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 for how living organisms can reproduce themselves. The methods of asexual reproduction are quite diverse. All of them consist in the fact that the cells begin to share and reproduce the child. In unicellular protists, the whole 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 and some species of animals, asexual reproduction is characteristic. Reproduction methods can be: division, spore formation. Separately note the forms of the 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.

Features of the simplest reproduction

In all organisms that are capable of producing offspring 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 daughter cells that have formed, a constriction appears, 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 are no different from the parents. 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 fungi and plants reproduce by means of special 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 spores 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.

In most fungi and plants, formed spores are cells that are protected by special membranes. 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.

During vegetative propagation, special structures can form in plants. 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 of a mustache. 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 thalli.

Fragmentation

This type of reproduction is characterized by the fact that when the mother's body is divided into several parts, a new individual is formed from each of them. Some annular and flatworms, 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 a star from a starfish is torn off, a new specimen will form from it. 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 allow reproducing exact 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, such asexual reproduction is characteristic. Ways of reproduction are rather curious. On the body of the parent there is a growth, which increases. Once it reaches the size of an adult, it separates.