Researchers in Australia, Britain and Italy have built complex mathematical models to analyze the shape changes of dinosaurs in the evolution process based on more than 1.500 anatomical features of 1.20 dinosaurs. The analysis shows that theropod dinosaur is the only dinosaur whose size is shrinking. Their evolution speed is four times that of other dinosaurs, and finally they have the characteristics of feathers, wings and so on, and evolved into Archaeopteryx about 65.438+0.6 billion years ago. If this ancient evolutionary process is really true, it has been 50 million years since theropod dinosaurs became birds.
"Smaller and lighter will provide new opportunities for bird ancestors, such as learning to climb trees, glide and fly," said Li Liwei, the first author of the paper and an associate professor at the University of Adelaide, Australia. "This evolutionary adaptability may help bird ancestors survive the asteroid collision (65 million years ago), while their dinosaur relatives gradually became extinct."
The researchers found that all theropods related to birds were small dinosaurs, and their size was reduced by 12 stage. The average body weight was 163 kg 2100000 years ago, and it has dropped to 0.8 kg when it evolved into Archaeopteryx.