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The evolutionary trend among birds has been the reduction of anatomical elements to save weight. The first element to disappear was the bony tail, being reduced to a pygostyle and the tail function taken over by feathers. Confuciusornis is an example of their trend. While keeping the clawed fingers, perhaps for climbing, it had a pygostyle tail ...
A turning point came in the early twentieth century with the writings of Gerhard Heilmann of Denmark.An artist by trade, Heilmann had a scholarly interest in birds and from 1913 to 1916, expanding on earlier work by Othenio Abel, [12] published the results of his research in several parts, dealing with the anatomy, embryology, behavior, paleontology, and evolution of birds. [13]
Avialae ("bird wings") is a clade containing the only living dinosaurs, the birds, and their closest relatives.It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used (see below).
There are only two suprafamilial clades (natural groups) among the birds traditionally classified as Gruiformes. Rails (), flufftails (Sarothruridae), finfoots and sungrebe (Heliornithidae), adzebills (Aptornithidae), trumpeters (), limpkin (), and cranes compose the suborder Grues and are termed "core-Gruiformes". [4]
The black-chinned hummingbird (Archilochus alexandri) is the bird species known to have the smallest genome among birds, which is only 0.91 Gb long.The genomic evolution of birds has come under scrutiny since the advent of rapid DNA sequencing, as birds have the smallest genomes of the amniotes despite acquiring highly derived phenotypic traits.
ɪ ˈ θ ɒ n t ɪ f ɔːr m iː z / are an order of birds. They contain one extant family, the tropicbirds (Phaethontidae), and one extinct family Prophaethontidae from the early Cenozoic. Several fossil genera have been described, with well-preserved fossils known as early as the Paleocene . [ 2 ]
The placement of the pseudo-toothed birds in the evolutionary tree of birds has been problematic, with some supporting the placement of them near the orders Procellariformes and Pelecaniformes based on features in the sternum. [3] In 2005 a cladistic analysis had found support in placing pseudo-toothed birds as the sister group to waterfowl. [2]
The tree of life or universal tree of life is a metaphor, conceptual model, and research tool used to explore the evolution of life and describe the relationships between organisms, both living and extinct, as described in a famous passage in Charles Darwin's On the Origin of Species (1859). [1]