Duplication is the process of reproducing organisms similar, ensuring the continued existence of the species. There are two main types of reproduction is asexual and sexual. When the first of them is the parent individual or pockets (i.e. separated a small part of the parent body, which develops then either a new individual, or more or less independent member of the colony of living organisms), or disintegrates into fragments, capable of self-reproduction (for example, Hydra), or produces spores (parasitic protozoa).
In sexual reproduction two parental individuals give the male and female gametes (sex cells), which merge to form a new organism.
The development of female gametes in some animal species can occur without fertilization (see) - parthenogenesis. The phenomenon of parthenogenesis occurs in the invertebrates (bees, wasps and other) and vertebrates (amphibians). Each type of reproduction has its advantages and special importance in the living world. During asexual reproduction heredity (see) subsequent generations does not change, but increases the total number of individuals (which in some cases is very important). In sexual reproduction, on the contrary, increases the likelihood of genetic variability (see), so when fertilization occurs merger germ cells of organisms with different heredity.
In the life cycle of parasites of humans and animals can occur in the process of alternation of sexual and asexual reproduction.

Reproduction (synonym: self-replication, the generative process) is the process of reproducing organisms similar. In the basis of reproduction is the cell division, accompanied by the reproduction of cancer cells, each of which occurs only on their own and, if lost, could not be restored. These organelles are the chromosomes (see), chromatophores from algae, as well as, perhaps, mitochondria and plastids. The chromatophores from, plastids and mitochondria multiply by division. When the replication of chromosomes in the maternal chromosome, as in the matrix, is based subsidiary, DNA, which remains the same regular alternation of nucleotides that in maternal DNA strands (see Genetics). Thus, when the reproduction is stored material succession of generations of conservation of molecular structures, characteristic of the maternal organism.
Asexual reproduction is the growth of the subsidiary body outside the parent. It can be performed as a separate cells (AGANA Sithonia)and multicellular formations (vegetative reproduction). AGANA Sithonia occurs or by cell division into two equal parts, as many single-celled, or by maternal education cage smaller subsidiaries (the split, for example in yeast), or the mother's body separates special cells or falls into cells that are essential for reproduction (disputes). Can be special bodies vegetative propagation - bulbs and tubers.
Sexual reproduction is that the number of cell divisions interrupted sexual process. While merging two cells or two cores, which sooner or later must meiosis (see). The product of the sexual process - zygote - contains twice as many chromosomes than gametes, or germ cells. Halobiontic (many algae and fungi) meiosis occurs during germination zygotes and all cells of the body have one set of chromosomes. Diploobjetos (all animals, some algae) cells of the body have two sets of chromosomes and meiosis occurs in the maturing of gametes. Haplo-diploobjetos (most plants) alternate diploid generation, producing as a result of meiosis disputes, and haploid breeding sexually. The ciliates sexual process is reduced to the exchange of nuclei, pre undergo meiosis; after the merger of these nuclei during conjugation of infusoria is restored double set of chromosomes.
In the process of gamegenie, or gametogenesis, i.e., cell division, leading to the formation of gametes and arise from the maternal cells called gametocytes. Isogametes - sex cells, the same in both sexes; anisogamy differ in the size and behavior. Sexual process often occurs between organisms of different origin (amphimixis), sometimes between organisms originating from one cell (automaxes), between the two sister cells (pedagogia) and even between the two cores within the same cell (outagamie). Female sex cells can and sometimes without fertilization (see) to give the body (parthenogenesis, or virgin reproduction). Many insects, some vertebrates, such as lizards and turkeys, many flowering plants parthenogenesis is a natural phenomenon; some species - rule, the other is an exception.
Artificial parthenogenesis, you can call a number of influences, such as injection needles.
In some cases, sexual and asexual reproduction occur simultaneously. In other cases, they naturally alternate. Haplo-diploobjetos alternation of generations is called antithetical. When it asexual and sexual generation differ in the number of chromosomes. Such differences century the number of chromosomes is no striping vegetative and sexual reproduction in the catagenetic processes (for example, hydromedusa), as well as with the alternation of sexual reproduction and parthenogenetic called heterogenea (for example, the aphid).