Search results
Results from the WOW.Com Content Network
Oviparous animals laying eggs with thick calcium shells, such as chickens, or thick leathery shells generally reproduce via internal fertilisation so that the sperm fertilises the egg without having to pass through the thick, protective, tertiary layer of the egg. Ovoviviparous and viviparous animals also use internal fertilisation.
Eggs of various birds, a reptile, various cartilaginous fish, a cuttlefish and various butterflies and moths. (Click on image for key) Diagram of a fertilized chicken egg in its ninth day. Membranes: allantois, chorion, amnion, and vitellus/yolk. Six commercial chicken eggs — view from the top against a white background
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 mother.
The fertilized egg cell is known as the zygote. [2] [5] To prevent more than one sperm fertilizing the egg , fast block and slow block to polyspermy are used. Fast block, the membrane potential rapidly depolarizing and then returning to normal, happens immediately after an egg is fertilized by a single sperm.
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.
Cock: a fertile adult male chicken [6] [7] Cockerel: a young male chicken [8] Hen: an adult female chicken [9] Pullet: a young female chicken less than a year old. [10] In the poultry industry, a pullet is a sexually immature chicken less than 22 weeks of age. [11] Rooster: a fertile adult male chicken
The only living mammals that lay eggs are echidnas and platypuses. In the latter, the eggs develop in utero for about 28 days, with only about 10 days of external incubation (in contrast to a chicken egg, which spends about one day in tract and 21 days externally). [11] After laying her eggs, the female curls around them.
This chicken egg has been soaked in vinegar for a few days and has become translucent and flexible. Anatomy of a chicken egg. The bird egg is a fertilized gamete (or, in the case of some birds, such as chickens, possibly unfertilized) located on the yolk surface and surrounded by albumen , or egg white.