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  2. Parthenogenesis - Wikipedia

    en.wikipedia.org/wiki/Parthenogenesis

    In species that use the XY sex-determination system, parthenogenetic offspring have two X chromosomes and are female. In species that use the ZW sex-determination system the offspring genotype may be one of ZW (female), [28] [29] ZZ (male), or WW (non-viable in most species, [31] but a fertile, [dubious – discuss] viable female in a few, e.g ...

  3. Sexual differentiation in humans - Wikipedia

    en.wikipedia.org/wiki/Sexual_differentiation_in...

    In the absence of a Y chromosome, the fetus will undergo female development. This is because of the presence of the sex-determining region of the Y chromosome, also known as the SRY gene. [5] Thus, male mammals typically have an X and a Y chromosome (XY), while female mammals typically have two X chromosomes (XX).

  4. Parthenogenesis in squamates - Wikipedia

    en.wikipedia.org/wiki/Parthenogenesis_in_squamates

    Parthenogenesis is a mode of asexual reproduction in which offspring are produced by females without the genetic contribution of a male. Among all the sexual vertebrates, the only examples of true parthenogenesis, in which all-female populations reproduce without the involvement of males, are found in squamate reptiles (snakes and lizards). [1]

  5. Gynogenesis - Wikipedia

    en.wikipedia.org/wiki/Gynogenesis

    Gynogenesis with haplodiploidy in the ant Myrmecia impaternata. The ant Myrmecia impaternata is a hybrid of M. banksi and M. pilosula. [7] In ants, sex is determined by the haplodiploidy system: unfertilized eggs result in haploid males, while fertilized eggs result in diploid females.

  6. XY sex-determination system - Wikipedia

    en.wikipedia.org/wiki/XY_sex-determination_system

    In the XY sex-determination system, the female-provided ovum contributes an X chromosome and the male-provided sperm contributes either an X chromosome or a Y chromosome, resulting in female (XX) or male (XY) offspring, respectively. Hormone levels in the male parent affect the sex ratio of sperm in humans. [25]

  7. Sexual differentiation - Wikipedia

    en.wikipedia.org/wiki/Sexual_differentiation

    Sexual differentiation is the process of development of the sex differences between males and females from an undifferentiated zygote. [1] [2] Sex determination is often distinct from sex differentiation; sex determination is the designation for the development stage towards either male or female, while sex differentiation is the pathway towards the development of the phenotype.

  8. Sex-determination system - Wikipedia

    en.wikipedia.org/wiki/Sex-determination_system

    In some species, there are hermaphrodites, i.e., individuals that can function reproductively as either female or male. [2] There are also some species in which only one sex is present, temporarily or permanently. This can be due to parthenogenesis, the act of a female reproducing without fertilization.

  9. Sexual reproduction - Wikipedia

    en.wikipedia.org/wiki/Sexual_reproduction

    Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. [6] [7] Sexual reproduction also occurs in some unicellular eukaryotes. [2] [8] Sexual reproduction does not occur in prokaryotes, unicellular organisms without cell nuclei, such as bacteria and archaea.