Birds were among the very first animals that man domesticated to his use, probably right on the heels of the dog. Domestic chickens date back to the first permanent human settlement in India, about 5,000 years ago. And, even before early man had settled fully into stationary communities, nomadic peoples were using falcons and other raptors as a means of hunting. Birds are vertebrate, warm-blooded, walking or just remain on the thighs, while the front limbs are modified as wings, which, like many other unique anatomical features are adaptations for flying, although not all fly . They have the body covered with feathers and birds present a toothless horny beak. Lay eggs to reproduce, which hatch to hatch... and eat larves before they become big. His group is called a taxonomic class Aves to classical systematics, but in this current systematic phylogenetic clade has no range, and is included in turn successively within the clades: Theropoda, Dinosauria, Archosauria, sauropsids, tetrapods, etc.., But there are more nests with intermediate title. The birds originated from bipedal carnivorous dinosaurs of the Jurassic, 150-200 million years ago. Subsequent developments resulted, after a strong radiation at about 10,000 species today. Birds are tetrapods more diverse, however, have a great morphological homogeneity in comparison with mammals. Kinship relations of the families of birds can not always be defined by morphology, but DNA analysis are beginning to be clarified. The birds live in all terrestrial biomes, and also in all the oceans. The size can range from 6.4 cm in the hummingbird zunzuncito to 2.74 meters in the sand. Behavior are diverse and remarkable as nesting, feeding their young, migration, mating and the tendency for the partnership group. Communication between these birds is variable and can involve visual signals, calls and songs. Some emit a large variety of sounds, and are noted for their intelligence and capacity for cultural transmission of knowledge to new generations. The human being has an intense relationship with the birds. In the human economy poultry and game are food sources. The song and the parrots are popular as pets. Use the down of domestic ducks and geese to fill pillows, and before many birds are hunted for their feathers to decorate hats. The guano of birds used in the fertilization of soils. Some birds are revered or repudiated religious, superstitions, prejudices or error. Many are cultural symbols and frequent reference to the art. Since the seventeenth century, have become extinct more than 120 species as a result of human activities, and currently are more than 1,200 threatened birds they need for their conservation efforts. Decorate your indoors with birds and ourdoors with fishes.
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