Definition of biology as a science. Communication of biology with other sciences. The value of biology for medicine. Definition of the concept of "life" at the present stage of science. Fundamental properties of living things.
Biology(Greek bios - “life”; logos - teaching) - the science of life (wildlife), one of the natural sciences, the subject of which is living beings and their interaction with the environment. Biology studies all aspects of life, in particular the structure, function, growth, origin, evolution and distribution of living organisms on Earth. Classifies and describes living beings, the origin of their species, interaction with each other and with the environment.
Relationship of biology with other sciences: Biology is closely related to other sciences and sometimes it is very difficult to draw a line between them. The study of the life of the cell includes the study of the molecular processes occurring inside the cell, this section is called molecular biology and sometimes refers to chemistry and not biology. Chemical reactions occurring in the body are studied by biochemistry, a science that is much closer to chemistry than to biology. Many aspects of the physical functioning of living organisms are studied by biophysics, which is very closely related to physics. The study of a large number of biological objects is inextricably linked with such sciences as mathematical statistics. Sometimes ecology is distinguished as an independent science - the science of the interaction of living organisms with the environment (living and inanimate nature). As a separate field of knowledge, the science that studies the health of living organisms has long stood out. This area includes veterinary medicine and a very important applied science - medicine, which is responsible for human health.
Importance of biology for medicine:
Genetic research has made it possible to develop methods for early diagnosis, treatment and prevention of human hereditary diseases;
The selection of microorganisms makes it possible to obtain enzymes, vitamins, hormones necessary for the treatment of a number of diseases;
Genetic engineering allows the production of biologically active compounds and drugs;
Definition of the concept of "life" at the present stage of science. Fundamental properties of living things: It is quite difficult to give a complete and unambiguous definition of the concept of life, given the huge variety of its manifestations. In most definitions of the concept of life, which were given by many scientists and thinkers over the centuries, the leading qualities that distinguish the living from the non-living were taken into account. For example, Aristotle said that life is "nutrition, growth and decrepitude" of the organism; A. L. Lavoisier defined life as a “chemical function”; G. R. Treviranus believed that life is "a stable uniformity of processes with a difference in external influences." It is clear that such definitions could not satisfy scientists, since they did not reflect (and could not reflect) all the properties of living matter. In addition, observations indicate that the properties of the living are not exceptional and unique, as it seemed before, they are separately found among non-living objects. AI Oparin defined life as "a special, very complex form of the movement of matter." This definition reflects the qualitative originality of life, which cannot be reduced to simple chemical or physical laws. However, even in this case, the definition is of a general nature and does not reveal the specific peculiarity of this movement.
F. Engels in "Dialectics of Nature" wrote: "Life is a mode of existence of protein bodies, the essential point of which is the exchange of matter and energy with the environment."
For practical application, those definitions are useful, which contain the basic properties that are necessarily inherent in all living forms. Here is one of them: life is a macromolecular open system, which is characterized by a hierarchical organization, the ability to self-reproduce, self-preservation and self-regulation, metabolism, a finely regulated flow of energy. According to this definition, life is a core of order spreading in a less ordered universe.
Life exists in the form of open systems. This means that any living form is not closed only on itself, but constantly exchanges matter, energy and information with the environment.
2. Evolutionary-conditioned levels of life organization: There are such levels of organization of living matter - levels of biological organization: molecular, cellular, tissue, organ, organism, population-species and ecosystem.
Molecular level of organization- this is the level of functioning of biological macromolecules - biopolymers: nucleic acids, proteins, polysaccharides, lipids, steroids. From this level, the most important life processes begin: metabolism, energy conversion, transmission of hereditary information. This level is studied: biochemistry, molecular genetics, molecular biology, genetics, biophysics.
Cellular level- this is the level of cells (cells of bacteria, cyanobacteria, unicellular animals and algae, unicellular fungi, cells of multicellular organisms). A cell is a structural unit of the living, a functional unit, a unit of development. This level is studied by cytology, cytochemistry, cytogenetics, microbiology.
Tissue level of organization- This is the level at which the structure and functioning of tissues is studied. This level is studied by histology and histochemistry.
Organ level of organization- This is the level of organs of multicellular organisms. Anatomy, physiology, embryology study this level.
Organismal level of organization- this is the level of unicellular, colonial and multicellular organisms. The specificity of the organismic level is that at this level the decoding and implementation of genetic information takes place, the formation of features inherent in individuals of a given species. This level is studied by morphology (anatomy and embryology), physiology, genetics, paleontology.
Population-species level is the level of aggregates of individuals - populations and species. This level is studied by systematics, taxonomy, ecology, biogeography, and population genetics. At this level, genetic and ecological features of populations, elementary evolutionary factors and their influence on the gene pool (microevolution), the problem of species conservation are studied.
Biogeocenotic level of life organization - represented by a variety of natural and cultural biogeocenoses in all living environments . Components- Populations of different species; environmental factors ; Food webs, matter and energy flows ; Basic processes; Biochemical cycling and energy flow that sustain life ; Moving equilibrium between living organisms and the abiotic environment (homeostasis) ; Providing living organisms with living conditions and resources (food and shelter). Sciences leading research at this level: Biogeography, Biogeocenology Ecology
Biospheric level of life organization
It is represented by the highest, global form of organization of biosystems - the biosphere. Components - Biogeocenoses; Anthropogenic impact; Basic processes; Active interaction of living and non-living matter of the planet; Biological global circulation of matter and energy;
Active biogeochemical participation of man in all processes of the biosphere, his economic and ethnocultural activities
Sciences leading research at this level: Ecology; Global ecology; Space ecology; Social ecology.
The levels of organization of the organic world are discrete states of biological systems, characterized by subordination, interconnectedness, and specific patterns.
Structural levels of life organization are extremely diverse, but the main ones are molecular, cellular, ontogenetic, population-species, biocenotic and biospheric.
1. Molecular genetic level life. The most important tasks of biology at this stage is the study of the mechanisms of transmission of genetic information, heredity and variability.
There are several mechanisms of variability at the molecular level. The most important of them is the mechanism of gene mutation - the direct transformation of the genes themselves under the influence of external factors. The factors causing the mutation are: radiation, toxic chemical compounds, viruses.
Another mechanism of variability is gene recombination. Such a process takes place during sexual reproduction in higher organisms. In this case, there is no change in the total amount of genetic information.
Another mechanism of variability was discovered only in the 1950s. This is a non-classical recombination of genes, in which there is a general increase in the amount of genetic information due to the inclusion of new genetic elements in the cell genome. Most often, these elements are introduced into the cell by viruses.
2. Cellular level. Today, science has reliably established that the smallest independent unit of the structure, functioning and development of a living organism is a cell, which is an elementary biological system capable of self-renewal, self-reproduction and development. Cytology is a science that studies a living cell, its structure, functioning as an elementary living system, explores the functions of individual cellular components, the process of cell reproduction, adaptation to environmental conditions, etc. Cytology also studies the features of specialized cells, the formation of their special functions and the development of specific cellular structures . Thus, modern cytology has been called cell physiology.
A significant advance in the study of cells occurred at the beginning of the 19th century, when the cell nucleus was discovered and described. Based on these studies, the cellular theory was created, which became the greatest event in biology in the 19th century. It was this theory that served as the foundation for the development of embryology, physiology, and the theory of evolution.
The most important part of all cells is the nucleus, which stores and reproduces genetic information, regulates the metabolic processes in the cell.
All cells are divided into two groups:
Prokaryotes - cells lacking a nucleus
eukaryotes are cells that contain nuclei
Studying a living cell, scientists drew attention to the existence of two main types of its nutrition, which allowed all organisms to be divided into two types:
Autotrophic - produce their own nutrients
· Heterotrophic - can not do without organic food.
Later, such important factors as the ability of organisms to synthesize the necessary substances (vitamins, hormones), provide themselves with energy, dependence on the ecological environment, etc. were clarified. Thus, the complex and differentiated nature of the relationships indicates the need for a systematic approach to the study of life at the ontogenetic level. .
3. ontogenetic level. multicellular organisms. This level arose as a result of the formation of living organisms. The basic unit of life is an individual, and the elementary phenomenon is ontogenesis. Physiology deals with the study of the functioning and development of multicellular living organisms. This science considers the mechanisms of action of various functions of a living organism, their relationship with each other, regulation and adaptation to the external environment, origin and formation in the process of evolution and individual development of an individual. In fact, this is the process of ontogenesis - the development of the organism from birth to death. In this case, growth, movement of individual structures, differentiation and complication of the organism occur.
All multicellular organisms are composed of organs and tissues. Tissues are a group of physically connected cells and intercellular substances to perform certain functions. Their study is the subject of histology.
Organs are relatively large functional units that combine various tissues into certain physiological complexes. In turn, organs are part of larger units - body systems. Among them are the nervous, digestive, cardiovascular, respiratory and other systems. Only animals have internal organs.
4. Population-biocenotic level. This is a supra-organismal level of life, the basic unit of which is the population. In contrast to a population, a species is a collection of individuals that are similar in structure and physiological properties, have a common origin, and can freely interbreed and produce fertile offspring. A species exists only through populations representing genetically open systems. Population biology is the study of populations.
The term "population" was introduced by one of the founders of genetics, V. Johansen, who called it a genetically heterogeneous set of organisms. Later, the population began to be considered an integral system, continuously interacting with the environment. It is the populations that are the real systems through which the species of living organisms exist.
Populations are genetically open systems, since the isolation of populations is not absolute and the exchange of genetic information is not possible from time to time. It is populations that act as elementary units of evolution; changes in their gene pool lead to the emergence of new species.
Populations capable of independent existence and transformation are united in the aggregate of the next supraorganismal level - biocenoses. Biocenosis - a set of populations living in a certain area.
The biocenosis is a system closed to foreign populations, for its constituent populations it is an open system.
5. Biogeocetonic level. Biogeocenosis is a stable system that can exist for a long time. Equilibrium in a living system is dynamic, i.e. represents a constant movement around a certain point of stability. For its stable functioning, it is necessary to have feedback between its control and executing subsystems. This way of maintaining a dynamic balance between various elements of biogeocenosis, caused by the mass reproduction of some species and the reduction or disappearance of others, leading to a change in the quality of the environment, is called an ecological disaster.
Biogeocenosis is an integral self-regulating system in which several types of subsystems are distinguished. Primary systems are producers that directly process inanimate matter; consumers - a secondary level at which matter and energy are obtained through the use of producers; then come second-order consumers. There are also scavengers and decomposers.
The cycle of substances passes through these levels in the biogeocenosis: life is involved in the use, processing and restoration of various structures. In biogeocenosis - a unidirectional energy flow. This makes it an open system, continuously connected with neighboring biogeocenoses.
Self-regulation of biogeocens proceeds the more successfully, the more diverse the number of its constituent elements. The stability of biogeocenoses also depends on the diversity of its components. The loss of one or more components can lead to an irreversible imbalance and its death as an integral system.
6. biospheric level. This is the highest level of life organization, covering all the phenomena of life on our planet. The biosphere is the living matter of the planet and the environment transformed by it. Biological metabolism is a factor that unites all other levels of life organization into one biosphere. At this level, there is a circulation of substances and the transformation of energy associated with the vital activity of all living organisms living on Earth. Thus, the biosphere is a single ecological system. The study of the functioning of this system, its structure and functions is the most important task of biology at this level of life. Ecology, biocenology and biogeochemistry are engaged in the study of these problems.
The development of the doctrine of the biosphere is inextricably linked with the name of the outstanding Russian scientist V.I. Vernadsky. It was he who managed to prove the connection of the organic world of our planet, acting as a single inseparable whole, with geological processes on Earth. Vernadsky discovered and studied the biogeochemical functions of living matter.
All wildlife is a collection of biological systems of different levels of organization and different subordination.
The level of organization of living matter is understood as the functional place that a given biological structure occupies in the general system of organization of nature.
The level of organization of living matter is a set of quantitative and qualitative parameters of a certain biological system (cell, organism, population, etc.), which determine the conditions and boundaries of its existence.
There are several levels of organization of living systems, which reflect the subordination, hierarchy of the structural organization of life.
- Molecular (molecular-genetic) level represented by individual biopolymers (DNA, RNA, proteins, lipids, carbohydrates and other compounds); at this level of life, phenomena associated with changes (mutations) and the reproduction of genetic material, metabolism are studied. This is the science of molecular biology.
- Cellularlevel- the level at which life exists in the form of a cell - the structural and functional unit of life, is studied by cytology. At this level, processes such as metabolism and energy, information exchange, reproduction, photosynthesis, transmission of nerve impulses, and many others are studied.
The cell is the structural unit of all living things.
- tissue level studying histology.
Tissue is a combination of intercellular substance and cells similar in structure, origin and functions.
- Organlevel. An organ contains several tissues.
- Organismiclevel- the independent existence of a single individual - a unicellular or multicellular organism, for example, is studied by physiology and autecology (ecology of individuals). An individual as an integral organism is an elementary unit of life. Life in nature does not exist in any other form.
An organism is a real carrier of life, characterized by all its properties.
- population-specieslevel- level, which is represented by a group of individuals of the same species - population; it is in the population that elementary evolutionary processes (accumulation, manifestation, and selection of mutations) take place. This level of organization is studied by such sciences as de-ecology (or population ecology), evolutionary doctrine.
A population is a collection of individuals of the same species that exist for a long time in a certain area, interbreed freely and are relatively isolated from other individuals of the same species.
- Biogeocenoticlevel- represented by communities (ecosystems) consisting of different populations and their habitats. This level of organization is studied by biocenology or synecology (community ecology).
Biogeocenosis is a combination of all species with varying complexity of organization and all factors of their habitat.
- biosphericlevel- level representing the totality of all biogeocenoses. In the biosphere, the circulation of substances and the transformation of energy with the participation of organisms take place.
1) The German biologist is considered the founder of ecology E. Haeckel(1834-1919), who for the first time in 1866 used the term "ecology". He wrote: “By ecology we mean the general science of the relationship between the organism and the environment, where we include all the “conditions of existence” in the broadest sense of the word. They are partly organic and partly inorganic.”
Initially, this science was biology, which studies the populations of animals and plants in their habitat.
Ecology studies systems at a level above the individual organism. The main objects of its study are:
population - a group of organisms belonging to the same or similar species and occupying a certain territory;
ecosystem, including the biotic community (the totality of populations in the territory under consideration) and habitat;
biosphere- area of life on earth.
The interaction of Man with Nature has its own specifics. Man is endowed with reason, and this gives him the opportunity to realize his place in nature and purpose on Earth. Since the beginning of the development of civilization, Man has been thinking about his role in nature. Being, of course, part of nature, man created a special environment, which is called human civilization. As it developed, it increasingly came into conflict with nature. Now humanity has already come to the realization that the further exploitation of nature can threaten its own existence. Goals and objectives of modern ecology
One of the main goals of modern ecology as a science is to study the basic laws and develop the theory of rational interaction in the system "man - society - nature", considering human society as an integral part of the biosphere.
The main goal of modern ecology at this stage of the development of human society - to lead Mankind out of the global ecological crisis onto the path of sustainable development, in which the satisfaction of the vital needs of the present generation will be achieved without depriving future generations of such an opportunity.
To achieve these goals, environmental science will have to solve a number of diverse and complex tasks, including:
develop theories and methods for assessing the sustainability of ecological systems at all levels;
to study the mechanisms of regulation of the number of populations and biotic diversity, the role of biota (flora and fauna) as a regulator of biosphere stability;
study and create forecasts of changes in the biosphere under the influence of natural and anthropogenic factors;
evaluate the state and dynamics of natural resources and the environmental consequences of their consumption;
develop methods of environmental quality management;
to form an understanding of the problems of the biosphere and the ecological culture of society.
Surrounding us live environment is not a random and random combination of living beings. It is a stable and organized system that has developed in the process of evolution of the organic world. Any systems are amenable to modeling, i.e. it is possible to predict how this or that system will react to external influence. The system approach is the basis for studying environmental problems. The place of ecology in the system of natural sciences. Modern ecology belongs to the type of sciences that arose at the junction of many scientific areas. It reflects both the global nature of the modern tasks facing humanity, and various forms of integration of the methods of directions and scientific research. The transformation of ecology from a purely biological discipline into a branch of knowledge, which also included social and technical sciences, into a field of activity based on the solution of a number of complex political, ideological, economic, ethical and other issues, has determined its significant place in modern life, made it a kind of knot, which combines various areas of science and human practice. Ecology, in my opinion, is becoming more and more one of the human sciences and is of interest to many scientific areas. And although this process is still very far from completion, its main trends are already quite clearly visible in our time.
2) Subject, tasks and methods of ecology Ecology(Greek oikos - dwelling, residence, logos - science) - biological science of the relationship between living organisms and their environment.
Ecology objects are predominantly systems above the level of organisms, i.e., the study of the organization and functioning of supraorganismal systems: populations, biocenoses (communities), biogeocenoses (ecosystems) and the biosphere as a whole. In other words, the main object of study in ecology is ecosystems, that is, unified natural complexes formed by living organisms and the environment.
Tasks of ecology change depending on the studied level of organization of living matter. Population ecology explores patterns of population dynamics and structure, as well as interaction processes (competition, predation) between populations of different species. To tasks community ecology (biocenology) includes the study of the patterns of organization of various communities, or biocenoses, their structure and functioning (the circulation of substances and the transformation of energy in food chains).
The main theoretical and practical task of ecology is to reveal the general patterns of life organization and, on this basis, to develop principles for the rational use of natural resources in the face of ever-increasing human influence on the biosphere.
The range of environmental problems also includes issues of environmental education and enlightenment, moral, ethical, philosophical and even legal issues. Consequently, ecology becomes a science not only biological, but also social. Ecology methods subdivided into field(the study of the life of organisms and their communities in natural conditions, i.e., long-term observation in nature using various equipment) and experimental(experiments in stationary laboratories, where it is possible not only to vary, but also strictly control the effect of any factors on living organisms according to a given program). At the same time, ecologists operate not only with biological, but also with modern physical and chemical methods, use modeling of biological phenomena, i.e., reproduction in artificial ecosystems of various processes occurring in wildlife. Through modeling, it is possible to study the behavior of any system in order to assess the possible consequences of applying various resource management strategies and methods, i.e. for environmental forecasting. 3) In the history of the development of ecology as a science, three main stages can be distinguished. First stage - the origin and formation of ecology as a science (until the 1960s), when data on the relationship of living organisms with their environment were accumulated, the first scientific generalizations were made. In the same period, the French biologist Lamarck and the English priest Malthus for the first time warned humanity about the possible negative consequences of human impact on nature.
Second phase - registration of ecology as an independent branch of knowledge (after the 1960s to the 1950s). The beginning of the stage was marked by the publication of the works of Russian scientists K.F. Ruler, N.A. Severtseva, V.V. Dokuchaev, who first substantiated a number of principles and concepts of ecology. After Charles Darwin's studies in the field of evolution of the organic world, the German zoologist E. Haeckel was the first to understand what Darwin called the "struggle for existence", is an independent area of biology, and called it ecology(1866).
As an independent science, ecology finally took shape at the beginning of the 20th century. During this period, the American scientist C. Adams created the first summary of ecology, and other important generalizations were published. The largest Russian scientist of the XX century. IN AND. Vernadsky creates a fundamental the doctrine of the biosphere.
In the 1930s-1940s, at first, the English botanist A. Tensley (1935) put forward the concept of "ecosystem", and a little later V. Ya. Sukachev(1940) substantiated a concept close to him about biogeocenosis.
Third stage(1950s - to the present) - the transformation of ecology into a complex science, including the sciences of protecting the human environment. Simultaneously with the development of the theoretical foundations of ecology, applied issues related to ecology were also solved.
In our country, in the 1960s-1980s, almost every year the government adopted resolutions on strengthening nature protection; Land, water, forest and other codes were published. However, as the practice of their application has shown, they did not give the required results.
Today Russia is experiencing an ecological crisis: about 15% of the territory are actually zones of ecological disaster; 85% of the population breathe air polluted significantly above the MPC. The number of "environmentally caused" diseases is growing. There is degradation and reduction of natural resources.
A similar situation has developed in other countries of the world. The question of what will happen to mankind in the event of the degradation of natural ecological systems and the loss of the ability of the biosphere to maintain biochemical cycles becomes one of the most urgent.
4) 1. Molecular level of organization of living nature
The chemical composition of cells: organic and inorganic substances,
Metabolism (metabolism): processes of dissimilation and assimilation,
absorption and release of energy.
The molecular level affects all biochemical processes that occur inside any living organism - from unicellular to multicellular.
This level difficult to call "alive". It is rather a "biochemical" level - therefore, it is the basis for all other levels of organization of wildlife. Therefore, it was he who formed the basis for the classification of Wildlife to the kingdoms which nutrient is the main one in the body: in animals - protein, in fungi - chitin, in plants it is carbohydrates.
Sciences that study living organisms at this level:
2. Cellular level of wildlife organization
Includes previous - molecular level of organization.
At this level, the term "cell" already appears as "the smallest indivisible biological system"
The metabolism and energy of a given cell (different depending on which kingdom the organism belongs to);
Organoids of the cell;
Life cycles - origin, growth and development and cell division
Sciences studying cellular level of organization:
Genetics and embryology study this level, but this is not the main object of study.
3. Tissue level of organization:
Includes 2 previous levels - molecular and cellular.
This level can be calledmulticellular "- after all, the fabric iscollection of cells with a similar structure and performing the same functions.
Science - Histology
4. Organ (stress on the first syllable) level of organization of life
In unicellular organs, these are organelles - there are common organelles - characteristic of all eukaryotic or prokaryotic cells, there are different ones.
In multicellular organisms, cells of a common structure and functions are combined into tissues, and those, respectively, into bodies, which, in turn, are combined into systems and must interact harmoniously with each other.
Tissue and organ levels of organization - study the sciences:
5. Organism level
Includes all previous levels: molecular, cellular, tissue levels and organ.
At this level, there is a division of Wildlife into kingdoms - animals, plants and fungi.
Characteristics of this level:
Metabolism (both at the level of the body and at the cellular level too)
The structure (morphology) of the body
Nutrition (metabolism and energy)
homeostasis
reproduction
Interaction between organisms (competition, symbiosis, etc.)
Interaction with the environment
6. Population-species level of life organization
Includes molecular, cellular, tissue levels, organ and body.
If several organisms are morphologically similar (in other words, have the same structure), and have the same genotype, then they form one species or population.
The main processes at this level are:
The interaction of organisms with each other (competition or reproduction)
microevolution (change of an organism under the influence of external conditions)
Sciences studying this level:
7. Biogeocenotic level of life organization
At this level, almost everything is already taken into account:
Nutritional interaction of organisms with each other - food chains and networks
Inter- and intraspecific interaction of organisms - competition and reproduction
The influence of the environment on organisms and, accordingly, the influence of organisms on their habitat
The science that studies this level is Ecology
Well, the last level is the highest!
8. Biospheric level of wildlife organization
It includes:
Interaction of both living and non-living components of nature
Biogeocenoses
Human influence - "anthropogenic factors"
The cycle of substances in nature
5) The ecological system, or ecosystem, is the main functional unit in ecology, since it includes organisms and
inanimate environment - components that mutually influence each other's properties, and the necessary conditions for maintaining life in its form that exists on Earth. Term ecosystem was first proposed in 1935 by an English ecologist A. Tensley.
Thus, an ecosystem is understood as a set of living organisms (communities) and their habitat, which, thanks to the circulation of substances, form a stable system of life.
Communities of organisms are connected with the inorganic environment by the closest material and energy ties. Plants can only exist due to the constant supply of carbon dioxide, water, oxygen, and mineral salts. Heterotrophs live off autotrophs, but need inorganic compounds such as oxygen and water.
In any particular habitat, the reserves of inorganic compounds necessary to maintain the vital activity of the organisms inhabiting it would suffice for a short time if these reserves were not renewed. The return of biogenic elements to the environment occurs both during the life of organisms (as a result of respiration, excretion, defecation) and after their death, as a result of the decomposition of corpses and plant residues.
Consequently, the community forms a certain system with the inorganic medium, in which the flow of atoms, caused by the vital activity of organisms, tends to be closed in a cycle.
Rice. 8.1. The structure of biogeocenosis and the scheme of interaction between the components
In the domestic literature, the term "biogeocenosis", proposed in 1940, is widely used. B. HSukachev. According to his definition, biogeocenosis is “a set of homogeneous natural phenomena (atmosphere, rocks, soil and hydrological conditions) over a known extent of the earth's surface, which has a special specificity of interactions of these constituent components and a certain type of exchange of matter and energy between themselves and other natural phenomena. and representing an internally contradictory dialectical unity, which is in constant motion, development.
In biogeocenosis V.N. Sukachev singled out two blocks: ecotope- a set of conditions of the abiotic environment and biocenosis- the totality of all living organisms (Fig. 8.1). An ecotope is often considered as an abiotic environment not transformed by plants (the primary complex of factors of the physical and geographical environment), and a biotope is considered as a set of elements of the abiotic environment modified by the environment-forming activity of living organisms.
There is an opinion that the term "biogeocenosis" to a much greater extent reflects the structural characteristics of the macrosystem under study, while the concept of "ecosystem" primarily includes its functional essence. In fact, there is no difference between these terms.
It should be pointed out that the combination of a specific physical and chemical environment (biotope) with a community of living organisms (biocenosis) forms an ecosystem:
Ecosystem = Biotope + Biocenosis.
The equilibrium (sustainable) state of the ecosystem is ensured on the basis of the circulation of substances (see paragraph 1.5). All components of ecosystems are directly involved in these cycles.
To maintain the circulation of substances in an ecosystem, it is necessary to have a stock of inorganic substances in an assimilated form and three functionally different ecological groups of organisms: producers, consumers, and decomposers.
Producers autotrophic organisms act, capable of building their bodies at the expense of inorganic compounds (Fig. 8.2).
Rice. 8.2. Producers
Consumers - heterotrophic organisms that consume the organic matter of producers or other consumers and transform it into new forms.
decomposers live at the expense of dead organic matter, translating it again into inorganic compounds. This classification is relative, since both consumers and producers themselves partially act as decomposers during their life, releasing mineral metabolic products into the environment.
In principle, the circulation of atoms can be maintained in the system without an intermediate link - consumers, due to the activity of two other groups. However, such ecosystems are found rather as exceptions, for example, in those areas where communities formed only from microorganisms function. The role of consumers in nature is performed mainly by animals, their activity in maintaining and accelerating the cyclic migration of atoms in ecosystems is complex and diverse.
The scale of the ecosystem in nature is very different. The degree of closure of the cycles of matter maintained in them is also not the same, i.e. repeated involvement of the same elements in cycles. As separate ecosystems, one can consider, for example, a pillow of lichens on a tree trunk, and a collapsing stump with its population, and a small temporary reservoir, meadow, forest, steppe, desert, the entire ocean, and, finally, the entire surface of the Earth occupied by life.
In some types of ecosystems, the removal of matter outside their boundaries is so great that their stability is maintained mainly due to the influx of the same amount of matter from outside, while the internal circulation is ineffective. These are flowing reservoirs, rivers, streams, areas on the steep slopes of mountains. Other ecosystems have a much more complete cycle of substances and are relatively autonomous (forests, meadows, lakes, etc.).
An ecosystem is a practically closed system. This is the fundamental difference between ecosystems and communities and populations, which are open systems exchanging energy, matter and information with the environment.
However, not a single ecosystem of the Earth has a completely closed cycle, since the minimum exchange of mass with the environment still occurs.
The ecosystem is a set of interconnected energy consumers doing work to maintain its non-equilibrium state relative to the environment through the use of solar energy flow.
In accordance with the hierarchy of communities, life on Earth is also manifested in the hierarchy of the corresponding ecosystems. The ecosystem organization of life is one of the necessary conditions for its existence. As already noted, the reserves of biogenic elements necessary for the life of organisms on the Earth as a whole and in each specific area on its surface are not unlimited. Only a system of cycles could give these reserves the property of infinity, necessary for the continuation of life.
Only functionally different groups of organisms can support and carry out the cycle. The functional and ecological diversity of living beings and the organization of the flow of substances extracted from the environment into cycles are the most ancient property of life.
From this point of view, the sustainable existence of many species in an ecosystem is achieved through natural habitat disturbances that constantly occur in it, allowing new generations to occupy the newly vacated space.
Ecosystem (ecological system)- the main functional unit of ecology, which is a unity of living organisms and their habitat, organized by energy flows and the biological cycle of substances. This is a fundamental commonality of the living and its habitat, any set of living organisms living together and the conditions for their existence (Fig. 8).
Rice. 8. Various ecosystems: a - ponds of the middle lane (1 - phytoplankton; 2 - zooplankton; 3 - swimming beetles (larvae and adults); 4 - young carps; 5 - pikes; 6 - larvae of horonomids (twitching mosquitoes); 7 - bacteria; 8 - insects of coastal vegetation; b - meadows (I - abiotic substances, i.e. the main inorganic and organic components); II - producers (vegetation); III - macroconsumers (animals): A - herbivores (fillies, field mice, etc.); B - indirect or detritus-eating consumers, or saprobes (soil invertebrates); C - "riding" predators (hawks); IV - decomposers (putrefactive bacteria and fungi)
From a functional point of view, it is advisable to analyze the ecosystem in the following areas:
1) energy flows;
2) food chains;
3) structure of spatio-temporal diversity;
4) biogeochemical cycles;
5) development and evolution;
6) management (cybernetics);
Ecosystems can also be classified by:
the structure;
· Productivity;
· Sustainability;
Types of ecosystems (according to Komov):
· Accumulative (high bogs);
Transit (powerful removal of matter);
Organization levels living systems reflect the subordination, hierarchy of the structural organization of life; differ from each other in the complexity of the organization of the system (the cell is simpler in comparison with a multicellular organism or population).
Standard of living - this is the form and way of its existence (the virus exists in the form of a DNA or RNA molecule enclosed in a protein shell - the form of the existence of the virus. However, the properties of a living system the virus shows only when it enters the cell of another organism, where it multiplies - the way it exists).
Organization levels |
Biological system |
The components that make up the system |
Core Processes |
|
1. |
Molecule |
Separate biopolymers (DNA, RNA, proteins, lipids, carbohydrates, etc.); |
At this level of life, phenomena associated with changes (mutations) and the reproduction of genetic material, metabolism are studied. |
|
2. |
Complexes of molecules of chemical compounds and cell organelles |
Synthesis of specific organic substances; regulation of chemical reactions; cell division; the involvement of the chemical elements of the Earth and the energy of the Sun in biosystems |
|
|
3. |
Cells and intercellular substance |
Metabolism; irritability |
|
|
4. |
Fabrics of different types |
Digestion; gas exchange; transport of substances; movement, etc. |
|
|
5. Organismic |
organism |
Organ systems |
Metabolism; irritability; reproduction; ontogenesis. Neuro-humoral regulation of vital processes. Ensuring harmonious conformity of the organism to its environment |
|
6. Population-species |
population |
Groups of related individuals united by a certain gene pool and specific interaction with the environment |
genetic identity; interaction between individuals and populations; accumulation of elementary evolutionary transformations; development of adaptation to changing environmental conditions |
|
7. |
Biogeocenosis |
Populations of different species; environmental factors; space with a complex of environmental conditions |
The biological cycle of substances and the flow of energy that support life; mobile balance between the living population and the abiotic environment; providing the living population with living conditions and resources |
|
8. |
Biosphere |
Biogeocenoses and anthropogenic impact |
Active interaction of living and non-living (inert) matter of the planet; biological global circulation; active biogeochemical participation of man in all processes of the biosphere |
THEMATIC ASSIGNMENTS
Part A
A1. The level at which the processes of biogenic migration of atoms are studied is called:
1) biogeocenotic
2) biosphere
3) population-species
4) molecular genetic
A2. At the population-species level, they study:
1) gene mutations
2) the relationship of organisms of the same species
3) organ systems
4) metabolic processes in the body
A3. Maintaining a relatively constant chemical composition of the body is called
1) metabolism
2) assimilation
3) homeostasis
4) adaptation
A4. The occurrence of mutations is associated with such a property of the organism as
1) heredity
2) variability
3) irritability
4) self-reproduction
A5. Which of the following biological systems forms the highest standard of living?
1) amoeba cell
2) smallpox virus
3) a herd of deer
4) nature reserve
A6. Pulling the hand away from a hot object is an example
1) irritability
2) ability to adapt
3) inheritance of traits from parents
4) self-regulation
A7. Photosynthesis, protein biosynthesis are examples
1) plastic metabolism
2) energy metabolism
3) nutrition and breathing
4) homeostasis
A8. Which of the terms is synonymous with the concept of "metabolism"?
1) anabolism
2) catabolism
3) assimilation
4) metabolism
Part B
IN 1. Select the processes studied at the molecular genetic level of life:
1) DNA replication
2) inheritance of Down's disease
3) enzymatic reactions
4) the structure of mitochondria
5) cell membrane structure
6) blood circulation
IN 2. Correlate the nature of the adaptation of organisms with the conditions to which they were developed.
Part C
C1. What adaptations of plants provide them with reproduction and resettlement?
C2. What is common and what are the differences between different levels of organization of life?
