Reproduction, in which one or more cells separate from a part of the mother's body, is called asexual. At the same time, one parent is enough for the appearance of offspring.
Types of asexual reproduction
In nature, there are several options for how living organisms can reproduce their own kind. Methods of asexual reproduction are quite diverse. All of them lie in the fact that cells begin to divide and reproduce daughter individuals. In unicellular protozoa, the entire body is divided into two parts. In multicellular reproduction begins with the division of one or more cells at the same time.
For the simplest organisms, plants, fungi and some animal species, asexual reproduction is characteristic. Reproduction methods can be as follows: division, sporulation. Separately, the forms of the appearance of offspring are noted, in which it is formed from a group of cells of the maternal individual. They are called vegetative propagation. Separately allocate budding, fragmentation. These are common ways of asexualbreeding. The table makes it possible to understand how they differ.
| Propagation method | Features | Species of organisms |
| division | The cell is divided into 2 parts, forming 2 new individuals | Blue-green algae, bacteria, protozoa |
| Sporulation | Spores are formed in special parts of the body (spores) | Some plants, mushrooms, some protozoa |
| Vegetative | From several cells of a parent individual, a daughter organism is formed | Annelled worms, coelenterates, plants |
Features of the simplest reproduction
In all organisms that are capable of producing offspring by fission, the ring chromosome is preliminarily doubled. The nucleus is divided into two parts. Two child cells are formed from one parent cell. Each of them contains identical genetic material. A constriction appears between the two formed daughter cells, along which the parent individual is divided into two cells. This is the simplest asexual reproduction.
Methods of reproduction may be different. But euglena are green, chlamydomonas, amoeba, ciliates use division. The resulting offspring is no different from the parent individuals. He has exactly the same set of chromosomes. This methodreproduction allows you to quickly get a large number of identical organisms.
Sporulation
Some fungi and plants reproduce using special haploid cells. They are called disputes. In many fungi and lower plants, these cells are formed during mitosis. And in higher plant organisms, their formation is preceded by meiosis. A feature of this process is that the spores of such plants contain a haploid set of chromosomes. They are able to give rise to a new generation that is different from the mother. It can reproduce sexually. At the same time, one should not forget their unique feature. The methods of sexual and asexual reproduction in such plants alternate.
In most fungi and plants, spores are formed - these are cells that are protected by special membranes. They can be stored for a certain time in adverse conditions. When they change, the membranes open, and the cell begins to actively divide by mitosis. The result is a new organism.
Vegetative self-reproduction
Most higher plants use other methods of asexual reproduction. The table allows you to figure out what types of vegetative reproduction exist.
| Vegetative propagation method | Features |
| Separation of roots, cuttings, bulbs, whiskers, tubers, rhizomes | Requires a well-formed part to reproducemother's organism, from which the child begins to develop |
| Fragmentation | The parent individual is divided into several parts, each developing a separate independent organism |
| Budding | A kidney is formed on the parent body, from which a new full-fledged organism is formed |
During vegetative reproduction, plants can form special structures. For example, potatoes and dahlias create offspring by tubers. So called root or stem thickening. The swollen base of the stem from which the offspring is formed is called the corm.
Rhizomes reproduce plants such as aster and valerian. Also called horizontally growing underground stems from which buds and leaves emerge.
Strawberries, strawberries form offspring with a mustache. They grow quickly enough, new leaves and buds appear from them. All these methods of asexual reproduction of organisms are called vegetative. They also include reproduction using cuttings of stems, roots, parts of thalli.
Fragmentation
This type of reproduction is characterized by the fact that when the mother organism is divided into several parts, a new individual is formed from each of them. Some annelids, flatworms, and echinoderms (starfish) use such asexual reproduction. Methods of reproduction by fragmentation are based on the fact that someorganisms can recover by regeneration.
For example, if a ray is torn off from a starfish, then a new individual will form from it. The same thing will happen with an earthworm divided into several parts. Hydra, by the way, can recover from 1/200 of the part separated from its body. Typically, such reproduction is observed with damage. Spontaneous fragmentation has been observed in molds and some marine worms.
Budding
Methods of asexual reproduction allow reproduction of exact copies of parental organisms. In some cases, daughter individuals are formed from special cells - kidneys. This method of self-reproduction is typical for some fungi, animals (sponges, protozoa, coelenterates, a number of worms, wing-gills, tunicates), liver mosses.
For coelenterates, for example, such asexual reproduction is typical. Their breeding methods are quite curious. An outgrowth appears on the body of the mother individual, which increases. As soon as it reaches the size of an adult, then it separates.
