The ability of any living organism to form its own kind is called self-reproduction. The idea of this process at the cellular level was formed among biologists only in the middle of the 19th century.
The need for self-reproduction
The ability of organisms to create their own kind is called reproduction, or reproduction. It is with its help that species diversity is maintained.
Before finding out what self-reproduction of living organisms is, you need to understand that this is their fundamental feature. It is characterized by a wide variety of mechanisms and forms that provide the possibility of reproduction.
Self-reproduction is necessary for species to continue to exist, since the lifespan of each individual organism is limited. Reproduction allows you to compensate natural process death of living individuals. During the process of evolution, methods of reproduction have undergone changes. Therefore, now there are several options for how living organisms reproduce.
Cellular features
The ability of different individuals to create their own kind is based on the unique properties of nucleic acids. They are the ones who can reproduce themselves. The phenomenon is also important matrix synthesis DNA. This is the basis for the formation of new proteins and nucleic acid molecules. It is their peculiar combinations that determine the specificity of various organisms.
Only at the beginning of the 20th century was it possible to determine what self-reproduction of living organisms is and to understand how cell mitosis occurs. Using microscopes, it was established that their separation is preceded by the splitting of chromosomes. They, in turn, are evenly divided between the newly formed cells. The chromosomes of mother and daughter cells are identical in structure.
Features of sexual reproduction
The most progressive type of self-reproduction involves the fusion of two germ cells - female and male. The genetic material provided by both parents is combined. The resulting individual can combine properties and form new features that were absent in its predecessors.
Information about this makes it possible to understand what self-reproduction of living organisms is and how it can occur. The process of combining gametes is called fertilization. In living organisms it can be external or internal. The first type is typical for individuals living in aquatic environment- fish, amphibians. In most animals, fertilization takes place inside the mother's body. In plants, this process is possible in a specially designed organ.
Allows living organisms to occupy larger number ecological niches, they are more widely distributed across the Earth. When new individuals are created, the genetic material is updated and the descendants are improved. They are distinguished by better adaptability to changing conditions.
Self-reproduction- the ability of a living organism, its organ, tissue, cell or cellular organelle or inclusion to form its own kind. Self-reproduction in living organisms occurs through reproduction.
[edit] Types of self-reproduction
Main article:Reproduction
- Self-reproduction of organisms:
- Asexual reproduction is a form of reproduction that is not associated with the exchange of genetic information between individuals - the sexual process.
- Sexual reproduction- reproduction associated with the fusion of germ cells.
- Self-reproduction of cells in multicellular organisms occurs by dividing them.
- Mitochondria, plastids and centrioles are capable of self-reproduction.
- Viruses are capable of self-reproduction inside living cells.
A unique feature of organisms like open systems is their ability to self-reproduce, that is, to create copies of themselves.
The reaction of DNA synthesis with the participation of DNA polymerase (for example, in PCR) is often called self-reproduction of DNA, and the DNA molecule is the only self-replicating molecule. In reality, self-reproduction is a property much more complex systems. In fact, DNA replication requires the participation of DNA polymerase, and this enzyme not only catalyzes the formation of the 3,5" phosphodiester bond, but also determines, along with the DNA matrix, right choice another nucleotide. In other words, DNA does not reproduce itself, but is synthesized by an apparatus containing a DNA template and a DNA polymerase protein. And this two-component system does not self-replicate, since the amount of DNA polymerase does not increase (on the contrary, it decreases as a result of denaturation; the replication rate decreases accordingly). In order for this system to self-replicate, a DNA polymerase synthesis mechanism is needed. And this requires the presence of a DNA polymerase gene in the DNA matrix, and many more genes encoding proteins necessary for the expression (transcription and translation) of all these genes. A colossal complication of the system! However, this is not all. Many substances necessary for self-reproduction are unstable and are practically absent from food, for example nucleoside triphosphates), therefore there must be mechanisms for their formation in the system itself, i.e. metabolism is needed. This means that many more genes and corresponding proteins are required.
Prerequisites for evolution:
variability and heredity
Variability and heredity as a property of living things are prerequisites for the evolution of life. The main goal of their knowledge should be: 1) clarification of the role of these phenomena in organic evolution and 2) proof of the impossibility of reducing evolution to these premises. Solving the mentioned problems is possible only with a closer acquaintance with variability and heredity.
The ability to reproduce itself is one of the distinctive features living organisms. In nature, there are several methods of reproduction that ensure the continuity of generations on the planet.
Self-reproduction of organisms
Without the process of reproduction, living organisms would cease to exist. But the most important thing is the essence of this process. The transmission of information about all the structural features enshrined in the genetic material of organisms is ensured by self-reproduction. This is the most important condition for the existence of life. After all, if a new organism appears with different characteristics, it simply will not survive in certain environmental conditions and will die. For example, imagine: a fish is born with lungs instead of gills. Several generations of such animals are doomed. They simply do not have time to adapt to the aquatic environment and die. But this does not happen in nature due to the presence of several methods of reproduction.
Asexual reproduction
Self-reproduction of cells can occur without the participation of germ cells. In plants it is carried out with the help of vegetative organs. Many mushrooms, mosses, horsetails, ferns and mosses produce spores - cells of asexual reproduction. In some organisms, a protrusion forms on the body, which grows and over time turns into a new organism. Let's consider these methods of reproduction in more detail.
Sporulation
Self-reproduction of organisms using spores can first be found in the most primitive plants - algae. For example, spores of unicellular Chlamydomonas, leaving the cell membrane of the mother’s body, come out and quickly grow to its size. After just one week, young individuals are able to form asexual reproduction cells. This process is repeated many times.
Higher spore plants in their development cycle alternate sexual and asexual generations. Their spores are formed in special organs. For example, in mosses they are represented by a box on a stalk, inside which there are asexual cells. The significance of this process is that an exact copy of the maternal organism is formed from the spores.
Vegetative propagation
The stem, leaves and root are the organs through which self-reproduction is also carried out. These are the vegetative parts of the plant. The essence of this process is to restore the missing parts of the body. For example, on the petiole of a Uzambara violet leaf, in the presence of water, heat and solar radiation, a root grows.
Woody leafy plants are often propagated using petioles - parts of shoots of a certain length. Moreover, they can exist in different life forms. This is how grapes, currants, and gooseberries are planted. The most important thing is that there are viable buds on the petiole.
Used for reproduction and modification of vegetative organs. Potato tubers, strawberry tendrils, tulip bulbs, lily of the valley rhizomes are examples of plants that have transformed shoots. A modification of the root that is used for vegetative propagation is the root tuber. Dahlia and sweet potato reproduce with its help.
Budding
Self-reproduction is the process of creating others like yourself. Another way this happens is called budding. This is how yeast multiplies freshwater hydra, scyphoid polyps and corals. In most cases, the bud that forms on the mother's body splits off from it and begins an independent existence. But this does not happen in corals. As a result, reefs of bizarre shapes are formed.
Forms of the sexual process
Generative reproduction occurs with the participation of gametes - germ cells. The most primitive forms of the sexual process are conjugation and parthenogenesis. The first of them can be considered using the example of the slipper ciliate. A cytoplasmic bridge is formed between the cells of animal organisms, through which sections of genetic material contained in DNA molecules are exchanged.
Parthenogenesis is also self-reproduction. This is the process of developing a new organism from an unfertilized egg. The existence of parthenogenesis as a method of reproduction is very important biological significance. After all, a situation may arise in which a male individual is absent for a long time. And then the existence of the species will be under threat. And the emergence of an individual from a female reproductive cell without the process of fertilization solves this problem.
In higher angiosperms, the generative organ is the flower. Its main functional parts - the stamen and pistil - contain gametes: sperm and egg, respectively. The process of fertilization is necessarily preceded by pollination - the transfer of pollen from the stamen to the stigma. This happens with the help of wind, insects or humans. Further, when the sex cells merge, they form an embryo and a reserve cell. nutrient- endosperm. Together, a seed is formed, which is also an organ of sexual reproduction.
Self-reproduction is the preservation of one's life. The ability to reproduce, along with nutrition, respiration, growth and development, is a characteristic of living organisms. There are also such representatives organic world, for which this process is the only one. These are viruses - noncellular forms life. They consist of nucleic acid molecules (DNA or RNA) and a protein shell. With such a structure, the ability to reproduce is the only possible process, determining belonging to living organisms. Penetrating into the host's body, they begin to produce their own nucleic acid and protein. This method of reproduction is called self-assembly. At the same time, similar processes in the host’s body are suspended. The virus is beginning to dominate. This is how influenza, herpes, encephalitis and other diseases with a similar genesis begin. Viral particles die due to the action of colorless blood cells - leukocytes. They capture pathogenic organisms, destroying them.
Thus, representatives of all kingdoms of living nature are capable of self-reproduction. And the process of reproduction itself is very important, since it determines the continuity of generations and the provision of life on Earth.
Self-reproduction... Spelling dictionary-reference book
Reproduction Dictionary of Russian synonyms. self-reproduction noun, number of synonyms: 1 reproduction (11) ASIS Dictionary of Synonyms. V.N... Synonym dictionary
The unique ability of living matter (a matrix used for the synthesis of species-specific molecules, i.e., containing information about the structure of these molecules) for identical self-duplication (replication). Ecological encyclopedic Dictionary. Chisinau:... ... Ecological dictionary
self-reproduction- ▲ reproduction of organisms spontaneous self-reproduction the ability of living things to form something similar to themselves is characteristic of whole organisms, their individual organs, cells, cellular inclusions and many organelles. regeneration ability... ... Ideographic Dictionary of the Russian Language
self-reproduction- self-reproduction, I... Russian spelling dictionary
self-reproduction- self-reproduction, I... Together. Apart. Hyphenated.
Playback (self-playback)- the ability of living forms to form something similar to themselves; one of the fundamental characteristics of life. Reproduction occurs in a wide variety of ways through vegetative, sexual and asexual reproduction, in animals by fission,... ... Beginnings modern natural science
- (metabolism), the totality of all chemical changes and all types of transformations of substances and energy in organisms, ensuring development, life activity and self-reproduction, connection with environment and adaptation to changes external conditions.… … encyclopedic Dictionary
Maurits Cornelis Escher Self-portrait, 1929 Birth name: Maurits Cornelis Escher Date of birth: June 17, 1898 Place of birth: Leeuwarden, Netherlands ... Wikipedia
This term has other meanings, see 3D. 3D printer. A 3D printer is a device that uses the method of layer-by-layer creation of a physical object based on virtual 3D ... Wikipedia
Books
- Theory of self-reproducing automata, J. von Neumann, Research by one of the greatest mathematicians of our time, J. von Neumann, on the theory of self-reproducing automata represents one of the significant stages in the formation of this theory.… Category: Radio electronics Series: Artificial Sciences Publisher:
