TOEFL Integrated Writing

📖 Reading Passage

The extinction of the woolly mammoth has long been attributed to human overhunting, but a closer examination of the evidence suggests that climate change was the primary driver. First, the timing of mammoth decline aligns closely with the end of the last Ice Age, around 10,000 years ago, when global temperatures rose significantly. This warming caused dramatic shifts in vegetation, replacing the cold, dry steppe grasslands—the mammoth’s primary food source—with boreal forests and tundra, which offered far less nutritious forage. Second, archaeological evidence shows that human hunting pressure was relatively low. Sparse population densities and limited hunting technology, such as spears, would have made it difficult for early humans to drive such large, formidable animals to extinction, especially over vast geographic ranges. Third, genetic studies reveal that mammoth populations experienced severe bottlenecks and inbreeding long before human contact in many regions. For example, the last surviving population on Wrangel Island showed reduced genetic diversity, indicating that environmental stress, not hunting, weakened their resilience. Thus, while humans may have delivered the final blow, the primary cause was climate-induced habitat loss and demographic collapse.

🎧 Listening Lecture

The lecture challenges the reading’s claim that climate change was the main cause of woolly mammoth extinction, arguing instead that human hunting played a decisive role. First, the timing argument is flawed. While warming began 10,000 years ago, mammoths survived for several thousand years in some areas, such as mainland Siberia, where climate conditions remained suitable. Their disappearance coincides more closely with the arrival of advanced human hunters, who used sophisticated tools like atlatls and coordinated group strategies. Second, the reading underestimates human impact. Even with low population densities, humans could have exerted disproportionate pressure by targeting juvenile mammoths, which were easier to kill, thereby disrupting reproduction. Moreover, recent archaeological sites show mass kill sites with mammoth bones, contradicting the idea of limited hunting. Third, the genetic evidence does not support climate stress. The bottlenecks observed in late populations, like those on Wrangel Island, were likely the result of small population size after human-induced range contraction, not a cause of decline. In fact, populations that were not yet in contact with humans, such as those in unglaciated refugia, maintained high genetic diversity until humans arrived. Therefore, the lecture concludes that human overhunting, not climate, was the primary factor driving mammoth extinction.