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 the mammoth’s decline correlates more closely with the warming period at the end of the last Ice Age, around 10,000 years ago, than with the arrival of human hunters. Human populations in Siberia and North America were sparse at that time, and archaeological sites show only occasional mammoth kills. Second, the warming climate caused a dramatic shift in vegetation. Mammoths relied on dry, grassy steppe ecosystems, but as temperatures rose, these were replaced by dense forests and wetlands, reducing their primary food source. Isotopic analyses of mammoth bones from this period reveal a dietary shift to less nutritious plants, indicating food stress. Third, the mammoth’s physical adaptations—thick fur, small ears, and a hump of fat—were suited for cold, dry environments. As the climate became warmer and wetter, these traits became liabilities, increasing heat stress and vulnerability to disease. Thus, the evidence points to climate-driven habitat loss and physiological mismatch as the main causes of extinction, not human hunting.
🎧 听力讲座
🎯 模拟考试环境：先点「播放讲座」听完内容，再作答。听力原文默认隐藏。
The reading’s argument that climate change alone drove the woolly mammoth to extinction overlooks critical evidence. While it is true that warming altered the environment, this does not explain why mammoths survived earlier interglacial periods with similar warming. During previous warm phases, mammoth populations persisted, suggesting they could adapt to some climate shifts. What was different in the late Pleistocene was the presence of highly efficient human hunters. Recent archaeological findings reveal that human settlements expanded precisely into mammoth habitats at the time of their decline, and kill sites show butchery patterns indicating systematic hunting, not just occasional scavenging. Moreover, the dietary shift noted in the reading may have been caused by competition with other large herbivores, not solely by climate. But more importantly, on isolated islands where mammoths survived for thousands of years after the mainland extinction, such as Wrangel Island, the climate was similar to that on the mainland. The only difference was the absence of humans. When humans finally arrived on Wrangel Island, the mammoths disappeared within a few centuries. This pattern strongly implicates human overhunting as the decisive factor, with climate change playing only a secondary role.
📝 Hướng dẫn viết Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific points made in the reading passage.
📊 TOEFL Integrated Writing Rubric
Content Accuracy: Accurately capture the relationship between lecture and reading
Information Completeness: Cover all key counter-arguments from the lecture
Structure & Coherence: Logical organization and progression
Language Use: Grammar, vocabulary, expression accuracy
Scored 0-30 based on holistic scoring (original 0-5, scaled to 30).
