Presentation on the topic of ecosystem sustainability. Development of a biology lesson on the topic “Causes of sustainability and change of ecosystems” (grade 11)

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Lecture 10. Topic: Properties of ecosystems. Change of ecosystems. Objectives: To generate knowledge about self-regulation mechanisms that ensure the sustainability of ecosystems. Characterize the self-development of ecosystems, the natural replacement of less stable communities with more stable ones. Matveenko Olga Albertovna

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1. Resilience Resilience is the ability of a community and ecosystem to withstand changes created by external influences. An ecosystem can be described by a complex pattern of forward and feedback connections that maintain homeostasis of the system. Usually, two types of homeostasis are distinguished: resistant - the ability of ecosystems to maintain structure and function under negative external influences and elastic - the ability of an ecosystem to restore structure and function when some components of the ecosystem are lost.

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1. Stability The stability of an ecosystem is ensured by: Diversity of food chains Wide species composition Presence of symbiotic relationships Long food chains

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2. Self-regulation Self-regulation is characteristic of any biogeocenosis. It is determined mainly by maintaining the optimal number of organisms in the system. The population size of any species in a biogeocenosis is controlled “from above” and “from below”. “From below” it is controlled by vital resources, “from above” - by organisms of the next trophic level.

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2. Self-regulation The more species are included in the biogeocenosis, the more complex the food network, the more stable it is. The loss of one link in such an ecosystem usually does not lead to its death.

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2. Self-regulation. Examples. In Alaska, in one of the reserves, in order to protect four thousand deer, a complete shooting of wolves was organized. As a result, after 10 years there were 42 thousand deer, they undermined their food supply and began to die out.

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2. Self-regulation. Examples. Just 12 pairs of rabbits, which were brought to Australia in the mid-19th century, over 40 years multiplied to 100 million individuals, deprived sheep of food and brought huge losses to farms.

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2. Self-regulation. Examples. - The absence of natural enemies of the Colorado potato beetle reduces potato yields in Eurasia. - The massive proliferation of prickly pear imported from America as a hedge in Australia dramatically affected the quality of pastures; no mechanical or chemical methods of control helped. Cactus moth Colorado potato beetle

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2. Self-regulation. Examples African dung beetle scarab St. John's wort Poisonous ragweed. Is a strong allergen.

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3. Change of ecosystems For example, after a fire or deforestation of a spruce forest, it self-regenerates through a number of less stable ecosystems: first, a community of light-loving herbaceous plants develops, then light-loving tree species grow, spruce seedlings appear under their protection, and after about two hundred years, spruce trees displace light-loving tree species .

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3. Change of ecosystems Succession that begins in a place absolutely devoid of life is called primary. It goes from the primary stage to the mature stage. The number of species gradually increases, and the biomass of the community also increases.

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3. Change of ecosystems If a community develops in a place where a well-developed biocenosis existed, then succession will be secondary. In such places, rich life resources are usually preserved, so secondary successions lead to the formation of a mature community much faster than primary ones.

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The following four types of successional changes can be mentioned as the main ones. 1. Species of plants and animals continuously change during the process of succession. Changes in species composition are often determined by the competition of different species for the same food or other resources, because changes in the ecosystem that occur during succession create favorable conditions for the colonization of a community by new species. 2. Successional changes are always accompanied by an increase in species richness, i.e., the diversity of organisms. 3. There is an increase in the biomass of organic matter. The population of the community seems to become denser as species richness increases. 4. There is a decrease in the growth rate of community biomass (community products) and an increase in the amount of energy required to maintain its life. This is the most important phenomenon of succession. In the early stages of primary succession, the rate of biomass growth by plants is high, but in subsequent stages it decreases. 3. Change of ecosystems

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3. Change of ecosystems As a result of successions, mature plant communities are formed, communities of plants best suited for growing together in specific climatic zones. From north to south, tundra phytocenoses are formed, then taiga with a predominance of coniferous species, then mixed and broad-leaved forests; under conditions of lack of moisture, steppe plant communities dominate; in the most favorable climatic zones, subtropical and tropical plant communities are formed.

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3. Change of ecosystems Russian scientist L.G. Ramensky figuratively called them “lions”, “camels” and “jackals”. “Lions” are organisms that live in favorable conditions and are always strong competitors,

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3. Change of ecosystems “Jackals” prefer an abundance of resources, but have weak competitive ability and dominate in the absence of “lions.” “Jackals,” for example, include weeds and field crops. “Camels” are undemanding, adapted to life in extreme conditions; it is the “camel” strategy that helps to survive in harsh conditions.

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Let's summarize: How does self-regulation manifest itself in an ecosystem? The population size of any species in a biogeocenosis remains fairly stable and is controlled “from below” and “from above.” How is population control carried out “from below” and “from above”? “From below” it is controlled by vital resources, “from above” - by organisms of the next trophic level. What does the sustainability of an ecosystem depend on? The more species are included in the biogeocenosis, the more complex the food network, the more stable it is. The loss of one link in such an ecosystem usually does not lead to its death. Why did the appearance of rabbits in Australia lead to an environmental disaster? There was not enough control from above. What are the consequences of lack of control from above? To intensive reproduction and growth in numbers, destruction of the food supply, the spread of infectious diseases and a sharp decline in numbers. What is succession? The natural change of biogeocenoses is called succession. Which community is called a mature community? A mature community is a community of living organisms that is the most stable for given environmental conditions.

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Let's summarize: What succession is called primary? Succession that begins in a place completely devoid of life is called primary. Which succession is called secondary? If a community develops in a place where a well-developed biocenosis existed, then succession will be secondary. How does the number of species change as a result of succession? Successional changes are always accompanied by an increase in species richness, that is, the diversity of organisms. What happens to biomass as a result of succession? There is an increase in the biomass of organic matter. The population of the community seems to become denser as species richness increases. How does the rate of biomass growth change as a result of succession? There is a decrease in the growth rate of community biomass (community production) and an increase in the amount of energy required to maintain its life. This is the most important phenomenon of succession. In the early stages of primary succession, the rate of biomass growth by plants is high, but in subsequent stages it decreases.

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Topic: Agrocenoses Objectives: To characterize ecosystems created as a result of human economic activity.

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Agrocenoses Biocenoses that arise on agricultural lands are called agrocenoses. Gardens, parks, and crops are called agrocenoses. 1. Energy source? Not only sunlight, but the energy of applied organic fertilizers, the energy of human labor activity, the energy of burned fuel.

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Agrocenoses 2. What is characteristic of producers? The biocenosis is characterized by a smaller variety of species; often one crop of plants is cultivated (monoculture) - wheat, rye, corn. 3. What is characteristic of consumers? Fewer species, but larger numbers. The rule of the German ecologist Thienemann is fulfilled: “The poorer the community is in species, the higher the number of each individual species can be.”

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Agrocenoses 4. How does the cycle of substances differ from the cycle of substances in an oak forest? The cycle is incomplete. The harvest is taken by a person. As a result, the soil becomes depleted and in order to restore its fertility, it is necessary to apply fertilizers.

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Agrocenoses 6. In natural biogeocenoses, natural selection plays a leading role, but in agrocenoses? A significant difference is that in agrocenoses the effect of natural selection is weakened; the guiding factor is artificial selection, selection in favor of the most productive plant varieties.

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Increasing the productivity of agrocenoses In 2000, 6 billion people lived on Earth. The annual net increase is 87.6 million people - almost the same number currently living in all of Germany. The number of earthlings increases by almost a quarter of a million people per day, and by 10 thousand per hour. 1. Creation of highly productive plant varieties that are resistant to diseases and adapted to different climatic zones.

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Increasing the productivity of agrocenoses It is more economically profitable to create drought-resistant plants than to organize irrigation of large areas. Irrigation causes secondary soil salinization, so it is more advisable to pay attention to dry farming.

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Increasing the productivity of agrocenoses 2. The main resource of an agrocenosis is soil. Correct and timely tillage of the soil is necessary - spring and autumn plowing, loosening, additional watering. 3. Crop rotation - alternating different crops on one field makes it easier to control agricultural pests and weeds.

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1) An agrocenosis is: A) field B) forest C) lake D) swamp 2) In an agroecosystem, unlike a natural ecosystem: A) species are interconnected by food chains B) branched food chains are formed B) in addition to solar energy, additional energy is used D ) mainly solar energy is used 3) Agrocenoses, unlike biogeocenosis: A) do not participate in the cycle of substances B) exist due to microorganisms C) consist of a large number of species D) cannot exist without human participation. 4) The agrocenosis of a wheat field is characterized by short food chains, since: A) one type of producer predominates B) a high number of decomposers C) there are no consumers D) a wide variety of producers 5) The introduction of legumes into the crop rotation of agrocenoses contributes to: A) reduction of sown areas B) reduction of soil erosion C) accumulation of nitrogen in the soil D) enrichment of the soil with phosphorus compounds. TEST. PART A

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TEST. PART C 1) The amount of energy transferred from one trophic level to another is from the amount of energy of the previous level: a) 1%; b) 5%; c) 10%; d) 15%. 2) According to the rule of the pyramid of numbers, the total number of individuals participating in food chains, with each link: a) decreases; b) increases; c) remains unchanged; d) changes according to a sinusoidal curve (cyclically). 3) The reasons for the change from one biogeocenosis to another are: a) seasonal changes in nature; b) changes in weather conditions; c) fluctuations in the number of populations of one species; d) changes in the habitat as a result of the vital activity of organisms. 4) During the process of succession, the following main changes occur in the community: a) a change in the species composition of plants and animals; b) reduction in species diversity of organisms; c) reduction in biomass of organic matter; D) an increase in the net output of the community. 5) Choose the wrong answer. Trampling in a forest park leads to: a) damage to the undergrowth of trees; b) soil compaction; c) the disappearance of meadow grasses; d) the disappearance of forest grasses.

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“Preservation of the diversity of biogeocenoses” - Feeling of anger. Preservation of the diversity of biogeocenoses. These species have disappeared from the face of the Earth forever. Transformation of landscapes. The importance of biogeocenoses for humans. Human activity in agrocenoses. Forms of protection of BGC. Man is the king of nature. Human impact on nature. A. Fet. Tasmanian wolf.

“The structure of biogeocenosis” - Vernadsky. Producers. The concept of ecosystem and biogeocenosis. Consumers of the first order. Consumers of II and more orders. Decomposers. Homogeneous area. Structure of biogeocenosis. Trophic structure of biocenosis. Matryoshka ecosystems. Biocenosis. Organic destroyers. Biogeocenotic level. Community. Project assignment. Knowledge about natural communities. Biocenosis and biogeocenosis.

“Components of biogeocenosis” - Ecological task. Groups of organisms. Power network. Chain of eating. Characteristic features. Pond biocenosis. Terms. Power circuit. Biocenosis of oak forest. Compare the network and the power circuit. Product pyramid. Additional information. Biogeocenoses. Necessary components of the ecosystem.

“Characteristics of ecosystems” - Ranks of ecosystems. Climatope. Succession. “Climatope” was defined by V.N. Sukachev. The biosphere covers the entire surface of the Earth. The structure of an ecosystem (biogeocenosis) according to Reimers N. F. Biogeocenosis. Ecotop. Ecosystem concept. Functional blocks of organisms. Biodiversity and sustainability in ecosystems. Coral reefs. Ecosystem concept. Plan. Temporal boundaries of the ecosystem. Yu. Odum. Definitions. An example of the stage of autotrophic succession - a forest grows in place of a fallow land.

“Biocenosis and its stability” - Morbidity. Iron indicator. Centers of biotic stabilization. Choosing the optimal location for a waste disposal site. Biosphere stability. Nitrogen indicators. Poor quality water. Properties of biogeocenosis. Carrying out certification. Indicators of water oxidation. Consequences of anthropogenic intervention. Biocenosis and its stability. Local biogeocenoses.

“Connections in biogeocenosis” - Symbiosis. Method of nutrition. Consider types of relationships. Mutualism. Involving students in collective, student-oriented activities. Types of connections and dependencies in biogeocenosis. Competition. Trophic connections. Biotic connections. Predation. Tenancy. Linden. Beneficial neutral relationships. Eagle. Mutually harmful relationships. Beneficial relationships. Mutually beneficial relationships. Organisms. Methods of obtaining food.

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Concept The concept of biogeocenosis was introduced by V.N. Sukachev (1940), which was a logical development of the ideas of Russian scientists V.V. Dokuchaeva, G.F. Morozova, G.N. Vysotsky and others about the connections between living and inert bodies of nature and the ideas of V.I. Vernadsky about the planetary role of living organisms. Biogeocenosis in the understanding of V.N. Sukacheva is close to the ecosystem. In the interpretation of the English phytocenologist A. Tansley, biogeocenosis is an elementary cell of the biogeosphere, understood within the boundaries of specific plant communities, while the ecosystem concept is dimensionless and can cover a space of any extent - from a drop of pond water to the biosphere as a whole.

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Definition Biogeocenosis is an interdependent complex of living and inert components interconnected by metabolism and energy; one of the most complex natural systems.

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Properties of biogeocenosis Natural, historically developed system; A system capable of self-regulation and maintaining its composition at a certain constant level; The circulation of substances is characteristic; An open system for the entry and exit of energy, the main source of which is the Sun.

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Basic indicators of biogeocenosis Species composition - the number of species living in the biogeocenosis. Species diversity is the number of species living in a biogeocenosis per unit area or volume. Biomass is the number of organisms of a biogeocenosis, expressed in units of mass. biomass of producers biomass of consumers biomass of decomposers

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Mechanisms of stability of biogeocenoses One of the properties of biogeocenoses is the ability to self-regulate, that is, to maintain its composition at a certain stable level. This is achieved thanks to the stable circulation of energy substances. The stability of the cycle itself is ensured by several mechanisms: Sufficiency of living space, that is, such a volume or area that provides one organism with all the resources it needs.

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Mechanisms of stability of biogeocenoses Richness of species composition. The richer it is, the more stable the food chain and, consequently, the circulation of substances. A variety of species interactions that also maintain the strength of trophic relationships. Environment-forming properties of species, that is, the participation of species in the synthesis or oxidation of substances. Direction of anthropogenic impact.

Class: 11

Target:

• To create conditions for students to deepen and assimilate knowledge about biogeocenoses as integral systems, the factors that determine their natural change, the reasons and types of change in biogeocenosis, and the need for their protection.
• Improve the skills of independent work with sources of information and analysis of cause-and-effect relationships occurring in nature as a result of changes in biogeocenosis.
• Through modeling the processes of change of biogeocenoses, using a computer, to recreate a holistic picture of the stages of change of biogeocenoses.

Learning Tools:

• Electronic textbook CD-ROM “Biology Lessons from Cyril and Methodius,” General Biology, 11th grade. 2007
• Tables illustrating the change in biogeocenosis “Overgrowing of a reservoir.”
• Textbooks: “General biology. 11th grade”, D.K. Belyaev;
• "Biology. General patterns. 11th grade", S.G. Mamontov, V.V. Zakharov, N.I. Sonin.
• Slide presentation of the lesson (application).

Lesson progress

Updating of ZUN.

1. Completing level test tasks"A" and "B". Slide No. 1,2

2. Solving biological problems.

Task No. 1. When they talk about producers, they mean green plants. Can representatives of other kingdoms play the role of producers? If so, what organisms are they and why?

Task No. 2. In any biogeocenosis you can find a variety of insects. Which unit includes insects? Create a food chain that includes insects. What role do insects play in BGC?

3. Performing training tasks using an electronic textbook.

4. Comparative characteristics of biogeocenosis and agrocenosis and identification of similarities and differences based on the table. Slide No. 3,4,5 .

Raising the problem and discussing it. Slide number 6

The stability of biogeocenosis is expressed in the diversity of food chains, a wide species composition, the presence of symbiotic relationships, and long food chains.

What happens when food chains are disrupted?

What is happening to the lake’s biogeocenosis? Explain from the perspective of the properties of natural biogeocenosis. Slide number 7.

Do we observe this process in nature?

Give examples.

Goal setting: Determining the topic of the lesson, setting goals and putting forward the main supporting points of the lesson. Slide number 7, 8.

Studying new educational material.

Despite the fact that biogeocenosis has the properties of stability, self-reproduction and self-development, under the influence of various factors and a number of reasons, their destruction or change occurs.

1. Scheme analysis. Slide number 9 .
2. Conversation to clarify the characteristic features of succession types. Give examples of gradual and abrupt changes in biogeocenosis. What are their similarities and differences? Define the concept of succession?
3. Preparation of a supporting summary. Slide number 10.
4. Analysis of animation of the electronic textbook “Self-development of biogeocenosis.”

Conclusion . Primary succession starts on substrates. Not affected by soil formation (rocky rocks, reservoirs), during which not only phytocenoses, but also soil are formed.

Secondary succession occurs on the site of formed biocenoses after their disturbance (as a result of erosion, volcanic eruptions, drought, fire, deforestation, etc.) A classic example is the transformation of abandoned fields into broad-leaved forests in the eastern United States.

Both primary and secondary succession require a source of seeds and spores of plants, as well as animals capable of inhabiting the habitat at a stage suitable for it. If not, then succession will stop or take an atypical path. Secondary succession is characterized by the presence of a fertile soil layer. If it is destroyed, it will go like the primary one.

5. Preparation of a summary and logical chain of development of a sustainable ecological system based on independent work with a textbook and a slide presentation.

Task No. 1. Highlight the main stages of primary succession and write it down in a notebook based on the main components of the proposed biogeocenosis. Slide number 11, 12.

6. Secondary succession occurs at the site of an already formed biogeocenosis.

Often the reason for a change in biogeocenosis is an anthropogenic factor: construction, fire, trampling, acclimatization and resettlement of animals, etc. Slide No. 13

Conclusion. A sudden or catastrophic change leads to the destruction of all BGC connections, soil destruction, degradation or death of the biogeocenosis. This change is caused by a factor foreign to the BGC. But after the factor ceases to act. Ultimately, a new indigenous community appears, similar to the one destroyed.

6. Demonstration of the animation “Fire in the Forest”.

Task No. 2. Analyze and make assumptions about the disruption of the ecological balance after fire and trampling.

Discussion of the problem of changing biogeocenosis in our area under human influence. As a result of economic activity, people cut down forests, drain swamps, etc. Is self-healing of a destroyed community possible? If so, what processes will lead to self-healing? Slide number 14.

Reflection:

What is the importance of this topic?

Problems of environmental protection, flora and fauna of our area. Deforestation .

“What is a biocenosis in biology” - Biocenosis of G.A. Fominykh. biology teacher. Characteristic features of the biocenosis. Pond biocenosis. Biocenosis is a collection of populations of different species living in a certain territory. Biocenosis of oak forest. The term was introduced by Karl Möbius in 1877. Biocenoses are not random collections of various organisms. In nature, biocenoses come in different sizes.

“Change of ecosystems” - Such a natural change of biogeocenoses is called succession. Gardens, parks, and crops are called agrocenoses. 1. Energy source? 4. How does the cycle of substances differ from the cycle of substances in an oak forest? 1. Self-regulation. Therefore, a person himself has to regulate the number of many consumers in an agrocenosis.

“Fundamentals of environmental management” - B.V. Shchurov, L.N. Gubanov, V.I. Zvereva. Section 5. Economic mechanism of environmental management as a function of public administration. Nizhny Novgorod, 2003. Section 3. Legal methods of environmental management. Environmental management. Section 4. State environmental management bodies.

“Biogeocenosis” - Self-development Self-reproduction Sustainability. Succession – “continuity” “heritage”. Part a. Lesson topic. primary Self-development. Climate change In the process of evolution. Agrocenosis, in contrast to biogeocenosis, is characterized by. Change of biogecenosis. Properties of biogeocenosis. Gradual (Succession) Changes in the environment by the organisms themselves.

“Biological Resources of Russia” - 3- streamlining hunting and economic activities in relation to existing conditions; 4 - fulfillment of the obligations of the Russian Federation under the Convention on Biological Diversity and a number of other international agreements; 5 - carrying out activities to test and organize the gradual introduction of payments for biological resources in accordance with the current legislation of the Russian Federation.

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