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  2. Internal fertilization - Wikipedia

    en.wikipedia.org/wiki/Internal_fertilization

    Over time amphibians have been found evolving to increasing internal fertilization. [citation needed] Within amphibians, it is common for high vertebrates to internally fertilize because of the transition from water to land during vertebrate evolution. There is an advantage for the amphibians who are internally fertilizing allowing for the ...

  3. Amniote - Wikipedia

    en.wikipedia.org/wiki/Amniote

    After internal fertilization and the habit of laying eggs in terrestrial environments became a reproduction strategy amongst the amniote ancestors, the next major breakthrough appears to have involved a gradual replacement of the gelatinous coating covering the amphibian egg with a fibrous shell membrane. This allowed the egg to increase both ...

  4. Parthenogenesis - Wikipedia

    en.wikipedia.org/wiki/Parthenogenesis

    Parthenogenesis occurs naturally in some plants, algae, invertebrate animal species (including nematodes, some tardigrades, water fleas, some scorpions, aphids, some mites, some bees, some Phasmatodea, and parasitic wasps), and a few vertebrates, such as some fish, amphibians, and reptiles. This type of reproduction has been induced ...

  5. Anamniotes - Wikipedia

    en.wikipedia.org/wiki/Anamniotes

    The anamniotes are an informal group of craniates comprising all fish and amphibians, which lay their eggs in aquatic environments.They are distinguished from the amniotes (reptiles, birds and mammals), which can reproduce on dry land either by laying shelled eggs or by carrying fertilized eggs within the female.

  6. Parthenogenesis in amphibians - Wikipedia

    en.wikipedia.org/wiki/Parthenogenesis_in_Amphibians

    Parthenogenesis is a form of reproduction where eggs develop without fertilization, resulting in unisexual species. This phenomenon is closely related with reproductive modes such as hybridogenesis, where fertilization occurs, but the paternal DNA is not passed on.

  7. External fertilization - Wikipedia

    en.wikipedia.org/wiki/External_fertilization

    External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. [1] It is contrasted with internal fertilization , in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism.

  8. 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]

  9. Animal embryonic development - Wikipedia

    en.wikipedia.org/wiki/Animal_embryonic_development

    Fertilization is the fusion of gametes to produce a new organism. In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. Depending on the animal species, the process can occur within the body of the female in internal fertilization, or outside in the case of external fertilization.