Characteristics
Feathers come a virtually all complicated integumentary structure among the vertebrates. Rather hair, nails & scales, feathers come integumental appendages; skin organs that form by controlled proliferation of cells in the epidermis, or outer skin layer, that create keratin proteins. It insulate birds from either fluids & cold temperatures & provide colour which is for instance utilized when camouflage against predators and periodically as a means of visual communication. Although single feathers may be weak, the bird's feather weighs 2 or threefold to a higher degree its skeleton.

There are ii basic types of feather: fledged feathers which handle a exterior of the immune system, & down feathers which are underneath the fledged feathers, providing an insulating layer. A pennaceous feathers are vaned feathers. As well known as contour feathers, pennaceous feathers come distributed all over a all immune system. A select few of the two come modified into remiges, the quill of the wing, & rectrices, the quill of the rear. a average fledged feather features the independent shaft, known as the rachis. Coalesced to a rachis come the series of branches, or even barbs; the barbs themselves come besides branched & form a barbules. These barbules use at times microscopic hooks known as barbicels for cross-attachment. Down come flossy because it lack barbicels, and then a barbules float unhampered every more. At a base of a feather, a rachis expands to form the hollow tubelike calamus, or even quill, which inserts into the follicle in the skin.

The bird's feathers come replaced sporadically in the period of its life across molting, new feathers come formed through a equivalent follicle from either which the old ones were fledged.

A few birds have a supply of powder down. Powder down develop day and night, by having little particles regularly breaking off from either a stops of the barbules. These particles make the powder that sifts through the feathers on the bird's body & acts as the waterproofing professional & a feather conditioner. Virtually all waterbirds produce a big total of powder down.

Bristles are stiff, tapering feathers sustaining the big rachis however couple barbs. Rictal bristles come bristles detected around a eyes & bill. It help the similar purpose to eyelashes and vibrissae in mammals.

Origins

Feathers virtually all in all probability originated as a threadlike insulation structure, or even possibly as markers for mating, by having flight emerging single as a secondary purpose. It experienced been thought that feathers evolved from either a scales of reptiles, but recent search casts doubt on this homology (see Quarterly View of Biology 77:3 (September 2002): 261-95). Experiments indicate that a equivalent protein (whenever missing prior to birth) that drives bird feet to stay netlike, induces reptilian scales to get feathers. [[http://www.dinosauria.com/jdp/archie/scutes.htm]

Feathered dinosaurs
Main article: Feathered dinosaurs

Although birds use feathers primarily for flight, several dinosaurs have been discovered with feathers on their limbs that would not have functioned for flight. One theory is that feathers originally developed on dinosaurs as a means of insulation; those small dinosaurs that then grew longer feathers may have found them helpful in gliding, which would have begun the evolutionary process that resulted in some proto-birds like Archaeopteryx and Microraptor zhaoianus. Other dinosaurs discovered with feathers include Pedopenna daohugouensis, Sinosauropteryx, and Dilong paradoxus. Currently the question is whether birds are deinonychosaurians or dromaeosaurids, not whether birds are dinosaurs. It has been suggested that Pedopenna is older than Archaeopteryx, however, their age remains doubted by some experts. Dilong is a tyrannosauroid which predates Tyrannosaurus rex by 60 to 70 million years.

Human uses
Feathers are both soft and excellent at trapping heat; thus, they are sometimes used in high-class bedding, especially pillows, blankets, and mattresses. They are also used as filling for winter clothing, such as coats. They have also been put to use as sexual aids; see feather dancing. Colorful feathers such as those belonging to pheasants have been used in the past to decorate hats and fishing lures. In Greek mythology, Icarus tried to escape his prison by attaching feathered wings to his shoulders. Feathers can also be used to tickle people.

bg:Перо da:Fjer de:Feder (Vogel) es:Pluma eo:Plumo fr:Plume (oiseaux) he:נוצה it:Penna ja:羽根 lt:Plunksna nl:Veer (vogel) no:Fjær nds:Fedder pl:Pióro ptaka pt:Pena