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  2. Sexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Sexual_reproduction

    Animals have life cycles with a single diploid multicellular phase that produces haploid gametes directly by meiosis. Male gametes are called sperm, and female gametes are called eggs or ova. In animals, fertilization of the ovum by a sperm results in the formation of a diploid zygote that develops by repeated mitotic divisions into a diploid ...

  3. Human reproduction - Wikipedia

    en.wikipedia.org/wiki/Human_reproduction

    During sexual intercourse, sperm cells are ejaculated into the vagina through the penis, resulting in fertilization of an ovum to form a zygote. [1] While normal cells contain 46 chromosomes (23 pairs), gamete cells contain only half that number, and it is when these two cells merge into one combined zygote cell that genetic recombination occurs.

  4. Human fertilization - Wikipedia

    en.wikipedia.org/wiki/Human_fertilization

    The following are a few of the diseases that can occur and be present during the process. Polyspermy results from multiple sperm fertilizing an egg, leading to an offset number of chromosomes within the embryo. [34] Polyspermy, while physiologically possible in some species of vertebrates and invertebrates, is a lethal condition for the human ...

  5. Reproduction - Wikipedia

    en.wikipedia.org/wiki/Reproduction

    Sexual reproduction typically requires the sexual interaction of two specialized reproductive cells, 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 create a fertilized zygote. This produces offspring organisms whose ...

  6. Human embryonic development - Wikipedia

    en.wikipedia.org/wiki/Human_embryonic_development

    The zygote contains the combined genetic material carried by both the male and female gametes which consists of the 23 chromosomes from the nucleus of the ovum and the 23 chromosomes from the nucleus of the sperm. The 46 chromosomes undergo changes prior to the mitotic division which leads to the formation of the embryo having two cells.

  7. Fertilisation - Wikipedia

    en.wikipedia.org/wiki/Fertilisation

    This is an accepted version of this page This is the latest accepted revision, reviewed on 4 February 2025. Union of opposite-sex gametes in sexual reproduction to form a zygote This article is about fertilisation in animals and plants. For fertilisation in humans specifically, see Human fertilization. For soil improvement, see Fertilizer. "Conceive" redirects here. For the health magazine ...

  8. Human reproductive system - Wikipedia

    en.wikipedia.org/wiki/Human_reproductive_system

    In males, this process is known as spermatogenesis and occurs only after puberty in the seminiferous tubules of the testes. The immature spermatozoa or sperm are then sent to the epididymis, where they gain a tail, enabling motility. Each of the original diploid germ cells or primary spermatocytes forms four functional gametes, each forever young.

  9. Asexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Asexual_reproduction

    Budding is also known on a multicellular level; an animal example is the hydra, [10] which reproduces by budding. The buds grow into fully matured individuals which eventually break away from the parent organism. Internal budding is a process of asexual reproduction, favoured by parasites such as Toxoplasma gondii.