It has long been suspected that birds are related to dinosaurs. The first to put forward this idea was the famous British biologist Thomas Henry Huxley.
Thomas Henry Huxley
He was an active advocate of Darwin's theory of evolution, while also first proposing the hypothesis that birds originated from dinosaurs. In 1927, the Danish paleontologist Gerhard Heilmann supported this view, arguing in a classic book, The Evolution of Birds, that birds were very similar to dinosaurs. But he believes that dinosaurs have become very specific, birds will not evolve directly from dinosaurs, but have a common ancestor with dinosaurs, which is the ancient troodonts that originated in the Triassic Period, which is the common ancestor of dinosaurs, birds, including crocodiles and other vertebrates. Heilman's view prevailed for half a century.
From 1973 to 1985, the dinosaur origin theory of birds was revived again. The revival stemmed from an important discovery in which a feathered dinosaur fossil was found, which brought birds and dinosaurs back together. Beginning in 1986, the theory of dinosaur origins has continued to prevail, and a growing body of fossil evidence has been found to support this view.
In this study, a fossil called "Gorgeous Feather King Dragon" found by the Chinese Archaeological Institute has caused quite a stir. In 2012, Chinese archaeologists found a feathered Cretaceous dinosaur fossil with feathers, the "Gorgeous Feather king dragon" fossil, a dinosaur fossil with "forked feathers".
According to the appearance of the fossil reproduction of the "Gorgeous Feather King Dragon"
This is a carnivorous dinosaur, they have a huge body, although they have feathers, but they are distant relatives of Tyrannosaurus rex, more than forty times larger than the size of the "small feathered dragon" found in the past, and they are the representative of the largest feathered dragon.
The arrows in the figure refer to the traces of feathers
This discovery subverted the previous understanding that feathers only appeared in small dinosaurs, and further confirmed the complexity of feather evolution, thus causing great shock in international paleontology. Media such as the New York Times, Christian Monitor, National Geographic, and The Daily Mail of the United Kingdom have reported in prominent positions.
The above research progress was carried out in the comparison of dinosaurs and birds, and these comparisons include: the comparison of the common points between the earliest birds Archaeopteryx and dinosaurs and modern birds; Comparison of dinosaur eggs and bird eggs; Comparison of egg-laying behaviors of dinosaurs and birds; Feather analysis of dinosaurs and birds; In the earliest bird fossils, dinosaur-like feet and toes are compared to birds; Comparison of the "hooked" structure similar to the dinosaur respiratory system with birds; The shape of the skull and jaw of the dinosaur is compared with that of birds, and from these comparisons, various common features of dinosaurs and birds are found.
In recent years, due to the development of biological genetic information and computer technology, the study of the evolutionary relationship between birds and dinosaurs has been more in-depth and rapid development. A team of 20 countries spent four years analyzing the genetic sequences of 48 bird species, including crows, chickens, ostriches and vultures. After supercomputer calculations, the time of the appearance of these 48 birds was systematically screened, and the editing of the "Bird Tree of Life" was completed. After combing through the similarities and differences between these bird species, an important conclusion is drawn: the evolution of all birds today can be traced back to a feathered dinosaur that survived the mass extinction 66 million years ago. Between 65 million and 15 million years ago, this dinosaur evolved into a two-legged, feathered and egg-laying animal.
The sequence of evolution is shown in the figure below, from top to bottom: Bald-jawed Dragon, the undiscovered Ring, Archaeopteryx, and Pigeon.
From today's study of bird DNA sequences, researchers have further found new evidence for the evolution of birds. They have the most primitive chromosome patterns, and in evolution, the 5 genes associated with the teeth of birds quickly failed, and after losing their sharp teeth, they gradually grew a bird's beak. After the extinction of dinosaurs, due to the full living space, birds developed rapidly, and under the adaptation of various ecological environments, they gradually survived and evolved, and the number also increased sharply, evolving into today's birds. The findings were reported in the Washington Post on July 31, 2014, titled "Dinosaur Evolution as a Study of the Trajectory of Early Birds," and published in Science on August 2, 2014, under the title "Continued Miniaturization and Anatomical Innovation of Early Birds From Dinosaur Birds."
This discovery is considered the most important and latest evidence for the origin of avian dinosaurs. These people concluded that the dinosaurs did not go extinct, but appeared to the world in the form of birds. Some people exclaimed that nature's creative power was so miraculous that it shrunk the huge dinosaur into such a small bird. Sure enough, living in South America today, the hummingbird, as small as a bee, can be called the world's "smallest dinosaur"!
Source: 365 Days in the History of Science, slightly edited
Author: Wei Fengwen Wu Yi