How did the fourth-class dinosaurs fly into the blue sky? During the visit, let's cross just visiting.

When it comes to dinosaurs, people often think of the fierce Tyrannosaurus Rex or the heavy and dull Mamenxilong. When it comes to birds, our minds will naturally float with light pigeons or colorful peacocks. The two seem to have nothing to do with each other, but a large number of fossils discovered in recent years show that during the Mesozoic era, a branch of dinosaurs eventually became a bird soaring in the air after a long evolution. As early as19th century, British scholar Huxley noticed that dinosaurs and birds had many similarities in bone structure. After studying a large number of dinosaur and bird fossils, scientists suggested that birds were not only related to dinosaurs, but also probably descended from a small dinosaur. According to this hypothesis, some dinosaurs closely related to birds should have feathers, but the related fossils have never been found. At the end of the 20th century, scientists in China first discovered dinosaur fossils with feathers in western Liaoning, which immediately made researchers all over the world ecstatic. The discovery of western Liaoning showed the world the evidence of dinosaur feathers and drew this picture drawn by paleontologists. Let's travel through the time tunnel, visit the Mesozoic earth and see this evolution! The first dinosaur on earth appeared about 230 million years ago. It is about the size of a dog, and supports itself with two hind legs like an ostrich. Tens of millions of years later, its descendants multiplied into a huge family with different shapes: some dinosaurs ran on two feet like their ancestors, while others walked on four feet; Some dinosaurs were tens of meters long and weighed dozens of tons, while others were small and weighed less than a few kilograms. Some dinosaurs ate meat fiercely, while others were gentle and lovely, feeding on plants. Among them, some carnivorous dinosaurs gradually became smaller and more like birds: hollow bones and light bodies; The skull is enlarged and moves quickly; The front legs are getting longer and longer, and they can flap like bird wings; They have grown beautiful feathers, and there are no scales or scales on them. Some of them may move to trees to survive in order to avoid enemies or find food. These arboreal dinosaurs jumped and landed among trees, gradually gained gliding ability, and finally were able to fly autonomously. However, some scientists believe that flight did not start with arboreal creatures. They speculated that a feathered dinosaur lived on the ground, and I learned to fly while running. In any case, there is no doubt that the flightless dinosaurs finally became the favored ones. They flew into the blue sky, thus opening up a brand-new life world. Hundreds of millions of years ago, a feathered dinosaur flew into the blue sky from its own kind and evolved into today's bird family. Scientists hope to reproduce this historical process. With the discovery of more and more exquisite fossils, they left this wish.