Birds are sometimes referred to as glorified reptiles. And even though modern birds are structurally very different from 1 , some show minor evidence of their 2 , like scales on their feet or claws on their toes. However flying reptile disappeared more than 70 million years ago, but birds have obviously managed to survive. You remember that the 3 success of any group of organism is measured by the number of species and individuals in the group. There are 4 through out the world and of course their ability to adapt to all kinds of 5 conditions. On the basis of these criteria birds are considered one of the most successful vertebrates in modern times. Their success means they were probably not only better adapted than the reptile for flying but also for life on land and on water. But when did this glorification begin and how fast did the changes occur? It would seem logical to assume that at some time millions of years ago 6 stages between reptiles and birds existed. And in fact one of the most important clues came with the discovery of the fossils called Archaeopteryx which literally means 7 bird. The Archaeopteryx dates back 150 million years to the Jurassic period. Fortunately the fossils not only included the skeleton but also impressions of the feathers of the wings and the double rare of tail feathers. If it were not for these feathers, scientist would have 8 it as a reptile because it has many characteristics more like a lizard than a bird. Archaeopteryx is not, however, considered as the ancestor of modern birds. But it probably was deprived from ancestral form that also gave rise to modern birds. Up until the mid 1980s the Archaeopteryx was considered the most ancient of all birds. Then in 1986, a fossil was discovered called Protoavis that shows a 9 of dinosaur and bird-like characteristics. But it lived 225 million years ago, about 75 million years before the Archaeopteryx. So clearly the final work is not yet in on the 10 of birds.