Classification of Chicken Classification,of,Chicken洪恩在线 -> 轻松英语 -> 外教专栏
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Classification of Chicken
来源：洪恩论坛 Andy's Column
日期：2005-2-27
作者：dragonlin
阅读：5211 次
The chicken is a kind of bird; in fact, it is the most common bird in the world.
It belongs to the phylum Chordata, or vertebrates, and to the class Aves, or birds. Its subclass is Neorniothes, or modern birds, and its order, Galliformes, meaning chicken-like birds. Then its family is Phasianidae, meaning pheasants, its subfamily is Phasianinae, and its genus is jungle fowl.
Galliformes is a large and diverse group made up of some 70 genera and more than
250 species, among them 'gallinaceous birds'. Chicken-like in appearance, Gallinaceous birds have a short, heavy, down-curved bill, enabling them to peck on the ground.
Because most Gallinaceous birds have short, rounded wings, they rarely fly more
than a few feet at a time. The tail length varies, according to the species. Some of the birds have virtually no tail, while some have beautiful long tails with
colourful and elaborate patterns.
One or more spurs may be present on the tarsus. The legs are usually strong, so
that they are able at scratching and running. Some gallinaceous birds have elaborate head and neck ornamentation, including feathers, wattles and casques.
The Phasianidae is a very large family of gallinaceous birds. The family is divided into two subfamilies: Phasianinae, or pheasants, and Perdicinae, or partridges. Among the pheasant subfamily are pheasants themselves, peacocks and jungle fowl, the ancestor of the domestic chicken. Among the partridge subfamily are partridges and quails.
Birds belonging to the pheasant subfamily are characterised by strong sexual dimorphism, meaning that the males are highly ornate and brightly coloured, with adornments such as wattles and long tails, while the females are much less showy,
tending to have brown, reddish-brown, and grey feathers, and short tails. The beautiful appearance of the male is designed to attract a female as a mate. Some scientists believe that a long and symmetrical tail indicates a healthy bird, offering a better chance of producing healthy offspring.
Birds of the partridge subfamily are much smaller than those of the pheasant subfamily. The blue-breasted quail is the smallest in body among the species of galliform. Male and female partridges look almost the same. Sometimes even bird experts cannot distinguish between the two sexes.
Chickens were originally tree-dwelling birds living in the jungles of Asia. The
recorded domestication of this kind of bird dates back to 8000 B.C. in Vietnam.
After that, the people of China, India and Egypt learnt how to domesticate chickens. Later, the Greeks and Romans raised chicken rearing to a fine art, fattening chickens with barley and milk and confining them in cages to keep them tender.
By the Middle Ages, chicken and eggs were favorite foods throughout Europe. After centuries of selection and breeding, chickens now exist in many colors, sizes
and shapes. There are more than 350 combinations of physical features known today.
