1. Living organisms are an important component of the biosphere. Cellular structure is a characteristic feature of all organisms, with the exception of viruses. The presence of a plasma membrane, cytoplasm, and nucleus in cells. Feature of bacteria: lack of a formed nucleus, mitochondria, chloroplasts. Features of plants: the presence of a cell wall, chloroplasts, vacuoles with cell sap in the cell, an autotrophic method of nutrition. Features of animals: absence of chloroplasts, vacuoles with cell sap, cell membranes in cells, heterotrophic mode of nutrition.
2. The presence of organic substances in living organisms: sugar, starch, fat, protein, nucleic acids and inorganic substances: water and mineral salts. The similarity of the chemical composition of representatives of different kingdoms of living nature.
3. Metabolism is the main feature of living things, including nutrition, respiration, transport of substances, their transformation and the creation of substances and structures of one’s own body from them, the release of energy in some processes and use in others, the release of final products of vital activity. Exchange of substances and energy with the environment.
4. Reproduction, reproduction of offspring is a sign of living organisms. The development of a daughter organism from one cell (zygote in sexual reproduction) or a group of cells (in vegetative reproduction) of the mother organism. The importance of reproduction is in increasing the number of individuals of a species, their settlement and development of new territories, maintaining similarity and continuity between parents and offspring over many generations.
5. Heredity and variability - properties of organisms. Heredity is the property of organisms to transmit their inherent structural and developmental features to their offspring. Examples of heredity: birch plants grow from birch seeds, a cat gives birth to kittens similar to their parents. Variability is the emergence of new characteristics in the offspring. Examples of variability: birch plants grown from the seeds of a mother plant of one generation differ in the length and color of the trunk, the number of leaves, etc.
6. Irritability is a property of living organisms. The ability of organisms to perceive irritations from the environment and, in accordance with them, coordinate their activities and behavior is a complex of adaptive motor reactions that arise in response to various irritations from the environment. Features of animal behavior. Reflexes and elements of rational activity of animals. Behavior of plants, bacteria, fungi: different forms of movement - tropisms, nastia, taxis.
Only a complex of all the listed characteristics characterizes living organisms.
Living systems have common characteristics:
1. Unity of chemical composition testifies to the unity and connection of living and nonliving matter.
Example:
Living organisms contain the same chemical elements as inanimate objects, 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 is accounted for by 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 existing 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 the 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 is 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-reproduction (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 doubling DNA molecules followed by 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 (constancy of the internal environment of the body). Persistent disruption of homeostasis leads to the death of the body.
6. Development and growth. The development of living things is represented by the individual development of the organism (ontogenesis) and the historical development of living nature (phylogeny).
- In the process of individual development, the individual properties of the organism gradually and consistently manifest themselves and its growth occurs (all living organisms grow during their lives).
- The result of historical development is the general progressive complication of life and the diversity of living organisms on Earth. Development refers to both individual development and historical development.
7. Irritability- the body’s ability to selectively respond to external and internal stimuli (reflexes in animals; tropisms, taxis and nasties in plants).
8. Heredity and variability represent factors of evolution, since thanks to them material for selection arises.
- Variability- the ability of organisms to acquire new characteristics 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 transmit 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 holistic 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, since it consists 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 processes of energy exchange and transformation, but it is not capable of self-regulation and self-reproduction.
As a child, I thought it was extremely easy to separate the living from the nonliving. However, this is not entirely true. In my answer, I will briefly tell you about all the characteristics of living systems.
Distinctive features of living and nonliving things
The organisms of our planet are very diverse and unique in their own way. However, there are special distinctive features that are inherent in absolutely all creatures, and not separately, but all at once. Among these signs I will mention the following.
- Movement. This process is easy to discern in most organisms. But sometimes the movement can be very, very slow.
- Irritation and the ability to feel. All living systems are capable of feeling influences on them from the environment, just like humans.
- Height.
- Reproduction, that is, reproduction. The ability to create offspring and pass on one’s genetic characteristics to them.
- Selection. The consequence of metabolic reactions in the body is the appearance of waste, which is then safely excreted. Excretion is another term for excretion.
- Consumption of nutrients necessary for life (proteins, fats and carbohydrates).
Well, the last sign is that all organisms consist of cells (or one cell, if it is unicellular).
Starfish move very slowly! But they still move. Set of signs
As I already said, all these signs must be together, that is, as a whole. Separately, some of them can be found in inanimate nature. By accelerating a board, you will establish that it is also moving, and by breaking glass, you will notice that it will “multiply.” Therefore, for scientists, separating living organisms from inanimate nature may not be a difficult job, but it requires observations.
Mechanisms of adaptation and struggle for survival
Another characteristic feature of living beings is the struggle for survival and adaptation to environmental conditions. Nature has provided for everything, and these mechanisms select the best of the species, who then pass on their hereditary data to their offspring. This topic is quite complex, so it deserves separate consideration.
All objects in our Universe belong to the natural world. It, in turn, is divided into living and nonliving. In order to distinguish one from another, you need to know the signs and properties of living organisms.
Distinctive characteristics of living organisms
First of all, you should know that living organisms are an important component of the biosphere. Their characteristic feature is their cellular structure, with the only exception being viruses. Cells also contain: a plasma membrane, cytoplasm, and nucleus. Despite the fact that bacteria do not have a formed nucleus, mitochondria, or chloroplasts, they also belong to living organisms, since they have a number of other characteristics inherent to them. Features of plants include the presence in the cell of a cell wall, vacuoles with cell sap, chloroplasts, and an autotrophic method of nutrition. While in animals there are no vacuoles with cell sap, cell membranes, chloroplasts, or a heterotrophic method of nutrition in their cells.
Living organisms contain organic substances: sugar, starch, fat, protein, nucleic acids. Also inorganic substances: water and mineral salts. In addition, you should know that representatives of various kingdoms of living nature have similar chemical compositions. Also, characteristic features of living organisms include metabolism, including: respiration, nutrition, transport of substances, their restructuring and the creation of structures and substances of their own body from them, the release of final products of vital activity, the release of energy in some processes and its use in others. This also includes reproduction and reproduction of offspring. Development from one or more cells of a daughter organism, as well as heredity and variability. In addition, among the signs of living organisms we can safely write down: irritability and the ability to coordinate one’s activities in accordance with them.
Living organisms differ from nonliving bodies in having a more complex structure. To maintain their vital functions, they receive energy from the outside, and almost all use solar energy. Living organisms actively move, overcome resistance, and react to their environment. Many may argue that not all objects of living nature have all of the above characteristics clearly expressed. For example, plants hardly move and the way they breathe cannot be seen with the naked eye. And many animals in captivity lose the ability to reproduce. But, with all this, other signs of representatives of living nature are expressed in them. Therefore, plants and bacteria also belong to living nature and are studied in the biology section. Now you know the main characteristics of living organisms!
