The extinction of the woolly mammoth has long been attributed to human overhunting, but recent evidence suggests that climate change was the primary driver. First, the timing of mammoth decline correlates closely with the end of the last Ice Age, when temperatures rose dramatically. As the ice retreated, the open grasslands that mammoths depended on were replaced by dense forests and wetlands, reducing their food supply. Second, genetic studies show a severe population bottleneck among mammoths well before humans reached their main habitats in North America and Siberia. This indicates that their numbers were already dwindling due to habitat loss, not hunting pressure. Third, human hunting practices at the time were likely inefficient, as early humans used simple spears and lacked the advanced weapons needed to regularly kill such massive animals. Moreover, archaeological sites with mammoth remains are rare, suggesting that hunting was opportunistic and not a major cause of mortality. Therefore, the extinction is best explained by climate-induced habitat change, not human activity.
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The professor challenges the reading's claim that climate change alone caused woolly mammoth extinction. First, while the warming period did alter habitats, mammoths had survived previous interglacial warm periods with similar vegetation shifts. Thus, habitat change alone cannot explain their final disappearance. Second, the genetic bottleneck the reading cites may actually reflect a population that rebounded before the final extinction. In fact, mammoth numbers remained high in some regions until humans arrived, and their last known populations survived on isolated islands where climate was stable but humans eventually appeared. Third, the argument about inefficient hunting ignores evidence of sophisticated hunting strategies. Found spear points and butchery sites show that humans drove mammoths into traps or used natural barriers, and bones with cut marks indicate systematic processing. Even if hunting was not the sole cause, it likely delivered the final blow to populations already stressed by climate, making human impact a critical factor. Thus, the reading oversimplifies the cause by dismissing human involvement.
📝 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.
