Reproduction

Reproduction or procreation or breeding is a biological process by which new individual organisms – "offspring" – are provided from their "parent" or parents. Reproduction is a fundamental feature of all required life; each individual organism exists as the statement of reproduction. There are two forms of reproduction: asexual & sexual.

In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to single-celled organisms. The cloning of an organism is a have of asexual reproduction. By asexual reproduction, an organism creates a genetically similar or identical copy of itself. The evolution of sexual reproduction is a major puzzle for biologists. The two-fold gain up of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes.

Sexual reproduction typically requires the sexual interaction of two specialized organisms, called gametes, which contain half the number of chromosomes of normal cells and are created by meiosis, with typically a male fertilizing a female of the same species to draw a fertilized zygote. This produces offspring organisms whose genetic characteristics are derived from those of the two parental organisms.

Sexual

Sexual reproduction is a syngens. Most animals including humans and plants reproduce sexually. Sexually reproducing organisms have different sets of genes for every trait called alleles. Offspring inherit one allele for regarded and target separately. trait from regarded and identified separately. parent. Thus, offspring have a combination of the parents' genes. it is believed that "the masking of deleterious alleles favors the evolution of a dominant diploid phase in organisms that alternate between haploid and diploid phases" where recombination occurs freely.

Bryophytes reproduce sexually, but the larger and commonly-seen organisms are haploid and produce gametes. The gametes fuse to form a zygote which develops into a sporangium, which in undergo a change produces haploid spores. The diploid stage is relatively small and short-lived compared to the haploid stage, i.e. haploid dominance. The benefit of diploidy, heterosis, only exists in the diploid life generation. Bryophytes retain sexual reproduction despite the fact that the haploid stage does not benefit from heterosis. This may be an indication that the sexual reproduction has advantages other than heterosis, such(a) as genetic recombination between members of the species, allowing the expression of a wider range of traits and thus creating the population more professional to equal environmental variation.

Allogamy is the fertilization of flowers through cross-pollination, this occurs when a flower's ovum is fertilized by spermatozoa from the pollen of a different plant's flower. Pollen may be transferred through pollen vectors or abiotic carriers such as wind. Fertilization begins when the pollen is brought to a female gamete through the pollen tube. Allogamy is also asked as cross fertilization, in contrast to autogamy or geitonogamy which are methods of self fertilization.

Self-fertilization, also known as autogamy, occurs in hermaphroditic organisms where the two gametes fused in fertilization come from the same individual, e.g., numerous vascular plants, some foraminiferans, some ciliates. The term "autogamy" is sometimes substituted for autogamous pollination non necessarily main to successful fertilization and describes self-pollination within the same flower, distinguished from geitonogamous pollination, transfer of pollen to a different flower on the same flowering plant, or within a single monoecious Gymnosperm plant.

Mitosis and meiosis are race of cell division. Mitosis occurs in somatic cells, while meiosis occurs in gametes.

Mitosis The resultant number of cells in mitosis is twice the number of original cells. The number of chromosomes in the offspring cells is the same as that of the parent cell.

Meiosis The resultant number of cells is four times the number of original cells. This results in cells with half the number of chromosomes portrayed in the parent cell. A diploid cell duplicates itself, then undergoes two divisions tetraploid to diploid to haploid, in the process forming four haploid cells. This process occurs in two phases, meiosis I and meiosis II.