Most people believe that the retreat of the ice age at the end of Pleistocene led to drastic changes in climate and vegetation, and cold and dry grasslands gave way to warm and humid tundra and forests. Large herbivorous mammals can't adapt to this drastic change of ecosystem, so they go to the end. With the disappearance of large herbivores, large carnivores that prey on these animals, including saber-toothed tigers and cave lions, will soon become extinct.
Another theory blames the extinction of animals on the extinction of Homo sapiens (the scientific name of modern people). Supporters of this "Blitzkrieg Killing Hypothesis" believe that it is no coincidence that the extinction of animals and the large-scale migration of early modern people to the disaster-stricken areas. These foreign intelligent animals rounded up and killed the slow-moving herds with their stone javelins and "coordinated operations". Animal losses in North America are the most serious. Local human hunters crossed the Bering Continental Bridge from 15000 years ago and came to 10000 years ago to find a continent rich in animal resources and not yet slaughtered. Climate mutation
The Northeast Science Station of Russian Academy of Sciences is located in Chershi, Sakha, where Zimov is the director, and he is particularly interested in the extinction of animals in northeast Siberia at the end of Pleistocene. He insisted that the "Blitzkrieg Killing Hypothesis" was convincing and that he could prove through experiments that climate change should not be responsible for animal extinction.
In the late Pleistocene, northeast Siberia was a part of the largest ecosystem in the world, extending from western Europe through the Bering Strait to Canada. It extends from the North Pole to northern China, accounting for about half of the total land area of the earth. Most of these areas have been repeatedly attacked by glaciers, and there are still a large number of ice-free areas in northeastern Siberia. Due to glacier movement, a large number of herbivores, such as mammoths, bison, elk, hairy rhinoceros, yak, Saiga antelope, horses, reindeer, musk oxen and moose, began to appear in cold and arid grasslands and undulating grasslands. Zimov called this ecosystem "Mammoth Grassland".
The mammoth grassland suddenly disappeared about 654.38 million years ago, and most large animals became extinct-only reindeer and moose survived, and the grassland that provided food suddenly disappeared and was replaced by forests and tundra. What caused this disaster? Zimov believes that, first of all, due to the indiscriminate killing of human beings, animals began to become extinct, and the extinction of animals led to changes in the landscape. In other words, it is herbivores, not other creatures, that keep the mammoth grassland running normally. They eat grass, excrete feces to make the soil more fertile, and constantly "trample" moss and bushes. Groups of herbivores effectively stopped the spread of moss.
Zimov pointed out that today's Central African prairie is a good example, which proves that groups of large herbivores can maintain the normal operation of grassland ecosystem. He said: "Although we have not witnessed how humans exterminated large animals in northern Siberia, and we have not found direct evidence, the sudden climate change there should not be the chief culprit in the extinction of these animals. Think about it, how many species have been destroyed by humans, and we suspect that the mammoth grassland ecosystem has also been destroyed by our ancestors. "
Zimov believes that the abrupt climate change at the end of Pleistocene did not cause any vegetation changes.
Zimov said that there are many reasons for us to believe that climate change alone cannot explain why the "mammoth grassland" suddenly disappeared. First of all, the abrupt climate change at the end of Pleistocene was not a one-off event. From cold and dry to mild and humid, such changes occurred countless times during the ice age, but none of them caused vegetation changes or even the extinction of herbivores. In addition, according to the recent 14 carbon dating data, some large mammals still survived at the end of Pleistocene. Until about 4,000 years ago, mammoths lived on Vrangel Island in the East Siberian Sea, which was the time when humans first landed on this land. This naturally makes people associate human landing on the island with the extinction of mammoths.
In Alaska, wild yaks also survived for a long time at the end of the Pleistocene, until human hunters began the "big cleaning" operation. Zimov said: "The local elders are still telling stories about how their ancestors enjoyed yak meat." Alaska has successfully reintroduced bison. Similarly, in the past 100 years or so, musk oxen also moved from the cold and arid Canadian Arctic Islands to the warm and humid Alaska, and this race began to flourish. Zimov believes that all these phenomena show that Pleistocene animals can fully adapt to the warm and humid climate, and they can grow and reproduce as long as they are not in danger of being killed. Xinshi Park.
Zmov is not satisfied with defending climate change in a utopian way. He hopes to put the "Blitzkrieg Killing Hypothesis" into practice and prove it with scientific experiments. The reason is simple: if the extinction of animals is caused by human killing, people can "atone" in the opposite way; If herbivores can help maintain the mammoth grassland ecosystem, people can make this ecosystem prosper again by reintroducing it.
The Pleistocene Park is still small, with only 50 hectares of pasture, 6 horses and 3 moose. Zimov admits: "It's hard to call such a small area an ecosystem." However, he said that his team is building a 1600 hectare pasture with strong guardrails around it, which can accommodate 300 to 400 animals. If carried out as planned, the park will enter the next stage of development, establishing new pastures for large herbivores or their close relatives who are still alive in the mammoth ecosystem. The first batch will introduce 20 horses and 20 reindeer. Zimov has also been trying to introduce the Canadian forest bison, which is related to the extinct grassland bison. Musk ox and moose will be the next residents.
Wu, an associate researcher at the Institute of vertebrate paleontology and Paleoanthropology, Chinese Academy of Sciences, published a paper on ONE. Based on the study of late Pleistocene Xu Jiayao (also known as Houjiayao) in China, the researchers pointed out that the incidence of rare human diseases in Pleistocene was extremely high, which provided new evidence for exploring the reasons for the extinction or replacement of ancient humans in Pleistocene.
Fossils of Xu Jiayao people were found in a long ditch on the west side of Houjiayao Village, Yangyuan County, Zhangjiakou City, Hebei Province. Its geological age is inferred as early Late Pleistocene, from104,000 years ago to125,000 years ago.
The reported individual is Xu Jiayao 1 1, which belongs to the middle and posterior part of bilateral parietal bones of an adult. This specimen has an unusual feature: there is an obvious abnormal perforation about two centimeters behind the bone wall. This unusual place caught the attention of researchers. After excluding other causes such as trauma, the identification results show that perforation is a rare giant apical foramen disease. Giant apical foramen disease is a congenital anomaly of vascular system. The specimen Xu Jiayao 1 1 is the first huge apical foramen discovered by Pleistocene ancient humans.
Zhengzhou, 7 Mar (Reporter Guijuan)-The Luoyang Institute of Cultural Relics and Archaeology recently discovered the Middle Pleistocene hominid fossils at the Sun Jiadong site, which is the first time that Homo erectus (Homo erectus) fossils have been found in caves in Henan Province, providing important information for studying the origin and evolution of human beings in East Asia.
Vertebrate paleontology Institute of Paleoanthropology, Institute of Archaeology, Chinese Academy of Social Sciences, Peking University and other related experts and scholars were invited by the Henan Provincial Cultural Relics Bureau to have a discussion on the spot. Experts believe that the unearthed ancient human tooth fossils are clear, reliable and well preserved, and agree to name them "Homo erectus Luanchuan species" or "Luanchuan people" for short.
Sun Jiadong Paleolithic Site is located on a cliff head on the south bank of yi river, Luanchuan County. This excavation unearthed ancient human fossils, stone products, river pebbles, rich animal fossils and animal feces fossils.
Shi, director of Luoyang Institute of Cultural Relics and Archaeology, said that it is particularly important to find six ancient human teeth, including two young teeth,/kloc-0 incisors and three molars, and two broken gums. Generally speaking, the teeth are well preserved and the wear is not very severe. Some even young individuals, teeth have not yet grown in the gums. No matter the size or shape of the occlusal surface, the preserved morphological information is clear.
Zhanyang Li, a researcher at Henan Institute of Cultural Relics and Archaeology, said that according to the types of unearthed fossils, Luanchuan people should be as old as Beijingers and belong to the Middle Pleistocene in geological age. If this site is in the same period as Zhoukoudian Peking Man Site, then the highest dating date of Peking Man Site is 730,000 years ago, and Luanchuan Man may not be later than Peking Man. If so, the history of ancient human existence in the Central Plains will be greatly advanced.
A researcher at the Institute of vertebrate paleontology and Paleoanthropology, Chinese Academy of Sciences, is pleased that although the fossils of Homo erectus in the Middle Pleistocene have been found in China and all over the world, there are actually very few materials, and many periods and regions are blank. The discovery of Sun Jiadong site not only fills the blank in the Central Plains, but also makes the human chain more complete. More importantly, these materials are very rich and conclusive and have clear academic value.
Experts believe that dozens of vertebrate fossils have been unearthed in Sun Jiadong site, which is expected to become one of the important animal fossils in China, and is of great significance for studying the evolution of Quaternary paleontology and the changes of paleoclimate and environment in China. Luanchuan is located near the geographical boundary between north and south of China, which plays an important role in studying the fauna species and characteristics of this transitional area in China during the Middle Pleistocene, and also provides important information for the evolution of fauna and the changes of paleoclimate and environment.
According to researcher Zhanyang Li, Homo erectus, commonly known as Homo erectus, has unearthed Homo erectus fossils in Africa, Asia and Europe. The most familiar is Beijingers, also known as Homo erectus Beijingers. Homo erectus lived from more than 2 million years ago to about 200 thousand years ago, belonging to Pleistocene in geological age, mainly distributed in the middle Pleistocene.