Birds-1 - fluffy. They trap an insulating layer of air...

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Birds - Structure and function 1 Birds - structure and function beak nostril eye primary flight feathers position of ear metatarsus tail feathers wing covert feathers toe claw External features of a Chaffinch Birds are vertebrates - they have a vertebral column and a skull. They are ‘warm blooded’; that means they maintain their body temperature at a constant level and above that of their surroundings. Their chief distinguishing characteristics are that they have feathers and their forelimbs are modified to form wings. The feathers consist of a shaft with rows of fine filaments ( barbs ) on each side. The barbs themselves have finer filaments ( barbules ) branching from them. In the down feathers, the barbs and barbules are loose and
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Unformatted text preview: fluffy. They trap an insulating layer of air close to the body and so reduce heat losses. The barbs and barbules of the flight and covert (or contour) feathers are organised in a regular way forming a smooth, water resistant cover. The barbules overlap so that the hooks on one set of barbules engage with grooves on the other set rather like Velcro. If the feathers get damaged in flight, they can be restored to shape by preening. barbs and barbules shaft shaft barbs and barbules hook in lower barbule locks into trough in upper barbule barb (c) Simplified model of interlocking mechanism of barbules (a) Down feathers ( b) Flight feather Feather structure D.G. Mackean vane...
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This note was uploaded on 11/29/2011 for the course BIO 218 taught by Professor Young during the Fall '11 term at BYU.

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