Reproduction, in which one or more cells are separated from a part of the mother's body, is called asexual. At the same time for the emergence of offspring enough one parent.
Types of Asexual Reproduction
For the simplest organisms, plants, fungi andSome species of animals are characterized by asexual reproduction. The ways of reproduction can be: division, sporulation. Separately note the forms of appearance of offspring, under which it is formed from a group of cells of the parent. They are called vegetative reproduction. Separately, budding, fragmentation is distinguished. This is a common method of asexual reproduction. The table provides an opportunity to understand how they differ.
Method of reproduction | Features | Kinds of organisms |
division | The cell is divided into 2 parts, forming 2 new individuals | Blue-green algae, bacteria, protozoa |
Spore formation | In special departments of the body (sporganiyah) spores are formed | Some plants, mushrooms, individual protozoa |
Vegetative | Of several cells of the parent, a daughter organism is formed | Ringworms, coelenterates, plants |
Features of the simplest reproduction
In all organisms that are able to receiveoffspring by division, the ring chromosome is doubled beforehand. The core is divided into two parts. Two daughter cells are formed from one parent cell. Each of them contains identical genetic material. Between the two formed daughter cells there is a constriction, along which the parent is divided into two cells. This is the simplest asexual reproduction.
Methods of reproduction may be different.But euglenae green, chlamydomonades, amoebae, infusoria use division. The resulting offspring is no different from the parental specimens. He has such a set of chromosomes. This method of reproduction allows a large number of identical organisms to be obtained in a short time.
Spore formation
Some mushrooms and plants multiply withspecial haploid cells. They are called spores. In many fungi and lower plants, these cells are formed during mitosis. And in higher plant organisms, their formation is preceded by meiosis. The peculiarity of this process is that in the disputes of such plants a haploid set of chromosomes is contained. They are able to give birth to a new generation, which differs from the mother. It can reproduce sexually. In this case, do not forget for their unique feature. The methods of sexual and asexual reproduction in such plants alternate.
Most mushrooms and plants are educatedSpores are cells that are protected by special shells. They can be stored for a certain time under unfavorable conditions. When they change, the membranes are opened, and the cell begins to actively divide by mitosis. As a result, a new organism is formed.
Vegetative self-reproduction
Most higher plants use other methods of asexual reproduction. The table allows you to understand what kinds of vegetative reproduction exist.
Method of vegetative reproduction | Features |
Separation of roots, cuttings, bulbs, mustaches, tubers, rhizomes | For reproduction, a well-formed part of the maternal organism is necessary, from which the daughter |
Fragmentation | The parent is divided into several parts, each of which develops a separate independent organism |
Pocification | On the parental body a kidney is formed, from which a new full-fledged organism is formed |
In vegetative propagation in plants,special structures are formed. For example, potatoes and dahlias create offspring with tubers. The so-called root or cauline thickening. The bloated base of the stem, from which the offspring is formed, is called corms.
Rhizomes multiply plants such as aster and valerian. Also called horizontally growing underground stems, from which buds and leaves appear.
Strawberry, strawberry forms offspring with the help ofmustache. They grow quickly enough, new leaves and kidneys appear from them. All these methods of asexual reproduction of organisms are called vegetative. They also include reproduction with the help of cuttings of stems, roots, part of thallus.
Fragmentation
For example, if you tear off a star from a starfish, thenfrom it a new individual will form. The same will happen with the earthworm, divided into several parts. Hydra, by the way, can be restored from 1/200 parts, separated from its body. Usually such reproduction is observed in case of damage. Spontaneous fragmentation is observed in mold fungi and some marine worms.
Pocification
The methods of asexual reproduction allowreproduce replicas of parental organisms. In some cases, the offspring are formed from special cells - the kidneys. This method of self-reproduction is characteristic for some fungi, animals (sponges, protozoa, coelenterates, a number of worms, albinoids, shells), hepatic mosses.
For coelenterates, for example,asexual reproduction. Ways of reproduction are rather curious. On the body of the parent there is a growth, which increases. As soon as it reaches the size of an adult, its separation occurs.
