Connections in the biocenosis. Community (biocenosis) - a living component of the system Independent work of students on assignments

BASES OF GENERAL ECOLOGY

1.1. STRUCTURE OF MODERN ECOLOGY

All environmental sciences can be systematized either according to the objects of study, or according to the methods they use.

1. In accordance with the size of the objects of study, the following areas are distinguished:

Autoecology (Greek autos - itself) - a section of ecology that studies the relationship of an individual organism (artificially isolated organism) with the environment;

Demecology (Greek demos - people) - studies the population and its environment;

Eidecology (Greek eidos - image) - ecology of species;

Synecology (Greek syn - together) - considers communities as complete systems;

Landscape ecology - studies the ability of organisms to exist in different geographic environments;

Megaecology or global ecology is the science of the Earth's biosphere and the position of man in it.

2. In accordance with the attitude to the object of study, the following sections of ecology will be distinguished:

Ecology of microorganisms;

Ecology of mushrooms;

plant ecology;

Animal ecologists;

Social ecology - considers the interaction of man and human society with the environment;

Human ecology - includes the study of the interaction of human society with nature, the ecology of the human personality and the ecology of human populations, including the doctrine of ethnic groups;

Ecology industrial or engineering - considers the mutual influence of industry and transport on nature;

Agricultural ecology - studies ways to obtain agricultural products without depletion natural resources;

Medical ecology - studies human diseases associated with environmental pollution and ways to prevent and treat them.

3. In accordance with the environments and components, the following disciplines are distinguished:

Land Ecology;

Ecology of the seas;

Ecology of rivers;

Desert ecology;

Forest ecology - studies ways to use forest resources with their constant restoration;

Highlands ecology;

Urban ecology (lat. urbanus - urban) - the ecology of urban planning;

4. In accordance with the methods used, the following applied environmental sciences are distinguished:

Mathematical ecology - creates mathematical models to predict the state and behavior of populations and communities when environmental conditions change;

Chemical ecology - develops methods for analyzing pollutants and ways to reduce harm from chemical pollution;

Economic ecology - creates economic mechanisms for rational use of natural resources;

Legal ecology - aims to develop a system of environmental laws.

1.2.LEVEL OF ORGANIZATION OF LIVING MATTER

In order to get a holistic view of ecology, to understand the role that it plays among the sciences that study living organisms, it is necessary to familiarize yourself with the concept of the levels of organization of living matter and the hierarchy of biological systems (Fig. 1).

Biosystems are systems in which biotic components (all living organisms) of different levels of organization interact in an orderly manner with the surrounding biotic environment, i.e. abiotic components (energy and matter).

Fig.1. Hierarchy of levels of organization of living matter:

Molecular - it manifests such processes as metabolism and energy conversion, transfer hereditary information;

Cellular - a cell is the main structural and functional unit of all life on planet Earth;

Organismic - an organism (Latin organizo - I arrange, I give a slender appearance) is used both in the narrow sense - an individual, an individual, a “living being”, and in a broad, most general sense - a complexly organized whole. This is the real carrier of life, characterized by all its signs;

Population-species - a population (lat. populus - people), according to the definition of Academician S.S. Schwartz, is an elementary grouping of organisms of a certain species, which has all the necessary conditions to maintain its numbers indefinitely long time in constantly changing conditions. The term "population" was introduced by V. Iogazen in 1903. A population is a specific form of existence of a species in nature. A biological species is a collection of individuals that have common characteristics, are able to freely interbreed with each other and produce fertile offspring, occupying a certain area (Latin area - area, space) and delimited from other species by non-crossing in natural conditions. The concept of species as the main structural and classification unit in the system of living organisms was introduced by K. Linnaeus, who published his work "Systems of Nature" in 1735;

Biocenotic - biocenosis (Greek bios - life, koinos - general) - a set of organisms different types and varying complexity of the organization with all the factors of a particular habitat. The term "biocenosis" was proposed by K. Möbius in 1877. The habitat of a biocenosis is called a biotope. A biotope (Greek: bios - life, topos - place) is a space with homogeneous conditions (relief, climate), inhabited by a certain biocenosis. Any biocenosis is inextricably linked with the biotope, forming with it a stable biological macrosystem of an even higher rank - biogeocenosis. The term "biogeocenosis" was proposed in 1940 by Vladimir Nikolaevich Sukachev. According to V.N. Sukachev, biogeocenosis is a set over a known extent earth's surface homogeneous natural phenomena: atmosphere, rocks, hydrological conditions, vegetation, wildlife, microorganisms and soil. Thus, the concept of biocenosis is used to refer only to terrestrial ecosystems, the boundaries of which are determined by the boundaries of phytocenosis (vegetation). Biogeocenosis is a special case of a large ecosystem;

Biosphere (Greek bios - life, spharia - ball) - the global ecosystem of everything the globe, the shell of the Earth, consisting of the totality of all living organisms (biota), substances, their components and their habitat. The biosphere is the area of ​​distribution of life on Earth, which includes the lower part of the atmosphere, the entire hydrosphere and the upper part of the lithosphere. The term “biosphere” was introduced by the Austrian geologist E. Suess and in 1873. The main provisions of the doctrine of the biosphere were published by V. I. Vernadsky in 1926. In his work, which is called “Biosphere”, V. I. Vernadsky develops the idea of ​​surface evolution of the globe as an integral process of interaction between inanimate or "inert" matter with living matter.

1.4. MAIN CRITERIA OF THE VIEW

According to various estimates, the total number of biological species on Earth ranges from 1.5 to 3 million. To date, about 0.5 million plant species and approximately 1.5 million animal species have been described. Man is one of the biological species known today on Earth.

The evolutionary stability of a species is ensured by the existence within a species of genetically diverse populations. Species differ from each other in many ways.

Species criteria are features and properties characteristic of a species. There are morphological, genetic, physiological, geographical and ecological criteria of the species. To establish the belonging of individuals to one species, it is not enough to use any one criterion. Only the application of a set of criteria with mutual confirmation of various features and properties of individuals in their totality characterizes a species.

The morphological criterion is based on the similarity of the external and internal structure individuals of the same species. But individuals within a species are sometimes so variable that only morphological criterion it is not always possible to determine the species. In addition, there are species that are morphologically similar, but individuals of such species do not interbreed - these are twin species.

A genetic criterion is a set of chromosomes characteristic of each species, a strictly defined number, size and shape. It is the main feature of the species. Individuals of different species with different sets of chromosomes cannot interbreed. However, in nature there are cases when individuals of different species interbreed and give fertile offspring.

The physiological criterion is the similarity of all vital processes in individuals of the same species, first of all, the similarity of reproductive processes.

A geographical criterion is a certain area (territory, water area) occupied by a species in nature.

An environmental criterion is a combination of factors external environment, in which the view exists.

1.5. POPULATION AND TYPES OF INTERACTIONS CHARACTERISTIC FOR IT

In the life of any living being, relationships with representatives of their own species play an important role. These relationships are realized in populations.

There are the following types of populations:

An elementary (local) population is a group of individuals of the same species occupying some small area of ​​​​a square that is homogeneous in terms of habitat conditions.

Ecological population - a set of elementary populations. Basically, these are intraspecific groups confined to specific ecosystems.

Geographical populations - a set of ecological populations inhabiting a territory with geographically homogeneous conditions of existence.

Relationships in populations are intraspecific interactions. By the nature of these interactions, populations of different species are extremely diverse. In populations, there are all types of relationships inherent in living organisms, but the most common are mutually beneficial and competitive relationships. In some species, individuals live alone, meeting only for reproduction. Others create temporary or permanent families. Some, within populations, unite in large groups: flocks, herds, colonies. Others form clusters during unfavorable periods, surviving winter or drought together. A population has features that characterize the group as a whole, and not individual individuals in the group. Such characteristics are the structure, number and density of the population. The structure of a population is the quantitative ratio of individuals of different sexes, ages, sizes, genotypes, etc. Accordingly, sex, age, size, genetic and other population structures are distinguished.

The population structure depends on various reasons. For example, the age structure of a population depends on two factors:

From the features of the life cycle of the species;

from external conditions.

There are species with a very simple age structure of the population, which consist of representatives of almost the same age (annual plants, locusts). Complex age structures populations arise when all age groups are represented in them (a flock of monkeys, a herd of elephants).

Unfavorable external conditions can change the age composition of the population due to the death of the weakest individuals, but the most stable age groups survive and then restore the structure of the population. The spatial structure of the population is determined by the nature of the distribution of individuals in space and depends both on the features environment, and on the characteristics of the behavior of the species itself. Any population tends to disperse. Settlement continues until the population encounters any barrier. The main parameters of a population are its abundance and density.

The population size is the total number of individuals in a given area or in a given volume. The population level that guarantees its conservation depends on the specific species.

Population density is the number of individuals per unit area or volume. The higher the number, the higher the adaptability of the organisms of this population. The population size is never constant and depends on the ratio of the intensity of reproduction (fertility) and mortality, i.e. the number of individuals that died in a given period. Population density is also variable, depending on the abundance. With an increase in the number, the density does not increase only if the expansion of the population range is possible. In nature, the size of any population is extremely dynamic.

The population regulates its numbers and adapts to changing environmental conditions by updating and replacing individuals. Individuals appear in the population through birth and immigration, and disappear as a result of death and emigration.

The population size is also affected by the age composition, the total life span of individuals, the period of reaching puberty, and the duration of the breeding season.

For a population of each species there are upper and lower limits of density, beyond which it cannot go. These resource limits are called the environmental capacity for specific populations. Under natural conditions, due to the ability to self-regulate, the number of populations usually fluctuates around a certain level corresponding to the capacity of the environment.

BIOCENOSIS AND RELATIONSHIPS CHARACTERISTIC FOR IT

Biocenoses are not random collections of different organisms. In similar natural conditions and with a similar composition of fauna and flora, similar, regularly repeating biocenoses arise. Biocenoses have a specific and spatial structure.

species structure biocenosis means the number of species in a given biocenosis. The diversity of species reflects the diversity of habitat conditions. Species that dominate the community in terms of numbers are called dominants. Dominant species determine the main connections in the biocenosis, create its basic structure and appearance. Usually, terrestrial biocenoses are named according to the dominant species (birch grove, spruce forest, feather grass steppe). Part mass species are species without which other species cannot exist. They are called edificators (environment-formers), their removal will lead to the complete destruction of the community. Usually the dominant species is also an edificator. The most diverse in biocenoses are rare and few species. Few species constitute the reserve of the biocenosis. Their predominance is a guarantee of sustainable development. In the richest biocenoses, basically, all species are few in number, but the lower the diversity, the more dominants.

The spatial structure of the biocenosis is determined by the characteristics of the atmosphere, the rock of the soil and its waters. In the course of a long evolutionary transformation, adapting to certain conditions, living organisms are placed in biocenoses in such a way that they practically do not interfere with each other. Vegetation forms the basis of this distribution. Plants create layering in biocenoses, placing foliage under each other in accordance with their form of growth and light-loving.

Each tier has its own system of relationships, so the tier can be considered as structural unit biocenosis.

In addition to layering, in the spatial structure of the biocenosis, mosaicism is observed - a change in the vegetation of the animal world horizontally.

Neighboring biocenoses usually gradually pass one into another; it is impossible to draw a clear boundary between them. In the border zone, typical conditions of neighboring biocenoses are intertwined, some plant and animal species disappear and others appear. Species that have adapted in the border zone are called ecotones. The abundance of plants attracts a variety of animals here, so that the border zone is more diverse and rich in species than each of the adjacent biocenoses. This phenomenon is called the edge effect and is often used to create parks where they want to restore species diversity.

The species structure of the biocenosis, the spatial distribution of species within the biotope, is mainly determined by the relationship between species and the functional role of the species in the community.

ECOLOGICAL NICHE

To determine the role that a particular species plays in the ecosystem, J. Grinnell introduced the concept of "ecological niche". An ecological niche is a set of all environmental parameters within which a species can exist in nature, its position in space and its functional role in the ecosystem. Y. Odum figuratively presented an ecological niche as an occupation, a “profession” of an organism in a biocenosis, and its habitat is the “address” of the species where it lives. In order to study the organism, it is necessary to know not only its address, but also its profession. G. E. Hutchinson quantified the ecological niche. In his opinion, the niche must be determined taking into account all the physical, chemical and biotic environmental factors to which the species must be adapted. G. E. Hutchinson distinguishes two types of ecological niche: fundamental and realized. The ecological niche, determined only by the physiological characteristics of organisms, is called fundamental (potential), and the one within which the species actually occurs in nature is called realized. The latter is that part of the potential niche that this species is able to defend in competition. Species coexist in the same ecosystem as part of a biocenosis in cases where they differ in ecological requirements and thereby weaken competition with each other. Two species in one biocenosis cannot occupy the same ecological niche. Often, even closely related species, living side by side in the same biocenosis, occupy different ecological niches. This leads to a decrease in the competitive tension between them. In addition, the same species may occupy different ecological niches in different periods of its development.

Intraspecific and interspecific relationships of organisms in biocenosis

Select the symptoms that are most characteristic of the indicated diseases

lesson type - combined

Methods: partially exploratory, problem presentation, reproductive, explanatory-illustrative.

Target: mastering the ability to apply biological knowledge in practical activities, use information about modern achievements in the field of biology; work with biological devices, tools, reference books; conduct observations of biological objects;

Tasks:

Educational: the formation of a cognitive culture, mastered in the process of educational activities, and aesthetic culture as an ability to have an emotional and valuable attitude towards objects of wildlife.

Developing: development of cognitive motives aimed at obtaining new knowledge about wildlife; cognitive qualities of a person associated with the assimilation of the basics of scientific knowledge, mastering the methods of studying nature, the formation of intellectual skills;

Educational: orientation in the system of moral norms and values: recognition of the high value of life in all its manifestations, the health of one's own and other people; ecological consciousness; education of love for nature;

Personal: understanding of responsibility for the quality of acquired knowledge; understanding the value of an adequate assessment of one's own achievements and capabilities;

cognitive: the ability to analyze and evaluate the impact of environmental factors, risk factors on health, the consequences of human activities in ecosystems, the impact of one's own actions on living organisms and ecosystems; focus on continuous development and self-development; the ability to work with various sources of information, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.

Regulatory: the ability to organize independently the execution of tasks, evaluate the correctness of the work, reflection of their activities.

Communicative: the formation of communicative competence in communication and cooperation with peers, understanding the characteristics of gender socialization in adolescence, socially useful, educational and research, creative and other types of activities.

Technologies : Health saving, problematic, developmental education, group activities

Activities (elements of content, control)

Formation of students' activity abilities and abilities to structure and systematize the studied subject content: collective work - study of the text and illustrative material, compilation of the table "Systematic groups of multicellular organisms" with the advisory assistance of expert students, followed by self-examination; pair or group performance of laboratory work with the advisory assistance of a teacher, followed by mutual verification; independent work on the studied material.

Planned results

subject

understand the meaning of biological terms;

describe the features of the structure and the main processes of life of animals of different systematic groups; compare the structural features of protozoa and multicellular animals;

recognize organs and systems of organs of animals of different systematic groups; compare and explain the reasons for similarities and differences;

to establish the relationship between the features of the structure of organs and the functions that they perform;

give examples of animals of different systematic groups;

to distinguish in drawings, tables and natural objects the main systematic groups of protozoa and multicellular animals;

characterize the direction of evolution of the animal world; give evidence of the evolution of the animal world;

Metasubject UUD

Cognitive:

work with different sources of information, analyze and evaluate information, convert it from one form to another;

draw up abstracts, various types of plans (simple, complex, etc.), structure educational material, give definitions of concepts;

make observations, set up elementary experiments and explain the results obtained;

compare and classify, independently choosing criteria for the specified logical operations;

build logical reasoning, including the establishment of cause-and-effect relationships;

create schematic models highlighting the essential characteristics of objects;

identify possible sources of necessary information, search for information, analyze and evaluate its reliability;

Regulatory:

organize and plan your learning activities- determine the purpose of the work, the sequence of actions, set tasks, predict the results of the work;

independently put forward options for solving the tasks set, foresee the final results of the work, choose the means to achieve the goal;

work according to a plan, compare your actions with the goal and, if necessary, correct mistakes yourself;

own the basics of self-control and self-assessment for making decisions and making a conscious choice in educational and cognitive and educational and practical activities;

Communicative:

listen and engage in dialogue, participate in a collective discussion of problems;

integrate and build productive interaction with peers and adults;

adequately use speech means for discussion and argumentation of one's position, compare different points of view, argue one's point of view, defend one's position.

Personal UUD

Formation and development of cognitive interest in the study of biology and the history of the development of knowledge about nature

Receptions: analysis, synthesis, conclusion, transfer of information from one type to another, generalization.

Basic concepts

The concept of "food chain", the direction of the flow of energy in food chains; concepts: biomass pyramid, energy pyramid

During the classes

Learning new material(teacher's story with elements of conversation)

The relationship of the components of the biocenosis and their adaptability to each other

Each biocenosis is characterized by a certain composition of components - various species of animals, plants, fungi, bacteria. There are close relationships between these living organisms in the biocenosis. They are extremely diverse and boil down mainly to obtaining food, preserving life, the ability to produce offspring, to conquer a new living space.

Organisms various kinds in the biocenosis, food, or trophic, connections are characteristic: according to the habitat, the characteristics of the material used, the method of settlement.

The food connections of animals are manifested directly and indirectly.

Direct connections are traced while the animals are eating their food.

Hare eating spring grass; a bee collecting nectar from plant flowers; dung beetle, processing droppings of domestic and wild ungulates; the fish leech adhering to the mucous surface of the fish cover are examples of the existence of direct trophic relationships.

Diverse and indirect trophic relationships arising on the basis of the activity of one species, which contributes to the emergence of access to food to another species. Caterpillars of nun butterflies and silkworms eat pine needles, weaken their protective properties and provide bark beetles with tree colonization.

Numerous in biocenoses are animal connections to find various building materials for building dwellings - nests by birds, anthills by ants, termite mounds, trapping nets by predatory larvae of caddisflies and spiders, trapping funnels by antlions, the formation of oothec capsules designed to protect and develop offspring by female cockroaches , honeycomb bees. During its life, as it grows, the hermit crab repeatedly changes small shells of mollusks for larger ones, which serve it to protect the soft abdomen. To build their structures, animals use various materials - fluff and feathers of birds, mammalian hair, dried blades of grass, twigs, grains of sand, fragments of mollusk shells, secretion products of various glands, wax and pebbles.

Relationships that promote the dispersal or spread of one species by another are also widely represented in nature and human life. Many types of ticks move from one place to another, attaching themselves to the body of bumblebees, rhinoceros beetles. Human transportation of fruits and vegetables contributes to the resettlement of their pests. Traveling on ships and trains helps rodents, dipterans and other animals settle. Interest in keeping exotic animals has led to the fact that they live on almost all continents, however, in artificial conditions. Many of them have adapted to breed in captivity.

The long-term coexistence of different species in the biocenosis leads to the division of food resources between them. This reduces competition for food and leads to food specialization. For example, the inhabitants of the biocenosis can be divided into environmental groups according to the predominant food items.

Relationships of organisms in biocenoses

Individuals of different species do not exist in isolation in biocenoses, they enter into a variety of direct and indirect relationships. They are usually divided into four types: trophic, tonic, phoric, factory.

Trophic relationships arise when one species in the biocenosis feeds on another (either its dead remains or its metabolic products). Ladybug, eating aphids, a cow in a meadow eating grass, a wolf hunting a hare are all examples of direct trophic relationships between species.

When two species compete for a food resource, an indirect trophic relationship arises between them. Thus, a wolf and a fox enter into indirect trophic relationships when using such a common food resource as a hare.

The transfer of plant seeds is usually carried out with the help of special devices. Animals can seize them passively. So, burdock seeds or a string can cling to the hair of large mammals with their spikes and be transported over long distances.

Undigested seeds that have passed through the digestive tract of animals, most often birds, are actively transferred. For example, in rooks, about a third of the seeds are hatched suitable for germination. In a number of cases, the adaptation of plants to zoochory has gone so far that the germinating capacity of seeds that have passed through the intestines of birds and exposed to the action of digestive juices increases. Insects play an important role in the transfer of fungal spores.

Animal phoresia- this is a passive way of settling, characteristic of species that need to be transferred from one biotope to another for normal life. The larvae of a number of ticks, being on other animals, such as insects, settle with the help of other people's wings. Dung beetles are sometimes unable to lower their elytra because of the densely accumulated mites on their bodies. Birds often carry on feathers and paws small animals or their eggs, as well as protozoan cysts. The caviar of some fish, for example, can withstand two weeks of drying. Quite fresh mollusk caviar was found on the legs of a duck shot in the Sahara, 160 km from the nearest reservoir. For short distances, waterfowl can carry even fish fry that accidentally fall into their plumage.

factory connections- a type of biopenotic relationship in which individuals of one species use excretory products, dead remains, or even living individuals of another species for their structures. For example, birds build nests from dry twigs, grass, mammal hair, etc. Caddisfly larvae use pieces of bark, grains of sand, debris or shells with live mollusks for construction.

Of all types of biotic relationships between species in a biocenosis highest value have topical and trophic links, since they keep organisms of different species near each other, uniting them into fairly stable communities (biocenoses) of different scales.

Independent work

1. The relationship of the components of the biocenosis

Types of relationships between organisms in a biocenosis

Types of Relationships Between Aquarium Organisms

Independent work of students on assignments:

consider and identify the organisms that inhabit the aquarium;

name the types of relationships that exist between the inhabitants of the aquarium;

explain how the inhabitants of the aquarium are adapted to each other.

Answer the questions

Question 1. What biocenoses in your locality can serve as an example of the relationship of components?

Question 2. Give examples of the relationship between the components of the biocenosis in the aquarium. An aquarium can be considered as a model of biocenosis. Of course, without human intervention, the existence of such an artificial biocenosis is practically impossible, however, subject to certain conditions, its maximum stability can be achieved. Producers in the aquarium are all types of plants - from microscopic algae to flowering plants. Plants, in the course of their vital activity, produce primary organic substances under the action of light and release oxygen, which is necessary for the respiration of all inhabitants of the aquarium. The organic production of plants in aquariums is practically not used, since, as a rule, animals that are consumers of the first order are not kept in aquariums. A person takes care of the nutrition of consumers of the second order - fish - with the corresponding dry or live food. Very rarely, predatory fish are kept in aquariums, which could play the role of third-order consumers. As decomposers living in an aquarium, one can consider various representatives of mollusks and some microorganisms that process the waste products of the inhabitants of the aquarium. In addition, the work of cleaning organic waste in the biocenosis of the aquarium is performed by a person.

Question 3. Prove that in an aquarium it is possible to show all kinds of adaptability of its components to each other.. In an aquarium, it is possible to show all kinds of adaptability of its components to each other only under conditions of very large volumes and with minimal human intervention. To do this, you must first take care of all the main components of the biocenosis. Provide mineral plant nutrition; organize water aeration, populate the aquarium with herbivorous animals, the number of which could provide food for those consumers of the first order that will feed on them; pick up predators and, finally, animals that act as decomposers.

Relationshipsorganisms.

PresentationRelationshipsbetweenorganisms

Presentation Types of relationships between organisms

Presentation Relationships between organisms and research

Resources

Biology. Animals. Grade 7 textbook for general education. institutions / V. V. Latyushin, V. A. Shapkin.

Active FormsAndbiology teaching methods: Animals. Kp. for the teacher: From work experience, —M.:, Enlightenment. Molis S. S. Molis S. A

Working programm in biology, grade 7 to the Teaching Methods of V.V. Latyushina, V.A. Shapkina (M.: Bustard).

V.V. Latyushin, E. A. Lamekhova. Biology. 7th grade. Workbook for the textbook by V.V. Latyushina, V.A. Shapkin "Biology. Animals. 7th grade". - M.: Bustard.

Zakharova N. Yu. Control and verification work in biology: to the textbook by V. V. Latyushin and V. A. Shapkin “Biology. Animals. Grade 7 "/ N. Yu. Zakharova. 2nd ed. - M.: Publishing house "Exam"

Presentation Hosting

Individuals of different species do not exist in isolation in biocenoses, they enter into a variety of direct and indirect relationships. They are usually divided into four types: trophic, tonic, phoric, factory.

Trophic relationships arise when one species in the biocenosis feeds on another (either its dead remains or its metabolic products). A ladybug eating aphids, a cow eating grass in a meadow, a wolf hunting a hare are all examples of direct trophic relationships between species.

When two species compete for a food resource, an indirect trophic relationship arises between them. Thus, a wolf and a fox enter into indirect trophic relationships when using such a common food resource as a hare.

The transfer of plant seeds is usually carried out with the help of special devices. Animals can seize them passively. So, burdock seeds or a string can cling to the hair of large mammals with their spikes and be transported over long distances.

Undigested seeds that have passed through the digestive tract of animals, most often birds, are actively transferred. For example, in rooks, about a third of the seeds are hatched suitable for germination. In a number of cases, the adaptation of plants to zoochory has gone so far that the germinating capacity of seeds that have passed through the intestines of birds and exposed to the action of digestive juices increases. Insects play an important role in the transfer of fungal spores.

Animal phoresia is a passive way of settling, characteristic of species that need to be transferred from one biotope to another for normal life. The larvae of a number of ticks, being on other animals, such as insects, settle with the help of other people's wings. Dung beetles are sometimes unable to lower their elytra because of the densely accumulated mites on their bodies. Birds often carry on feathers and paws small animals or their eggs, as well as protozoan cysts. The caviar of some fish, for example, can withstand two weeks of drying. Quite fresh mollusk caviar was found on the legs of a duck shot in the Sahara, 160 km from the nearest reservoir. For short distances, waterfowl can carry even fish fry that accidentally fall into their plumage.

factory connections- a type of biopenotic relationship in which individuals of one species use excretory products, dead remains, or even living individuals of another species for their structures. For example, birds build nests from dry twigs, grass, mammal hair, etc. Caddisfly larvae use pieces of bark, grains of sand, debris or shells with live mollusks for construction.

Of all types of biotic relationships between species in a biocenosis, topical and trophic relationships are of the greatest importance, since they keep organisms of different species near each other, uniting them into fairly stable communities (biocenoses) of different scales.

Interaction of populations in biocenoses

The types of population interactions in biocenoses are usually conditionally divided into positive (useful), negative (unfavorable) and neutral. However, in an equilibrium community, the interactions and connections of all populations ensure the maximum stability of the ecosystem, and from this point of view, all interactions are useful.

Positive and negative are only interactions in a non-equilibrium population during its spontaneous movement towards equilibrium.

Ecological connections between predators and prey direct the course of evolution of conjugated populations.

Commensalism- a form of relationship between two populations, when the activity of one of them delivers food or shelter to the other (commensal). In other words, commensalism is the unilateral use of one population by another without harming the first.

Neutralism- such a form of biotic relations in which the cohabitation of two populations in the same territory does not entail either positive or negative consequences for them. Relations such as neutralism are especially developed in communities saturated with populations.

With amensalism for one of the two interacting populations, the consequences of living together are negative, while the other receives neither harm nor benefit from them. This form of interaction is more common in plants.

Competition - the relationship of populations with similar ecological requirements, existing due to common resources available in short supply. Competition is the only form of ecological relationship that has a negative effect on both interacting populations.

If two populations with the same ecological needs find themselves in the same community, sooner or later one competitor displaces the other. This is one of the most common environmental rules, which is called the law of competitive exclusion. Competing populations can coexist in a biocenosis even if a predator does not allow an increase in the number of a stronger competitor.

Consequently, each group of organisms contains a significant number of potential or partial competitors that are in dynamic relationships with each other.

Competition has a dual meaning in biocenoses. It is a factor that largely determines the species composition of communities, since intensely competing populations do not get along together. At the same time, partial or potential competition allows populations to quickly seize additional resources that are released when the activity of neighbors is weakened, and mix them into biocenotic relationships, which preserves and stabilizes the biocenosis as a whole.

Complementarity and cooperation arise when the interaction is useful for both populations, but they are not completely dependent on one another, therefore they can exist separately. This is the most evolutionarily important form of positive interactions between populations in biocenoses. This also includes all the main forms of interactions in communities in the series producers - consumers - decomposers.

Positive interactions have become the basis for biota to remove restrictions on the resource by organizing nutrient cycles.

All of the listed types of biocenotic relationships, distinguished by the criterion of benefit or harm of mutual contacts for individual partners, are characteristic not only for interspecific, but also for intraspecific relationships.

biocenosis ecosystem nature man

BIOCENOSIS (Greek bios - life, coenosis - general) is a historically established stable set of populations of plants, animals, fungi and microorganisms adapted to cohabitation in a homogeneous area of ​​\u200b\u200bthe territory or water area.

The term "Biocenosis" was proposed by the German biologist K. Möbius (1877). Biocenosis is a complex of organisms of biogeocenosis, which is formed as a result of the struggle for existence, natural selection and other factors of evolution.

According to participation in the biogenic cycle of substances in the biocenosis, there are three groups of organisms: producers, consumers and decomposers.

Producers (manufacturers) - autotrophic (self-feeding) organisms capable of producing (synthesizing) complex organic substances from simple ones. organic compounds.

There are two types of such organisms: photosynthetic and chemosynthetic.

Photosynthetic organisms synthesize organic compounds from CO2, H2O and minerals using solar energy. These organisms include green plants, algae, and some bacteria.

Chemosynthetic organisms carry out the synthesis of organic compounds due to the energy obtained from the oxidation of ammonia, hydrogen sulfide, iron, etc. Chemosynthesis takes place underground deep water zones World Ocean. Compared with photosynthesis, it plays an insignificant role in the primary production of organic substances, although the role of this process in the cycle chemical elements large enough in the biosphere.

The total amount of biomass of organic matter synthesized by producers is the gross primary production. Part of the synthesized biomass in the process of plant life is spent on their own needs. The rest is called pure primary production, which serves as a source of nutrition for organisms of the next trophic level (Greek trophe - food, nutrition) - consumers.

Consumers are heterotrophic (Greek heteros-other) organisms, i.e. organisms that use organic substances produced by other organisms (animals, a significant part of microorganisms, insectivorous plants) as a food source.

Consumers form several trophic levels (no more than 3-4):

Consumers of the 1st order - organisms that are direct consumers of primary organic products. In general, these are herbivorous animals (phytophages). Part of the food they use to ensure life processes. The remaining food is transformed into new organic substances, called net secondary production.

Consumers of the second order are animals with a carnivorous type of nutrition (zoophages). As a rule, all predators are included in this group, regardless of whether the prey is a phytophage or zoophagous. Zoophages are characterized by specific adaptations for feeding. In many zoophages, the mouth apparatus is adapted for grasping and holding food, and sometimes for destroying the protective cover. In some cases, the way food is obtained is extremely unusual. For example, predatory mollusks destroy the shells of victims with the help of mineral acids produced by special glands.

Reducers (lat. reducentis - returning, restoring) or destructors - organisms that decompose the dead organic matter and turning it into inorganic substances. Decomposers include bacteria, fungi, protozoa, i.e. soil heterotrophic microorganisms. The mentioned inorganic substances can again be involved by plants in the cycle of substances, thereby closing it.

Biocenosis is a dialectically developing unity that changes as a result of the activity of its constituent components, as a result of which a natural change and change of biocenosis (succession) occur, which can lead to the restoration of sharply disturbed biocenoses (for example, forests after a fire, etc.).

A biocenosis is characterized by a division into smaller subordinate units - merocenoses, that is, naturally formed complexes that depend on the biocenosis as a whole (for example, a complex of inhabitants of rotting oak stumps in an oak forest). If the energy source of the biocenosis is not autotrophs, but animals (for example, the bats in the biocenosis of caves), then such biocenoses depend on the influx of energy from the outside and are inferior, representing in essence merocenoses. In the biocenosis, other subordinate groups of organisms can be distinguished, for example, sinusia. The biocenosis is also characterized by a division into vertical groupings of organisms (tiers of the biocenosis). In the annual cycle in the biocenosis, the number, stages of development and activity change. certain types, regular seasonal aspects of the biocenosis are created.

The components of the biocenosis are phytocenosis (a stable community of plants), zoocenosis (a set of interrelated animal species), mycocenosis (community of fungi) and microbiocenosis (community of microorganisms).

Biocenosis is an open system and does not occupy clearly defined areas. Often, different biocenoses are so intertwined that it is fundamentally impossible to determine their boundaries.

The scales of biocenotic groupings of organisms (biocenoses) are different - from communities on a tree trunk, in a hole or on a swamp tussock (they are called microcommunities) to the population of an oak forest, pine or spruce forest, meadow, lake, swamp or pond. There is no fundamental difference between biocenoses of different scales, since small communities are an integral part of larger ones, which are characterized by an increase in complexity and the proportion of indirect relationships between species.

There are saturated and unsaturated biocenoses.

In a saturated biocenosis, all ecological niches are occupied and the introduction of a new species is impossible without the destruction or subsequent displacement of c.-l. component of the biocenosis.

Unsaturated biocenoses are characterized by the possibility of introducing new species into them without destroying other components.

It is possible to distinguish between primary biocenoses that have developed without human influence (virgin steppe, virgin forest), and secondary ones, changed by human activity (forests that have grown on the site of flattened ones, the population of reservoirs).

A special category is represented by agrobiocenoses, where the complexes of the main components of the biocenosis are consciously regulated by man. There is a whole gamut of transitions between the primary biocenosis and the agrobiocenosis. The study of biocenosis is important for the rational development of lands and water spaces, since only correct understanding regulatory processes in the biocenosis allows a person to withdraw part of the production of the biocenosis without disturbing and destroying it.

A piece of the earth's surface (land or water) with homogeneous living conditions, occupied by one or another biocenosis, is called a biotope (Greek bios - life, topos - place).

Each biocenosis corresponds to a zone with homogeneous abiotic environmental factors, called a biotope (Greek topos - place). A biotope is a natural, fairly homogeneous living space of a biocenosis. The composition of the biotope includes climatotope, edaphotope and hydrotope, which characterize homogeneous climatic, soil and soil conditions, conditions of humidity and pH of the environment (Fig. 1).

The subsystem "biotope - biocenosis" are in dynamic equilibrium, thereby ensuring the stability of the system more high level- biogeocenosis.

The close interaction between the biocenosis and the biotope is based on the constant exchange of energy, matter and information.

In spatial terms, the biotope corresponds to the biocenosis. The boundaries of the biocenosis are established by the phytocenosis, which has easily recognizable features. For example, pine forests are easily distinguished from spruce forests, an upland swamp from a lowland one, etc. In addition, phytocenosis is the main structural component any biocenosis, since it determines the species composition of zoo-, myco- and microbiocenoses.

The adaptability of the members of the biocenosis to living together is expressed in a certain similarity of their requirements for the most important abiotic environmental conditions (illumination, the nature of soil and air moisture, thermal conditions, etc.) and in regular relationships with each other. Communication between organisms is necessary for their nutrition, reproduction, resettlement, protection, etc. However, it also contains a certain threat and even a danger to the existence of one or another individual. Biotic factors of the environment, on the one hand, weaken the organism, on the other hand, they form the basis of natural selection, the most important factor in speciation.

Thus, the transfer of energy and matter, which underlies the circulation of substances in nature, is carried out. There can be a lot of such chains in a biocenosis, they can include up to six links.

An example would be oak, it is a producer. The caterpillars of the oak leafworm butterfly, eating green leaves, receive the energy accumulated in them. The caterpillar is the primary consumer, or consumer of the first order. Part of the energy in the leaves is lost when they are processed by the caterpillar, part of the energy is spent by the caterpillar on vital activity, part of the energy goes to the bird that pecked the caterpillar - this is a secondary consumer, or secondary consumer. If a bird becomes a victim of a predator, then its carcass will become a source of energy for the tertiary consumer. Predatory bird in the future, it may die, and its corpse can be eaten by a wolf, crow, magpie or carrion-eating insects. Their work will be completed by microorganisms - decomposers.

In nature, they are very rare, but there are organisms that eat only one type of plant or animal. They are called monophages, for example, the Apollo caterpillar butterfly feeds only on stonecrop leaves (Fig. 2), and the giant panda only feeds on several species of bamboo leaves (Fig. 2).

Rice. 2. Monophages ()

Oligophages- these are organisms that feed on representatives of a few species, for example, the caterpillar of the wine hawk eats fireweed, bedstraw, impatiens and several other plant species (Fig. 3). Polyphages able to eat various foods, the titmouse is a characteristic polyphage (Fig. 3).

Rice. 3. Representatives of oligophages and polyphages ()

When feeding, each next link in the food chain loses part of the substances obtained from food and loses part of the energy received, about 10% of the total mass of food eaten is spent on increasing its own mass, the same happens with energy, a food pyramid is obtained (Fig. 4) .

Rice. 4. Food pyramid ()

About 10% of the potential energy of the food goes to each tier of the food pyramid, the rest of the energy is lost in the process of digestion of food and dissipated in the form of heat. The food pyramid allows you to evaluate the potential productivity of natural natural biocenoses. IN artificial biocenoses it allows you to evaluate the effectiveness of management or the need for any changes.

Food, or trophic, links of animals can be manifested directly or indirectly, direct connections is the direct consumption of food by animals.

Indirect trophic links- this is either competition for food, or, conversely, the involuntary help of one species to another in capturing food.

Each biocenosis is characterized by its own special set of components, various species of animals, plants, fungi and bacteria. Close ties are established between all these living beings, they are extremely diverse and can be divided into three large groups: symbiosis, predation and amensalism.

Symbiosis- this is a close and prolonged coexistence of representatives of different biological species. With prolonged symbiosis, these species adapt to each other, their mutual adaptation.

Mutually beneficial symbiosis is called mutualism.

Commensalism- this is a relationship that is useful to one, but indifferent to another symbiont.

Amensalism- a type of interspecific relationship in which one species, called amensal, undergoes inhibition of growth and development, and the second, called an inhibitor, is not subject to such tests. Amensalism is fundamentally different from symbiosis in that none of the species benefits; as a rule, such species do not live together.

These are forms of interaction between organisms of different species (Fig. 4).

Rice. 5. Forms of interaction between organisms of different species ()

The long coexistence of animals in the same biocenosis leads to the division of food resources between them, this reduces competition for food. Only those animals survived that found their food and specialized, adapting to eat it. It is possible to distinguish ecological groups based on the prevailing food objects, for example, herbivorous animals are called phytophages(Fig. 6). Among them are philophages(Fig. 6) - animals that eat leaves, carpophages- eating fruits, or xylophages- wood eaters (Fig. 7).

Rice. 6. Phytophages and phyllophages ()

Rice. 7. Carpophages and xylophages ()

Today we discussed the relationship between the components of the biocenosis, got acquainted with the variety of relationships between the components in the biocenosis and their adaptability to life in one community.

Bibliography

1. Latyushin V.V., Shapkin V.A. Biology Animals. Grade 7 - Bustard, 2011
2. Sonin N.I., Zakharov V.B. Biology. variety of living organisms. Animals. Grade 8, - M.: Drofa, 2009
3. Konstantinov V.M., Babenko V.G., Kuchmenko V.S. Biology: Animals: A Textbook for Grade 7 Students of Educational Institutions / Ed. prof. V.M. Konstantinov. - 2nd ed., revised. - M.: Ventana-Count.

Homework

1. What relationships exist between organisms in a biocenosis?
2. How do the relationships between organisms affect the stability of the biocenosis?
3. In connection with what are ecological groups formed in the biocenosis?

1. Internet portal Bono-esse.ru ( ).
2. Internet portal Grandars.ru ().
3. Internet portal Vsesochineniya.ru ().