托福综合写作

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The extinction of the woolly mammoth has long been attributed to climate change at the end of the last Ice Age. However, a growing body of evidence suggests that human hunting was the primary driver. Three key arguments support this view. First, archaeological sites across North America and Eurasia show clear signs of mammoth butchery, with stone tools and bone fragments bearing cut marks. These sites date to exactly the period when mammoth populations declined sharply, implying a direct causal link. Second, the timing of extinction correlates with human migration. Mammoths survived on isolated islands like Wrangel Island until about 4,000 years ago, long after the climate had warmed, but they disappeared soon after humans arrived there. This pattern strongly implicates human activity. Third, modeling studies indicate that even a modest hunting pressure—killing only a small percentage of juvenile and adult females per year—would have been sufficient to drive populations to extinction over several centuries, given the mammoth’s slow reproductive rate. Thus, while climate change may have stressed mammoth populations, it was ultimately human predation that delivered the fatal blow.

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The professor challenges the reading’s claim that humans caused the woolly mammoth’s extinction. While the evidence for hunting is real, it does not prove human agency. First, the butchered remains are few and scattered; they represent scavenging of already dead animals rather than active hunting. Many cut marks appear on bones from animals that died of natural causes, and no kill sites with mass graves have been found. Second, the island survival argument is flawed. Wrangel Island’s mammoths survived until 4,000 years ago, but human arrival there is dated to about 3,600 years ago—after the mammoths disappeared. Thus, humans cannot be responsible for their final extinction on that island. Third, the modeling studies are overly simplistic. They ignore factors like disease, inbreeding depression, and the loss of genetic diversity, which are known to have affected late-surviving populations. These factors, combined with the shrinking of suitable habitat as sea levels rose, would have made extinction inevitable even without any human hunting. In fact, the last mammoths show signs of genetic deterioration, and their extinction coincides with the final loss of steppe grasslands. Therefore, climate and ecological changes, not human hunters, are the more plausible explanation.