托福综合写作

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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 with the end of the last Ice Age, when temperatures rose dramatically. As the glacial habitats shrank, mammoths lost their preferred steppe-tundra foraging grounds, leading to population fragmentation. Second, genetic studies of ancient mammoth remains show a steady loss of genetic diversity well before humans arrived in their final refuges, indicating that populations were already stressed by environmental shifts. Third, archaeological evidence from human settlement sites shows that early hunters primarily targeted smaller game, such as reindeer and bison, rather than large megafauna. Even where mammoth bones are found near human tools, cut marks are rare, suggesting scavenging rather than active hunting. Thus, while humans may have delivered a final blow, the primary cause of extinction was climate-driven habitat loss and demographic decline.

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The reading's argument that climate change alone drove mammoth extinction is flawed. First, while temperature rise did alter habitats, mammoths had survived previous interglacial periods with similar warming. What made the last period unique was the presence of skilled human hunters with advanced projectile weapons. Second, the genetic diversity loss cited actually began around 20,000 years ago, but mammoth populations recovered during later cold phases. The final rapid decline coincided exactly with human expansion into Siberia and North America, not with gradual climate trends. Third, the claim that early hunters ignored megafauna is misleading. At sites like Clovis in North America, mammoth bones with unmistakable spear points embedded in ribs and vertebrae have been found, proving direct hunting. Moreover, even if hunting was occasional, mammoths had low reproductive rates—a single calf every few years—so even modest hunting pressure could drive populations to extinction. Therefore, human predation was the decisive factor, not climate.