Reproduction is what? What are the ways and organs of reproduction?

One of the most complex, mysterious and amazing processes in nature is reproduction. It is very important, and thanks to it the life of absolutely all living organisms on earth is supported. To begin with, let us examine in more detail what it is. Reproduction is the ability of all living beings to produce organisms similar to themselves. Without this ability, no living representative of nature could live on the earth.

Methods of reproduction

Now consider all types of reproduction, there are only two. They differ significantly from each other, but sometimes in the most insignificant details you can see the similarities.

Reproduction is asexual

Reproduction of organisms, such as protozoa, fungi, bacteria, coelenterates, algae, sponges, shells, vascular plants and bryozoans, is called asexual.

The simplest kind of reproduction can be attributed to viruses. Nucleic acids play an important role in this process , as well as the ability of their molecules to independently double. It is also based on fragile hydrogen bonds among nucleotides.

There are other ways of asexual reproduction for organisms - vegetative and due to sporulation.

First, consider the vegetative. This reproduction is the development of a new organism from a part separated from the mother. A similar method is the increase in the population of unicellular and multicellular, but it manifests itself in different ways.

When vegetative multiplication of multicellular animals begins division of their body into equal parts, then a living organism emerges from it. Similarly, the population of flatworms, nemertines, sponges, hydras and many other creatures is maintained. Still there is such a thing as polyembryony in animals. During this process, the embryo at a certain time begins to divide into parts that later develop into a separate organism. Such a course of reproduction is observed in armadillos. It is worth noting that they reproduce only sexually.

The vegetative reproduction of unicellular animals has several forms - budding, division and multiple division.

Multiple division is also called schizogony, in this case the nucleus is divided and then the cytoplasm is separated into parts.

In the process of simple division, the mitotic course of the fission of the nucleus takes place, where a cytoplasmic constriction then arises.

Now let's proceed to asexual budding. Such reproduction is the emergence of special cells or spores that contain a nucleus. They have a dense shell and can live for quite some time in the most unfavorable conditions for this. This also works great for their further resettlement. This type of reproduction is characteristic of mosses, fungi, algae, bacteria and ferns. There is the possibility of the formation of zoospore from some cells of green algae.

The reproduction of animals by spore formation can be found in the plasmodium of the malarial and sporophores.

Many organisms can combine asexual reproduction with sex.

Sexual reproduction

Sexual reproduction is a more complex process, and two individuals, male and female, are needed for a full flow. In the course of his exchange of genetic data through the gametes (this is the sex cells). This process is called gametogenesis.

In this case, it is also possible to distinguish several categories: the fusion of organisms of unicellular and sex cells, such as spermatozoa and ovules. In this process there are zygotes, from which a new organism is formed. After he reaches maturity, he begins to independently reproduce gametes.

There are several types of sexual reproduction, in which various cells and organs of reproduction take part.

Forms and types of reproduction

It is necessary to consider each process in more detail separately, since they all have different bases and flow.

About gametogenesis has already been mentioned earlier, so we will not repeat.

Isogamy and anisogamy

In these two species, two cells are involved, but in isogamy, the cells are identical in structure, but are derived from different parents. Anisogamy is based on different sex cells - microgametes and macrogamets, which differ in size.

Egg and sperm cells

The so-called female and male sex cells. They are formed in the sexual organs of the corresponding individuals.

The egg consists of halide chromosomes and can not be shared independently.

Spermatozoa are slightly smaller than female cells. They have an amazing structure that provides them with active movement. The presence in the axoplasma of certain enzymes ensures the splitting of the walls of the egg for penetration and further fertilization. Each sex cell contains a part of the genetic information of the parents and is transmitted to the future offspring.

Parthenogenesis optional

Such reproduction is an atypical sexual process. It can be noted the replacement of a typical and atypical reproduction. The female develops from the fertilized eggs, and the male - from the unfertilized. Thus there is an increase in the population of bees.

There are also other varieties of parthenogenesis, namely, constant and cyclic. In the first case, the offspring develops from eggs that are not prone to fertilization. This can be observed in such individuals whose parent partners do not have the opportunity to meet for reproduction.

In the case of cyclic parthenogenesis, an important role is played by environmental conditions. Under its influence, there is an alternation of typical reproduction with parthenogenesis.

All the information presented is only a small part of the description of the most surprising and mysterious process on earth - reproduction. Thanks to him today there are all living organisms and plants. If only for a moment to think about how everything in this process is carefully, wisely thought out and arranged, then one can realize the power of all nature. At the level of molecules and chromosomes, amazing things happen that are difficult for a simple person to understand.