Recently, the latest research from the United Kingdom has conveyed a message: For 10,000 years, human beings have been keeping pace or even retrogressive in terms of brain volume and height. From this, it was pessimistically deduced that the human race, which has been evolving for millions of years, has stopped and reached its limit. This reporter interviewed Professor Li Fajun of the Department of Anthropology at Sun Yat-sen University. He believes that there are misunderstandings about this anxieties. The evolution of human beings has never stopped. It is more objective to use “microevolution†to understand the subtle changes in the plus and minus of human constitution.
Planning Zhao Jie
Write Li Wen
Ancient human fossils: more robust than today
Dr. Marta Lacher, a human evolutionist at Cambridge University, United Kingdom, published her latest research findings at the Royal Society of England. She found that modern people are worse than many ancestors in terms of physical strength. Through comparative analysis, human fossils discovered in Ethiopia 200,000 years ago were more massive than modern people and were “more energeticâ€. The human fossils found in Israel from 120,000 to 100,000 years ago are also tall and muscular. Ten years ago, the average weight of ordinary people was between 79.83 kg and 85.28 kg, while the average weight of modern people was between 69.85 kg and 79.83 kg. Lahrer pointed out to the media: "Humanity is still evolving, but the evolution of body size has stopped since 10,000 years ago." Why does this happen? She believes that, starting 9000 years ago, the transformation of the lifestyle of hunting into a mode of agricultural production has changed the course of human physique. Although agriculture has made food supplies more abundant, the reduction in food types has led to a serious shortage of vitamins and minerals in humans, which hinders human growth.
In addition to physical aspects, human brain capacity seems to have encountered the same problem. Lacher pointed out that the volume of a male brain 20,000 years ago was 1500 cubic centimeters. Modern men have an average brain volume of 1,350 cubic centimeters, which reduces the size of a tennis ball. The female brain has the same reduced proportion.
Brain capacity limit: The bulk may become stupid instead?
In the past, many people were inclined to think that the future human head would become bigger and bigger. It now appears that this seems to be a misunderstanding. More and more brain scientists believe that there are limits to the development of the human brain. Although the human brain has tripled in size during the 2 million years of evolution, our brain capacity has not been able to increase all the time. Responding to Rahul's research, recently, the Dutch neuroscientist Michel Hoffman also put forward a reason why the brain cannot always grow - that is, the issue of high energy consumption. Although the brain weighs only 2% of the body's weight, it consumes 25% of the body's energy, which is much higher than other organs. If the brain continues to grow, it will take more energy and nutrients from other important organs, which threatens the viability of the human species. If the brain grows, the volume of neurons will increase, which will increase the distance between brain cells, and the axons connecting cells must become thicker and longer. This will undoubtedly make the time of the electrical pulse of the cell longer, so that the brain cannot process information at the normal speed. Therefore, the big head may not be smart. On the contrary, it may make us dull. In this case, the smaller size does not necessarily mean that we become more stupid, on the contrary, we are likely to learn how to make greater use of our limited brain capacity resources.
Case from China: The human brain capacity of Guilin Rock is larger than that of modern people
Some scholars in China have also studied the changes in human brain capacity today. An anthropologist Wu Xiujie once wrote that the male skeletal capacity of the Neolithic inhabitants of the Neolithic Age, unearthed in the southern suburbs of Guilin, China, averaged 1,459 milliliters in males and 1,434 milliliters in females. The average cranial volume in modern North China residents is 1406 ml and 1360 ml in women. From the Neolithic era to the present, male cranial volume decreased by 53 milliliters and female cranial volume decreased by 74 milliliters. The decrease in cranial volume means that the size of the skull is shrinking and the human physical characteristics are still changing.
In terms of height, it is not always straight forward. Wu Xiujie pointed out that height is closely related to nutritional status. The Neolithic residents of China from 6,000 to 4,000 years ago have an average height of 1.65 meters for men and 1.54 meters for women. The residents of the Western Zhou Dynasty and Western Han Dynasty from 3000 to 1800 years ago have an average height of 1.67 meters for men and 1.55 meters for women. During the Sui and Tang dynasties and the Song and Ming dynasties, the average height of men was 1.66 meters, and women's average height was 1.56 meters. However, by the 1960s, the Chinese had a negative growth in height. According to statistics, in 1944, the height of male and female students aged 7 to 14 years old in Shanghai was 5.7 to 7.3 cm shorter than that of students of the same age from 1931 to 1932. At present, the average height of adult males in China is 1.69 meters, and the average female height is 1.58 meters. Wu Xiujie pointed out that with the improvement of people’s living standards, height will increase to some extent, but it will not always show a growth trend. According to surveys, in taller families, the height of their offspring will not be older than one generation. After reaching a certain level, the height of their offspring will show a downward trend.
Expert doubts
Limits, declines are inaccurate
Diverse microcosmic evolution has never stopped
Is it possible to deduce from an anthropologist's study the pessimistic conclusion that "Human evolution has reached its limit", "Humanity has passed the peak of development", or "is the continuation of human physique for ten thousand years?" Professor Li Fajun of the Department of Anthropology at Sun Yat-sen University believes that instead of saying that “human evolution has reached its limitâ€, it is better to use “human microcosmic evolution†to better reflect the objective facts of human development. The occurrence of any variation in human head and brain capacity is the result of microscopic evolution. From this perspective, there is no such thing as “reaching the limit†or simply “evolution†or “degenerationâ€.
Li Fajun believes that the views put forward by experts at Cambridge University are in line with the facts of modern human evolution, but it does not mean that humans have passed their peak period. “Humanity is a species that has both natural and social properties. Culture plays a decisive role in the evolution of humans in the later period. The fusion and isolation of cultures and the change in production methods have all shaped different cultures in different periods of time,†he said. . This makes the evolution of human beings not monolithic, but full of diversity and change. Li Fajun pointed out that modern human brain capacity is indeed smaller than the early stage of the Homo sapiens, but it is basically kept within minor differences. In order to adapt to the natural environment, the result is a significant difference in the body mass of the modern population, but their genetic structure differences are very small. The assertion that "the continuation of human constitution has been declining for ten thousand years" is also problematic. The emergence and development of agriculture and the emergence of urbanization have indeed adversely affected health and led to the spread of diseases. Many paleopathological studies have already demonstrated this. But these are the motives that lead to the constant evolution of mankind. As long as some humans have adapted to these “factors that influence evolutionâ€, human genes will continue. We cannot say that the human constitution is declining or degenerating.
Flores, Indonesia:
Realistic version of the Hobbit dwarves live well
If you are still cherishing the ideal homage to "people and horses", the existence of the Indonesian Flores will completely subvert your dedication.
In 2004, researchers from the University of New England, Australia and Indonesia presented the latest discoveries shocking the world in the journal Nature. It turns out that the Hobbits in Lord of the Rings really existed. The researchers found a dwarf female fossil about 18,000 years ago in a cave on Flores Island in Indonesia. She is only 0.91 meters tall. The woman was at least 20 years old when she died. Her head is only the size of a grapefruit, only a quarter of modern people, and it is estimated that her brain volume is only 380 milliliters. Scientists named this fossil as "dwarf" and named the new species "Flores." Subsequently, the researchers discovered six similar ancient human bones. The fragments of the six bones date back to 12,000 to 95,000 years ago. The researchers found that because of the lack of resources on isolated islands, and the difficulty of feeding on animals for long distances, it is more advantageous for small animals, and mammals larger than rabbits on the island have degenerated. Perhaps it is this special living environment that determines Flores who live in isolated islands to evolve into dwarves rather than big ones. It is generally believed that the Flores’ brain needs to be tripled in order to make tools. As a result, archaeologists discovered that near the fossilized elephant heads with similar heads on the island, there were well-made stone cones and drills for the dwarves. These seemed to be mounted on spears used to hunt saber-toothed swords. Like. Moreover, there is evidence that Flores who have small heads and small heads already know how to use the fire to barbecue. They lived well in a particularly reduced version of the island world.
You may feel relieved to see this. Heads are not tall, heads are big, really is not the only direction of human progress.
The difference between modern Chinese and ancients:
The face becomes smaller, the nose narrows, the eyelids get higher, and the head becomes round
Li Fajun pointed out that in terms of China, the modern people's body shape and height are less different from those in the Neolithic Age. The main differences are reflected in the facial and facial morphology. That is to say, we are still changing along the way in terms of appearance and appearance. Li Fajun pointed out that this is the result of the joint action of genes and culture.
Studies by anthropologists such as Wu Xiujie and Liu Wu also pointed out this interesting change in our face. Through the comparison, analysis and significance test of 718 cases of northern China's Neolithic Age, bronze iron age, and modern adult male skulls, the results show that from the Neolithic Age through the Age of Bronze Ironware to modern times, the Chinese Holocene human brain The skull and the skull tend to shrink, the nose tends to be narrow, the shape of the eyelids tends to be narrower, and the skull tends to be rounded. In layman's terms, our face is getting smaller, our nose is narrowing, our eyes are getting higher, and our heads are getting rounder.
Why did this change happen? Wu Xiujie and Liu Wu believe that the reason for this microscopic evolution cannot be simply attributed to the migration and integration of the people. The abrupt changes in the climate and the environment may also be an important cause of changes in our physical fitness. In the period from 2200 to 2000 BC, a sudden abrupt climate change occurred in the Yellow River basin. This mutation made the mid-latitude regions generally cool, with a cooling rate of about 3°C. In addition, changes in the way we live and eat have changed our face. With the development of agriculture, our ancestral lifestyle has gradually changed from hunting and gathering to eating soft, ploughed food. This allows our chewing organs to gradually degrade, and the upper and lower jaws, teeth, skulls, and muscles need not be as strong as they used to. This leads to a reduction and weakening of the facial bones. It seems that we can have a lean "face", not only to thank the beautician, but also to thank the modern technology provided by the fine rice flour it.
In addition to the Chinese people, in the past 10,000 years, 70% of the skulls in northern Chile have obvious changes in time; the heads of Americans have become longer and narrower, and the face has become narrower and higher; Nubia in northeast Africa The human skull is less thick, the skull tends to be rounded, and the teeth and mandible become smaller.
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