properties of living organisms. The ability of living organisms to respond to external influences is an innate property and a protective reaction. The result of the manifestation of which property of living organisms
The concept of a biosystem. According to modern concepts, living matter exists in the form living systems - biosystems. Recall that a system is called a holistic formation, created by a set of elements that are naturally connected with each other and perform special functions.
Living systems, or biosystems, are cells and organisms, species and populations, biogeocenoses and the biosphere (universal, global biosystem). In these biosystems of different complexity, life is manifested by a number of common properties of living matter.
Life properties. In biology, for a long time, the properties of living things have traditionally been considered using the example of such biosystems as an organism.
All living beings (both unicellular and multicellular) have the following distinctive properties: metabolism, irritability, mobility, the ability to grow and develop, reproduction (self-reproduction), the transfer of properties from generation to generation, orderliness in structure and functions, integrity and discreteness (isolation), energy dependence on the external environment. Living beings are also characterized by a specific relationship between themselves and with the environment, which provides them with a mobile balance (dynamic stability) of existence in nature. These properties are considered universal, as they are characteristic of all organisms. Some of these properties can also be in inanimate nature, but together they are characteristic only of living things. Let us briefly characterize these properties.
The unity of the chemical composition. Living organisms consist of the same chemical elements as the bodies of inanimate nature, but the ratio of these elements is characteristic only for the living. In living systems, about 98% of the chemical composition is accounted for by four chemical elements ( carbon, oxygen, nitrogen and hydrogen), which are part of organic substances, and in the total mass of body substances, the main share is water (at least 70-85%).
The unity of the structural organization. The unit of structure, life, reproduction and individual development is cell. No life has been found outside the cell.
Metabolism and energy is a set of chemical reactions that ensure the entry of energy and chemical compounds into the body from the external environment, their transformation in the body and removal from the body into the environment in the form of converted energy and waste products. Metabolism and energy flow realizes the connection of the organism with the external environment, which is the condition of his life.
Reproduction (self-reproduction)- this is the most important property of life, the essence of which was figuratively expressed by Louis Pasteur: "All living things come only from living things." Life, having once arisen by spontaneous generation, since then gives rise only to the living. This property is based on the unique ability to self-reproduce the main control systems of the body: chromosomes, DNA, genes. In this connection heredity as a mechanism of self-reproduction is a unique property of only living beings. Sometimes the reproduction of living organisms occurs with the introduction of changes that have arisen through mutations. Such changes, which cause the appearance of variability, can give some deviations from the initial state and diversity during reproduction.
Ability to grow and develop. Growth is an increase in the mass and size of an individual due to an increase in the mass and number of cells. Development is an irreversible, naturally directed process of qualitative changes in an organism from the moment of its birth to death. Distinguish between the individual development of organisms, or ontogenesis (Greek. ontos- "existing"; genesis- "origin"), and historical development - evolution. Evolution is an irreversible transformation of living nature, accompanied by the emergence of new species adapted to new environmental conditions.
Heredity- the property of living organisms to ensure material and functional continuity between generations, as well as to determine the specific nature of individual development in certain environmental conditions.
This property is carried out in the process of transferring the material units of heredity - the genes responsible for the formation of the characteristics and properties of the organism.
Variability- the property of living organisms to exist in various forms. Variation can be realized in individual organisms or cells in the course of individual development or within a group of organisms in a series of generations during sexual or asexual reproduction.
Irritability are the specific responses of organisms to changes in the environment. Responding to the influence of environmental factors with an active reaction of irritability, organisms interact with the environment and adapt to it, which helps them survive. The manifestations of irritability can be different: the mobility of animals in obtaining food, in protection from adverse conditions, in danger; oriented growth movements (tropisms) in plants and fungi towards the light, in search of mineral nutrition, etc.
Energy dependence. All organisms need energy for the implementation of vital processes, for movement, maintaining their orderliness, for reproduction. In most cases, organisms use solar energy for this: some directly are autotrophs (green plants and cyanobacteria), others indirectly, in the form of organic substances of food consumed, are heterotrophs (animals, fungi, bacteria and viruses). On this basis, all living systems are considered open systems, stably existing under conditions of continuous influx of matter and energy from the external environment and the removal of some of them after use by the biosystem into the external environment.
discreteness(lat. discretus- "divided", "isolated") and integrity. All organisms are relatively isolated from each other and represent well-distinguished individuals, populations, species, and other biosystems. Discreteness is the discontinuity of the structure of any living system, that is, the possibility of its division into separate components. Integrity is the structural and functional unity of a living system, the individual elements of which function as a single whole.
Rhythm are periodically recurring changes in the intensity and nature of biological processes and phenomena.
Rhythm is based on biological rhythms, which can have a period corresponding to a solar day (24 hours), a lunar day (12.4 or 24.8 hours), a lunar month (29.53 days) and an astronomical year.
Organisms in the course of their existence produce an environment-forming action of great importance. For example, earthworms are involved in soil formation and increase its fertility; plants enrich the atmosphere with oxygen, provide snow retention, regulate the level of groundwater, create the necessary conditions for their existence and for the settlement of organisms of other species. Thus, living beings depend on the environment, adapt to existence in it. At the same time, the environment itself changes due to the vital activity of organisms.
Living things are also characterized by certain rhythms of life processes, depending on the daily and seasonal dynamics of changes in weather and climate conditions on Earth.
All these criteria in their totality, characteristic only for wildlife, make it possible to clearly separate the living from the inanimate world.
The uniqueness of life lies in the fact that it arose on the Earth itself as a result of long-term geochemical transformations (a stage of chemical evolution in the history of our planet). Having once arisen, life from primitive unicellular living beings in the course of a long historical development (the stage of biological evolution) has reached a high degree of complexity and acquired a surprisingly large variety of its forms.
Thus, life is a special form of the motion of matter, expressed in the cumulative interaction of the universal properties of organisms.
As we can see, the modern understanding of life, along with its traditional characteristics (metabolism, growth, development, reproduction, heredity, irritability, etc.), includes such properties as orderliness, discreteness, and dynamic stability. At the same time, when characterizing the phenomenon of life, one should take into account its diversity and multi-quality, since it is represented on our planet by biosystems of varying complexity - from the molecular and cellular levels of organization to supra-organismal (biogeocenotic and biospheric).
A living organism is the main subject studied by such a science as biology. It is made up of cells, organs and tissues. A living organism is one that has a number of characteristic features. He breathes and eats, stirs or moves, and also has offspring.
Life Science
The term "biology" was introduced by J.B. Lamarck - a French naturalist - in 1802. At about the same time and independently of him, the German botanist G.R. gave such a name to the science of the living world. Treviranus.
Numerous branches of biology consider the diversity of not only currently existing, but also already extinct organisms. They study their origin and evolutionary processes, structure and function, as well as individual development and relationships with the environment and with each other.
Sections of biology consider particular and general patterns that are inherent in all living things in all properties and manifestations. This applies to reproduction, and metabolism, and heredity, and development, and growth.
The beginning of the historical stage
The first living organisms on our planet differed significantly in their structure from those currently existing. They were incomparably simpler. Throughout the entire stage of the formation of life on Earth, He contributed to the improvement of the structure of living beings, which allowed them to adapt to the conditions of the surrounding world.
At the initial stage, living organisms in nature ate only organic components that arose from primary carbohydrates. At the dawn of their history, both animals and plants were the smallest single-celled creatures. They were similar to today's amoebas, blue-green algae and bacteria. In the course of evolution, multicellular organisms began to appear, which were much more diverse and more complex than their predecessors.
Chemical composition
A living organism is one that is formed by molecules of inorganic and organic substances.
The first of these components is water, as well as mineral salts. found in the cells of living organisms are fats and proteins, nucleic acids and carbohydrates, ATP and many other elements. It is worth noting the fact that living organisms in their composition contain the same components that objects have. The main difference is in the ratio of these elements. Living organisms are those ninety-eight percent of whose composition is hydrogen, oxygen, carbon and nitrogen.
Classification
The organic world of our planet today has almost one and a half million diverse animal species, half a million plant species, and ten million microorganisms. Such diversity cannot be studied without its detailed systematization. The classification of living organisms was first developed by the Swedish naturalist Carl Linnaeus. He based his work on the hierarchical principle. The unit of systematization was the species, the name of which was proposed to be given only in Latin.
The classification of living organisms used in modern biology indicates family ties and evolutionary relationships of organic systems. At the same time, the principle of hierarchy is preserved.
The totality of living organisms that have a common origin, the same chromosome set, adapted to similar conditions, living in a certain area, freely interbreeding and producing offspring capable of reproduction, is a species.
There is another classification in biology. This science divides all cellular organisms into groups according to the presence or absence of a formed nucleus. This
The first group is represented by nuclear-free primitive organisms. A nuclear zone stands out in their cells, but it contains only a molecule. These are bacteria.
The true nuclear representatives of the organic world are eukaryotes. The cells of living organisms of this group have all the main structural components. Their core is also clearly defined. This group includes animals, plants and fungi.
The structure of living organisms can be not only cellular. Biology studies other forms of life. These include non-cellular organisms, such as viruses, as well as bacteriophages.
Classes of living organisms
In biological systematics, there is a rank of hierarchical classification, which scientists consider one of the main ones. He distinguishes classes of living organisms. The main ones include the following:
bacteria;
Animals;
Plants;
Seaweed.
Description of classes
A bacterium is a living organism. It is a unicellular organism that reproduces by division. The cell of a bacterium is enclosed in a shell and has a cytoplasm.
Mushrooms belong to the next class of living organisms. In nature, there are about fifty thousand species of these representatives of the organic world. However, biologists have studied only five percent of their total. Interestingly, fungi share some characteristics of both plants and animals. An important role of living organisms of this class lies in the ability to decompose organic material. That is why mushrooms can be found in almost all biological niches.
The animal world boasts a great diversity. Representatives of this class can be found in areas where, it would seem, there are no conditions for existence.
Warm-blooded animals are the most highly organized class. They got their name from the way they feed their offspring. All representatives of mammals are divided into ungulates (giraffe, horse) and carnivores (fox, wolf, bear).
Representatives of the animal world are insects. There are a huge number of them on Earth. They swim and fly, crawl and jump. Many of the insects are so small that they are not even able to withstand water tension.
Amphibians and reptiles were among the first vertebrates that came to land in distant historical times. Until now, the life of representatives of this class is connected with water. So, the habitat of adults is dry land, and their breathing is carried out by lungs. The larvae breathe through gills and swim in the water. Currently, there are about seven thousand species of this class of living organisms on Earth.
Birds are unique representatives of the fauna of our planet. Indeed, unlike other animals, they are able to fly. Almost eight thousand six hundred species of birds live on Earth. Representatives of this class are characterized by plumage and oviposition.
Fish belong to a huge group of vertebrates. They live in water bodies and have fins and gills. Biologists divide fish into two groups. These are cartilage and bone. Currently, there are about twenty thousand different types of fish.
Within the class of plants there is its own gradation. Representatives of the flora are divided into dicots and monocots. In the first of these groups, the seed contains an embryo consisting of two cotyledons. You can identify representatives of this species by the leaves. They are pierced with a mesh of veins (corn, beets). The embryo has only one cotyledon. On the leaves of such plants, the veins are arranged in parallel (onions, wheat).
The class of algae includes more than thirty thousand species. These are water-dwelling spore plants that do not have vessels, but have chlorophyll. This component contributes to the implementation of the process of photosynthesis. Algae do not form seeds. Their reproduction occurs vegetatively or by spores. This class of living organisms differs from higher plants in the absence of stems, leaves and roots. They have only the so-called body, which is called the thallus.
Functions inherent in living organisms
What is fundamental for any representative of the organic world? This is the implementation of the processes of energy and matter exchange. In a living organism, there is a constant transformation of various substances into energy, as well as physical and chemical changes.
This function is an indispensable condition for the existence of a living organism. It is thanks to metabolism that the world of organic beings differs from the inorganic. Yes, in inanimate objects there are also changes in matter and the transformation of energy. However, these processes have their fundamental differences. The metabolism that occurs in inorganic objects destroys them. At the same time, living organisms without metabolic processes cannot continue their existence. The consequence of metabolism is the renewal of the organic system. The cessation of metabolic processes entails death.
The functions of a living organism are varied. But all of them are directly related to the metabolic processes taking place in it. This can be growth and reproduction, development and digestion, nutrition and respiration, reactions and movement, excretion of waste products and secretion, etc. The basis of any function of the body is a set of processes of transformation of energy and substances. Moreover, this is equally relevant to the capabilities of both tissue, cell, organ, and the whole organism.
Metabolism in humans and animals includes the processes of nutrition and digestion. In plants, it is carried out with the help of photosynthesis. A living organism in the implementation of metabolism supplies itself with the substances necessary for existence.
An important distinguishing feature of the objects of the organic world is the use of external energy sources. An example of this is light and food.
Properties inherent in living organisms
Any biological unit has in its composition separate elements, which, in turn, form an inextricably linked system. For example, in the aggregate, all organs and functions of a person represent his body. The properties of living organisms are diverse. In addition to a single chemical composition and the possibility of implementing metabolic processes, objects of the organic world are capable of organization. Certain structures are formed from the chaotic molecular movement. This creates a certain order in time and space for all living things. Structural organization is a whole complex of the most complex self-regulating processes that proceed in a certain order. This allows you to maintain the constancy of the internal environment at the required level. For example, the hormone insulin reduces the amount of glucose in the blood when it is in excess. With a lack of this component, it is replenished by adrenaline and glucagon. Also, warm-blooded organisms have numerous mechanisms of thermoregulation. This is the expansion of skin capillaries, and intense sweating. As you can see, this is an important function that the body performs.
The properties of living organisms, characteristic only for the organic world, are also included in the process of self-reproduction, because the existence of any has a time limit. Only self-reproduction can sustain life. This function is based on the process of formation of new structures and molecules, due to the information that is embedded in DNA. Self-reproduction is inextricably linked with heredity. After all, each of the living beings gives birth to their own kind. Through heredity, living organisms transmit their developmental features, properties and signs. This property is due to constancy. It exists in the structure of DNA molecules.
Another property characteristic of living organisms is irritability. Organic systems always react to internal and external changes (impacts). As for the irritability of the human body, it is inextricably linked with the properties inherent in muscle, nervous, and glandular tissue. These components are able to give impetus to the response after muscle contraction, the departure of a nerve impulse, as well as the secretion of various substances (hormones, saliva, etc.). And if a living organism is deprived of the nervous system? The properties of living organisms in the form of irritability are manifested in this case by movement. For example, protozoa leave solutions in which the salt concentration is too high. As for plants, they are able to change the position of the shoots in order to absorb light as much as possible.
Any living system can respond to the action of a stimulus. This is another property of the objects of the organic world - excitability. This process is provided by muscle and glandular tissues. One of the final reactions of excitability is movement. The ability to move is a common property of all living things, despite the fact that outwardly some organisms are deprived of it. After all, the movement of the cytoplasm occurs in any cell. Attached animals also move. Growth movements due to an increase in the number of cells are observed in plants.
Habitat
The existence of objects of the organic world is possible only under certain conditions. Some part of space invariably surrounds a living organism or a whole group. This is the habitat.
In the life of any organism, organic and inorganic components of nature play a significant role. They have an effect on him. Living organisms are forced to adapt to existing conditions. So, some of the animals can live in the Far North at very low temperatures. Others are able to exist only in the tropics.
There are several habitats on planet Earth. Among them are:
Land-water;
ground;
soil;
Living organism;
Ground-air.
The role of living organisms in nature
Life on planet Earth has been around for three billion years. And during all this time organisms developed, changed, settled and at the same time affected their environment.
The influence of organic systems on the atmosphere caused the appearance of more oxygen. This significantly reduced the amount of carbon dioxide. Plants are the main source of oxygen production.
Under the influence of living organisms, the composition of the waters of the World Ocean has also changed. Some rocks are of organic origin. Minerals (oil, coal, limestone) are also the result of the functioning of living organisms. In other words, the objects of the organic world are a powerful factor that transforms nature.
Living organisms are a kind of indicator indicating the quality of the human environment. They are connected by complex processes with vegetation and soil. With the loss of at least a single link from this chain, an imbalance of the ecological system as a whole will occur. That is why it is important for the circulation of energy and substances on the planet to preserve all the existing diversity of representatives of the organic world.
Isolation of the general properties of living organisms will make it possible to unambiguously distinguish living from non-living. There is no exact definition of what life or a living organism is, therefore, a living being is identified by a complex of its properties, or signs.
Unlike bodies of inanimate nature, living organisms differ in the complexity of their structure and functionality. But if we consider each property separately, then some of them in one form or another can be observed in inanimate nature. For example, crystals can also grow. Therefore, the totality of the properties of living organisms is so important.
At first glance, the observed diversity of organisms makes it difficult to identify their common properties and characteristics. However, with the historical development of the biological sciences, many general patterns of life observed in completely different groups of organisms became apparent.
In addition to the properties of living things listed below, they are also often isolated unity of chemical composition(the similarity in all organisms and the difference in the ratios of elements between living and non-living), discreteness(organisms are made up of cells, species are made up of individuals, etc.), participation in the process of evolution, interaction of organisms with each other, mobility, rhythm and etc.
There is no unambiguous list of signs of a living thing; this is partly a philosophical question. Often, highlighting one property, the second becomes its consequence. There are signs of the living, consisting of a number of others. In addition, the properties of living things are closely interconnected, and this interdependence together gives such a unique phenomenon of nature as life.
Metabolism is the main property of living
All living organisms exchange substances with the environment: certain substances enter the body from the environment, others are released into the environment from the body. This characterizes the organism as an open system (also the flow through the system of energy and information). The presence of selective metabolism indicates that the organism is alive.
The metabolism in the body itself includes two opposite, but interconnected and balanced processes - assimilation (anabolism) and dissimilation (catabolism). Each of them consists of numerous chemical reactions, combined and ordered into cycles and chains of transformation of one substance into another.
As a result of assimilation, the structures of the body are formed and updated due to the synthesis of the necessary complex organic substances from simpler organic, as well as inorganic substances. As a result of dissimilation, the splitting of organic substances occurs, while simpler substances necessary for the body to assimilate are formed, and energy is also stored in ATP molecules.
Metabolism requires an influx of substances from the outside, and a number of dissimilation products do not find use in the body and must be removed from it.
All living organisms somehow eat. Food serves as a source of necessary substances and energy. Plants feed on the process of photosynthesis. Animals and fungi absorb the organic substances of other organisms, after which they break them down into simpler components, from which they synthesize their substances.
It is common for living organisms selection a number of substances (in animals, these are mainly the breakdown products of proteins - nitrogenous compounds), which are the end products of metabolism.
An example of an assimilation process is protein synthesis from amino acids. An example of dissimilation is the oxidation of organic matter with the participation of oxygen, resulting in the formation of carbon dioxide (CO 2) and water, which are excreted from the body (water can be used).
Energy dependence of the living
For the implementation of vital processes, organisms need an influx of energy. In heterotrophic organisms, it enters with food, that is, their metabolism and energy flow are connected. During the breakdown of nutrients, energy is released, stored in other substances, and some is dissipated in the form of heat.
Plants are autotrophs and receive initial energy from the Sun (they capture its radiation). This energy goes to the synthesis of primary organic substances (in which it is stored) from inorganic ones. This does not mean that chemical reactions of decomposition (dissimilation) of organic substances do not occur in plants to obtain energy. However, plants do not receive organic matter from the outside through nutrition. She is completely "their own".
Energy goes to support the orderliness, structuredness of living organisms, which is important for the occurrence of numerous chemical reactions in them. The opposition to entropy is an important property of the living.
Breath- This is a process characteristic of living organisms, as a result of which the splitting of high-energy compounds occurs. The energy released in this process is stored in ATP.
In inanimate nature (when processes are left to chance), the structuredness of systems is sooner or later lost. In this case, one or another equilibrium is established (for example, a hot body gives off heat to others, the temperature of the bodies equalizes). The less order, the more entropy. If the system is closed and there are processes that do not balance each other, then the entropy increases (the second law of thermodynamics). Living organisms have the ability to reduce entropy by maintaining the internal structure due to the influx of energy from outside.
Heredity and variability as a property of the living
The self-renewal of the structures of living organisms, as well as the reproduction (self-reproduction) of organisms, is based on heredity, which is associated with the characteristics of DNA molecules. At the same time, changes can appear in DNA that lead to the variability of organisms and provide the possibility of the evolutionary process. Thus, living organisms have genetic (biological) information, which can also be designated as the main and exclusive feature of the living.
Despite the ability to self-renewal, it is not eternal in organisms. The lifespan of an individual is limited. However, the living remains immortal through the process breeding which can be either sexual or asexual. In this case, the traits of the parents are inherited by passing on their DNA to the descendants.
Biological information is recorded using a special genetic code that is universal for all organisms on Earth, which may indicate the unity of the origin of living things.
The genetic code is stored and implemented in biological polymers: DNA, RNA, proteins. Such complex molecules are also a feature of the living.
The information stored in DNA, when transferred to proteins, is expressed for living organisms in such properties as their genotype and phenotype. All organisms have them.
Growth and development - properties of living organisms
Growth and development are the properties of living organisms realized in the process of their ontogenesis (individual development). Growth is an increase in the size and weight of the body while maintaining the general plan of the structure. In the process of development, the organism changes, it acquires new features and functionality, others may be lost. That is, as a result of development, a new qualitative state arises. In living organisms, growth is usually accompanied by development (or development by growth). Development is directed and irreversible.
In addition to individual development, the historical development of life on Earth is distinguished, which is accompanied by the formation of new species and the complication of life forms.
Although growth can also be observed in inanimate nature (for example, in crystals or cave stalagmites), its mechanism in living organisms is different. In inanimate nature, growth is carried out by simply attaching a substance to the outer surface. Living organisms grow at the expense of nutrients ingested. At the same time, not so much the cells themselves increase in them, but their number increases.
Irritability and self-regulation
Living organisms have the ability to change their state within certain limits depending on the conditions of both the external and internal environment. In the process of evolution, species have developed various ways of registering environmental parameters (among other things through the sense organs) and responding to various stimuli.
The irritability of living organisms is selective, that is, they react only to what is important for their survival.
Irritability underlies the body's self-regulation, which, in turn, has an adaptive value. So, with an increase in body temperature in mammals, blood vessels expand, giving off heat to the environment in greater quantities. As a result, the temperature of the animal is normalized.
In higher animals, many reactions to external stimuli depend on fairly complex behavior.
Living systems have common features:
1. unity of chemical composition testifies to the unity and connection of living and inanimate matter.
Example:
the composition of living organisms includes the same chemical elements as in objects of inanimate nature, but in different quantitative ratios (i.e., living organisms have the ability to selectively accumulate and absorb elements). More than \(90\)% of the chemical composition falls on four elements: C, O, N, H, which are involved in the formation of complex organic molecules (proteins, nucleic acids, carbohydrates, lipids).
2. Cellular structure (Unity of structural organization). All organisms on earth are made up of cells. There is no life outside the cell.
3. Metabolism (Openness of living systems). All living organisms are "open systems".
System openness- a property of all living systems associated with a constant supply of energy from the outside and the removal of waste products (an organism is alive while it exchanges substances and energy with the environment).
Metabolism - a set of biochemical transformations occurring in the body and other biosystems.
Metabolism consists of two interrelated processes: the synthesis of organic substances (assimilation) in the body (due to external energy sources - light and food) and the process of decomposition of complex organic substances (dissimilation) with the release of energy, which is then consumed by the body. Metabolism ensures the constancy of the chemical composition in continuously changing environmental conditions.
4. Self-play (Reproduction)- the ability of living systems to reproduce their own kind. The ability to self-reproduce is the most important property of all living organisms. It is based on the process of duplication of DNA molecules with subsequent cell division.
5. Self-regulation (Homeostasis)- maintaining the constancy of the internal environment of the body in continuously changing environmental conditions. Any living organism ensures the maintenance of homeostasis (the constancy of the internal environment of the body). Persistent violation of homeostasis leads to the death of the body.
6. Development and growth. The development of the living is represented by the individual development of the organism (ontogenesis) and the historical development of living nature (phylogenesis).
- In the process of individual development, the individual properties of the organism are gradually and consistently manifested and its growth is carried out (all living organisms grow during their life).
- The result of historical development is a general progressive complication of life and all the diversity of living organisms on Earth. Development is understood as both individual development and historical development.
7. Irritability- the ability of the body to selectively respond to external and internal stimuli (reflexes in animals; tropisms, taxises and nastia in plants).
8. Heredity and variability are factors of evolution, because they produce material for selection.
- Variability- the ability of organisms to acquire new features and properties as a result of the influence of the external environment and / or changes in the hereditary apparatus (DNA molecules).
- Heredity- the ability of an organism to pass on its characteristics to subsequent generations.
9. Ability to adapt- in the process of historical development and under the influence of natural selection, organisms acquire adaptations to environmental conditions (adaptation). Organisms that do not have the necessary adaptations die out.
10. Integrity (Continuity) And discreteness (discontinuity). Life is integral and at the same time discrete. This pattern is inherent in both structure and function.
Any organism is an integral system, which at the same time consists of discrete units - cellular structures, cells, tissues, organs, organ systems. The organic world is integral, since all organisms and the processes occurring in it are interconnected. At the same time, it is discrete, as it is composed of individual organisms.
Some of the properties listed above may also be inherent in inanimate nature.
Example:
living organisms are characterized by growth, but crystals also grow! Although this growth does not have those qualitative and quantitative parameters that are inherent in the growth of living things.
Example:
a burning candle is characterized by the processes of energy exchange and transformation, but it is not capable of self-regulation and self-reproduction.
Biology is a science that studies life in all directions and the general properties of living things.
According to Engels, life is a way of existence of protein bodies, the essential moment of which is yavl. a constant exchange of substances with the environment, with the termination of which life ceases, which leads to the breakdown of proteins.
Modern definition: living bodies that exist on Earth are open self-regulating and self-reproducing systems built from biopolymers - proteins and nucleic acids.
Living organisms are characterized by properties that distinguish them from objects of inanimate nature:
1. certain chemical composition.
The composition of living organisms includes the same chemical elements as in inanimate objects, but in different proportions. Out of 100 elements, 20 are needed. Obligatory (organogenic) elements are distinguished - hydrogen, carbon, oxygen, nitrogen.
Sodium, potassium, calcium, magnesium, sulfur, phosphorus are also important. All organisms are built from proteins, fats, carbohydrates and nucleic acids.
2. The presence of a cellular structure (except bacteria).
A cell is a structural and functional unit of the living.
3. Metabolism and energy dependence.
A living organism is an open stable system, which, when energy is supplied from outside, is in dynamic equilibrium.
4. The ability to self-regulate.
Homeostasis is the ability to maintain the constancy of chemical and physical properties.
Indicators of homeostasis: temperature, pressure, amount of water, energy, rate of metabolic processes.
In tissues, the indicator of homeostasis is the number of cells.
In the organs - the intensity of work.
In populations, the ratio of age groups and sex composition.
5. The ability to reproduce itself.
a. Reproduction of one's own kind.
b. Transfer of hereditary information.
c. The main carrier of information yavl. chromosomes.
6. Heredity.
Heredity is the ability of living organisms to transmit traits and properties from generation to generation using DNA and RNA. Patterns are studied by genetics. Mendel suggested that traits are determined by genes. A gene is a section of a DNA molecule that codes for the primary structure of a protein.
Gene - protein - sign.
7. Variability.
Variability is the ability of living organisms to acquire new features and properties in the process of individual development. Variation creates material for natural selection.
8. Individual development.
Ontogenesis is the process of individual development of an organism from the moment of fertilization to the moment of death. Development is accompanied by growth, the duration of growth is limited by aging processes.
Ι. Proenthogenesis-gametogenesis, fertilization.
ΙΙ. The embryonic period is birth.
ΙΙΙ. Postembryonic - juvenile, stage of maturity, stage of old age.
9. Historical development.
Phylogeny - the historical development of the world; irreversible and directed development of wildlife, accompanied by the emergence of new species and the progressive complication of life. All the diversity of plant and animal species is the result of evolution.
10. Irritability.
Irritability is the ability of living organisms to respond to external and internal stimuli with specific reactions.
phototropism (turning leaves towards the sun);
geotropism (growth of the root tip in relation to the center of the Earth);
taxis (unidirectional movement TO or FROM the source of irritation);
reflex (the property of the body to respond to the action of stimuli with the mandatory participation of the nervous system).
11. Movement.
Organisms can move in a variety of ways:
a. Ameboid - with the help of pseudopods (common amoeba, leukocytes);
b. Reactive - by shooting a jet of water (jellyfish, cephalopods);
c. Ciliary - with the help of cilia - cell outgrowths surrounded by a cytolemma (ciliates-shoe).
d. Flagella - with the help of a flagellum - an outgrowth of a cell surrounded by a cytolemma, but longer than a cilia (euglena green, Volvox, sperm).
e. With the help of contractile muscles.
12. Rhythm.
Rhythm is the repetition of body states over a period of time in response to changes in the external environment. Biorhythms (ectogenous - external; endogenous - internal).
13. integrity and discreteness.
On the one hand, living nature is integral, organized, subject to certain laws. On the other hand, nature is discrete, i.e. Any biological system consists of isolated, but closely related elements.
The principle of discreteness formed the basis of ideas about the level of organization of living matter.
Levels of organization of living nature.
The level of organization of living nature is the functional place of a given biological system of a certain degree of complexity in the general system of living things.
The development of levels in the process of origin from the lower to the higher, with the advent of a higher level, the previous one did not disappear, but only lost its leading role, was included as a subordinate structure or functional unit.
Table number 1. Levels of organization of the living.
| Level name | Biosystem | concept | Elements, arr. system. | Science |
| Molecular genetic. (exchange of in-in and transmission of inherited information) | Biopolymers (proteins, nucleic acids, polysaccharides). | Biopolymers- complex organic substances with a huge molecular weight, consisting of monomers. | AA, nucleotides, monosaccharides | Genetics Mol. Biology Biochemistry Biophysics |
| Cellular. (except viruses) | Cell | Cell- structural and functional unit of the living. | Shell Cytoplasm Nucleus | Cytology |
| Organismic. Subordinates sublevels: Tissue Organ. | Tissue => Organs => Organ systems => Organism | Textile- a set of cells that are similar in structure, origin and perform common functions. Organ- a part of the body that performs certain functions. Organ system- a number of organs that have a common structural plan, unity of origin and perform one large function. organism- any creature that has the properties of a living thing. | Cells. Intercellular in-in. Textile. Organ systems | Histology Anatomy Physiology |
| supraorganismal levels | ||||
| Population-species. Subordinates: Population Species | Population Species | population- a set of individuals of the same species inhabiting a space with homogeneous conditions. View- a set of populations, individuals of which occupy a certain area, capable of interbreeding and producing fertile offspring. | Individuals Populations | Population ecology |
| Biogeocenotic | Biogeocenosis (community of living organisms) + Biotope (section of an abiotic environment) | Biogeocenosis- a set of organisms of different species living in a certain territory and interconnected by spatial and digestive ties. Main function - the circulation of matter and energy, which consists in the transformation of the energy of the Sun into all types of energy. | Kinds | Community ecology |
| biospheric | Biosphere | Biosphere- the shell of the Earth, inhabited by living organisms, includes the lower part of the atmosphere, the entire hydrosphere and the upper part of the lithosphere. | Biogeocenoses | Ecology |
Section 1.
Fundamentals of Cytology. The concept of cytology. The subject and task of cytology.
Cytology - a science that studies the structure, chemical composition, development and functions, the processes of reproduction, restoration and adaptation of the cell to changing environmental conditions.
Cytology, as an independent science, arose in the middle of the 10th century with the publication of cell theory of Schleiden and Schwann (1838-1839). Over the past 20-30 years, it has turned from a descriptive science into an experimental one.
The task of modern cytology: the study of the detailed structure of cells and their functioning; study of the functions of individual components, reproduction of cells and adaptation to the environment.
Cytology is the foundation for a number of sciences (anatomy, histology, genetics, physiology, biochemistry, ecology). Cytology is of great importance for medicine. any diseases have a pathology of specific cells, which is important for understanding the development of the disease, diagnosis, treatment and prevention.
History of the development of cytology.
The development of cytology is associated with the creation and improvement of optical devices that allow one to examine and study cells.
1610 - Dutch scientist Galileo Galilei constructed the first microscope, and after its improvement in 1924, it could be used for the first studies.
1665 - English scientist R. Hooke, using magnifying lenses, observed in a thin section of a cork plate and called them cells.
In the second half of the 15th century, Hooke's descriptions formed the basis of Malpighe's studies of plant anatomy, which confirmed Hooke's theory.
1680 - Dutch scientist Anthony van Leeuwenhoek discovered the world of unicellular organisms and saw animal cells. He discovered and described erythrocytes, spermatozoa, heart muscle cells.
Further progress in the study of the cell is associated with the development of microscopy in the 19th century. Ideas about the structure of cells have changed: not the cell wall, but the cytoplasm began to be considered the main thing in the organization of the cell (Purkinė, 1830).
In the 30s of the XΙX century, the English scientist English scientist Brown discovered the nucleus in plant cells and proposed the term "nucleus". Found the nucleus in the cells of fungi and animals. These and other numerous observations allowed Schwann to make a number of generalizations. So Schwann showed that the cells of plants and animals are fundamentally similar to each other. Schwann formulated the cell theory, because. when creating a theory, he used the works of Schleiden, then he is also considered the creator of the theory.
