Why is it difficult to define the concept of life? Life, properties of living things and their relativity. Why is it very difficult to define the concept of “life”

Question 1. Why is it very difficult to define the concept of “life”?
Life in its manifestations is distinguished by great diversity. That's why precise definition The concept of “life” is very difficult to define, since living organisms are characterized by a number of features that are absent in nonliving systems. But among these signs there is not a single one that would be noted only in living things. For example, growth is characteristic not only of living things, but also of minerals. Living and nonliving systems are also characterized by metabolism and energy and other processes.

Question 2. What is the difference chemical organization living organisms and inanimate objects?
The composition of living things includes the same chemical elements that make up the bodies of inanimate nature. However, their quantitative ratio in living and inanimate nature various. So, in earth's crust The first four places in abundance are oxygen, silicon, aluminum and sodium. The basis of living systems is carbon, hydrogen, oxygen, nitrogen, as well as phosphorus and sulfur. They are characterized by the formation of water-soluble compounds, which allows them to accumulate in living organisms. The ability of carbon atoms to connect with each other in long chains and at the same time form chemical bonds with other elements ensures the creation of complex organic molecules, sometimes having a huge molecular weight. These are proteins, fats, carbohydrates, nucleic acids and others organic compounds, along with the inorganic components of living matter.

Question 3. Why are living organisms called “open systems”?
Since living organisms exchange with environment matter and energy. Therefore, living systems are open systems. As a result of metabolic processes, most elements of a living system are continuously updated.

Question 4. How do metabolic processes differ between living organisms and inanimate nature?
Characteristic for living objects special shape interaction with the environment - metabolism. It is based on the interconnected and balanced processes of assimilation (anabolism) and dissimilation (catabolism). These processes are aimed at renewing the structures of the body, as well as providing various aspects of its life with the necessary nutrients and energy, i.e. the existence of an organism as open system. But this phenomenon also occurs in inanimate nature. When burning, oxygen is absorbed from the air and organic substances, such as coal, are used. At the same time, various compounds are released into the environment.
The main difference between metabolism in living nature is the ability to carry out reactions of synthesis of high-molecular compounds (proteins, lipids, carbohydrates, nucleic acids) and their decay.

Question 5. What is the role of variability and heredity in the development of life on our planet?
Heredity is the property of organisms to transmit signs of their structure, functioning and development to their descendants, from generation to generation. Variability is the ability of living systems to acquire new characteristics and properties. These two properties of living things are closely interrelated and play a huge role in the development of life on Earth.
Heredity and variability provide: individual inheritance and change in individual characteristics; reproduction in individuals of each generation of the entire complex of morphofunctional characteristics of the organism specific type; redistribution in species with sexual reproduction in the process of reproducing hereditary inclinations, as a result of which the descendant has a combination of characteristics that differs from their combination in the parents. Changes in genetic material lead to the appearance of new characteristics in organisms; their combinations determine the degree of adaptability of an individual in specific conditions. Therefore variability is the supplier variety of material to select the most viable individuals, who will then pass on the characteristics of their structure and development by inheritance. This leads to the emergence of new species of organisms.

Available big number definitions of the concept “life”, reflecting different approaches. Numerous definitions of the essence of life can be reduced to three main ones.

According to the first approach, life is determined by the carrier of its properties (for example, protein); according to the second approach, life is considered as a set of specific physical and chemical processes. And finally, the third approach is to determine the minimum possible set of mandatory properties, without which no life is possible.

The concept of “life” can be more or less accurately defined only by listing the qualities that distinguish it from non-life. There is currently no consensus on the concept of life, but scientists generally accept that the biological manifestation of life is characterized by: organization, metabolism, growth, adaptation, response to stimuli, and reproduction.

We can also say that life is a characteristic of the state of the organism.

Many consider a characteristic property of a living body to be its ability to move. After death, it loses mobility.

However, if we decided to define a living body as a body capable of movement, we would, of course, be mistaken, since, on the one hand, there are many undoubtedly living bodies known, but immobile, for example: sponges, almost all plants.

On the other hand, a number of bodies are known that are capable of active movement, but are undoubtedly inanimate, for example, all moving machines and mechanisms created by man. Thus, it is impossible to define a living body by its ability to move alone.

Another sign of living bodies is their ability to reproduce. Indeed, the ability to generate their own kind is a very characteristic property of living things. However, this sign cannot be considered a constant and reliable sign of life, since, on the one hand, there are a number of undoubtedly living creatures that are not capable of reproducing offspring, for example, worker bees, mules or castrated animals; on the other side, modern technology(technical cybernetics) can design and create machines capable of reproducing machines similar to themselves.

From the above it is clearly seen that characterizing the phenomenon of life is not an easy task. Life is the most complex system, therefore, any attempt to define the corresponding concept encounters insurmountable difficulties: it always slips beyond the scope of any no matter how precise and extensive definition.

As a starter, some information from Wikipedia:

Life - active form existence of matter, in a sense higher than its physical and chemical forms of existence; a set of physical and chemical processes occurring in a cell, allowing for metabolism and its division (life does not exist outside the cell, viruses exhibit the properties of living matter only after the transfer of genetic material into the cell). By adapting to its environment, a living cell forms the entire diversity of living organisms. The main attribute of living matter is genetic information used for replication.

The concept of “life” can be more or less accurately defined only by listing the qualities that distinguish it from non-life. There is currently no consensus on the concept of life, but scientists generally accept that the biological manifestation of life is characterized by: organization, metabolism, growth, adaptation, response to stimuli, and reproduction. We can also say that life is a characteristic of the state of the organism.

Also, the word “life” is understood as the period of existence of an individual organism from the moment of its emergence until its death.

Definitions

There are a large number of definitions of the concept “life”, reflecting different approaches. Numerous definitions of the essence of life can be reduced to three main ones. According to the first approach, life is determined by the carrier of its properties (for example, protein); according to the second approach, life is considered as a set of specific physical and chemical processes. And finally, the third approach is to determine the minimum possible set of mandatory properties, without which no life is possible.

Friedrich Engels gave the following definition: “Life is a way of existence of protein bodies, the essential point of which is the constant exchange of substances with the external nature surrounding them, and with the cessation of this metabolism, life also ceases, which leads to the decomposition of the protein.”

Life can be defined as the active maintenance and self-reproduction of a molecular structure, which involves the expenditure of energy received from outside.

Russian scientist M.V. Volkenstein gave a new definition to the concept of life: “Living bodies that exist on Earth are open, self-regulating and self-reproducing systems built from biopolymers - proteins and nucleic acids” [source not specified 822 days].

According to the views of one of the founders of thanatology, M. Bisha, life is a set of phenomena that resist death.

From the point of view of the second law of thermodynamics, life is a process, or a system, the vector of development of which is opposite in direction to the rest, “non-living” objects of the universe, and is aimed at reducing its own entropy (see Heat death).

V.N. Parmon gave the following definition: “Life is a phase-separated form of existence of functioning autocatalysts that are capable of chemical mutations and have undergone a fairly long evolution due to natural selection.”

According to Ozanger and Morowitz (English) Russian: “Life is a property of matter, leading to the conjugate circulation of bioelements in aquatic environment, driven, ultimately, by the energy of solar radiation along the path of increasing complexity"

There are also cybernetic definitions of life. According to A. A. Lyapunov’s definition, life is “a highly stable state of matter that uses information encoded by the states of individual molecules to develop conservation reactions.”

There is also a physiological definition of life, given in 1929 by A.F. Samoilov, which was not fully explored by the great scientist:

“Life is a vicious circle of reflex activity.” A break in this circle at any point (a “coma” state) means a sharp limitation of the parameters of life or even the absence of life. Now we can somewhat expand this concept and indicate the reasons on which this “vicious circle” depends. Namely: the state external environment, the “power of will” of the individual, the internal vegetative principles of the body, not subject to the “power of will”. Let us note that the concept of “power of will” was also introduced into scientific circulation by A.F. Samoilov.

1. What living organisms do you know?

Living organisms include animals, plants, bacteria, fungi, and viruses.

2. How do living organisms differ from nonliving ones?

Living biological systems differ sharply from non-living systems in the complexity of their structure and the high orderliness of the physiological processes occurring in them.

3. What properties of living things do you know?

6. All living things reproduce.

Questions

1. Why is it very difficult to define the concept of “life”?

The fact is that living organisms have a number of characteristics that are absent in most objects of inanimate nature, but among these characteristics there is not a single one that would be characteristic only of living things. For example, living organisms are characterized by growth, but crystals also grow. Therefore, the easiest way to define life is to list the basic properties of living things, or vital properties.

2. What is the difference between the chemical organization of living organisms and inanimate objects?

Living organisms are “built” from the same chemical elements, as well as objects of inanimate nature. However, their ratio in living and nonliving things is different. Living organisms are 98% composed of four elements - carbon, oxygen, nitrogen and hydrogen, which are involved in the formation of complex organic molecules - proteins, nucleic acids, carbohydrates, fats.

3. What are the main properties of living things?

1. Living organisms have a similar chemical composition and a common structural principle.

2. All living organisms are open biological systems, that is, systems that are stable only if they receive continuous energy and matter from the environment.

3. All living organisms are capable of metabolism with the environment: from it they receive substances necessary for life, and into it they secrete waste products.

4. Living organisms respond to changes in environmental factors.

5. Living organisms develop.

6. All living things reproduce.

7. All living organisms have heredity and variability.

8. Living organisms are adapted to a specific habitat.

4. How do metabolic processes in living organisms differ from similar processes found in inanimate nature?

In contrast to “metabolic processes” in inanimate nature, in living organisms the processes of biosynthesis and decomposition of substances have become the most important. Metabolism ensures consistency chemical composition and the structure of the organism, its growth, reproduction and existence in continuously changing environmental conditions.

5. How can the adaptation of organisms to their environment be manifested? Give relevant examples.

Even by appearance It is often possible to determine what kind of life a given organism leads. For example, you can immediately distinguish a bird of prey from a granivorous one, moisture-loving plants from desert plants.

Tasks

1. Explain why living organisms are called open biological systems.

Open biological systems are systems that are stable only if they receive continuous energy and matter from the environment.

Green plants use solar energy for the synthesis of organic substances from which their body is built. Other organisms obtain energy from the breakdown of complex organic substances in food into simpler ones. Thus, living organisms exist as long as they receive energy (solar or chemical) and nutrients from outside.

2. List the levels of organization of living things known to you. Try to give examples of biological systems that correspond to them.

Scientists distinguish the following levels of organization of living things: molecular (molecules that make up a cell), cellular (muscle cell), organismal (wolf), population-specific (population of wolves in a mixed forest), ecosystem ( Pine forest) and biosphere (biosphere).

>> The essence of life and the properties of living things

3. The essence of life and the properties of living things.

1. What living organisms do you know?
2. How do living organisms differ from nonliving ones?
3. What properties of living things do you know?