Viết tích hợp TOEFL

📖 Đoạn văn

The extinction of the woolly mammoth has long puzzled scientists. While climate change is often cited as the primary cause, a closer examination reveals that human hunting was the decisive factor. First, archaeological evidence shows that human populations expanded into mammoth habitats precisely when mammoth numbers declined. Sites in North America and Eurasia contain mammoth bones with cut marks from stone tools, indicating active hunting. Second, mammoths had survived previous interglacial warm periods, such as the Eemian (120,000 years ago), without going extinct, even though temperatures were similar to or warmer than those at the end of the Pleistocene. This suggests that climate alone was not sufficient to drive them to extinction. Third, the timing of extinction correlates with human arrival: on continents like North America, mammoths disappeared within a few thousand years of human entry, while on isolated islands such as Wrangel Island, they survived until around 2000 BCE, long after the climate had stabilized. Thus, human predation, not climate, was the primary driver of the woolly mammoth's demise.

🎧 Bài giảng

The reading's argument that human hunting drove mammoth extinction is flawed. First, cut marks on bones are rare and often ambiguous; many could result from scavenging carcasses of animals that died naturally, not from active hunting. Moreover, human populations at that time were too small to kill off vast herds across continents. Second, the comparison to the Eemian is misleading: during that earlier warm period, mammoths had different genetic diversity and faced different ecological pressures, including predators and diseases that are not comparable to later conditions. More importantly, the end-Pleistocene climate change was not just warmer—it caused dramatic shifts in vegetation, reducing the open grasslands that mammoths depended on. Pollen records show a rapid replacement of steppe-tundra by forests and wetlands, which would have fragmented habitats and reduced food availability. Third, the island survival on Wrangel actually supports the climate hypothesis: Wrangel Island had a more stable, cold environment that preserved grasses, and its small size limited but did not eliminate human hunting. The mammoths there eventually died out due to inbreeding and environmental changes, not because of a few hunters. Therefore, the evidence better supports climate-induced habitat loss as the primary cause.