Large Mesozoic mammals fed on young dinosaurs : Abstract : Nature. The Life of Birds. This theory was born with the discovery of a 150-million-year-old fossilised creature in a swamp in Germany in the 1860s.
Archaeopteryx was possibly the most controversial prehistoric remain ever dug up. It is the oldest known bird fossil. Most biologists accept it as conclusive proof that dinosaurs sired birds. Archaeopteryx had three toes armed with claws and long, strong legs. Bird Evolution - The Story of Prehistoric Birds. The First Dinosaurs. About 230 million years ago--give or take a few million years--the first dinosaurs evolved from the archosaurs, the "ruling lizards" that shared the earth with other families of early reptiles, including therapsids and pelycosaurs.
As a group, dinosaurs are defined by a host of (mostly obscure) anatomical features, but to simplify matters a bit, the main thing that distinguished them from their archosaur forebears was their erect posture (either bipedal or quadrupedal), as evidenced by the shape and arrangement of their hip and leg bones. (See a gallery of early theropod pictures.) As with all such evolutionary transitions, it's impossible to identify the exact moment when the first dinosaur walked the earth: for a few million years during the middle Triassic period, some reptile species would have evinced a confusing mixture of archosaur and dinosaur characteristics.
South America - Land of the First Dinosaurs The Specialization of the First Dinosaurs. Dinosaurs and Birds. How (and when) did dinosaurs evolve into birds?
What were the first feathered dinosaurs? And how did paleontologists manage to piece together the dinosaur/bird puzzle? Bird Evolution and ExtinctionThe very first birds evolved from the small, feathered theropods of the Jurassic period, after which birds spread to fill every available ecological niche: hunters, flyers, swimmers and more. Here's everything you need to know about the evolution (and extinction) of birds. The Feathered DinosaursIn the Mesozoic Era, there wasn't just one "missing link" that connected dinosaurs and birds, but dozens of them: small, feathered theropods that displayed a tantalizing mixture of dinosaur and bird features.