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 extinctions aligns with the rapid warming at the end of the Pleistocene, around 10,000 years ago. As temperatures rose, their grassland habitats shrank, reducing food availability. Second, genetic studies show that mammoth populations were already declining thousands of years before humans reached key regions, such as Wrangel Island, where the last mammoths survived until 4,000 years ago. This decline occurred during a period of climate instability, not heavy hunting. Third, the extinction of other megafauna, like the giant beaver and the short-faced bear, also coincides with climate change, even though these species were not major targets for human hunters. Thus, while humans may have contributed locally, climate-induced habitat loss best explains the global pattern of mammoth extinction.
🎧 听力讲座
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The reading presents a neat climate-based explanation, but it overlooks key evidence. First, the timing argument is flawed: mammoth extinction occurred at different times in different regions, and many populations disappeared during cold, stable periods, not just during warming. For example, mammoths in northern Siberia vanished during a cold snap, contradicting the idea that warmth alone killed them. Second, the genetic data cited actually supports human involvement. Studies show that on Wrangel Island, mammoths survived until about 4,000 years ago—long after the climate had stabilized—and their decline coincided with the arrival of humans, not with any major climate shift. Third, the comparison with other megafauna is misleading. Species like the giant beaver had different ecological needs and may have gone extinct for other reasons, such as predation by expanding human populations or competition with new species. Moreover, human hunting is known to have caused extinctions in isolated ecosystems, like the moa in New Zealand and the dodo in Mauritius, which shows the power of human impact. Therefore, the reading's climate-only theory fails to account for these regional and temporal patterns.
📝 Instrucciones de escritura 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).
