Feather

related topics
{specie, animal, plant}
{@card@, make, design}
{acid, form, water}
{law, state, case}
{food, make, wine}
{disease, patient, cell}
{group, member, jewish}
{service, military, aircraft}
{woman, child, man}
{mi², represent, 1st}

Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds. They are considered the most complex integumentary structures found in vertebrates,[1][2] and indeed a premier example of a complex evolutionary novelty.[3] They are among the characteristics that distinguish the extant Aves from other living groups. Feathers have also been noticed in those Theropoda which have been termed feathered dinosaurs. Although feathers cover most parts of the body of birds, they arise only from certain well-defined tracts on the skin. They aid in flight, thermal insulation, waterproofing and coloration that helps in communication and protection.[4]

Contents

Structure and characteristics

Feathers are among the most complex integumentary appendages found in vertebrates and are formed in tiny follicles in the epidermis, or outer skin layer, that produce keratin proteins. The β-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into β-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the α-keratins of mammalian hair, horns and hoof.[5][6] The exact signals that induce the growth of feathers on the skin are not known but it has been found that the transcription factor cDermo-1 induces the growth of feathers on skin and scales on the leg.[7]

Full article ▸

related documents
Velociraptor
Cheetah
Peafowl
Speciation
Sex
Labrador Retriever
Seabird
Coyote
Brown Bear
Kakapo
Thylacine
Jellyfish
Tuatara
Cichlid
Bipedalism
Catfish
Pinniped
Carnivora
Ascomycota
Kangaroo
American Bison
Beagle
Cloning
Arecaceae
Fox hunting
Endangered species
Hedgehog
Polar bear
Flowering plant
Asexual reproduction