TOEFL Integrated Writing

📖 Reading Passage

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 decline correlates closely with the warming period at the end of the last Ice Age, around 10,000 years ago. As temperatures rose, their grassland habitats shrank, reducing food availability and fragmenting populations. Second, genetic studies show that mammoth populations experienced severe bottlenecks before human populations in the same regions expanded, indicating that climate stress preceded human impact. Finally, on isolated islands where humans never arrived, such as Wrangel Island, mammoths survived until much later, only disappearing when sea level rise reduced their island to a critical size. This suggests that habitat loss due to climate, not hunting, was the decisive factor.

🎧 Listening Lecture

The lecture challenges the idea that climate change alone drove woolly mammoths to extinction. While the timing of their decline does overlap with warming, this correlation is weak. Many large mammals, such as bison and horses, also lived in the same grasslands but survived the warming period, so climate change did not universally cause megafaunal extinctions. Furthermore, the genetic bottlenecks cited in the reading may not reflect climate stress; they could be the result of human hunting that selectively removed healthy individuals, leaving small, inbred populations. The case of Wrangel Island is also misleading: mammoths there persisted for thousands of years after sea level rise, only disappearing when humans arrived on the island around 1700 BCE. Thus, the evidence actually points to human activity as the final and most critical factor, not climate change alone.