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  2. External fertilization - Wikipedia

    en.wikipedia.org/wiki/External_fertilization

    The only dilemma with turbulence is the possibility of dilution of sperm and egg because of over mixing. Rapid mixing can cause a lower probability to fertilize. [3] Sessile adult staged animals commonly produce gametes at the same times, also known as a synchronized release of gametes, for external fertilization in the water column.

  3. Fertilisation - Wikipedia

    en.wikipedia.org/wiki/Fertilisation

    This is an accepted version of this page This is the latest accepted revision, reviewed on 28 December 2024. Union of gametes of opposite sexes during the process of 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 ...

  4. Parthenogenesis - Wikipedia

    en.wikipedia.org/wiki/Parthenogenesis

    A female produces an ovum with a full set (two sets of genes) provided solely by the mother. Thus, a male is not needed to provide sperm to fertilize the egg. This form of asexual reproduction is thought in some cases to be a serious threat to biodiversity for the subsequent lack of gene variation and potentially decreased fitness of the offspring.

  5. 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 ...

  6. Superfecundation - Wikipedia

    en.wikipedia.org/wiki/Superfecundation

    Heteropaternal superfecundation is common in animals such as cats and dogs. Stray dogs can produce litters in which every puppy has a different sire. Though rare in humans, cases have been documented. In one study on humans, the frequency was 2.4% among dizygotic twins whose parents had been involved in paternity suits. [6]

  7. Sperm - Wikipedia

    en.wikipedia.org/wiki/Sperm

    Sperm and egg fusing (fertilisation) Dimensions of the human sperm head measured from a 39-year-old healthy human subject The mammalian sperm cell can be divided in 2 parts connected by a neck: Head: contains the nucleus with densely coiled chromatin fibers, surrounded anteriorly by a thin, flattened sac called the acrosome , which contains ...

  8. Human fertilization - Wikipedia

    en.wikipedia.org/wiki/Human_fertilization

    Human fertilization is the union of an egg and sperm, occurring primarily in the ampulla of the fallopian tube. [1] The result of this union leads to the production of a fertilized egg called a zygote, initiating embryonic development. Scientists discovered the dynamics of human fertilization in the 19th century. [2]

  9. Internal fertilization - Wikipedia

    en.wikipedia.org/wiki/Internal_fertilization

    Usually, the sperm is stored in spermathecae on the roof of the cloaca until it is needed at the time of oviposition. It is used by some salamander and newt species, by the Arachnida, some insects and some mollusks. [16] [17] In sponges, sperm cells are released into the water to fertilize ova that are retained by the female. Some species of ...