Are birds descendants of dinosaurs?

This is an article in the third1lesson of the fourth grade Chinese textbook in primary school. It should be true. They can't fool the future flowers of the motherland.

Dinosaurs flying into the blue sky

When it comes to dinosaurs, people often think of the fierce Tyrannosaurus Rex or the clumsy and slow Mamenxilong. When we talk about birds, we naturally think of frivolous pigeons or brightly colored 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 flying in the air.

As early as19th century, British scholar He (hè) Xu (xū) Li noticed that dinosaurs and birds had many similarities in bone structure. After studying a large number of dinosaur and bird fossils, scientists suggest that birds are not only related to dinosaurs, but also probably descendants of a small dinosaur. According to this hypothesis, some dinosaurs closely related to birds should have feathers, but 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 in western Liaoning showed the world the evidence that dinosaurs had feathers, which made the finishing touch for this picture drawn by paleontologists.

How did dinosaurs fly into the blue sky? Let's travel through time tunnel, visit the Mesozoic Earth and see the evolution process!

The first dinosaur on earth appeared about 230 million years ago. It is about the size of a dog and supports itself on two legs like a bird. 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 tens of tons (dūn), while others were very small and weighed less than a few kilograms. Some dinosaurs were ferocious and carnivorous, while others were docile and lovely, feeding on plants. Among them, some carnivorous dinosaurs gradually became smaller and looked more and more like birds: hollow bones and light bodies; Cranial (lú) swelling (péng) is large, with quick movements (mǐn) and quick movements (Jie); Forelimbs are getting longer and longer, and can flap like bird wings (y √); They have grown beautiful feathers, and there are no scales or scales on them. In order to avoid enemies or find food, some of them may move to trees to survive. 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 does not begin with the process of arboreal life. They speculated that a feathered dinosaur that lived on the ground learned to fly while running. In any case, there is no doubt that the flightless dinosaurs will eventually become favored birds. They flew into the blue sky and opened up a new life world.

Hundreds of millions of years ago, a feathered dinosaur broke away from its own kind, flew into the blue sky and evolved into today's big bird family. Scientists hope to reproduce this historical process. With the discovery of more and more exquisite fossils, they are getting closer and closer to the realization of this wish.