การเขียนเชิงบูรณาการ TOEFL

📖 เนื้อเรื่อง

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 extinction coincides with the rapid warming at the end of the last Ice Age, around 10,000 years ago. As temperatures rose, their cold-adapted grassland habitats, known as the mammoth steppe, shrank dramatically, replaced by forests and wetlands. Second, genetic studies of fossil remains reveal a severe population bottleneck thousands of years before humans arrived in high numbers, indicating that mammoth numbers were already declining due to environmental stress. Third, archaeological evidence shows that human hunting of mammoths was relatively rare; most kill sites contain only a few bones, and early human populations were too sparse to have caused a continent-wide extinction. Therefore, the disappearance of the woolly mammoth is best explained by climate-driven habitat loss, not human predation.

🎧 การบรรยาย

The reading’s argument that climate change alone drove mammoth extinction is flawed. While warming did reduce the steppe, it did not eliminate all suitable habitats; refugia in northern Siberia and islands remained, yet mammoths vanished there too, suggesting an additional factor—human hunting. Regarding the genetic bottleneck, the reading ignores that this decline occurred during an interglacial warm period, but mammoths recovered when cooler conditions returned, proving they could adapt to climate swings. The real final extinction coincided with the arrival of sophisticated human hunters, who used spears and drove animals off cliffs. As for the rarity of kill sites, this is misleading because early humans likely butchered mammoths at kill locations that are now submerged under rising sea levels, and we have found massive bone beds with cut marks in some regions, indicating mass hunting. Moreover, on isolated islands where mammoths survived longer, they disappeared shortly after humans arrived, not after any significant climate shift. Thus, human overhunting, not climate, was the decisive cause.