One of the most complex, mysterious and fascinating processes in nature - a reproduction.It is very important, and because it is supported by a life completely of all living organisms on earth.To start analyze in more detail what it is.The reproduction - is the ability of all living beings to give birth to such organisms themselves.Without this ability, no living representative nature could not dwell on the earth.
breeding methods
Now consider all types of reproduction, they are only two.They differ significantly from each other, but sometimes the most insignificant little things, you can see the similarities.
asexual reproduction
reproduction of organisms, such as protozoa, fungi, bacteria, coelenterates, algae, sponges, tunicates, bryozoans, and vascular plants is called asexual.
The simplest kind of breeding can be attributed to viruses.In this process, play an important role nucleic acid as well as the ability of the molecules to self-doubling.Yet it is based on unstable hydrogen bonds among the nucleotides.
There are other ways of asexual reproduction for organisms - vegetative and spore formation by.
first consider the vegetative.Such reproduction - is the development of a new organism from a portion separated from the mother.Similarly, the method is an increase in the population of unicellular and multicellular, but it manifests itself in different ways.
When vegetative reproduction of multicellular animals begin their division into equal parts of the body, then it arises from a living organism.Similarly, the population supported flatworms, nemerteans, sponges, hydras, and many other creatures.Yet there is such a thing as polyembryony animals.During this process, the embryo at a certain time begins to divide into parts, which are then developed into a separate body.Such a course of reproduction observed in armadillos.It is worth noting that they only reproduce sexually.
Vegetative reproduction of unicellular has several forms - budding, division and multiple division.
multiple division is called schizogony, in which case the divided core further separation occurs on a part of the cytoplasm.
The process is simply dividing the course of the mitotic division of the nucleus, where there is further constriction of the cytoplasm.
Now comes the asexual budding.Such reproduction - is the emergence of specialized cells or spores containing core.They have a thick shell, and can live for a long time in the most adverse of conditions.It is also a great effect on their future settlement.This type of reproduction is typical for moss, fungi, algae, bacteria and ferns.There is a possibility of the formation of zoospores of certain cells of green algae.
Animal reproduction sporulation can be found at the Plasmodium falciparum and Sporozoa.
Many organisms can be combined with sexual reproduction asexual.
Sexual reproduction Sexual reproduction
- is a more complex process, and the need for a full course of two individuals, both male and female.In the course of his genetic data is exchanged via the gametes (sex cells is).This process is called gametogenesis.
In this case, as there are several categories: single-celled organisms and the merging of sex cells, such as sperm and egg cells.In this process, there are a zygote, from which is formed a new organism.Once it reaches maturity, begins to play on their own gametes.
There are several kinds of sexual reproduction, which involve a variety of cells and organs of reproduction.
forms and types of breeding
necessary to consider in more detail each process separately, since they all have different bases and flow.
About gametogenesis mentioned earlier, so that will not be repeated.
isogamy and anisogamy
In these two types of cells are involved the two, but in the same isogamy implied by the structure of the cells, but descended from different parents.Anisogamy builds on various germ cells - and microgamete macrogametes that are different sizes.
egg and sperm
so called male and female germ cells.They are formed in the genitals relevant individuals.
The egg consists of a halide of chromosomes and can not share their own.
Sperm slightly smaller female cells.They have an amazing structure that provides them with an active movement.The presence of certain enzymes in axoplasm provides splitting walls to penetrate the egg and fertilization further.Each gamete contains the genetic information of the parents and pass on to future offspring.
facultative parthenogenesis
Such reproduction - is not a typical sexual process.It may be noted the change typical and atypical reproduction.Female develops from fertilized eggs, and male - from unfertilized.Thus there is an increase in the population of bees.
There are also other kinds of parthenogenesis, namely the constant and cyclical.In the first case, the offspring develop from eggs, are not subject to fertilization.It may be observed in such individuals, parents whose partners for reproduction are unable to meet.
In the case of cyclic parthenogenesis play an important role environmental conditions.Under its influence there is an alternation of the typical breeding with parthenogenesis.
All information is just a small part of the description of the surprising and mysterious process on the ground - breeding.Thanks to him, there are now all living organisms and plants.If only for a moment to think about how all this process carefully, wisely and thoughtfully arranged, it is possible to realize the power of all nature.At the level of molecules and chromosomes amazing things happen that are hard to understand the common man.
