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Debates about the origin of bird flight are almost as old as the idea that birds evolved from dinosaurs, which arose soon after the discovery of Archaeopteryx in 1862. Two theories have dominated most of the discussion since then: the cursorial ("from the ground up") theory proposes that birds evolved from small, fast predators that ran on the ...
The evolution of birds began in the Jurassic Period, with the earliest birds derived from a clade of theropod dinosaurs named Paraves. [1] Birds are categorized as a biological class , Aves. For more than a century, the small theropod dinosaur Archaeopteryx lithographica from the Late Jurassic period was considered to have been the earliest bird.
In the 1970s, John Ostrom, following Thomas Henry Huxley's lead in 1868, argued that birds evolved within theropod dinosaurs and Archaeopteryx was a critical piece of evidence for this argument; it had several avian features, such as a wishbone, flight feathers, wings, and a partially reversed first toe along with dinosaur and theropod features.
The age of the dinosaurs never really ended—it only evolved. Birds (and their more reptilian cousins, the Crocodilia ) are the modern-day legacy of dinosaur’s 165-million-year-long stint on Earth.
The fossil filled a 70-million-year gap in the understanding of how the brains of birds evolved: between the 150-million-year-old Archaeopteryx, the earliest known bird-like dinosaur, and birds ...
Several analyses of bird fossils show divergence of species prior to the K–Pg boundary, and that duck, chicken, and ratite bird relatives coexisted with non-avian dinosaurs. [142] Large collections of bird fossils representing a range of different species provide definitive evidence for the persistence of archaic birds to within 300,000 years ...
These features make Archaeopteryx a clear candidate for a transitional fossil between dinosaurs and birds, [15] making it important in the study both of dinosaurs and of the origin of birds. The first complete specimen was announced in 1861, and ten more Archaeopteryx fossils have been found since then. Most of the eleven known fossils include ...
Modern birds evolved from flying dinosaurs, but even with just the surviving skull, the researchers say Oculudentavis is very different from modern birds. "It's a new ecology, never seen before ...