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While a single specific cause is unknown, chronic egg laying is believed to be triggered by hormonal imbalances influenced by a series of external factors. [1] As in the domestic chicken, female parrots are capable of producing eggs without the involvement of a male – it is a biological process that may be triggered by environmental cues such as day length (days becoming longer, indicating ...
Usually, eggs are laid only by the queen, but the unmated workers may also lay haploid, male eggs either regularly (e.g. stingless bees) or under special circumstances. An example of non-viable parthenogenesis is common among domesticated honey bees. The queen bee is the only fertile female in the hive; if she dies without the possibility of a ...
Scientists believe that an unfertilized egg began to self-divide but then had some (but not all) of its cells fertilized by a sperm cell; this must have happened early in development, as self-activated eggs quickly lose their ability to be fertilized. The unfertilized cells eventually duplicated their DNA, boosting their chromosomes to 46.
The Australian budgerigar, or shell parakeet, is a popular pet and the most common parakeet. Parakeets comprise about 115 species of birds that are seed-eating parrots of small size, slender build, and long, tapering tails. [citation needed] The Australian budgerigar, also known as "budgie", Melopsittacus undulatus, is probably the most common ...
Females can produce full clones of themselves through a modification of the normal meiosis process used to produce haploid egg cells for sexual reproduction. The female's germ cells undergo a process of premeiotic genome doubling, or endoreduplication, so that two consecutive division cycles in the process of meiosis result in a diploid, rather than haploid, genome.
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.
The egg cell is generally asymmetric, having an animal pole (future ectoderm). It is covered with protective envelopes, with different layers. The first envelope – the one in contact with the membrane of the egg – is made of glycoproteins and is known as the vitelline membrane (zona pellucida in mammals).
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.