The extinction of the woolly mammoth has long been attributed to human overhunting. However, recent evidence suggests that climate change was the primary driver. First, the mammoth’s habitat, the mammoth steppe, expanded and contracted with glacial cycles. As the climate warmed at the end of the Pleistocene, this steppe shrank dramatically, reducing the available grazing land. Second, warming temperatures led to increased precipitation and the replacement of dry grasslands with wet, forested landscapes, which were unsuitable for mammoths. Third, the timing of extinction varies by region: mammoths survived on isolated islands like Wrangel Island until around 2000 BCE, long after humans had arrived, indicating that human presence alone did not cause their demise. Instead, these island populations only disappeared when sea-level rise and changing vegetation finally made their habitats unsustainable.
🎧 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 professor challenges the reading’s claim that climate change was the main cause of mammoth extinction. First, while the mammoth steppe did shrink, human hunting pressure was already intense during the same period. Archaeological sites show that early humans actively hunted mammoths, using their bones for tools and shelters. This combined effect of habitat loss and hunting likely exceeded the mammoths’ ability to recover. Second, the shift to wetter, forested areas did not necessarily eliminate all suitable habitat. Mammoths had previously survived interglacial periods with similar conditions, suggesting they could adapt if not overexploited. Third, the Wrangel Island case actually supports human involvement: those mammoths were dwarfed and genetically weakened due to inbreeding, making them more vulnerable to any stress, including the arrival of humans on the island. The reading overlooks that the island population likely died out shortly after human colonization, not purely from climate.
📝 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).
