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The fifth toe is lost completely except in some birds where it has become a spur. A number of birds have spurs on their feet or legs, usually formed from the lower portion of the tarsometatarsus bone. Best known are the spurs on chicken, though most galliform birds bear spurs. The spurs are mostly found in males, and used in mating competition ...
Their missing or vestigial hallux – like in ducks but unlike in pelicans which have all four toes fully developed and webbed – was held against a close relationship with pelicans. But as is known today, pelicans are closer to storks (which have a hallux but no webbing) than to pseudotooth birds and evolved their fully webbed toes independently.
Since the late 19th century, it has been accepted by palaeontologists, and celebrated in lay reference works, as being the oldest known bird, though a study in 2011 has cast doubt on this assessment, suggesting instead that it is a non-avialan dinosaur closely related to the origin of birds. [12] It lived in what is now southern Germany in the ...
View of birds flying around the Bird Key, a private island on Biscayne Bay that is now for sale as environmentalists are upset, because developers could build on the island, displacing all the ...
Birds have an added type of cone that allows them to see ultraviolet light. In addition to seeing a broader spectrum of colors, birds can also detect finer differences between them.
According to the International Union for Conservation of Nature (IUCN), 77 bird species in the United States are threatened with extinction. [1] The IUCN has classified each of these species into one of three conservation statuses: vulnerable VU, endangered EN, and critically endangered CR (v. 2013.2, the data is current as of March 5, 2014 [1]).
In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function.. Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [1]
Archaeopteryx (/ ˌ ɑːr k iː ˈ ɒ p t ər ɪ k s /; lit. ' old-wing '), sometimes referred to by its German name, "Urvogel" (lit. Primeval Bird) is a genus of bird-like dinosaurs.The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing".