L’origine et l’évolution des oiseaux : 35 années de progrès

Kevin PADIAN & Armand de RICQLÈS

fr Comptes Rendus Palevol 8 (2-3) - Pages 257-280

Published on 30 April 2009

This article is a part of the thematic issue Evolutionary history of Life

The origin and evolution of birds: 35 years of progress

Birds are dinosaurs – specifically, small feathered and flighted theropod dinosaurs that probably originated in Laurasia during the Late Jurassic over 140 million years ago. They are most closely related to other small theropods such as dromaeosaurs and troodontids, terrestrial predators that were fleet-footed hunters. The origin of birds is a classic example of two kinds of macroevolution: the phylogenetic origin of the group, and the sequential assembly of adaptations such as flight that are indelibly associated with birds. These adaptations were not assembled all at once. Rather, a great many characteristics associated with birds and flight first appeared in non-avian dinosaurs, where they were used for many purposes other than flight. These included insulation, brooding, and probably display and species recognition. Birds diversified steadily but gradually after their origin, which is identified with the origin of flight (Archaeopteryx); forelimb and other flight-associated features evolved more rapidly than features associated with the posterior skeleton. The first birds grew more slowly than extant birds do, and more like other small Mesozoic dinosaurs; like them, they probably matured sexually well before they completed their active skeletal growth. The origin of flight is not a problem of “trees down” or “ground up,” but rather an examination of the order in which diagnostic flight characters evolved, and what each stage can reveal about the functions and habits of bird outgroups at those evolutionary junctures.


Aves, Archaeopteryx, Dinosauria, Origin of birds, Origin of flight

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