Many netizens commented after seeing the hot searches that people evolved from apes before, but why do they now say that they evolved from fish? Some netizens asked: "Are I steamed at noon my ancestors?"
"From the current research, the fish found this time lived about 440 million years ago and belonged to jawed fish. They are indeed our ancestors, but they are also the ancestors of most vertebrates, such as the twelve zodiac signs we are familiar with, and their ancestors are also jawed fish. Today, we and the animals in the twelve zodiac signs are equivalent to branches on evolutionary trees. Deriving from the root, the main branch that finally gathers is jawed fish." Zhu Youan, one of the main members of the discovery team, and an associate researcher at the Institute of Vertebral Paleontology of the Chinese Academy of Sciences, told the Beijing Youth Daily reporter on the afternoon of the 29th.
Zhu You'an introduced that, including humans, 99.8% of the existing vertebrates on the earth have jaws (maxilla and chin). The emergence and rise of jaws are one of the most critical leaps in the history of vertebrates' evolution from "fish to humans". Many important organs and body configurations of humans can be traced back to the beginning of jaws' evolution. Finding the early appearance of jawed fish can help us understand the origin and evolution of human beings.
But for a long time, the beginning of this journey of origin and evolution of jawed fish has been about 30 million years, and our understanding of it is in a complete gap. Zhu Youan said that the research team discovered the "Chongqing Special Buried Fossil Library" and the "Guizhou Shiqian Fossil Library", and the jawed fish fossils found in them filled us with a gap of more than 10 million years.
But Zhu Youan admitted that the discovery of these jawfish fossils was by no means smooth sailing. The team members started related work 15 years ago, constantly accumulating relevant information, and finally found an area rich in jawfish fossils in 2019.
Zhu Youan said that although among the younger generations of jawfish, including giants such as blue whales and elephants, as well as earth overlords including humans and dinosaurs, jawfish 440 million years ago was less than 3 cm long and still lived in the shadow of the water overlord " sea scorpion " at that time. However, due to its strong evolutionary potential, the jawfish became the top predator of on the earth in a short time from an evolutionary perspective, and established its status as the younger generations, including us humans, and its contribution is worthy of human research and remembering.
The discoverer of human fish ancestors: The fish that netizens steamed and eaten by jaws, but they are not our ancestors
Reporter: Why is the jaws discovered this time called human ancestors?
Zhu You'an: We are not surprised by jaw bones including the upper jaw and chin today, but in fact, in the process of biological evolution, the emergence of jaw bones is crucial. The emergence of jaw bones has improved the predation ability of animals. Today, some jawless fish , such as lamprey , can only rely on a mouth like a suction cup to suck things. Moreover, since there is no jaw bone, their breathing efficiency is not high and they can only live in the torrent to obtain more oxygen . Moreover, due to the limitations of breathing efficiency, their size is not big either.
In fact, most large animals, including humans, are jaw-like, and the characteristics of jaw-like bones can be traced back to the early Silurian period about 440 million years ago, when jaw-like fish first appeared. From this point on, many organs that were previously jaw-free fish had not had before. It is these organs that give us the competitive advantage of jaws. Today, 99.8% of the existing vertebrates on Earth are descendants of jawfish, including humans.
Reporter: What do you think about the statement that some netizens were worried about steaming their ancestors at noon?
Zhu Youan: This is of course a joke from netizens.To be honest, the jawed fish discovered this time is very close to the common ancestor of today's fish and humans. This common ancestor looks like a fish, but it has lived for more than 400 million years, and it is not today's fish. Therefore, although the fish steamed by netizens also have jaws, they are not our ancestors. At most, they are distant relatives from far away, so they can be eaten with confidence.
Reporter: This discovery has appeared on the cover of the world's top scientific research publication "Natural ". Why is this discovery so important?
Zhu You'an: There are several key nodes on the road of human evolution that deserve our attention. For example, this time, the evolution of jawless fish from jawless fish was a key node. Later, a jawed fish said goodbye to the ocean and landed onto the land. It was another key node, and there were many similar nodes.
But on the road of evolution, the more important the node is, the faster its evolution speed. The evolution of some key nodes may only be calculated in 100,000 years or 1 million years. This period is just a short moment compared to the history of the earth of more than 4 billion years. Our work is similar to taking sports photos. Although a football game has ninety minutes, a key goal or foul is just a moment. We just want to capture that moment as much as possible and let the photo approach the moment it happened.
We had no idea about the first 30 million years of evolution of jawed fish, and this time we found that this 30 million year gap shortened to more than 10 million years. This is equivalent to not finally scoring a goal, but the moment the star shot the shot, taking a big step to understand the important events of our fish ancestors' evolution path.
A fight was made to discover the key to the gate of fossils of human ancestors. A type of jawed fish named after Shen Congwen
Reporter: Please introduce how the jawed fish fossils were discovered this time?
Zhu You'an: The discovery of fossils is due to a lot of preliminary preparation work, and it can even be traced back to many of the deceased geology predecessors. Many senior experts traveled all over China to confirm which strata in different regions of the country belongs to. We therefore already know where the early strata of Silurian , which greatly narrowed the scope of search.
On the other hand, my team has a teacher who has carried out related work 15 years ago. Since 2017, we have collected more information. One day in September 2019, Dr. Li Qiang, a member of our team, was looking for fossils in the mountains. It rained all day that day, and everyone was very tired from crossing mountains and ridges, but they found nothing. Dr. Li Qiang called Teacher Zhu Min to report. Teacher Zhu Min looked at the map software and found that a new highway was built nearby, which may reveal newly excavated stones. He suggested that everyone try there.
Several members of the team arrived at the place pointed out by Teacher Zhu Min and climbed up the mountain. In order to fight against fatigue, they saw a pile of stones on the roadside when they were fighting each other. They had just rolled down from the cliff. Everyone knocked on the stones and found a complete fossil of jawfish. However, this batch of fossils originated from the late Silurian period and had been around for a long time since the appearance of jawfish. But this discovery inspired everyone to continue searching in the surrounding areas. After a year, in 2020, we found early jawless fish fossils nearby.
Soon, in October 2020, we found a large number of preserved jawed fish fossils, which is one of the results of our release this time.
In fact, we were also very grateful later that the fossils of jawfish found by the team members during the fight belonged to silt sandstone , with a texture very similar to chalk. It was also raining at that time. If we were a little late, the fossils might have turned into powder mud.
Reporter: After finds the fossil, how to confirm that it belongs to a jawed fish?
Zhu You'an: These fossils are very small. We need to take the fossils under a microscope and clean them bit by bit with steel needles. We remove a grain of sand-sized surrounding rock at a time, and then repeatedly observe and compare the details of these fossils to find and determine whether they have the iconic characteristics of jawed fish and confirm whether these fossils are jawed fish.
Reporter: Some of the jawed fish found this time have very Chinese-style names, such as Shen's thorn fish, Fanjing mountain fish, Xiushan fish, etc. How are these names named?
Zhu You'an: This is the hope that through naming, we can spread some of our Chinese culture to the world. In our research, some of the periods of Silurian were named after the place name of Wales in England. Although I have never been to Wales , I have known the names of many small towns there. This time we named the fishes we found by Fanjing Mountain, Xiushan Mountain and other place names, Tujia, because we hope that more people in the world can take the opportunity to learn about China's place names and the culture behind them.
Shen's thornfish was named after the writer Mr. Shen Congwen. We found that the place where the Shen's thornfish is located at the junction of Chongqing and Hunan, near the ancient town of the border town. In addition, Teacher Zhu Min likes Shen Congwen's works very much, so we named this fish Shen's thornfish.
Human ancestors were less than 3 cm long and were once a 1-meter-long "sea scorpion" prey
Reporter: From your perspective, you can imagine what the place where jawfish was discovered was about 440 million years ago.
Zhu You'an: At that time, from Sichuan, Chongqing to Nanjing, Jiangsu, it was a sea. Due to the influx of rivers, it brought a lot of nutrients. There were plenty of plankton here, which were also a delicacy for fish. Therefore, there are many jawless and jawless fish living here.
But this sea is very shallow, often only a few meters deep, and the fish are usually very small. The longest fossils of jawed fish we found this time is less than 3 cm. At that time, there were still "sea scorpions" living in this sea, which were chelid animals, with body length of about 1 meter. They used pliers and other to prey on our ancestors, and our ancestors lived under the shadow of these "sea scorpions" all day long.
But jaw animals have huge evolutionary advantages, which means they can adapt to more environments and have better development potential. The fact is that after about 10 million years, some of the jawfish had become the top predators on the earth at that time. This status extended to its descendants, Tyrannosaurus Rex , and also to us humans.
Source: Beijing Youth Daily
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