Asexual reproduction. Asexual reproduction methods: table

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

In nature, there are several options,how living organisms can reproduce their own kind. The methods of asexual reproduction are quite diverse. All of them consist in the fact that the cells begin to share and reproduce the children. In unicellular protists, the entire body is divided into two parts. In multicellular multiplication begins with the division of one or more cells simultaneously.

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

This type of reproduction is characterized by the fact thatdivision of the maternal organism into several parts, from each of them a new individual is formed. Some annular and flat worms, echinoderms (starfish) use asexual reproduction. The ways of reproduction by fragmentation are based on the fact that some organisms can be regenerated by regeneration.

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.

</ p>