What is the purpose of the author's first talk about Eskimos and his last talk about Dorset? What research methods can be used for reference?

Recently, researchers from the University of Copenhagen in Denmark confirmed that the earliest humans living in the Arctic were not the same as modern Eskimos, but directly descended from East Asia. In the Arctic regions of Greenland and Alaska, people from East Asia began to migrate 4000 years ago, which has been confirmed in past studies. Before that, where did humans living in the Arctic come from? Although people used to think that they were the ancestors of Eskimos, modern Eskimos inherited a very important whaling culture with a history of only about 1000 years. In addition, in the Eskimo legend, there is a saying that "there were some giants named' Zenit' who lived in the Arctic. They have a good heart, but if they see our ancestors, they will run away with blood in their eyes. " It shows that the ancestors of Eskimos may have driven away the residents who originally lived here. So from all indications, people's previous guesses may not be accurate. This time, the researchers excavated a human settlement about 3000 years ago in Greenland and found some frozen human hair. The researchers determined the arrangement of dna in hair through tests and compared it with modern people. The results show that the owners of these hairs are very close to the modern aborigines living around the Bering Strait and Siberia, but not the same as the Eskimos in modern and ancient times, thus proving that the earliest inhabitants of the Arctic actually came directly from East Asia. The researchers analyzed that although the ancestors of Eskimos also came from East Asia, the migration of ancient East Asian humans occurred many times, and the East Asian humans who first lived in the Arctic were likely to be driven away and replaced by Eskimos who were native Americans, so Eskimos became the ultimate residents of the Arctic. The relationship between ancient Eskimos and Asians is obvious, not only in race, but also in gene. Moreover, in religious beliefs, such as Shamanism, which was once widely popular in Northeast Asia, and wizards who came to seek medical treatment, rain or divination, are also very popular among Eskimos. Shamanism believes that everything in the world has a soul, and Eskimos still do. When they catch a seal, they pour some water into its mouth to comfort its soul and let it continue to cycle, so that seals can eat it later. This is especially true for polar bears. They eat their meat and worship them as gods. Interestingly, this is somewhat similar to the Oroqen people in China. They believe that everything in the world is a god or a relic of shamanism. Since about 500 BC, the survival technology of ancient Eskimos has undergone profound changes, the most important of which is to shift the main target of capture to marine mammals and learn to use the oil of these animals to light lamps to obtain heat and light. Some people think that the igloo may have been used at this time. In some areas, large semi-underground houses built of stones and turf have begun to appear, which can accommodate more people and facilitate longer-term residence. Anthropologists call these ancient Eskimos Dorset, and their corresponding culture is Dorset culture. The central area of Dorset culture is along Hudson Bay and Fox Bay, extending to ellesmere island in the north, Victoria Island in the west and Newfoundland in the south. It lasted about 2000 years. They are the direct ancestors of modern Eskimos, so their culture is also the direct source of modern Eskimo culture. For example, igloos, kayaks and harpoons are all inherited from them. Moreover, Eskimos even remember them today, calling them Tunit, saying that they are all giants with great strength, but they are all stupid. A man can easily carry a one-ton walrus for a long distance, while modern Eskimos can only carry a seal weighing only 72.6 kilograms. From this, people will naturally think of Bergman's law. According to this law, people living in the cold regions of the Arctic should have much larger physique than southerners. Many Setters are also the result of the long-term evolution of this natural law. The most powerful weightlifter in modern times can only lift a few hundred kilograms and can't move. It can be inferred that Dorset must be much bigger than modern people. However, it is a pity that they can only adapt to a rather cold environment. Therefore, more than 2,500 years ago, some parts of the Arctic became colder and entered an ice age, and then developed and reached its peak. Later, when the weather turned warmer, they gradually became extinct and eventually disappeared from the earth, replaced by modern Eskimos. Perhaps only the most beautiful handicrafts in the Arctic have been preserved: very exquisite statues of falcons, ravens, bears and humans. It is speculated that all these things may have religious meanings. By about 800 AD, the Inuit living in Alaska had completely adapted to the cold living environment in the Arctic, developed a fairly perfect polar culture and began to migrate eastward. In less than 200 years, it occupied most of the North American Arctic, replacing or assimilating Dorset, the Eskimos today. They kill almost all marine mammals with perfect hunting techniques, from small ringed seals to giant bowhead whales. Nevertheless, they still struggle to death and live in extreme poverty.