The structure of the feather birds. Types and meaning of feathers
Birds are often called feathered. Why? These are the only animals on the planet whose body is covered with feathers. Their color and size can be very diverse. There are several types of feathers, each of which performs its functions. We will talk about the external structure of birds and the structure of feathers in this article.
Birds are warm-blooded vertebrates that breed by laying eggs. Most of them can fly. Flightless birds have lost this opportunity again. All members of the class have a beak completely devoid of teeth. The main distinguishing feature is the feather cover of the body.
For flights, the birds had to change a lot. In the course of evolution, their forelimbs became wings, many vertebrae grew together, forming a strong framework. Some of their bones are filled with air, providing them with extra lightness. Flying birds on the sternum have a flat bony outgrowth - the keel, to which the muscles are attached, lowering the wing.
The ability to fly reflected on the shape of the body, respiratory and digestive systems. The body is feathered with a streamlined shape, which reduces friction with air. They are able to travel considerable distances and travel hundreds or even thousands of kilometers. For this you need a lot of energy, and to get it helps accelerated metabolism.
Birds are the most numerous group of higher vertebrates. Of the living, more than 10,600 species are known. They settled in almost all corners of the planet, from single ocean islands to megacities, from deserts and tropics to the inner parts of Antarctica.
Feathers grow in birds on all parts of the body, they are missing only on the beak and hind limbs. In some species, such as American griffins, ostriches, turkeys, the plumage on the neck and head is thin and rare, and sometimes completely absent.
Features of the structure of bird feathers, their appearance and number depend on the specific type and lifestyle of animals. And the color of the covers is largely related to their habitat. As a rule, the larger the view, the more feathers it has. So, in swans their number reaches 25 thousand, in gulls - up to 6 thousand, in the smallest members of the class, hummingbirds, there are about a thousand.
There are no glands on their skin, the only one located at the base of the tail and called the oil gland. She highlights a special secret that makes feathers more resilient, disinfects and prevents them from sticking together when wet. Animals squeeze it with a beak and grease the plumage several times a day.
The structure of the feather birds
In all birds it is the same. In ostriches, kiwi, cassowary and penguin feathers cover the body evenly. In other species, they grow in rows, leaving between themselves empty areas - apterias. Growth lines are called pteriliae. They are divided into brachial, caudal, dorsal, pectoral, femoral, cephalic, etc.
In the structure of the feather birds emit ochin, rod and fan. Ochin - is the "bare" part of the stem of the pen. It is round in section, and there is a hole at its end. The lower part of the fender enters the recess in the skin and contains a branch of the artery.
It is followed by a hollow rod having four faces across. On the two sides, hems are attached to it - the hairy parts of the feather. There are two of them, each consisting of barrels of the first and second order (barbits).
A similar principle is observed in the structure of the crown of a tree.The first barbs grow straight from the rod, and from them the barbits are already moving away. Second-order beards have hooks that attach to adjacent beards. This structure of bird feathers does not allow air and allows you to push off from it when flying.
The plow of birds is very durable and resilient. It consists of keratin protein - the same material as our hair, nails, as well as turtle shells and rhino horns. The general structure of bird feathers is the same, but their elements may differ in appearance and quality. On this basis, emit contour, primary, down, thread-like feathers.
Contour or cover feathers - the main. They overlap each other like tiles or fish scales, covering the whole body and giving it a streamlined shape. Fly feathers are more elongated and long. They are located on the wing and are necessary when flying.
About a dozen wing feathers are located on the tassels of the bird, a few dozen are placed on the forearm. On the tail are steering elements. They are involved in reversing and balancing. In some species reach quite large sizes.
The structure of the down feather of birds and their down differs from others,as they are necessary to maintain heat. They have a thin rod, and their beards are free from hooks and fly apart in different directions. The core of the fluff is even weaker, but the vane is not pronounced and looks like cotton wool.
On the beak are thin single feathers, devoid of the veil. They look like sparse hairs. These are thread-like feathers or vibrissae that are used for touch.
Color and its meaning
Color is no less important than the structure of the feathers of birds. For flight, it does not matter, but plays a crucial role for survival and reproduction. The color of plumage is given by pigments: melanin (brown, yellow, black), carotenoids (yellow, orange, red) and porphyrins (green, red).
In many species, the color corresponds to the environment, masking its owner. For example, in steppe and rocky inhabitants the plumage is gray, gray, brown. In tropical species, colors are brighter and more varied.
In addition, color is important in the social life of birds. Thus, within the same species and population, the color may differ in animals of different sex, age and status. Males, as a rule, look brighter and more pretentious, as they are forced to fight for the attention of females in the mating season.