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 glaciers retreated, the open grasslands—the mammoth’s primary habitat—were replaced by dense forests and wetlands, reducing their food supply. Second, genetic studies show that mammoth populations experienced a severe bottleneck long before humans reached their main habitats in Siberia and North America. This indicates that climate-induced habitat loss had already weakened the species. Third, archaeological evidence reveals that human hunting was not intensive enough to cause extinction. The number of known kill sites is small, and early human populations were too sparse to have a significant impact on such a widespread species.

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The reading’s argument that climate change alone drove the woolly mammoth to extinction is flawed. While it is true that the climate warmed, similar warming events had occurred earlier in the mammoth’s history, yet the species survived. The key difference in the final extinction was the presence of modern humans. Moreover, the genetic bottleneck mentioned in the reading actually occurred around 300,000 years ago, long before the last Ice Age, and the population recovered afterward. This does not support a climate-driven decline at the end of the Pleistocene. Finally, the claim that hunting was insignificant ignores that humans did not need to kill many mammoths to cause extinction. Even a low level of hunting, combined with the fact that mammoths had slow reproductive rates, could have tipped the balance. In fact, on islands where humans arrived late, such as Wrangel Island, mammoths survived until just after human colonization, despite stable climate conditions.