Dinosaurs and birds are closely related.
In the Cretaceous period, dinosaur species reached their peak. The most famous dinosaur at this time was Tyrannosaurus Rex, the largest carnivore that ever appeared on land. At the end of the Cretaceous period, a large number of animals in the sea and land became extinct, and only a few survived. The once prosperous dinosaur family was completely extinct, becoming one of the most significant biological extinction events in the history of the earth.
“In fact, dinosaurs have not disappeared, but have evolved.” Dr. Guo Zhenyu of the Nanjing Museum of Paleontology told reporters that at that time, dinosaurs were extremely advanced animals. Although they had four limbs, they walked on two legs. Their survivability and competitiveness exceed those of ordinary reptiles, so most researchers believe that today's birds and chickens evolved from dinosaurs.
Researchers agree that birds came from dinosaurs, but when did dinosaurs start turning into birds? Newly discovered fossils in Siberia, Russia, show that a characteristic feature of birds - the presence of feathers - was deeply engrained in the dinosaur evolutionary tree.
In fact, dinosaurs may have had feathers very early in their existence (240 million years ago). This is the first time researchers have discovered a herbivorous dinosaur fossil with feathers, which shows that feathers are not exclusive to carnivorous dinosaurs, and perhaps all dinosaurs had feathers.
Dinosaur appearance characteristics:
For large herbivorous dinosaurs, strength is the most important requirement. Their leg bones are large and strong enough to support their huge bodies. At the same time, they have evolved an ingenious structure that reduces the weight of other bones without causing a loss of strength.
Those smaller, faster-moving dinosaurs evolved a feature that can also be seen in modern animals: thin-walled long bones. The skeleton is like a hollow tube, with a thin outer wall made of heavy bone and a much lighter marrow in the center. Fast-moving herbivorous dinosaurs, such as Oakosaurus, had these thin-walled long bones. We can assume that this skeleton was created to reduce weight, allowing for greater speed when escaping from predators.
Reference for the above content: People's Daily Online - Caucasians may have appeared in Nanjing 500,000 years ago. Birds and chickens evolved from dinosaurs