The extinction of the woolly mammoth has long been attributed to human overhunting. However, recent evidence suggests that climate change at the end of the last Ice Age was the primary driver. First, the warming climate caused a dramatic reduction in the mammoth’s grassland habitat. As temperatures rose, vast steppe-tundra regions were replaced by forests and wetlands, which could not support large herds. Second, the timing of extinction aligns more closely with climate shifts than with human arrival. In many regions, mammoths disappeared thousands of years after humans first appeared, but their decline coincided with rapid warming events. Third, genetic studies show a severe population bottleneck before human hunting intensified, indicating that mammoth populations were already stressed by environmental factors. Thus, climate change, not human activity, was the decisive factor in their demise.
🎧 听力讲座
The reading claims that climate change alone drove the woolly mammoth to extinction, but this view overlooks critical evidence. First, while habitat loss occurred, it was not uniform. In areas like Wrangel Island, mammoths survived for thousands of years after the main habitat change, suggesting that climate alone was not sufficient. Second, the timing argument is flawed. In North America, human arrival at around 13,000 years ago coincides almost exactly with the final extinction of mammoths, and archaeological sites show clear evidence of hunting. Third, the genetic bottleneck mentioned in the reading actually occurred after human contact, not before—the decline in diversity matches the period of intensified hunting, not just warming. Moreover, similar large mammals that experienced the same climate shifts but were not hunted by humans, such as bison, survived. Therefore, human overhunting, not climate, was the primary cause of the mammoth’s extinction.
📝 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.