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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), [30] [31] ZZ (male), or WW (non-viable in most species, [33] but a fertile, [dubious – discuss] viable female in a few, e.g ...

  3. Monogamy in animals - Wikipedia

    en.wikipedia.org/wiki/Monogamy_in_animals

    Monogamy is defined as a pair bond between two adult animals of the same species. This pair may cohabitate in an area or territory for some duration of time, and in some cases may copulate and reproduce with only each other. Monogamy may either be short-term, lasting one to a few seasons or long-term, lasting many seasons and in extreme cases ...

  4. ZW sex-determination system - Wikipedia

    en.wikipedia.org/wiki/ZW_sex-determination_system

    The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.

  5. Hybrid (biology) - Wikipedia

    en.wikipedia.org/wiki/Hybrid_(biology)

    A mule is a sterile hybrid of a male donkey and a female horse.Mules are smaller than horses but stronger than donkeys, making them useful as pack animals.. In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction.

  6. 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 ...

  7. Semelparity and iteroparity - Wikipedia

    en.wikipedia.org/wiki/Semelparity_and_iteroparity

    For example, imagine two species—an iteroparous species that has annual litters averaging three offspring each, and a semelparous species that has one litter of four, and then dies. These two species have the same rate of population growth, which suggests that even a tiny fecundity advantage of one additional offspring would favor the ...

  8. The bird at the center of the worst single-species mortality ...

    www.aol.com/news/bird-center-worst-single...

    A record 4 million common murres died as a result of a two-year marine heat wave in Alaska, a study found. ... marking the largest recorded die-off of a single species in modern history, research ...

  9. Species - Wikipedia

    en.wikipedia.org/wiki/Species

    A species (pl.: species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. [1] It is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity .