On April 22, tourist Zhong Lin stood in front of an ancient fish fossil statue in the fossil square of Lixi Town, Wuning County, Jiangxi Province, and was stunned: "These ancient fish are so cute and cute, they are so similar to humans, what does it have to do with us?"
Fossil statues on the fossil square in Lixi Town, Wuning County, Jiangxi Province.
This is also a question that scientists have been thinking about for a long time. Fossils are like words that record the history of the earth, and the study of paleontological fossils is to continuously interpret these "words", so that people can understand the evolution of life and geological changes more systematically. Fortunately, thanks to the blessing of science and technology, scientists have deepened their understanding of "writing" and gradually restored the true appearance of extinct creatures.
1
Mechanical processing of fossils is no longer the first choice
One day in May 2023, several young paleontological researchers half-crouched in the earth and rock pit, carefully digging up the earth and rocks with shovels. They dug out stones of different sizes and unevenness, rubbed them in their hands, observed, and once they felt something unusual, they would hold the stones and ask the middle-aged man not far away.
"Teacher Gai, come and see this!"
Gai Zhikun, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (hereinafter referred to as the Institute of Paleovertebrate), wearing a straw hat and carrying a tool kit, is also looking at a stone.
"This time there should be a new discovery. Gai Zhikun carefully held the stone, and a smile immediately appeared.
Sure enough, this time they found Jiujiang Jiangxia fish fossils in the Wuning area of Jiujiang, Jiangxi. This fish is an armoured fish, an extinct jawless species. Its unique "split" feature not only enriches scientists' understanding of paleobiodiversity, but also reveals deeper information in the process of biological evolution.
Jiujiang Jiangxia fish fossil.
The reason for the search for these ancient fish stems from a worldwide problem: the origin of the jaw.
To solve the puzzle, the first thing to do is to find a creature that has two separate nasal sacs or nostrils, but no jaws.
This creature is called an armored fish.
The armoured fishes are endemic to East Asia and have only been found in China and northern Vietnam, Gai said.
After years of hard work, he and his team made a major discovery in Changxing, Zhejiang Province in 2002: there was once the most primitive true armor fish here, and it was later named Akebo.
Difficulties also followed. "The specimen of the apokeno is the size of a fingernail and needs to be scanned with a synchrotron radiation device, a large scientific device. Gai Zhikun said.
Unfortunately, synchrotron radiation technology had not yet been developed on the mainland at that time, and the research had to be put on hold for the time being.
For a long time, paleontologists wanted to further study the internal fine structure of fossils, generally using the method of slicing ancient tissues or continuous grinding sections. Zhang Miman, an academician of the Chinese Academy of Sciences, used continuous grinding technology to reconstruct the head of the flesh-finned fish Yang's fish, and found that it had no internal nostrils and was a primitive lungfish, thus making outstanding contributions to the search for the direct ancestor of the landed fish.
If the number of fossil samples is large, this mechanical processing method can be used. But if fossils are inherently rare, this time-consuming and sample-destroying method is no longer preferred.
Nowadays, technologies such as dedicated CT, AI identification, X-ray, and 3D modeling have been gradually applied to paleontological research. Mainland scientists have continued to overcome difficulties, reconstruct the history of paleontological evolution, and produced many important original scientific research results.
2
CT technology allows the stone to speak
In 2006, Gai Zhikun took the specimen of Aqueotheus to the light source center in Switzerland for synchrotron radiation scanning.
Scans revealed that armoured fish were species located in the middle of living jawless and jawed species. And this link is what developmental biologists predict as the intermediate stage required for the origin and development of the jaw.
Thus, armoured fish provide reliable fossil evidence for the origin of the jaw. Gai Zhikun's team provided Chinese wisdom to solve the world's problem of jaw origin.
In the past, Gai Zhikun encountered the dilemma of lack of research instruments in his work, and now there will be a solution.
The mainland's first high-energy synchrotron radiation light source (HEPS) is expected to emit its first beam of light in 2024, with delivery and commissioning in 2025.
In Gai Zhikun's view, technological innovation can become an "accelerator" for scientific research.
Liu Yu, director of the Yunnan Provincial Key Laboratory of Paleontology and vice president of the Institute of Paleontology at Yunnan University, feels the same way.
In front of a micro-CT machine, Liu Yu, dressed in a white lab coat, looked like a doctor. But he is not dealing with a sick person, but with a paleontological fossil that has traveled through more than 500 million years.
By taking a CT of the fossils, Liu Yu unveiled the secrets of the Cambrian fossils one by one.
In 2023, an international scientific research team composed of researchers from the Institute of Paleontology of Yunnan University, the Chengjiang Fossil Land World Natural Heritage Museum, and Harvard University in the United States used advanced technologies such as micro-CT tomography to take a number of relatively complete CT images of Cambrian arthropods, such as stingers, providing new morphological evidence for the academic community to study the early evolution of arthropods.
and other stinging insect restoration maps.
"CT is the equivalent of making the fossil speak. Liu Yu said that just like taking CT of patients in hospitals, taking CT of fossils can model the surface and internal information of the stone in 3D.
"This was something that was difficult to do before. Liu Yu said. Earlier, while studying and working abroad, Liu Yu tried to do CT scans of Chengjiang fossils, and explored a set of technical routes that can clearly present the micron-level three-dimensional microstructure of Chengjiang fossils. "In the past, we could only see two-dimensional information from the surface of fossils, whether it was needle repair or drawing, but micro-CT technology can present a near-complete, three-dimensional image of animals. He said.
After returning to China, Liu Yu applied advanced research methods and methods such as fluorescence microscopy, electron scanning microscopy and micro-CT, which were at the forefront of international biological research at that time, to the study of fossil specimens of Chengjiang fauna.
Micro-CT technology has broken through the limitations of traditional optical microscopy for two-dimensional morphological research, and achieved a breakthrough in paleontological research technology from "0" to "1", and the amount of information obtained from fossils has increased by about 60% to 90% compared with before.
The application of advanced technology has made the study of Chengjiang fossils more in-depth. At the end of 2021, Liu Yu's team won the second prize of the 2020 National Natural Science Award for the project "Cambrian-specific preservation of fossils and early evolution of arthropods".
3
AI technology helps paleontobiometrics
Archaeologists are also looking forward to technology to solve the puzzle of the pen stone.
The penstone is a group of planktonic or swimming animals that lived in the Cambrian to Carboniferous oceans, and is currently extinct. They are usually preserved in shale, and different penstone species hold secrets from different periods.
However, penstone fossils tend to be small, and the morphological differences between species are very small. Accurate and rapid identification of penfossils is a challenge for geologists and paleontologists.
"If you want to solve the mystery, big data and artificial intelligence technology may be able to help. Xu Honghe, a researcher at the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, said. At the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, he and his team set out to study these fossil specimens.
"We collected scientific information on 1,500 penfossil specimens in detail, took about 50,000 fossil specimen images, and annotated these images at the pixel level to create a scientifically authoritative dataset of penfossil specimens. Xu Honghe said. His research team also proposed a metadata standard for fossil specimens, and promoted the specifications and standards of the dataset at home and abroad.
For the multimodal dataset of fossil specimens, Xu Honghe's team proposed the concept of artificial intelligence paleontology. "The identification of paleontological fossils is different from the common problem of image classification. Xu Honghe said that paleontology itself has a hierarchical structure in the systematic classification, because the morphological characteristics based on it are very subtle, and the requirements for professionalism are extremely high.
After more than two years, the research team completed the dataset preparation, labeling, and model training, and developed an algorithm suitable for fossil image classification.
"We applied these results to the pen stone recognition model, and the artificial intelligence deep learning model trained on the AI deep learning model can achieve a recognition accuracy of about 86% for 113 important Ordovician and Silurian pen stone species. Xu Honghe said excitedly that this is much higher than the average domain expert.
"The integration of the latest artificial intelligence and deep learning algorithms into traditional paleontological research is a very novel approach. Xu Honghe said that this research has created a new form of interdisciplinarity, and its research results can directly serve shale gas exploration and development.
Because the research ideas and methods are the first, Xu Honghe's team has obtained a Chinese invention patent and a US invention patent.
"This research is a deep intersection and integration of paleontology, computational science, and information science. Xu Honghe said that this method has been deployed in the fossil ontology database of the stratigraphic paleontology big data center, and the relevant algorithms have also been applied to the identification software of some other common fossil phyla, and an application for mobile devices has been developed.
4
X-rays paint a portrait of a paleontology
Standing in front of the world's only Dong's Chinese raptor fossil skeleton in the Chinese Ancient Zoological Museum, the people who came to visit were deeply shocked at the same time, and at the same time, they were also making up a picture in their minds: what does it look like?
The answer to this question can now be "drawn" by X-rays.
"Soft bodies such as muscles and internal organs often decay quickly after death and cannot be preserved in the strata, so it is difficult to restore the true shape of an organism from hard fossils alone. Wang Wei, a researcher at the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, said that the Guizhou dragons, which were active more than 200 million years ago, did they have strong muscles or a fat body? Do they look like lizards with large sacs on their chests, or do they look like crocodiles with big bellies?
Wang Wei showed reporters two schematic diagrams of Guizhou dragon fossils. These two pictures look very similar, but in fact they have their own differences.
Schematic diagram of Guizhou dragon fossils
"On the left is the Guizhou dragon fossil to be tested, and on the right is the calcium content distribution map, the higher the calcium content, the darker the color shown in the figure. Wang Wei said that this is a schematic diagram of the distribution of elements obtained by detecting Guizhou dragon fossils through a three-dimensional X-ray fluorescence scanner. Preliminary studies have shown that the anterior thorax of Guizhou Longtou has a wider distribution area of calcium than the abdomen, indicating that the soft body of the anterior thorax may be more enlarged.
After the death of organisms, they are buried in sediments (such as sediment), and their muscles and internal organs will produce various organic matter in the process of decay, and the organic matter reacts with the surrounding sediments, often leaving some chemical element information in the rocks around the fossils. Therefore, the distribution of chemical elements on the surface of the fossil and its surrounding rock can be used to find clues to the shape or contour of these biosoft bodies.
"Commonly used technical means, such as carrying out a certain area of detection, need to grind a plane out of fossils and surrounding rocks, and it is urgent to explore non-destructive detection methods. Wang Wei said.
In order to solve the above problems, Wang Wei's research group has improved the defects of the most advanced large-format material surface chemical element scanning equipment in the world based on innovative design in many aspects, and developed an X-ray fluorescence non-destructive analyzer that can analyze the distribution of chemical elements on the surface of irregular and three-dimensional fossils.
"Not only does this instrument eliminate the need to grind and destroy fossil samples, but it also adds an inert gas vent, which reduces the influence of atmospheric oxygen and nitrogen on the measurement results, making the measurement environment comparable to vacuum. Wang Wei said that the instrument uses a laser beam to assist light to measure the roughness of the surface of fossils and other samples, and corrects the detected X-ray fluorescence, making it possible to non-destructively measure the distribution of chemical elements on the surface of large fossils. Wang Wei said that the instrument can carry out non-destructive testing of immovable samples in the field.
3D X-ray fluorescence scanner.
In addition to 3D X-ray fluorescence scanners, X-rays are helping scientists solve more fossil puzzles.
Most of the fossils in the Rehe biota are flattened plates, which are difficult to accurately scan and reconstruct with ordinary CT equipment. To this end, Continental has developed the first high-resolution X-ray microtomography device for plate-shaped fossils, Micro-CL, which greatly meets the research needs of the paleontological community. Through these high-precision imaging techniques, scientists are able to explore the internal structure of paleontology in greater depth, providing critical evidence for revealing the history and evolution of biodiversity.
5
Establishment of a database of biological groups
In the interview, many experts said that the study of paleontology is a key to open the "double door": it can not only open the door of "discussing the present with the past", but also open the door of "enlightening the present with the past".
Low carbon environmental protection, energy conservation and emission reduction, environmental governance...... These areas do not seem to have anything to do with paleontological research.
Xiao Yilin, a professor at the University of Science and Technology of China, believes that studying the process of paleontology from prosperity to extinction is of great significance, not only to help us understand the history of the earth and the evolution of life, but also to stimulate the public's interest in nature conservation.
Recently, Xiao Yilin's research team, in collaboration with the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences and Hefei University of Technology, conducted a study of two typical Late Devonian marine carbonate profiles in Guilin, South China, and found that global climate cooling led to a mass extinction event 370 million years ago, and about 80% of marine invertebrates were extinct in this disaster.
A similar example is the fact that in June 2019, the Mauna Loa Observatory in Hawaii recorded a record high of 414.7 parts per million carbon dioxide concentrations in the atmosphere. If this concentration continues to rise, what will happen to the Earth's environment? Scientists have found part of the answer to this question from the fossil record.
At the end of the Triassic period, the Earth experienced a period of intense volcanic activity, and fossils have estimated that the atmospheric carbon dioxide concentration at that time was as high as 4,400 ppm, and the Earth experienced a mass extinction, which provides valuable boundary limits for models predicting the future evolution of the Earth system.
Xing Lida, an associate professor at the China University of Geosciences in Beijing, spends more than seven months a year in the wilderness, searching for fossilized dinosaur footprints scattered around the world.
At the end of February this year, Xing Lida's research team released the latest results, after cleaning and repairing thousands of fossil fragments found during road construction and excavation in Huichang County, Jiangxi Province, a new species of Ankylosaurus subfamily - Yingliang Datailong.
"Dinosaurs were 160 million years old and are particularly well suited to explain the evolution of life on Earth. Xing Lida believes that the evolution of life is the ultimate problem of paleontology.
Paleontological research, but also to see the future.
"It is a new direction to use ecosystem research methods to promote the interaction between organisms and the environment. Xu Xing, an academician of the Chinese Academy of Sciences and a researcher at the Institute of Paleospine, said that using ecosystem research methods to restore and rebuild ancient ecosystems can help us better face future challenges.
Xu Xing said that the next step is not only to promote the integration and development of paleontology and modern biology, but also to carry out paleontological research based on big data and establish a database of related biological groups.
There is good news that the Institute of Paleospine is promoting cooperation with the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Automation, and will use the platform of large scientific equipment to carry out paleontological research for the first time in the future.
Evolution has lasted for hundreds of millions of years, and life has been rising higher and higher.
Paleontology, which is in its 200s, is an ancient discipline. Today, technology has injected new impetus into paleontological research. High-precision science and technology not only allow us to see the traces of life from fossils, but also gradually let us see the evolution of paleontology in ancient times.
Our understanding of the natural world is very limited compared to the vastness of the universe, but Chinese scientists are constantly trying to push the boundaries of the evolution of biology.
Source: Science and Technology Daily