An 80-million-year transition was capped with a burst of feathered diversity
Birds evolved from dinosaurs in patchwork fashion over tens of millions of years before finally taking to the skies some 150 million years ago, paleontologists report.
Birds are defined by a plethora of traits that are unique
to them, such as feathers, hollow bones, a wishbone, and beaks.
Paleontologists once supposed that the earliest bird,
150-million-year-old Archaeopteryx,
represented a great evolutionary leap from dinosaurs. But over the past
two decades, new discoveries have revealed that many of its avian
traits had evolved in dinosaurs long before.
The Current Biology journal report
released on Thursday confirms this new picture, finding that the
dinosaur forebears of birds began gradually evolving avian traits almost
as soon as dinosaurs appeared on Earth some 230 million years ago.
(Related: Watch "Dinosaur Birds.")
The new study also supports a view proposed by the American Museum of Natural History paleontologist George Gaylord Simpson
in 1944. He suggested that evolutionary novelty, flight in this case,
can lead to rapid diversification among species exploiting new
environmental niches.
No comments:
Post a Comment