Molecular level of organization of life science. Basic levels of life organization

Molecular genetic. The elementary unit of organization is the gene. An elementary phenomenon - DNA reduplication, transfer genetic information to the daughter cell. Molecular level The organization of life is the subject of molecular biology. She studies the structure of proteins, their functions (including as enzymes), the role nucleic acids in the storage, replication and implementation of genetic information, i.e. processes of synthesis of DNA, RNA, proteins.

Cellular level. This level of organization of living things is represented by cells - independent organisms (bacteria, protozoa, etc.), as well as cells of multicellular organisms. The most important specific feature of the cellular level is that from this level life begins, since matrix synthesis occurring at the molecular level occurs in cells. Being capable of life, growth and reproduction, cells are the main form of organization of living matter, its elementary units from which all living beings are built. Characteristic feature cellular level is the specialization of cells. At the cellular level, there is a differentiation and ordering of life processes in space and time.

Tissue level. Tissue is a collection of cells that have a common origin, similar structure and perform the same functions. In mammals, for example, there are four main types of tissue: epithelial, connective, muscle and nervous.

Organismal (ontogenetic) level. At the organismal level, they study the individual and its structural features as a whole, physiological processes, including differentiation, mechanisms of adaptation and behavior. The elementary indivisible unit of life organization at this level is the individual. Life is always represented in the form of discrete individuals. These can be single-celled individuals, or multicellular, consisting of millions and billions of cells.

Population-species level. The basic elementary structural unit at this level is the population. Population- a local, geographically separated to one degree or another from others group of individuals of the same species, freely interbreeding with each other and having a common genetic fund. The elementary phenomenon of the population-species level is a change in the genotypic composition of the population, and the elementary material is mutation. At the population-species level, factors influencing the size of populations, problems of conservation of endangered species, and the dynamics of the genetic composition of populations are studied.

Biocenotic level. Populations different types always form complex communities in the Earth's biosphere. Such communities in specific areas of the biosphere are called biocenoses. Biocenosis- a complex consisting of plant community(phytocenosis), the fauna inhabiting it (zoocenosis), microorganisms and the corresponding area earth's surface. All components of the biocenosis are interconnected by the cycle of substances. Biocenosis is a product of joint historical development species differing in systematic position.

Highlight next levels organizations of life: molecular, cellular, organ-tissue (sometimes they are separated), organismal, population-species, biogeocenotic, biosphere. Wildlife is a system, and the various levels of its organization form its complex hierarchical structure, when the underlying simpler levels determine the properties of the higher ones.

So complex organic molecules are part of cells and determine their structure and vital functions. In multicellular organisms, cells are organized into tissues, and several tissues form an organ. A multicellular organism consists of organ systems; on the other hand, the organism itself is an elementary unit of a population and biological species. A community is represented by interacting populations of different species. The community and environment form a biogeocenosis (ecosystem). The totality of planet Earth's ecosystems forms its biosphere.

At each level, new properties of living things arise that are absent at the underlying level, and their own elementary phenomena and elementary units are distinguished. At the same time, in many ways the levels reflect the course of the evolutionary process.

The identification of levels is convenient for studying life as a complex natural phenomenon.

Let's take a closer look at each level of life organization.

Molecular level

Although molecules are made up of atoms, the difference between living and nonliving matter begins to appear only at the molecular level. Only found in living organisms large number complex organic substances - biopolymers (proteins, fats, carbohydrates, nucleic acids). However, the molecular level of organization of living things also includes inorganic molecules that enter cells and play important role in their life.

The functioning of biological molecules underlies a living system. At the molecular level of life, metabolism and energy conversion are manifested as chemical reactions, transmission and change of hereditary information (reduplication and mutations), as well as a number of other cellular processes. Sometimes the molecular level is called molecular genetic.

Cellular level of life

It is the cell that is the structural and functional unit of living things. There is no life outside the cell. Even viruses can exhibit the properties of a living thing only when they are in the host cell. Biopolymers fully demonstrate their reactivity when organized into a cell, which can be considered as complex system interconnected primarily by various chemical reactions of molecules.

At this cellular level, the phenomenon of life manifests itself, the mechanisms of transmission of genetic information and the transformation of substances and energy are coupled.

Organ-tissue

Only multicellular organisms have tissues. Tissue is a collection of cells similar in structure and function.

Tissues are formed in the process of ontogenesis by differentiation of cells having the same genetic information. At this level, cell specialization occurs.

In plants and animals they secrete different types fabrics. So in plants it is a meristem, protective, basic and conductive tissue. In animals - epithelial, connective, muscular and nervous. Tissues may include a list of subtissues.

An organ usually consists of several tissues interconnected into a structural and functional unity.

Organs form organ systems, each of which is responsible for an important function for the body.

Organ level single-celled organisms represented by various cell organelles that perform the functions of digestion, excretion, respiration, etc.

Organismic level of organization of living things

Along with the cellular level, separate structural units are distinguished at the organismal (or ontogenetic) level. Tissues and organs cannot live independently, organisms and cells (if it is a single-celled organism) can.

Multicellular organisms are made up of organ systems.

At the organismal level, such life phenomena as reproduction, ontogenesis, metabolism, irritability, neurohumoral regulation, and homeostasis are manifested. In other words, its elementary phenomena constitute the natural changes of the organism in individual development. The elementary unit is the individual.

Population-species

Organisms of the same species, united by a common habitat, form a population. A species usually consists of many populations.

Populations have a common gene pool. Within a species, they can exchange genes, i.e. they are genetically open systems.

Elementary evolutionary phenomena occur in populations, ultimately leading to speciation. Living nature can evolve only at supraorganism levels.

At this level, the potential immortality of the living arises.

Biogeocenotic level

Biogeocenosis is an interacting set of organisms of different species with various factors their habitat. Elementary phenomena are represented by matter-energy cycles, provided primarily by living organisms.

The role of the biogeocenotic level is the formation of stable communities of organisms of different species, adapted to living together in a certain habitat.

Biosphere

The biosphere level of life organization is a system higher order life on Earth. The biosphere covers all manifestations of life on the planet. At this level, there is a global circulation of substances and a flow of energy (encompassing all biogeocenoses).

There are such levels of organization of living matter - levels of biological organization: molecular, cellular, tissue, organ, organismal, population-species and ecosystem.

Molecular level of organization- this is the level of functioning of biological macromolecules - biopolymers: nucleic acids, proteins, polysaccharides, lipids, steroids. The most important life processes begin from this level: metabolism, energy conversion, transmission of hereditary information. This level is studied: biochemistry, molecular genetics, molecular biology, genetics, biophysics.

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 living things, a functional unit, a unit of development. This level is studied by cytology, cytochemistry, cytogenetics, and 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, and embryology study this level.

Organismic level of organization- this is the level of unicellular, colonial and multicellular organisms. The specificity of the organismal level is that at this level the decoding and implementation of genetic information occurs, the formation of characteristics inherent in individuals of a given species. This level is studied by morphology (anatomy and embryology), physiology, genetics, and paleontology.

Population-species level- this 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, the genetic and ecological characteristics of populations, elementary evolutionary factors and their influence on the gene pool (microevolution), and the problem of species conservation are studied.

Ecosystem level of organization- this is the level of microecosystems, mesoecosystems, macroecosystems. At this level, types of nutrition, types of relationships between organisms and populations in an ecosystem, population size, population dynamics, population density, ecosystem productivity, and succession are studied. This level studies ecology.

Also distinguished biosphere level of organization living matter. The biosphere is a giant ecosystem that occupies part of geographic envelope Earth. This is a mega ecosystem. In the biosphere there is a cycle of substances and chemical elements, as well as the conversion of solar energy.

All living organisms in nature consist of the same levels of organization; this is a characteristic biological pattern common to all living organisms.
The following levels of organization of living organisms are distinguished: molecular, cellular, tissue, organ, organismal, population-species, biogeocenotic, biosphere.

Rice. 1. Molecular genetic level

1. Molecular genetic level. This is the most elementary level characteristic of life (Fig. 1). No matter how complex or simple the structure of any living organism, they all consist of the same molecular compounds. An example of this are nucleic acids, proteins, carbohydrates and other complex molecular complexes of organic and inorganic substances. They are sometimes called biological macromolecular substances. At the molecular level, various life processes of living organisms occur: metabolism, energy conversion. With the help of the molecular level, the transfer of hereditary information is carried out, individual organelles are formed and other processes occur.

Rice. 2. Cellular level

2. Cellular level. The cell is the structural and functional unit of all living organisms on Earth (Fig. 2). Individual organelles within a cell have a characteristic structure and perform a specific function. The functions of individual organelles in a cell are interconnected and perform common vital processes. In single-celled organisms (unicellular algae and protozoa), all life processes take place in one cell, and one cell exists as a separate organism. Remember unicellular algae, chlamydomonas, chlorella and the simplest animals - amoeba, ciliates, etc. In multicellular organisms, one cell cannot exist as a separate organism, but it is an elementary structural unit of the organism.

Rice. 3. Tissue level

3. Tissue level. A collection of cells and intercellular substances similar in origin, structure and function forms tissue. The tissue level is characteristic only of multicellular organisms. Also, individual tissues are not an independent integral organism (Fig. 3). For example, the bodies of animals and humans consist of four different tissues (epithelial, connective, muscle, nervous). Plant tissue are called: educational, integumentary, supporting, conductive and excretory. Remember the structure and functions of individual tissues.

Rice. 4. Organ level

4. Organ level. In multicellular organisms, the combination of several identical tissues, similar in structure, origin and function, forms the organ level (Fig. 4). Each organ contains several tissues, but among them one is the most significant. A separate organ cannot exist as a whole organism. Several organs, similar in structure and function, combine to form an organ system, for example, digestion, respiration, blood circulation, etc.

Rice. 5. Organismal level

5. Organismic level. Plants (Chlamydomonas, Chlorella) and animals (amoeba, ciliates, etc.), whose bodies consist of one cell, are an independent organism (Fig. 5). And an individual individual of multicellular organisms is considered as a separate organism. In each individual organism, all life processes characteristic of all living organisms occur - nutrition, respiration, metabolism, irritability, reproduction, etc. Each independent organism leaves behind offspring. In multicellular organisms, cells, tissues, organs, and organ systems are not a separate organism. Only an integral system of organs that specifically perform various functions forms a separate independent organism. The development of an organism, from fertilization to the end of life, takes a certain period of time. This individual development each organism is called ontogenesis. An organism can exist in close relationship with its environment.

Rice. 6. Population-species level

6. Population-species level. A collection of individuals of one species or group that exists for a long time in a certain part of the range, relatively separately from other populations of the same species, constitutes a population. At the population level, the simplest evolutionary transformations are carried out, which contributes to the gradual emergence of a new species (Fig. 6).

Rice. 7 Biogeocenotic level

7. Biogeocenotic level. A set of organisms of different species and varying complexity of organization, adapted to the same conditions natural environment, is called biogeocenosis, or natural community. The biogeocenosis includes numerous species of living organisms and natural environmental conditions. In natural biogeocenoses, energy accumulates and is transferred from one organism to another. Biogeocenosis includes inorganic, organic compounds and living organisms (Fig. 7).

Rice. 8. Biosphere level

8. Biosphere level. The totality of all living organisms on our planet and their common natural habitat constitutes the biosphere level (Fig. 8). At the biosphere level, modern biology decides global problems, for example, determining the intensity of formation of free oxygen by the Earth's vegetation cover or changes in concentration carbon dioxide in the atmosphere associated with human activities. Main role at the biosphere level they are performed by “living substances,” i.e., the totality of living organisms inhabiting the Earth. Also at the biosphere level, “bio-inert substances” are important, formed as a result of the vital activity of living organisms and “inert” substances (i.e. conditions environment). At the biosphere level, the circulation of matter and energy occurs on Earth with the participation of all living organisms of the biosphere.

Levels of life organization. Population. Biogeocenosis. Biosphere.

1. Currently, there are several levels of organization of living organisms: molecular, cellular, tissue, organ, organismal, population-species, biogeocenotic and biosphere.
2. At the population-species level, elementary evolutionary transformations are carried out.
3. The cell is the most basic structural and functional unit of all living organisms.
4. A collection of cells and intercellular substances similar in origin, structure and function forms tissue.
5. The totality of all living organisms on the planet and their general natural habitat constitutes the biosphere level.
1. Name the levels of life organization in order.
2. What is fabric?
3. What are the main parts of a cell?
1. What organisms are characterized by the tissue level?
2. Describe the organ level.
3. What is a population?
1. Describe the organismal level.
2. Name the features of the biogeocenotic level.
3. Give examples of the interconnectedness of the levels of organization of life.

Fill out the table showing the structural features of each level of the organization:

LEVELS OF LIVING ORGANIZATION

There are molecular, cellular, tissue, organ, organismal, population, species, biocenotic and global (biosphere) levels of organization of living things. At all these levels all the properties characteristic of living things are manifested. Each of these levels is characterized by features inherent in other levels, but each level has its own specific features.

Molecular level. This level is deep in the organization of living things and is represented by molecules of nucleic acids, proteins, carbohydrates, lipids and steroids found in cells and called biological molecules. At this level, the most important life processes begin and are carried out (coding and transmission of hereditary information, respiration, metabolism and energy, variability, etc.). The physical and chemical specificity of this level is that the composition of living things includes a large number of chemical elements, but the bulk of living things are represented by carbon, oxygen, hydrogen and nitrogen. Molecules are formed from a group of atoms, and from the latter complex chemical compounds are formed that differ in structure and function. Most of these compounds in cells are represented by nucleic acids and proteins, the macromolecules of which are polymers synthesized as a result of the formation of monomers and the combination of the latter into in a certain order. In addition, monomers of macromolecules within the same compound have the same chemical groups and are connected by chemical bonds between atoms, their non-specific

ical parts (areas). All macromolecules are universal, since they are built according to the same plan, regardless of their species. Being universal, they are at the same time unique, because their structure is unique. For example, DNA nucleotides contain one nitrogenous base out of four known ones (adenine, guanine, cytosine or thymine), as a result of which any nucleotide is unique in its composition. Unique also secondary structure DNA molecules.

The biological specificity of the molecular level is determined by the functional specificity of biological molecules. For example, the specificity of nucleic acids lies in the fact that they encode genetic information about protein synthesis. Moreover, these processes are carried out as a result of the same metabolic steps. For example, the biosynthesis of nucleic acids, amino acids and proteins proceeds according to a similar pattern in all organisms. Fatty acid oxidation, glycolysis and other reactions are also universal.

The specificity of proteins is determined by the specific sequence of amino acids in their molecules. This sequence further defines specific biological properties proteins, since they are the main structural elements of cells, catalysts and regulators of reactions in cells. Carbohydrates and lipids serve as the most important sources of energy, while steroids are important for the regulation of a number of metabolic processes.

At the molecular level, energy is converted - radiant energy into chemical energy stored in carbohydrates and other chemical compounds, and the chemical energy of carbohydrates and other molecules - into biologically available energy stored in the form of macroergic bonds of ATP. Finally, here the energy of high-energy phosphate bonds is converted into work - mechanical, electrical, chemical, osmotic. The mechanisms of all metabolic and energy processes are universal.

Biological molecules also ensure continuity between molecules and the next level (cellular), since they are the material from which supramolecular structures are formed. The molecular level is the "arena" chemical reactions, which provide energy to the cellular level.

Cellular level. This level of organization of living things is represented by cells acting as independent organizations.

mov (bacteria, protozoa, etc.), as well as cells of multicellular organisms. The most important specific feature of this level is that life begins with it. Being capable of life, growth and reproduction, cells are the main form of organization of living matter, the elementary units from which all living beings (prokaryotes and eukaryotes) are built. There are no fundamental differences in structure and function between plant and animal cells. Some differences concern only the structure of their membranes and individual organelles. There are noticeable differences in structure between prokaryotic cells and eukaryotic cells, but in functional terms these differences are leveled out, because the “cell from cell” rule applies everywhere.

The specificity of the cellular level is determined by the specialization of cells, the existence of cells as specialized units of a multicellular organism. At the cellular level, there is a differentiation and ordering of vital processes in space and time, which is associated with the assignment of functions to different subcellular structures. For example, eukaryotic cells have significantly developed membrane systems (plasma membrane, cytoplasmic reticulum, lamellar complex) and cellular organelles (nucleus, chromosomes, centrioles, mitochondria, plastids, lysosomes, ribosomes). Membrane structures are an “arena” for the most important life processes, and the two-layer structure of the membrane system significantly increases the area of ​​the “arena”. In addition, membrane structures provide spatial separation of many biological molecules in cells, and their physical condition allows for the constant diffuse movement of some of the protein and phospholipid molecules they contain. Thus, membranes are a system whose components are in motion. They are characterized by various rearrangements, which determines the irritability of cells - the most important property of living things.

Tissue level. This level is represented by tissues that unite cells of a certain structure, size, location and similar functions. Tissues arose during historical development along with multicellularity. In multicellular organisms, they are formed during ontogenesis as a consequence of cell differentiation. In animals, there are several types of tissue (epithelial, connective, muscle, blood, nervous and reproductive). The races

In the shadows, meristematic, protective, basic and conductive tissues are distinguished. At this level, cell specialization occurs.

Organ level. Represented by organs of organisms. In plants and animals, organs are formed from different amounts of tissue. In protozoa, digestion, respiration, circulation of substances, excretion, movement and reproduction are carried out by various organelles. More advanced organisms have organ systems. Vertebrates are characterized by cephalization, which consists in concentrating the most important nerve centers and sensory organs in the head.

Organismic level. This level is represented by the organisms themselves - unicellular and multicellular organisms of plant and animal nature. Specific feature The organismal level is that at this level the decoding and implementation of genetic information, the creation of structural and functional features inherent in organisms of a given species occur.

Species level. This level is determined by the species of plants and animals. Currently, there are about 500 thousand species of plants and about 1.5 million species of animals, the representatives of which are characterized by a wide variety of habitats and occupy different ecological niches. Species is also a unit of classification of living things.

Population level. Plants and animals do not exist in isolation; they are united in populations that are characterized by a specific gene pool. Within the same species there can be from one to many thousands of populations. Elementary evolutionary transformations are carried out in populations, and a new adaptive form is developed.

Biocenotic level. It is represented by biocenoses - communities of organisms of different species. In such communities, organisms of different species depend on one another to one degree or another. In the course of historical development, biogeocenoses (ecosystems) have emerged, which are systems consisting of interdependent communities of organisms and abiotic environmental factors. Ecosystems are characterized by a fluid balance between organisms and abiotic factors. At that level, material and energy cycles associated with the life activity of organisms take place.

Global (biosphere) level. This level is highest form organization of living things (living systems). It is represented by the biosphere. At this level, all material and energy cycles are united into a single giant biosphere circulation of substances and energy.

There is a dialectical unity between different levels of organization of living things. Living things are organized according to the type of system organization, the basis of which is the hierarchy of systems. The transition from one level to another is associated with the preservation of functional mechanisms operating at previous levels, and is accompanied by the emergence of structure and functions of new types, as well as interaction characterized by new features, i.e., a new quality appears.