miércoles, 25 de mayo de 2011
Birds are dinosaurs!!!
The Strongest Evidence of Dinosaur Heritage:
Many anatomical reasons (some in dispute) have been offered for linking birds to dinosaurs; but the strongest evidence is circumstantial:
birds fly north to nest!
Birds fly north because of dinosaur heritage. North flight is the remnant of an ancient scheme. Birds evolved from predatory theropod dinosaurs that swam in attendance with the herds of herbivores on their periodic treks and that reared their own young at the herd periphery. The dinosaur had begun 230 million years ago to be genetically wired for a seasonal trip to the north – about 90 million years before a theropod line evolved into the first bird. Marine migrations of ancient dinosaurs are no more; but the genetodynamic compulsion to fly north to nest in season lingers in numerous bird genera. The herd was father to the flock.
Today, birds fly north to lay their eggs and to fledge their young in relative safety. Flocks (in analogy to herds) fly back and forth in season over the Mediterranean, the remnant of the western Tethys.
Taken from: http://www.flwildflowers.com/birdsdinosaurs/
Learn more at: http://teacher.scholastic.com/activities/dinosaurs/