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THE LONG HISTORY OF BIRDS

Birds are descended from archosaurs, the reptile group which also gave rise to the dinosaurs, flying pterosaurs and crocodiles.

Several fossils of Archaeopteryx, a pigeon-sized creature s with feathers and reptile-like teeth, have been found in limestone laid down in the late Jurassic period, around 140 million years ago. About 40 cm long (one-third being tail), it had claws on its wings, legs like a modern bird and a small sternum with attachment areas for wing muscles.

A fossil bird which may predate Archaeopteryx by about 7 million years was found recently in northeastern China. Its beak lacks teeth and it has been named Confuciusornis sanctus.

The next oldest fossil material discovered so far consists of bones and feathers, found in locations ranging from Spain to Australia and dating from around 115 million years ago, in the early Cretaceous period. Lines of ancient birds which eventually died out included toothed, flightless divers like the 1.7 meter-long. Hesperornis, and the seabird-like flier Ichthyornis.

Around 100 million years ago, the first of the "modern" groups of birds, the Neornithes (the "new birds"), appeared. They diversified into many groups during the "age of dinosaurs" and most survived the changes which led to the disappearance of dinosaurs and pterosaurs..

Read the text and speak on the evolution of the birds in Australia.

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