with forests. The lower mountain mixed broad-leaved forests of the Krasnodar Territory are distinguished by great diversity. They are made up of numerous forest-forming species: various types of oak, elm, maple, beech, hornbeam, ash, wild fruit trees - pear, apple, cherry plum, cherry, chestnut, and shrubs - rhododendron, hazel, dogwood and many others.
The dominant position belongs to oak forests, occupying more than half (54%) of the forested area. In the western part of the northern slope of the Caucasus Range, the most widespread are oak forests of winter oak with an undergrowth of yellow azalea; in addition, there are hornbeam-azale, dogwood-loquat, hornbeam-ozhin, pear-maple communities. In the eastern part of the northern slope, the dominant position in mixed broad-leaved forests belongs to two species - summer or pedunculate oak and winter or sessile oak, they are accompanied by ash, linden, hornbeam, mountain elm or birch bark, beautiful maple, sycamore maple, field maple, Gartvis oak, beech, pear. In certain habitats, some accompanying species become dominant, forming corresponding forests; most often this falls to the share of hornbeam and beech. The main types of shrubs that form the undergrowth are southern redwood, European euonymus, hazel, dogwood, and azalea. In terms of area occupied, oak forests of summer oak are in first place, winter oak is in second place, and forests of Gartvis oak are relatively rare, usually in river valleys. In the lower mountain belt of the eastern region there are also beech forests. They are usually located on northern, northwestern and northeastern slopes with thick, well-moistened dark gray soils. As a rule, beech forests are forests of the mid-mountain zone, but here they are interspersed with the background oak forests. At altitudes from 400 to 600, and sometimes up to 900 m above sea level, there are chestnut-oak, chestnut-beech forests, as well as pure chestnut forests.
Dubrava, how natural community(biogeocenosis), is one of the most complex among terrestrial biogeocenoses. Well, first of all, what is biogeocenosis? Biogeocenosis is a complex of interconnected species (populations of different species) living on certain territory with more or less homogeneous conditions existences. This definition will be needed for future use. Oak grove is a perfect and sustainable ecological system, capable of existing for centuries under constant external conditions. The oak forest biogeocenosis consists of more than a hundred plant species and several thousand animal species. It is clear that with such a diversity of species inhabiting the oak forest, it will be difficult to shake the stability of this biogeocenosis by exterminating one or several species of plants or animals. It is difficult, because as a result of the long coexistence of plant and animal species, from disparate species they became a single and perfect biogeocenosis - an oak forest, which, as mentioned above, is capable of existing for centuries under constant external conditions.
That would be the case if it weren't for anthropogenic factor. Man has the most powerful impact on the state of any biogeocenosis. In the oak grove he is clearing hard rocks, collects fruits wild pears, apple trees, dogwood, hawthorn. Here he hunts wild boars, after Sunday picnics leaves a myriad of garbage that has been stored in the forest for decades.
The purpose of my work: to study the structure of forest biogeocenosis in the vicinity of the village of Smolenskaya and to identify the influence of humans on it.
1. Biogeocenosis of oak forest.
1.1.Main components of biogeocenosis and connections between them.
Plants are the main link in the ecosystem. The basis of the vast majority of biogeocenosis are green plants, which, as is known, are producers of organic matter (producers). And since in biogeocenosis there are necessarily herbivorous and carnivorous animals - consumers of living organic matter (consumers) and, finally, destroyers of organic residues - mainly microorganisms that bring the breakdown of organic substances to simple mineral compounds (decomposers), it is not difficult to guess why plants are the main link in the ecosystem. But because in biogeocenosis everyone consumes organic substances, or compounds formed after the breakdown of organic substances, and it is clear that if plants - main source organic matter will disappear, then life in the biogeocenosis will practically disappear.
The circulation of substances in biogeocenosis - necessary condition existence of life. It arose in the process of the formation of life and became more complex during the evolution of living nature. On the other hand, in order for the circulation of substances to be possible in a biogeocenosis, it is necessary to have in the ecosystem organisms that create organic substances from inorganic ones and convert the energy of solar radiation, as well as organisms that use these organic substances and convert them again into inorganic compounds. All organisms are divided into two groups according to their method of nutrition - autotrophs and heterotrophs. Autotrophs (mainly plants) use inorganic compounds from the environment to synthesize organic substances. Heterotrophs (animals, humans, fungi, bacteria) feed on ready-made organic substances that were synthesized by autotrophs. Therefore, heterotrophs depend on autotrophs. In any biogeocenosis, all reserves of inorganic compounds would very soon dry up if they were not renewed during the life activity of organisms. As a result of respiration, decomposition of animal corpses and plant residues organic substances are converted into inorganic compounds, which are returned back to natural environment and can again be used by autotrophs. Thus, in biogeocenosis, as a result of the vital activity of organisms, there is a continuous flow of atoms from inanimate nature to living nature, and back, closing in a cycle. For the circulation of substances, an influx of energy from outside is necessary. The source of energy is the Sun. The movement of matter caused by the activity of organisms occurs cyclically; it can be used many times, while the flow of energy in this process is unidirectional. The radiation energy of the Sun in biogeocenosis is converted into various shapes: Into the energy of chemical bonds, into mechanical and, finally, into internal. From all that has been said, it is clear that the circulation of substances in a biogeocenosis is a necessary condition for the existence of life and plants (autotrophs); the most important link in it.
1.2. Diversity of species in biogeocenosis, their adaptability to living together.
A characteristic feature of the oak forest is the species diversity of vegetation. As mentioned above, the oak forest biogeocenosis consists of more than a hundred plant species and several thousand animal species. There is intense competition between plants for the basic living conditions: space, light, water with minerals dissolved in it. As a result of long-term natural selection, oak forest plants have developed adaptations that allow different species to exist together. This is clearly manifested in the layering characteristic of oak forests. The upper tier is formed by the most light-loving tree species: oak, ash, linden. Below are the accompanying less light-loving trees: maple, apple, pear, etc. Even lower is a layer of undergrowth formed by various shrubs: hazel, euonymus, buckthorn, viburnum, etc. Finally, a layer of herbaceous plants grows on the soil. The lower the tier, the more shade-tolerant the plants that form it. Tiering is also expressed in the location of root systems. Trees in the upper layers have the deepest root system and can use water and minerals from the deeper layers of the soil.
1.3. Factors causing changes in numbers; self-regulation in biogeocenosis.
Any biogeocenosis develops and evolves. The leading role in the process of changing terrestrial biogeocenoses belongs to plants, but their activity is inseparable from the activity of other components of the system, and the biogeocenosis always lives and changes as a single whole. Change occurs in certain directions, and the duration of existence of various biogeocenoses is very different. Oak groves can also turn into a different type of biogeocenosis. For example, after cutting down trees, it can turn into a meadow, field (agrocenosis) or something else. And life in this biocenosis will completely change.
2. Study of the local oak forest biogeocenosis and the influence of human activity.
2.1. The structure of the local biocenosis.
Oak forests of the North-Western Caucasus are distributed over an area of about 717 thousand hectares, which is almost 72% of their area in the North Caucasus and 20.3% of the total area of oak forests European Russia. Growing in the foothill zone and lower mountain zone, they have enormous soil-protective, water-regulating, recreational significance, and are a habitat for numerous representatives of animals and flora, a source of valuable oak wood. Reforestation of cleared areas is an indispensable condition for ensuring continuity and sustainability of forest management. Currently, oak in felled areas is restored mainly by self-sowing, i.e., its industrial restoration is not carried out.
According to domestic authors, the oak genus numbers from 250 to 450 and even up to 600 species. Some Western European taxonomists count more than 300 species in the genus. Due to large number and significant polymorphism of species, taxonomy of the genus is difficult. Therefore, a number of Caucasian oaks, after lengthy discussions among taxonomists, lost their independence in the rank of species. In the study area greatest distribution have four types of oak: English oak, or summer sessile oak, or Gartvis winter oak, or Armenian and downy oak.
The percentage participation of the main species in the crops ranges from 15...72%, averaging 35% for Gartvis oak and 41% for English oak. Under conditions of a fresh oak forest, the relative participation of Gartvis oak and English oak is the same and equals 34%. In humid conditions, Gartvis oak by percentage of trunks is 36, and pedunculate oak is 44%.
A natural admixture to the oak of seed origin is formed by the coppice oak, as well as other hard-leaved trees (common ash, field and Tatarian maples, rough elm, common hornbeam, oriental beech), wild fruits (Caucasian pear, hawthorn monopistillate) and soft-leaved trees (goat willow, trembling poplar, white poplar) species. It should be noted that hawthorn, as an element of the forest, is part of only the youngest oak crops up to 10...15 years of age, subsequently acting only as undergrowth.
Among the secondary hardwood species, the largest proportion of trees of seed origin is eastern beech (90%), and the smallest is maples (23–24%). Elm takes a noticeable part in natural seed regeneration in the area of partial oak crops. In general, 55% of hardwood species are represented in seed crops.
Soft-leaved and other (wild fruit) species are distributed approximately equally by regeneration method. It should only be noted that aspen, unlike other species, reproduces vegetatively, mainly by root suckers.
The composition of the undergrowth includes laxative jock geranium, European euonymus, common privet, hawthorn, black elderberry, male dogwood, common hazel, and southern pigweed. Most permanent species The undergrowth is hawthorn and redwood. Black elderberry forms a sparse undergrowth in the humid conditions of Gartvis oak crops, and dogwood - only in fresh oak forests of English oak.
Thus, 21 tree and shrub species were taken into account in the composition of oak forest crops. They occupy the fourth (upper) and third tiers of the biogeocenosis. Herbaceous plants grow below. Their diversity depends on the time of year. In early spring Caucasian hellebore, primrose, Caucasian candyk, Voronov's snowdrop, cyclamens, scillas, and violets are blooming. They are replaced by peony, lily of the valley, kupena, and in clearings - pollenhead and orchis, sylvestris, ash, St. John's wort, tansy, oregano and cereal grasses. Mushrooms, lichens and mosses grow in the lowest tier. The composition of herbaceous vegetation also depends on the composition of the upper tiers and on illumination.
2.2. The influence of human activity on the biocenosis
Since ancient times, humans have had an impact on local biocenoses. At first it was clearing forests for heating homes, building houses, and plowing for cultivating crops. In the forest, people always collected berries, mushrooms, fruits of wild trees, medicinal herbs. But this was not of a mass nature. Therefore, the biogeocenosis was gradually restored. Even after severe battles for the village of Smolenskaya, the destroyed forest was restored. Big role The local forestry played a role in its restoration. Every year, oak acorns were sown, schools were systematically maintained, and forestry workers fought pests and plant diseases. In a word, planned reforestation was carried out. The felling was carried out strictly in accordance with the standards. Almost no clear cuttings were carried out. Thinning was carried out in the forest and the forest could regenerate itself. During the period of perestroika, forest districts lost their importance, the number of people working in them decreased, and funds for reforestation ceased to be allocated. Currently, the situation has hardly improved. Reforestation is not being carried out, and logging continues. Hundreds of cubic meters of forest were cut down during the construction of the gas pipeline. The construction of the pipeline and the road along it has long been completed, but the forest continues to be cut down. As a result, the mountain slopes are exposed and the entire structure of the biogeocenosis will change. The third part of the harvested wood, having received the label "waste", remains in the forest to rot, or, in best case scenario, she will be burned.
People need wood more and more, therefore, the Caucasian forest will have to be cut down. Is a compromise possible? It is possible, but only under the condition that when logging in the mountains, it is necessary to simultaneously take care of nature. Obviously, the solution is that the efforts of the forestry association today be aimed at protecting nature and restoring the forest in the amount of effort and money that is spent on its destruction.
Hunting also affects the structure and species diversity of biogeocenosis. IN Lately There were more hunters in the forest than game. They hunt ducks, hares, wild boars, violating food connections.
Vacationers cause no less damage to the forest. Every weekend a column of cars stretches through the village. They all rush into the forest to relax and have fun. WITH early spring Loud music and laughter are heard in the forest. People forget that the forest is not a place for entertainment, but a home where birds and animals live. Birds usually nest in quiet places and therefore are forced to fly deeper into the forest, where people visit less often. Birds eat insects. And if there are no birds, then favorable conditions are created for insect pests and their insatiable jaws eat the leaves of the trees. In the last two years, the forest has suffered great damage gypsy moth. But, unfortunately, there was no money to fight it.
People pick armfuls of flowers, not thinking about the fact that a flower is an organ of generative reproduction, in the place of which fruits with seeds appear. After all, not all plants can reproduce vegetatively. Walking through the forest, a person tramples mosses, lichens, and disrupts the natural processes occurring in the biogeocenosis.
And the worst thing is the products of civilization that people leave behind: bags, plastic bottles, glass, which nature cannot recycle. Woe - tourists forget to put out fires, throw cigarette butts out of cars, which will lead to fires. Dozens of hectares of forest floor are burning, and the undergrowth is suffering.
Thus, it is clear that recently man has only negatively affected nature, violating natural biogeocenoses, polluting forest lands. It's time to return to reforestation and normal operation of forest departments.
References:
1. Materials from the site http://www. /
2. Nebel B. Environmental Science. M.: Mir, 1993.- T.1-2.
4. Reimers (theory, laws, rules and hypotheses). M.: magazine “Young Russia”, 1994.
5. , specially protected natural areas, M.: Mysl, 1982
6. Ulitsky hopes. M.: Enlightenment, 198 p.
7. , Shustova fundamentals of ecology. M.: Education, 199 p.
8. encyclopedic Dictionary– reference book Environment. M.: “Pangaea”, 1993.
Biology. General biology. Grade 11. Basic level Sivoglazov Vladislav Ivanovich
24. Ecosystem structure
24. Ecosystem structure
Remember!
What levels of organization of living nature do you know?
What is an ecosystem?
The influence of abiotic factors on living organisms and interactions between certain types form the basis of the life of any community. Community, or biocenosis, is a collection of coexisting populations of different species. Together with factors of inanimate nature (abiotic factors), the community forms ecosystem.
Ecosystem is a very broad concept. Rainforest and swamp, rotting stump and anthill, puddle in the middle of a country road and lonely standing tree with its inhabitants are different natural ecosystems. There are ecosystems of artificial origin, for example agricultural land, an aquarium, a farm. An ecosystem whose boundaries are defined plant community, for example, oak grove, meadow, spruce forest, Birch Grove, called biogeocenosis. The entire set of biogeocenoses globe forms a global ecosystem, or biosphere.
Any ecosystem has spatial, species and ecological structures.
Spatial structure of the ecosystem. The spatial structure of most biogeocenoses and, consequently, ecosystems is determined by the layered arrangement of vegetation (Fig. 75). For example, in a typical deciduous forest, canopy (tree), shrub, herbaceous and ground (ground) layers can be distinguished. By going deeper into the soil, you can also discover certain “floors” that are formed by the roots of certain plants and where they live. different types underground animals. This spatial organization of the ecosystem allows plants to effectively use sunlight and soil resources, and numerous animals and microorganisms to coexist together, occupying a variety of habitats. ecological niches.
Rice. 75. An example of a layered ecosystem. Tiered structure of deciduous forest
In the composition of any ecosystem, two main ones can be distinguished: structural components: a complex of factors of inanimate nature, the so-called abiotic environment, or biotope, and the totality of all living organisms - biocenosis. In turn, the biocenosis can be divided into zoocenosis(animal community), phytocenosis(plant community), microbiocenosis(community of microorganisms). A biotope is also a heterogeneous system; it consists of various abiotic factors, which together form certain climatic, geographical, soil and other parameters of the ecosystem.
Species structure ecosystems. The biocenosis of any ecosystem is characterized by a certain species diversity, i.e., the number of species that form it, and the quantitative ratio of individuals of these species. Species diversity ensures the stability of ecosystems. The high number of populations that make up the ecosystem indicates that these species are optimally adapted to specific conditions and are important for the stable existence of this ecosystem. Usually total number It is quite difficult to count individuals in populations, therefore, when characterizing ecosystems, the concept is used "population density"(§6).
Ecological structure of the ecosystem. Despite the enormous diversity of ecosystems, they all have approximately the same ecological structure. Ecological structure is the ratio of groups of species that occupy certain ecological niches and perform certain functions in the community. The presence of these groups is prerequisite stable existence of any ecosystem, because thanks to their interaction, the main property of ecosystems is ensured - ability to self-sustain. These essential components of any ecosystem are producers, consumers and decomposers.
Producers, or manufacturers, - these are autotrophs that, in the process of life activity, synthesize organic compounds from inorganic substances, using carbon dioxide as a carbon source. Biomass formed in an ecosystem by autotrophic organisms is called primary products. It serves as food and a source of energy for the rest of the organisms in the community.
The main producers are green plants, although photosynthetic and chemosynthetic bacteria also contribute to the formation of primary production of the ecosystem. For each large ecosystem or any biogeocenosis is characterized by its own specific plants that carry out photosynthesis, i.e., its own producers.
Consumers, or consumers, – these are heterotrophic organisms that use biomass synthesized by producers for their own life activities. By eating and processing plants, consumers obtain energy and form secondary products ecosystems.
Consumers are a wide variety of living organisms - from microscopic bacteria to large mammals, from protozoa to humans. From the point of view of the structure of the ecosystem and the role played by different consumers in maintaining its equilibrium state, all consumers can be divided into several subgroups, which we will do a little later, when we analyze the food connections of ecosystems.
decomposers, or decomposers, recycle dead organic matter ( detritus) to mineral compounds, which can again be used by producers. Many organisms, such as, for example, earthworms, millipedes, termites, ants, etc., feed on plant and animal debris, and some of the wood rots and decomposes during the activity of fungi and bacteria. When fungi and other decomposers die, they themselves turn into detritus and serve as food and a source of energy for other decomposers.
Thus, despite the diversity of ecosystems, they all have structural similarity. Each ecosystem capable of independent existence has its own producers, various types of consumers and decomposers (Fig. 76).
Oak forest ecosystem. Let's take an oak forest as an example - a very stable terrestrial ecosystem (Fig. 77). An oak grove is a typical broad-leaved forest with a layered structure, in which many hundreds of plant species and several thousand species of animals, microorganisms and fungi coexist.
The upper tree layer is formed by large (up to 20 m) perennial oaks and lindens. These light-loving plants, growing quite freely, create favorable conditions for the formation of a second tree layer, represented by low-growing and less light-loving pear, maple, and apple trees.
Rice. 76. Necessary components of an ecosystem
Under the canopy of two tiers a shrubby vegetation. Hazel, euonymus, viburnum, hawthorn, blackthorn, elderberry, buckthorn - this is not a complete list of plants that form the third tier up to a height of 2–4 m.
The next, herbaceous layer consists of numerous shrubs and subshrubs, ferns, tree shoots and various herbs. Moreover, throughout the year, the grass cover in the oak forest changes. In the spring, when there is no foliage on the trees yet and the surface of the soil is brightly lit, light-loving primroses bloom: lungwort, corydalis, anemone. In summer they are replaced by shade-tolerant plants.
In the ground layer, the height of which is only a few centimeters from the soil surface, lichens, mosses, mushrooms, and low grasses grow.
Hundreds of plant species ( producers), using the energy of the sun, create green oak forest biomass. Oak groves are very productive: over the course of a year, on an area of 1 hectare, they create up to 10 tons of plant mass growth.
Dead roots and fallen leaves form a litter in which numerous decomposers: earthworms, larvae of flies and butterflies, dung beetles and carnivores, woodlice and centipedes, springtails, mites, nematodes. By feeding, these organisms not only transform detritus, but also form soil structure. The activity of diggers such as moles, mice and some large invertebrates prevents the soil from caking. Numerous soil protozoa live in drops of water between soil particles, and fungi form a symbiosis with plant roots and participate in the decomposition of detritus.
Rice. 77. Oak forest ecosystem
Despite the fact that every year 3–4 tons of dead plants fall onto 1 hectare of soil surface in an oak forest, almost all of this mass is destroyed as a result of the activity of decomposers. Special role in this processing belongs to earthworms, of which there are a huge number in oak forests: several hundred individuals per 1 m 2.
The fauna of the upper tiers of the oak forest is diverse. Dozens of bird species nest in the treetops. Magpies and jackdaws, song thrushes and chaffinches, great tits and blue tits build nests. Eagle owls hatch chicks in hollows and tawny owl. Hobbies and sparrowhawks intimidate small songbirds. The bushes are home to Robins and Blackbirds, Pied Flycatchers and Nuthatch. Even lower are the nests of warblers and wrens. The gray squirrel moves along all tiers in search of food. Butterflies, bees, wasps, flies, mosquitoes, beetles - more than 1,600 species of insects are closely associated with oak! In the grass layer, grasshoppers and beetles, spiders and haymakers, mice, shrews and hedgehogs share their place in the sun. The largest consumers This ecosystem includes roe deer, fallow deer and wild boar.
The sustainability of this and any other ecosystem is ensured by a complex system relationships between all the organisms that make up it.
Review questions and assignments
1. What is biogeocenosis?
2. Tell us about the spatial structure of the ecosystem.
3. What essential components does any ecosystem include?
4. What are the relationships between the inhabitants of biocenoses? Describe these connections.
5. Describe the species composition and spatial structure of the oak forest ecosystem.
Think! Do it!
1. Name the common features of the biogeocenoses of a deciduous forest and a freshwater reservoir.
2. Is it possible for a biocenosis consisting only of plants to exist? Justify your point of view.
3. Do research on the topic “My home as an example of an ecosystem.”
4. Develop a tour that demonstrates the species, spatial and ecological structures of a typical ecosystem in your region (group project).
Work with computer
Refer to the electronic application. Study the material and complete the assignments.
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The textbook corresponds to the basic level of the Federal component of the state standard general education in biology and recommended by the Ministry of Education and Science of the Russian Federation.
The textbook is addressed to students in grades 10-11 and completes the line of N.I. Sonin. However, the peculiarities of the presentation of the material make it possible to use it at the final stage of studying biology after textbooks of all existing lines.
Any ecosystem has spatial, species and ecological structures.
Spatial structure of the ecosystem. The spatial structure of most biogeocenoses and, consequently, ecosystems is determined by the layered arrangement of vegetation (Fig. 161). For example, in a typical deciduous forest, canopy (tree), shrub, herbaceous, and ground (ground) layers can be distinguished. Going deeper into the soil, you can also find certain “floors” that are formed by roots certain plants and where different types of underground animals live. This spatial organization of the ecosystem allows plants to effectively use sunlight and soil resources, and numerous animals and microorganisms to coexist together, occupying a variety of ecological niches.
Rice. 161. An example of a layered ecosystem. Tiered structure of deciduous forest
In the composition of any ecosystem, two main structural components can be distinguished: a complex of factors of inanimate nature, the so-called abiotic environment, or biotope, and the totality of all living organisms - biocenosis. In turn, the biocenosis can be divided into zoocenosis(animal community), phytocenosis(plant community), microbiocenosis(community of microorganisms). A biotope is also not a homogeneous system; it consists of various abiotic factors, which together form certain climatic, geographical, soil and other parameters of the ecosystem.
Species structure of the ecosystem. The biocenosis of any ecosystem is characterized by a certain species diversity, i.e., the number of species that form it, and the quantitative ratio of individuals of these species. Species diversity ensures the stability of ecosystems. The high number of populations that make up the ecosystem indicates that these species are optimally adapted to specific conditions and are important for the stable existence of this ecosystem. It is usually quite difficult to calculate the total number of individuals in populations, therefore, when characterizing ecosystems, the concept is used population density (§ ).
Ecological structure of the ecosystem. Despite the enormous diversity of ecosystems, they all have approximately the same ecological structure. Ecological structure is the ratio of groups of species occupying certain ecological niches and performing certain functions in the community. The presence of these groups is a prerequisite for the stable existence of any ecosystem, because thanks to their interaction, the main property of ecosystems is ensured - ability to self-sustain. These essential components of any ecosystem are producers, consumers and decomposers.
Producers, or manufacturers, - these are autotrophs that, in the process of life activity, synthesize organic compounds from inorganic substances, using carbon dioxide as a carbon source. Biomass formed in an ecosystem by autotrophic organisms is called primary products. It serves as food and a source of energy for the rest of the organisms in the community.
The main producers are green plants, although photosynthetic and chemosynthetic bacteria also contribute to the formation of the primary production of the ecosystem. Each large ecosystem or any biogeocenosis is characterized by its own specific plants that carry out photosynthesis, i.e., its own producers.
Consumers, or consumers, – these are heterotrophic organisms that use biomass synthesized by producers for their own life activities. By eating and processing plants, consumers obtain energy and form secondary products ecosystems.
Consumers are a wide variety of living organisms - from microscopic bacteria to large mammals, from protozoa to humans. From the point of view of the structure of the ecosystem and the role played by different consumers in maintaining its equilibrium state, all consumers can be divided into several subgroups, which we will do a little later when we examine food connections ecosystems
decomposers, or decomposers, recycle dead organic matter ( detritus) to mineral compounds, which can again be used by producers. Many organisms, such as earthworms, millipedes, termites, ants, etc., feed on plant and animal debris, and some wood rots and decomposes during the activity of fungi and bacteria. When fungi and other decomposers die, they themselves turn into detritus and serve as food and a source of energy for other decomposers.
Thus, despite the diversity of ecosystems, they all have structural similarity. Each ecosystem capable of independent existence has its own producers, various types of consumers and decomposers (Fig. 162).
Oak forest ecosystem. Let's take an oak forest as an example - a very stable terrestrial ecosystem (Fig. 163). An oak grove is a typical broad-leaved forest with a layered structure, in which many hundreds of plant species and several thousand species of animals, microorganisms and fungi coexist.
The upper tree layer is formed by large (up to 20 m) perennial oaks and lindens. These light-loving plants, growing quite freely, create favorable conditions for the formation of a second tree layer, represented by low-growing and less light-loving pear, maple, and apple trees.
Rice. 162. Necessary components of an ecosystem
Shrub vegetation forms under the canopy of two tiers. Hazel, euonymus, viburnum, hawthorn, blackthorn, elderberry, buckthorn - this is not a complete list of plants that form the third tier up to a height of 2–4 m.
The next, herbaceous layer consists of numerous shrubs and subshrubs, ferns, tree shoots and various herbs. Moreover, throughout the year, the grass cover in the oak grove changes. In the spring, when there is still no foliage on the trees and the surface of the soil is brightly lit, light-loving primroses bloom: lungwort, corydalis, anemone. In summer they are replaced by shade-tolerant plants.
In the ground layer, the height of which is only a few centimeters from the soil surface, lichens, mosses, mushrooms, and low grasses grow.
Rice. 163. Oak forest ecosystem
Hundreds of plant species ( producers), using the energy of the Sun, create green oak forest biomass. Oak groves are very productive: over the course of a year, on an area of 1 hectare, they create up to 10 tons of plant mass growth.
Dead roots and fallen leaves form a litter that is home to numerous decomposers: earthworms, larvae of flies and butterflies, dung beetles and carnivores, woodlice and centipedes, springtails, mites, nematodes. By feeding, these organisms not only transform detritus, but also form soil structure. The activity of diggers such as moles, mice and some large invertebrates prevents the soil from caking. Numerous soil protozoa live in drops of water between soil particles, and fungi form a symbiosis with plant roots and participate in the decomposition of detritus.
Despite the fact that every year 3–4 tons of dead plants fall onto 1 hectare of soil surface in an oak forest, almost all of this mass is destroyed as a result of the activity of decomposers. A special role in this processing belongs to earthworms, of which there are a huge number in oak forests: several hundred individuals per 1 m2.
The fauna of the upper tiers of the oak forest is diverse. Dozens of bird species nest in the treetops. Magpies and jackdaws, song thrushes and chaffinches, great tits and blue tits build their nests. Eagle owls and tawny owls hatch chicks in hollows. Hobbies and sparrowhawks intimidate small songbirds. The bushes are home to Robins and Blackbirds, Pied Flycatchers and Nuthatch. Even lower are the nests of warblers and wrens. The gray squirrel moves along all tiers in search of food. Butterflies, bees, wasps, flies, mosquitoes, beetles - more than 1600 species of insects are closely associated with oak! In the grass layer, grasshoppers and beetles, spiders and haymakers, mice, shrews and hedgehogs share their place in the sun. The largest consumers This ecosystem includes roe deer, fallow deer and wild boar.
The stability of this and any other ecosystem is ensured by a complex system of relationships among all the organisms that make up it.
Review questions and assignments
1. What is biogeocenosis?
2. Tell us about the spatial structure of the ecosystem.
3. What essential components does any ecosystem include?
4. What are the relationships between the inhabitants of biocenoses? Describe these connections.
5. Describe the species composition and spatial structure of the oak forest ecosystem.
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