TOEFL統合ライティング

📖 読解文章

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 warming climate at the end of the Pleistocene reduced the mammoth’s grassland habitat, causing population fragmentation and decline. Second, genetic studies show that mammoth populations were already small and inbred long before humans reached their main habitats, indicating that climate stress, not hunting, initiated the decline. Finally, archaeological sites with mammoth kill sites are rare, and most human settlements from that era show little evidence of large-scale hunting, suggesting that humans were not a significant predator.

🎧 リスニング講義

The lecture challenges the idea that climate change alone caused woolly mammoth extinction. While habitat loss did occur, it was not uniform; mammoths survived in refugia with suitable vegetation until humans arrived, implying human activity delivered the final blow. Moreover, the genetic evidence of small populations can be explained by natural population cycles, not necessarily climate-driven decline. In fact, mammoth populations rebounded during brief cold spells, showing resilience to climate shifts. Finally, the scarcity of kill sites is misleading: mammoth bones are often preserved in non-archaeological contexts, and butchery marks may be overlooked. Recent findings show cut marks on mammoth bones at several sites, indicating that humans did hunt them, and those hunts could have been devastating for already stressed populations.