Birds Photo Wallpapers

Description: Birds (class Aves) are bipedal, endothermic (warm-blooded), vertebrate animals that lay eggs. There are around 10,000 living species, making them the most diverse tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.7 m (9 ft) Ostrich.... ( +expand to view full text )

Description: Birds (class Aves) are bipedal, endothermic (warm-blooded), vertebrate animals that lay eggs. There are around 10,000 living species, making them the most diverse tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the 5 cm (2 in) Bee Hummingbird to the 2.7 m (9 ft) Ostrich. The fossil record indicates that birds evolved from theropod dinosaurs during the Jurassic period, around 150¨C200 Ma (million years ago), and the earliest known bird is the Late Jurassic Archaeopteryx, c 155¨C150 Ma. Most paleontologists regard birds as the only clade of dinosaurs that survived the Cretaceous¨CTertiary extinction event approximately 65.5 Ma.