The latest research by Chinese scientists: the difference in diet between dinosaurs and dinosaurs may help birds escape the mass extinction
China News Service, Beijing, April 25 (Reporter Sun Zifa) During the 65 million years ago, the meteorite impacted the earth and frequent volcanic activities caused the earth to disappear every day, and a large number of plants that depended on photosynthesis died, resulting in phytophagy. , Carnivorous dinosaurs, etc. have been extinct.
In this mass extinction event caused by the collapse of the food chain, why did dinosaur descendants birds survive? This mystery of paleontological evolution, which has long been concerned by the academic community, was recently solved by the latest research results of Chinese scientists-the difference in diet between dinosaurs and dinosaurs may be the key to the survival of birds after surviving the mass extinction.
Fossil specimens of ancient birds from the early Cretaceous period-birds that can be seen (black arrows indicate the position of teeth), collected at the Ancient Spine Institute of the Chinese Academy of Sciences. Li Zhiheng / Photograph
The reporter learned on the 25th from the Institute of Paleontology and Paleontology of the Chinese Academy of Sciences (Institute of Paleontology of the Chinese Academy of Sciences) that the Li Zhiheng team of the institute and the Taiwan Synchrotron Radiation Research Center and other cooperative units jointly worked on the non-birds closest to the bird. The evolutionary characteristics of teeth from dinosaur-like to ancient birds are discussed. The research results reveal that the difference in diet between birds and dinosaurs is likely to be the key to their ability to survive the disaster of 65 million years ago.
According to the Institute of Ancient Spine of the Chinese Academy of Sciences, Li Zhiheng ’s research team used high-resolution penetrating X-ray microscopy with synchrotron radiation to treat small non-bird dinosaurs—including saccharodontosaurus, near-tosaurus, small raptor, and ancient birds— Contrast observation and research on the microstructures of teeth including modern birds, anti-birds, meeting birds, Rehe birds, and found that although the simple enamel layer is preserved in early ancient birds, but between the enamel and dentin The porous dentin layer has disappeared, and the porous dentin layer is considered to be a special shock-absorbing protective structure developed in carnivorous dinosaur teeth to prevent their teeth from breaking during predation. Not only in ancient birds, but also the dentin layer of a pirate dragon specimen studied this time has disappeared.
Evolution of internal microstructure of teeth of Cretaceous ancient birds and small non-bird theropod dinosaurs (a-toothed dragon, b-near bird dragon, c, d-little dragon, e-anti-bird undetermined species, f-present Birds, g-winged birds, h-birds). High-resolution synchrotron radiation microscopy images show that the porous mask dentin (IGS) in the teeth has disappeared in ancient birds and a small dinosaur, providing evidence of the evolution of food conversion. Li Zhiheng / Photograph
The research team believes that the above findings mean that birds and some dinosaurs with close kinship no longer need special mechanical protection structures for their teeth, which indirectly confirms their dietary habits, such as bite force and predation, and carnivorous dinosaurs. There has been a huge difference. By avoiding the competition with the carnivorous dinosaurs for the food niche through the conversion of food habits, the adaptability has been greatly improved, so as to spend the most difficult moments of the mass extinction event.
The research team pointed out that, compared with the evolutionary trend of the general herbivore or omnivorous of ancient birds, although a few groups of non-bird dinosaurs, such as Little Raptor, have also undergone convergent evolution, it is still difficult to avoid the crisis of extinction.
It is understood that this important paper on the evolution of dinosaurs to birds completed by Chinese scientists has been published online by the international academic journal "BMC Evolutionary Biology". (Finish)