Since 1970, many research reports have pointed out that modern birds are most likely the direct descendants of theropods. In recent years, the research tends to classify birds directly into Osteosaurus (including Tyrannosaurus Rex, egg sneakers, Deinonychus and so on). ).
There have been two opposing hypotheses about the flight of dinosaurs in academic circles.
One is said by Lu Yuan, and the other is said by Shu Yuan. The former believes that the flight of birds was inherited by their ancestor dinosaurs in the process of running and jumping.
The latter hypothesis holds that birds first glide with the help of the height of trees, and then gradually develop a unique ability to fly with wings. Both hypotheses of the origin of bird flight admit that the ancestors of birds had long tails, but their functions are not exactly the same.
According to the hypothesis of the origin of the earth, they beat their forelimbs when running to increase the speed of their hind limbs running on the ground. In this process, the scales on their bodies gradually increase and lengthen. In the process of running and jumping, the scales eventually developed into feathers, and the ancestors of birds eventually rose from the ground to the sky.
Archaeopteryx has always been a very important evidence in the theory of bird flying habitat. Scholars who hold this view believe that Archaeopteryx is an animal that runs on the ground.
According to the theory of arboreal origin, the ancestors of birds were small animals, and they climbed trees from the ground at the earliest, probably for their own safety.
The ancestors of birds first climbed trees and perched on them, and then began to jump between them. In these activities, the ancestors of birds gradually squashed their bodies, increased their body surface area, and gradually unfolded their feathers, thus learning to glide and finally having the unique ability to fly with wings.
Generally speaking, the arboreal origin theory of bird flight holds that early birds learned to fly by jumping and gliding between trees. According to the theory of the origin of ground flight of birds, it is believed that the dinosaur ancestors of birds lived underground and were fast-running animals, which gradually took off during the fast running.
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.
Among them, some carnivorous dinosaurs gradually became smaller and looked more 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.
Extended data:
Dinosaurs Flying to the Blue Sky is a popular science article written by Xu Xing. This paper mainly introduces a hypothesis put forward by scientists according to research: birds are probably descendants of a small dinosaur.
At the end of the 20th century, scientists in China first discovered dinosaur fossils with feather prints in western Liaoning, which provided evidence for people to imagine dinosaurs flying into the blue sky and becoming birds. This paper not only reveals the great discoveries made by scientists in paleontology research, but also opens a scientific door for students to explore paleontology and stimulates their strong interest in science.
References:
Baidu encyclopedia-dinosaur
Baidu Encyclopedia-Archaeopteryx (extinct feathered dinosaur)