Viết tích hợp TOEFL

📖 Đoạn văn

The extinction of the woolly mammoth (Mammuthus primigenius) has long been attributed to human overhunting, but recent studies suggest that climate change was the primary driver. First, the warming period at the end of the Pleistocene (approximately 10,000 years ago) led to a dramatic reduction in the mammoth’s grassland habitat. As forests and tundra expanded, the open steppe ecosystems that mammoths depended on for forage shrank, causing population fragmentation and food scarcity. Second, climate-driven changes in precipitation and seasonal patterns likely disrupted mammoth reproductive cycles. Fossil records indicate that mammoth populations declined sharply during rapid warming events, even in regions with no evidence of human presence, such as Wrangel Island. Third, the timing of the final extinction events aligns more closely with climate shifts than with human migration. On the mainland, mammoths disappeared by around 10,000 years ago, but isolated populations survived on Arctic islands until about 4,000 years ago, suggesting that they could withstand human hunting but not the cumulative effects of habitat loss and inbreeding. Therefore, while humans may have contributed to local declines, the overwhelming evidence points to climate change as the decisive factor in the woolly mammoth’s extinction.

🎧 Bài giảng

The lecture challenges the reading’s claim that climate change alone drove the woolly mammoth to extinction. While the reading emphasizes habitat loss and isolation, the professor argues that human hunting played a critical, even primary, role. First, the reduction in grassland was not uniform; mammoths could have adapted by shifting their range, as they did during earlier interglacial periods. However, the arrival of sophisticated human hunters with spears and coordinated strategies created a new, unsustainable pressure, as evidenced by kill sites with mammoth bones and butchery marks that coincide with human expansion. Second, the reading’s example of Wrangel Island is misleading. The mammoths there survived longer because the island was isolated and lacked permanent human settlement, but when humans finally arrived around 4,000 years ago, the last population vanished within a few centuries—too rapid to be explained by climate alone. Third, the timing argument is flawed: paleoclimate data show that the most rapid warming occurred before the main wave of human migration into North America and Eurasia, yet mammoth populations remained stable during those earlier warmings. It was only after humans appeared in large numbers that extinction accelerated. Thus, the lecture concludes that human hunting, not climate, was the decisive factor.