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  2. Origin and function of meiosis - Wikipedia

    en.wikipedia.org/wiki/Origin_and_function_of_meiosis

    It is the stage of the life cycle when a cell gives rise to haploid cells each having half as many chromosomes as the parental cell. Two such haploid gametes, ordinarily arising from different individual organisms, fuse by the process of fertilization, thus completing the sexual cycle.

  3. Sexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Sexual_reproduction

    Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete (haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes . [1]

  4. Evolution of sexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Evolution_of_sexual...

    Sexual reproduction appears to have arisen very early in eukaryotic evolution, implying that the essential features of meiosis were already present in the last eukaryotic common ancestor. [ 72 ] [ 68 ] [ 73 ] In extant organisms, proteins with central functions in meiosis are similar to key proteins in natural transformation in bacteria and DNA ...

  5. Reproduction - Wikipedia

    en.wikipedia.org/wiki/Reproduction

    Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: asexual and sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism.

  6. Isogamy - Wikipedia

    en.wikipedia.org/wiki/Isogamy

    Under the strict definition of isogamy, fertilization occurs when two gametes fuse to form a zygote. [8] Sexual reproduction between two cells that does not involve gametes (e.g. conjugation between two mycelia in basidiomycete fungi), is often called isogamy, although it is not technically isogametic reproduction in the strict sense.

  7. Reproductive biology - Wikipedia

    en.wikipedia.org/wiki/Reproductive_biology

    Animal reproduction occurs by two modes of action, including both sexual and asexual reproduction. [1] In asexual reproduction the generation of new organisms does not require the fusion sperm with an egg. [1] However, in sexual reproduction new organisms are formed by the fusion of haploid sperm and eggs resulting in what is known as the ...

  8. Eukaryogenesis - Wikipedia

    en.wikipedia.org/wiki/Eukaryogenesis

    Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The process is widely agreed to have involved symbiogenesis , in which an archaeon and a bacterium came together to create the first eukaryotic ...

  9. Human reproduction - Wikipedia

    en.wikipedia.org/wiki/Human_reproduction

    Human reproduction naturally takes place as internal fertilization by sexual intercourse. During this process, the man inserts his erect penis into the woman's vagina and then either partner initiates rhythmic pelvic thrusts until the man achieves orgasm , which leads to ejaculation of semen containing sperm into the vaginal canal.