Search results
Results From The WOW.Com Content Network
Oviparity: fertilisation is internal, but the female lays zygotes as eggs with a substantial quantity of yolk to feed the embryo while it remains in the egg. The egg is not retained in the body, or only for a limited time. [1] Oviparity is found in insects, birds. Among mammals, the monotremes are oviparous.
Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight.Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird to fly.
Cloaca of a red-tailed hawk. A cloaca (/ k l oʊ ˈ eɪ k ə / ⓘ kloh-AY-kə), pl.: cloacae (/ k l oʊ ˈ eɪ s i / kloh-AY-see or / k l oʊ ˈ eɪ k i / kloh-AY-kee), or vent, is the rear orifice that serves as the only opening for the digestive (), reproductive, and urinary tracts (if present) of many vertebrate animals.
Various visual signals act in combination to attract a mate and female choice will shift toward several particularly exaggerated traits. [20] In the red-legged partridge, male carotenoid ornamentation is positively correlated with relative reproductive investment of the female. This species has variable egg laying capacity and females who mated ...
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.
The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vulva, which leads to the vagina, the vaginal opening, to the uterus; the uterus, which ...
Sperm storage organs in the fruit fly Drosophila melanogaster.Female was first mated with GFP-male and then re-mated with RFP-male. Female sperm storage is a biological process and often a type of sexual selection in which sperm cells transferred to a female during mating are temporarily retained within a specific part of the reproductive tract before the oocyte, or egg, is fertilized.
In polyandry, one female mates with multiple males (and one male only mates with one female) and is a unique mating system which occurs in less than 1% of all bird species. Parental roles are reversed and cause males to provide most of the care given to offspring.