| Hence, the possession of feathers is unique to birds and defines all members of the class Aves. |
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| We performed phylogenetic analyses of introns from species from four avian orders that are representative of the two infraclasses within Aves. |
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| The vertebrate class Aves includes the birds, an extremely distinctive and successful clade, with an estimated 9000 species worldwide, including the snowy owl pictured here. |
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| During the same journey, he constructed a ship and visited the islands of Aruba and the Las Aves archipelago. |
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| Passerines are distinguished from other orders of Aves by the arrangement of their toes, three pointing forward and one back, which facilitates perching. |
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