The extinction of the woolly mammoth has long been attributed to overhunting by early humans. Proponents of this theory argue that human hunters, equipped with sophisticated tools and cooperative strategies, drove these massive herbivores to extinction as they migrated across the Bering Land Bridge into North America. First, archaeological evidence shows a strong temporal correlation between human arrival in Siberia and North America and the decline of mammoth populations. Radiocarbon dating of mammoth remains and human campsites indicates that the last known populations vanished shortly after humans appeared in their habitats. Second, the selective killing of juvenile and female mammoths, as evidenced by bone assemblages at kill sites, would have severely disrupted the species' reproductive capacity. Since mammoths had a long gestation period and low birth rates, even minimal hunting pressure could tip the balance toward extinction. Third, isotopic analysis of mammoth bones from the late Pleistocene reveals a sudden shift in diet, suggesting that humans may have altered the landscape through burning, which reduced the mammoths' preferred grazing areas. This combination of direct hunting and habitat modification, proponents argue, made human activity the primary driver of the mammoth's demise.
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The reading's claim that humans were the primary cause of mammoth extinction is not convincing. While the temporal correlation exists, it does not prove causation. Climate change at the end of the Pleistocene was far more dramatic than human impact. As the glaciers retreated, the vast grasslands known as the mammoth steppe shrank rapidly, replaced by forests and tundra, which offered poor forage. Indeed, the isotopic shift mentioned in the reading actually reflects a change in vegetation, not human burning; studies show that the shift occurred even in areas with no evidence of human presence. Regarding the kill sites, the bone assemblages may not represent hunting but scavenging—humans likely took meat from animals that had already died from starvation or disease, especially during harsh winters. Finally, the reproductive argument ignores that mammoths had survived previous warming periods without humans, and their population was already declining thousands of years before humans reached the Americas. Thus, climate-induced habitat loss, not human hunting, was the decisive factor.
📝 写作提示 Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific points made in the reading passage.
