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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.
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 ...
Eggs of various animals (mainly birds) Oviparous animals are animals that reproduce by depositing fertilized zygotes outside the body (known as laying or spawning ) in metabolically independent incubation organs known as eggs , which nurture the embryo into moving offsprings known as hatchlings with little or no embryonic development within the ...
Turtles lay and hatch from eggs – though, like hens, the females can lay eggs without mating. These eggs will not produce baby turtles. For pet turtles, unfertilized eggs should be removed and ...
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]
Adult male leopard tortoise, South Africa Tortoise laying eggs Young African sulcata tortoise. Most species of tortoises lay small clutch sizes, seldom exceeding 20 eggs, and many species have clutch sizes of only 1–2 eggs. Incubation is characteristically long in most species, the average incubation period are between 100 and 160.0 days.
While many reptiles lay eggs with flexible, calcified eggshells, there are some that lay hard eggs. Eggs laid by snakes generally have leathery shells which often adhere to one another. Depending on the species, turtles and tortoises lay hard or soft eggs. Several species lay eggs which are nearly indistinguishable from bird eggs. [citation needed]
Most fish species spawn eggs that are fertilized externally, typically with the male inseminating the eggs after the female lays them. These eggs do not have a shell and would dry out in the air. Even air-breathing amphibians lay their eggs in water, or in protective foam as with the Coast foam-nest treefrog, Chiromantis xerampelina.