托福综合写作

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The extinction of the woolly mammoth has long been attributed to overhunting by early humans. However, recent evidence suggests that climate change was the primary driver. First, the warming climate at the end of the Pleistocene reduced the mammoth’s grassland habitat, as forests and tundra replaced steppe. This habitat loss would have drastically reduced food availability, leading to population decline. Second, genetic studies of mammoth remains show a steady loss of genetic diversity before their final disappearance, which is more consistent with gradual environmental stress than with sudden human hunting. Finally, archaeological sites show that humans did not heavily hunt mammoths; most mammoth bones found in human settlements are from scavenged carcasses or tusks used for tools, not from active kills. Thus, climate-driven habitat change, not human predation, caused their extinction.

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The reading’s argument that climate change alone caused mammoth extinction is flawed. While habitat change did occur, it was not the decisive factor. First, mammoths had survived previous interglacial warming periods with similar habitat shifts, so they were resilient to such changes. In contrast, the arrival of humans on each landmass—Eurasia and then North America—closely coincided with rapid mammoth declines. Second, genetic diversity loss does not necessarily indicate slow environmental stress; it can also result from population bottlenecks caused by hunting. Moreover, human hunting can be selective, targeting juveniles or females, which would reduce genetic diversity quickly without leaving many kill sites. Third, the archaeological record is biased; early humans likely used mammoth carcasses but also hunted them, and many kill sites may have been destroyed or overlooked because they are now underwater or in unexcavated areas. Therefore, human hunting remains a more plausible primary cause.