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 tissues 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 union 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 of 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 collection of organisms of different species and varying complexity of organization, adapted to the same conditions of the natural environment, is called a 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 solves global problems, for example, determining the intensity of the formation of free oxygen by the Earth's vegetation or changes in the concentration of carbon dioxide in the atmosphere associated with human activity. The main role at the biosphere level is played by “living substances,” that is, 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., environmental conditions). 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.
- Currently, there are several levels of organization of living organisms: molecular, cellular, tissue, organ, organismal, population-species, biogeocenotic and biosphere.
- At the population-species level, elementary evolutionary transformations are carried out.
- The cell is the most basic structural and functional unit of all living organisms.
- A collection of cells and intercellular substances similar in origin, structure and function forms tissue.
- The totality of all living organisms on the planet and their general natural habitat constitutes the biosphere level.
- Name the levels of life organization in order.
- What is fabric?
- What are the main parts of a cell?
- What organisms are characterized by the tissue level?
- Describe the organ level.
- What is a population?
- Describe the organismal level.
- Name the features of the biogeocenotic level.
- 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:
| Serial number |
Levels of organization |
Peculiarities |
An organism is a historically established integral, ever-changing system, which has its own special structure and differences, capable of metabolism with the environment, growth and reproduction. An organism lives only in certain environmental conditions to which it is adapted.
The body is built from individual private structures - organs, tissues and tissue elements, combined into a single whole.
In the process of evolution of living beings, first non-cellular forms of life (protein “moneras”, viruses, etc.) arose, then cellular forms (unicellular and simple multicellular organisms). With the further complication of organization, individual parts of organisms began to specialize in performing individual functions, thanks to which the organism adapted to the conditions of its existence. In this regard, specialized complexes of these structures - tissues, organs and, finally, complexes of organs - systems began to emerge from non-cellular and cellular structures.
Reflecting this process of differentiation, the human body contains all of these structures within its body. Cells in the human body, like all multicellular animals, exist only as part of tissues.
INTEGRITY OF THE ORGANISM
An organism is a living biological integral system with the ability to self-reproduce, self-development and self-government. An organism is a single whole, and “the highest form of integrity” (K. Marx). The body manifests itself as a whole in various aspects.
The integrity of the body, i.e. its unification (integration), is ensured, firstly: 1) by the structural connection of all parts of the body, cells, tissues, organs, fluids, etc.); 2) the connection of all parts of the body with the help of: a) fluids circulating in its vessels, cavities and spaces (humoral connection, humor - fluid), b) the nervous system, which regulates all processes of the body (nervous regulation).
In the simplest unicellular organisms that do not yet have a nervous system (for example, amoeba), there is only one type of communication - humoral. With the advent of the nervous system, two types of communication arise - humoral and nervous, and as the organization of animals becomes more complex and the nervous system develops, the latter increasingly “takes control of the body” and subordinates all processes of the body, including humoral ones, as a result of which a unified neurohumoral regulation is created with the leading role of the nervous system.
Thus, the integrity of the body is achieved through the activity of the nervous system, which permeates with its branches all the organs and tissues of the body and which is the material anatomical substrate for the unification (integration) of the body into a single whole, along with the humoral connection.
The integrity of the organism lies, secondly, in the unity of the vegetative (plant) and animal (animal) processes of the body.
The integrity of the organism lies, thirdly, in the unity of spirit and body, the unity of the mental and somatic, bodily. Idealism separates the soul from the body, considering it independent and unknowable. Dialectical materialism believes that there is no psyche separated from the body. It is a function of a bodily organ - the brain, which represents the most highly developed and specially organized matter capable of thinking. Therefore, “it is impossible to separate thinking from the matter that thinks.”
This is the modern understanding of the integrity of the organism, built on the principles of dialectical materialism and its natural scientific basis - the physiological teachings of I. P. Pavlov.
The relationship between the organism as a whole and its constituent elements. The whole is a complex system of relationships between elements and processes, which has a special quality that distinguishes it from other systems; a part is an element of the system subordinate to the whole.
The body as a whole is more than the sum of its parts (cells, tissues, organs). This “more” is a new quality that arose due to the interaction of parts in the process of phylogeny and ontogenesis. A special quality of an organism is its ability to exist independently in a given environment. So, a single-celled organism; for example, amoeba) has the ability to live independently, and a cell that is part of the body (for example, a leukocyte) cannot exist outside the body and, when removed from the blood, dies. Only with artificial
under certain conditions, isolated organs and cells can exist (tissue culture). But the functions of such isolated cells are not identical to the functions of the cells of the whole organism, since they are excluded from the general exchange with other tissues.
The organism as a whole plays a leading role in relation to its parts, the expression of which is the subordination of the activities of all organs of neurohumoral regulation. Therefore, organs isolated from the body cannot perform the functions that are inherent to them within the whole organism. This explains the difficulty of organ transplantation. The organism as a whole can exist even after the loss of some parts, as evidenced by the surgical practice of surgical removal of individual organs and parts of the body (removal of one kidney or one lung, amputation of limbs, etc.).
The subordination of a part to the whole is not absolute, since the part has relative independence.
Possessing relative independence, a part can influence the whole, as evidenced by changes in the whole organism during diseases of individual organs.
An organ (organon - instrument) is a historically established system of various tissues (often all four main groups), of which one or more predominate and determine its specific structure and function.
For example, the heart contains not only striated muscle tissue, but also various types of connective tissue (fibrous, elastic),
elements of the nervous (nerves of the heart), endothelium and smooth muscle fibers (vessels). However, cardiac muscle tissue is predominant, the property of which (contractility) determines the structure and function of the heart as an organ of contraction.
An organ is an integral formation that has a specific form, structure, function, development and position in the body that is unique to it.
Some organs are built from many structures similar in structure, which in turn consist of different tissues. Each such part of the organ has everything necessary to perform the function characteristic of the organ. For example, the lung acinus is a small part of the organ, but it contains epithelium, connective tissue, smooth muscle tissue in the walls of blood vessels, and nervous tissue (nerve fibers). The acini carries out the main function of the lung - gas exchange. Such formations are called the structural and functional unit of the organ.
The human body is in constant interaction with abiotic and biotic environmental factors, which influence and change it. The origin of man has been of interest to science for a long time, and theories of its origin are varied. This is also the fact that man originated from a small cell, which gradually, forming colonies of similar cells, became multicellular and in the process of a long course of evolution turned into an anthropoid ape, and which, thanks to work, became a man.
The concept of levels of organization of the human body
During biology lessons in secondary school, the study of a living organism begins with the study of a plant cell and its components. Already in high school, during lessons, schoolchildren are asked the question: “Name the levels of organization of the human body.” What it is?
The concept of “levels of organization of the human body” is usually understood as its hierarchical structure from a small cell to the organism level. But this level is not the limit, and it is completed by the supraorganismal order, which includes the population-species and biosphere levels.
When highlighting the levels of organization of the human body, their hierarchy should be emphasized:
- Molecular genetic level.
- Cellular level.
- Tissue level.
- Organ level
- Organismic level.
Molecular genetic level
The study of molecular mechanisms allows us to characterize it by such components as:
- carriers of genetic information - DNA, RNA.
- biopolymers are proteins, fats and carbohydrates.
At this level, genes and their mutations are identified as a structural element, which determine variability at the organismal and cellular level.
The molecular genetic level of organization of the human body is represented by genetic material, which is encoded in a chain of DNA and RNA. Genetic information reflects such important components of the organization of human life as morbidity, metabolic processes, type of constitution, gender component and individual characteristics of a person.
The molecular level of organization of the human body is represented by metabolic processes, which consist of assimilation and dissimilation, regulation of metabolism, glycolysis, crossing over and mitosis, meiosis.
Property and structure of the DNA molecule
The main properties of genes are:
- convariant reduplication;
- ability for local structural changes;
- transmission of hereditary information at the intracellular level.
The DNA molecule consists of purine and pyrimidine bases, which are connected by hydrogen bonds to each other and require the enzyme DNA polymerase to join and break them. Convariant reduplication occurs according to the matrix principle, which ensures their connection at the residue of the nitrogenous bases guanine, adenine, cytosine and thymine. This process occurs in 100 seconds, and during this time 40 thousand pairs of nucleotides are assembled.
Cellular level of organization
Studying the cellular structure of the human body will help to understand and characterize the cellular level of organization of the human body. The cell is a structural component and consists of elements of D. I. Mendeleev’s periodic table, of which the most predominant are hydrogen, oxygen, nitrogen and carbon. The remaining elements are represented by a group of macroelements and microelements.
Cell structure
The cell was discovered by R. Hooke in the 17th century. The main structural elements of a cell are the cytoplasmic membrane, cytoplasm, cell organelles and nucleus. The cytoplasmic membrane consists of phospholipids and proteins as structural components to provide the cell with pores and channels for the exchange of substances between cells and the entry and exit of substances from them.
Cell nucleus
The cell nucleus consists of the nuclear envelope, nuclear sap, chromatin and nucleoli. The nuclear envelope performs a formative and transport function. Nuclear sap contains proteins that are involved in the synthesis of nucleic acids.
- storage of genetic information;
- reproduction and transmission;
- regulation of cell activity in its life-supporting processes.
Cell cytoplasm
The cytoplasm consists of general-purpose and specialized organelles. Organelles of general purpose are divided into membrane and non-membrane.
The main function of the cytoplasm is the constancy of the internal environment.
Membrane organelles:
- Endoplasmic reticulum. Its main tasks are the synthesis of biopolymers, intracellular transport of substances, and is a depot of Ca+ ions.
- Golgi apparatus. Synthesizes polysaccharides, glycoproteins, participates in protein synthesis after its release from the endoplasmic reticulum, transports and ferments secretions in the cell.
- Peroxisomes and lysosomes. They digest absorbed substances and break down macromolecules, neutralizing toxic substances.
- Vacuoles. Storage of substances and metabolic products.
- Mitochondria. Energy and respiratory processes inside the cell.
Non-membrane organelles:
- Ribosomes. Proteins are synthesized with the participation of RNA, which transfers genetic information about the structure and synthesis of proteins from the nucleus.
- Cellular center. Participates in cell division.
- Microtubules and microfilaments. They perform a supporting and contractile function.
- Cilia.
Specialized organelles are the sperm acrosome, small intestinal microvilli, microtubules and microcilia.
Now, to the question: “Characterize the cellular level of organization of the human body,” we can safely list the components and their role in organizing the structure of the cell.
Tissue level
In the human body, it is impossible to distinguish a level of organization in which some tissue consisting of specialized cells would not be present. Tissues are composed of cells and intercellular substance and, according to their specialization, are divided into:
- Nervous. Integrates the external and internal environment, regulates metabolic processes and higher nervous activity.
The levels of organization of the human body smoothly transition into each other and form an integral organ or system of organs that line many tissues. For example, the gastrointestinal tract, which has a tubular structure and consists of a serous, muscular and mucous layer. In addition, it has blood vessels and a neuromuscular system that feed it, which is controlled by the nervous system, as well as many enzymatic and humoral control systems.
Organ level
All levels of organization of the human body listed earlier are components of organs. Organs perform specific functions to ensure constancy of the internal environment and metabolism in the body and form systems of subsystems subordinate to it, which perform a specific function in the body. For example, the respiratory system consists of the lungs, airways, and respiratory center.
The levels of organization of the human body as a single whole represent an integrated and completely self-sustaining system of organs that forms the body.
The body as a whole
The combination of systems and organs forms an organism in which the integration of systems, metabolism, growth and reproduction, plasticity, and irritability takes place.
There are four types of integration: mechanical, humoral, nervous and chemical.
Mechanical integration is carried out by intercellular substance, connective tissue, and auxiliary organs. Humoral - blood and lymph. Nervous is the highest level of integration. Chemical - hormones of the endocrine glands.
The levels of organization of the human body are a hierarchical complication in the structure of its body. The organism as a whole has a physique - an external integrated form. Physique is the external appearance of a person, which has different gender and age characteristics, the structure and position of internal organs.
There are asthenic, normosthenic and hypersthenic types of body structure, which are differentiated by height, skeleton, muscles, and the presence or absence of subcutaneous fat. Also, depending on your body type, organ systems have different structures and positions, sizes and shapes.
The concept of ontogenesis
The individual development of an organism is determined not only by genetic material, but also by external environmental factors. Levels of organization of the human body, the concept of ontogenesis, or the individual development of the organism in the process of its development, uses different genetic materials involved in the functioning of the cell during its development. The work of genes is influenced by the external environment: through environmental factors, renewal occurs, the emergence of new genetic programs and mutations.
For example, hemoglobin changes three times during the entire development of the human body. Proteins that synthesize hemoglobin go through several stages from fetal hemoglobin, which passes into fetal hemoglobin. As the body matures, hemoglobin transforms into its adult form. These ontogenetic characteristics of the level of development of the human body briefly and clearly emphasize that the genetic regulation of the organism plays an important role in the process of development of the organism from cells to systems and the organism as a whole.
The study of organization allows us to answer the question: “What are the levels of organization of the human body?” The human body is regulated not only by neurohumoral mechanisms, but also by genetic ones, which are located in every cell of the human body.
The levels of organization of the human body can be briefly described as a complex subordinate system, which has the same structure and complexity as the entire system of living organisms. This pattern is an evolutionarily fixed feature of living organisms.
The levels of organization of living systems represent a certain orderliness, a hierarchical system, which is one of the main properties of living things, see table. 2.
table 2
Each living system consists of units of subordinate levels of organization and is a unit that is part of the living system to which it is subordinate. For example, an organism consists of cells that are living systems and is part of non-organismal biosystems (populations, biocenoses).
The existence of life at all levels is prepared and determined by the structure of the lower level:
· the nature of the cellular level of organization is determined by the molecular; · the nature of the organism is cellular; · population-specific – organismal, etc.
1. Molecular level. The molecular level bears separate, albeit significant, signs of life. At this level, an amazing monotony of discrete units is revealed. The basis of all animals, plants and viruses is 20 amino acids and 4 identical bases that make up nucleic acid molecules. In all organisms, biological energy is stored in the form of energy-rich adenosine triphosphoric acid (ATP). Everyone's hereditary information is contained in deoxyribonucleic acid (DNA) molecules, which are capable of self-reproduction. The implementation of hereditary information is carried out with the participation of ribonucleic acid (RNA) molecules.
2. Cellular level. The cell is the basic independently functioning elementary biological unit, characteristic of all living organisms. In all organisms, the biosynthesis and implementation of hereditary information is possible only at the cellular level. The cellular level in unicellular organisms coincides with the organismal level. There was a period in the history of life on our planet (the first half of the Proterozoic era ~ 2000 million years ago) when all organisms were at this level of organization. All species, biocenoses and the biosphere as a whole consisted of such organisms.
3. Tissue level. A collection of cells with the same type of organization constitutes a tissue. The tissue level arose with the emergence of multicellular animals and plants with different tissues. Great similarity between all organisms remains at the tissue level.
4. Organ level. Cells that function together and belong to different tissues make up organs. (Only six main tissues make up the organs of all animals, and six main tissues form the organs of plants).
5. Organismic level. At the organismal level, an extremely large variety of forms is found. The diversity of organisms belonging to different species, as well as within the same species, is explained not by the diversity of discrete units of a lower order (cells, tissues, organs), but by the complication of their combinations, which provide the qualitative characteristics of organisms. Currently, more than a million animal species and about half a million plant species live on Earth. Each species consists of separate individuals (organisms, individuals) that have their own distinctive features.
6. Population-species level. A collection of organisms of the same species inhabiting a certain territory constitutes a population. A population is an underorganized living system, which is an elementary unit of the evolutionary process; the processes of speciation begin in it. The population is part of biocenoses.
7. Biocenotic level. Biogeocenoses are historically established stable communities of populations of various species connected to each other and the environment by metabolism, energy and information. They are elementary systems in which the material-energy cycle occurs, determined by the vital activity of organisms.
8. Biosphere level. The totality of biogeocenoses constitutes the biosphere and determines all the processes occurring in it.
Thus, we see that the question of structural levels in biology has some features compared to its consideration in physics. This feature is that the study of each level of organization in biology sets as its main goal the explanation of the phenomenon of life. Indeed, if in physics the division into structural levels of matter is quite arbitrary (the criteria here are mass and size), then levels of matter in biology differ not so much in size or levels of complexity, but mainly in their patterns of functioning.
Indeed, if, for example, a researcher studied the physicochemical properties of a biological object and its structure, but did not establish its biological purpose in the entire system, this would mean that another specific object was studied, but not the level of living matter.
Another feature of the structuring of living matter is hierarchical [ 2] subordination levels. This means that the lower levels as a whole are included in the higher ones. This concept of structuring is called the “multi-level hierarchical nesting doll.”
It is also important to note that the number of levels allocated in biology depends on the depth of professional study of the living world.
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Control questions
1. Define biology. What is the subject of studying biology? 2. Name the main methods of biology. 3. List the main classifications of biological sciences. 4. Characterize traditional (naturalistic) biology. 5. What are the features of physical and chemical biology?
6. What does molecular biology study? 7. List the main experimental methods of physical and chemical biology. 8. What does evolutionary biology study? 9. What is theoretical biology? List the main prerequisites (theoretical principles) for its creation. 10. What is a biological system?
11. Name three main systemic properties of living things. 12. List the main qualities of living systems. 13. What is the openness of living systems? 14. Explain the statement: “Living systems are self-governing and self-organizing.” 15. What is the irritability of living systems?
16. “The only way to define what is alive is...” (continue). 17. What is the peculiarity of structural levels in biology compared to the structuring of matter in physics? 18. What is the concept of a multi-level hierarchical “matryoshka”? 19. List the structural levels of the organization of living things. 20. What is a population? 21. What is biogeocenosis? Ecological system?
Literature
1. Tulinov V.D., Nedelsky N.F., Oleynikov B.I. Concepts of modern natural science, M.: MUPC, 1995. 2. Kuznetsov V.I., Idlis G.M., Gutina V.N. Natural history M.: Agar, 1995. 3. Gryadovoy D.I. Concepts of modern natural science, M.: Uchpediz, 1995. 4. Dyagilev F.M. Concepts of modern natural science, M.: IMPE, 1998. 5. Yablokov A.V., Yusufov A.G. Evolutionary doctrine. – M.: Higher School, 1998.
[ 1] Chirality is the mirror asymmetry of molecules. The molecules from which living matter is formed can be of only one orientation - “left” or “right”. For example, the DNA molecule looks like a spiral, and this spiral is always right-handed.
[ 2] Hierarchy - arrangement of parts or elements of a whole in order from highest to lowest
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