Bird Wallpaper Desktop Biography
The first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae.[2] Carolus Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use.[3] Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda.[4] Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria. During the late 20th century, Aves was commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica.[5] However, an alternate definition proposed by scientists including Jacques Gauthier and adherents of the Phylocode system defined Aves to include only the modern bird groups, the crown group. This was done by excluding most groups known only from fossils, and assigning them, instead, to the Avialae,[6] in part to avoid the uncertainties about the placement of Archaeopteryx in relation to animals traditionally thought of as theropod dinosaurs.
All modern birds lie within the crown group Aves (alternately Neornithes), which has two subdivisions: the Palaeognathae, which includes the flightless ratites (such as the ostriches) and the weak-flying tinamous, and the extremely diverse Neognathae, containing all other birds.[4] These two subdivisions are often given the rank of superorder,[7] although Livezey and Zusi assigned them "cohort" rank.[4] Depending on the taxonomic viewpoint, the number of known living bird species varies anywhere from
The first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae.[2] Carolus Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use.[3] Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda.[4] Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria. During the late 20th century, Aves was commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica.[5] However, an alternate definition proposed by scientists including Jacques Gauthier and adherents of the Phylocode system defined Aves to include only the modern bird groups, the crown group. This was done by excluding most groups known only from fossils, and assigning them, instead, to the Avialae,[6] in part to avoid the uncertainties about the placement of Archaeopteryx in relation to animals traditionally thought of as theropod dinosaurs.
All modern birds lie within the crown group Aves (alternately Neornithes), which has two subdivisions: the Palaeognathae, which includes the flightless ratites (such as the ostriches) and the weak-flying tinamous, and the extremely diverse Neognathae, containing all other birds.[4] These two subdivisions are often given the rank of superorder,[7] although Livezey and Zusi assigned them "cohort" rank.[4] Depending on the taxonomic viewpoint, the number of known living bird species varies anywhere from
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Bird Wallpaper Desktop
Birds In Flight Up Close And Personal
Sparrow Landing In UltraSlo Motion
No comments:
Post a Comment