Self-reproduction is ... Self-reproduction of organisms

The ability to reproduce itself is one of the distinguishing features of living organisms. In nature, there are several ways of reproduction, ensuring 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 transfer of information about all the features of the structure, fixed in the genetic material of organisms, is provided by self-reproduction. This is the most important condition for the existence of life. After all, if a new organism appears with other signs, it simply does 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 just do not have time to adapt to the water environment and die. But such in nature does not occur due to the presence of several ways of reproduction.

Asexual reproduction

Self-reproduction of cells can occur without the participation of sex cells. In plants it is carried out with the help of vegetative organs. Many fungi, plauns, horsetails, ferns and mosses form spores - cells of asexual reproduction. In some organisms, protrusion is formed on the body, which grows and, over time, becomes a new organism. Consider these ways of reproduction in more detail.

Spore formation

Self reproduction of organisms by means of spores can be found for the first time in the most primitive algae plants. For example, spores of unicellular chlamydomonas, leaving the cell membrane of the mother's body, go out and quickly grow to its size. Already after one week, young individuals are able to form cells of asexual reproduction. This process is repeated many times.

Higher spore plants in the cycle of their development alternate sexual and asexual generation. Disputes in them are formed in special organs. For example, in mosses they are represented by a box on the stem, inside of which are asexual cells. The significance of this process is that an exact replica of the maternal organism is formed from the spores.

Vegetative reproduction

Stem, leaves and root are organs by means of which self-reproduction is also performed. 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 leaf petiole of the Uzambara violets, in the presence of water, heat and solar radiation, the root grows.

Wood leaf-and-leaf plants are often propagated with the help of petioles - parts of shoots of a certain length. In this case, they can exist in different life forms. So plant grapes, currants, gooseberries. The most important thing is that on the petiole there are viable kidneys.

They are used for reproduction and modification of vegetative organs. Potato tubers, strawberry whiskers, tulip bulbs, lily of the valley rhizomes are examples of plants that have transformed shoots. Modification of the root, which is used for vegetative propagation, is the root tuber. Dahlia and sweet potato reproduce precisely with the help of it.

Pocification

Self-reproduction is the process of creating oneself. Another way in which this happens is called budding. So yeast, freshwater hydra, scythoid polyps and corals breed. In most cases, the kidney, which is formed on the mother's body, is split off from it and begins to exist independently. But corals do not. As a result, reefs of a bizarre shape are formed.

Forms of sexual process

Generative reproduction occurs with the participation of gamete - sex cells. The most primitive forms of the sexual process are conjugation and parthenogenesis. The first of them can be considered on the example of infusoria-shoes. Between the cells of animal organisms, a cytoplasmic bridge is formed, through which the genetic material contained in the DNA molecules is exchanged.

Parthenogenesis is also a self-reproduction. This is the process of developing a new organism from an unfertilized ovum. The existence of parthenogenesis as a method of reproduction has a very important biological significance. After all, there can be a situation of the absence of a male for a long time. And then the existence of the species will be endangered. And the appearance of an individual from the female reproductive cell without the process of fertilization solves this problem.

In higher angiosperms, a generative organ is a flower. Its main functional parts - stamen and pistil - contain gametes: sperm and egg, respectively. The process of fertilization is preceded by pollination - the transfer of pollen from the stamen to the stigma of the pistil. This happens with the help of wind, insects or a person. Next, the germ cells form a fusion and a reserve nutrient - endosperm. Together, a seed is formed, which is also the organ of sexual reproduction.

In animals, gametes are located in the glands, proceeding outward along the outgoing pathways. By the type of the structure of the reproductive system, they are dioecious and hermaphroditic - organisms in which both female and male sex cells are simultaneously formed. Basically, these are parasitic animals that feed at the expense of the host and do not have their own digestive system, inhabiting the ducts of its intestines.

Meaning of self-reproduction

Self-reproduction is the preservation of one's life. The ability to reproduce, along with nutrition, respiration, growth and development, is a sign of living organisms. There are also representatives of the organic world, for which this process is the only one. These are viruses - non-cellular forms of life. They consist of nucleic acid molecules (DNA or RNA) and a protein coat. With such a structure, the ability to reproduce is the only possible process that determines the belonging to living organisms. Penetrating into the body of the host, they begin to produce their own nucleic acid and protein. This method of reproduction is called self-assembly. In this case, similar processes in the host are suspended. The virus begins to dominate. So begins the flu, herpes, encephalitis and other diseases with a similar genesis. Viral particles are killed due to the action of colorless blood cells - leukocytes. They capture pathogens, destroying them.

Thus, representatives of all the kingdoms of living nature are capable of self-reproduction . And the process of reproduction is very important, because it determines the continuity of generations and the provision of life on Earth.