TOEFL Integrated Writing

📖 Reading Passage

The extinction of the woolly mammoth has long been attributed to overhunting by early humans. However, a closer examination of the evidence suggests that climate change was the primary driver. First, the timing of the mammoth’s disappearance coincides with the end of the last Ice Age, when global temperatures rose rapidly. This warming caused dramatic shifts in vegetation, replacing the cold, dry steppe grasslands that mammoths depended on with forests and wetlands, which provided insufficient forage. Second, while human hunting may have occurred, archaeological sites from the period show only sporadic evidence of mammoth kills, with far fewer butchered remains compared to other prey like reindeer or bison. This suggests that hunting pressure was not intense enough to drive a species to extinction. Third, genetic studies of ancient mammoth remains reveal a significant decline in genetic diversity long before human populations expanded, indicating that populations were already shrinking due to environmental stress. Thus, climate-induced habitat loss, not human hunting, was the decisive factor in the mammoth’s demise.

🎧 Listening Lecture

The reading’s argument that climate change alone caused the woolly mammoth’s extinction is flawed. First, the claim that vegetation shifts made food scarce ignores the fact that mammoths were highly adaptable. Fossilized dung and teeth analyses show they could consume a variety of plants, including grasses, sedges, and even tree bark. Moreover, similar warming events occurred earlier in the Ice Age without causing extinction, so why would this one be fatal? Second, the scarcity of archaeological kill sites is misleading. Humans may have used spears or traps that left few traces, and many mammoth carcasses were likely scavenged or processed at locations that have not been preserved due to sea-level rise. In fact, recent discoveries show massive kill sites in Siberia with hundreds of mammoth bones, indicating sustained hunting. Third, the genetic diversity decline actually supports the hunting hypothesis. When human hunters target the largest individuals—often the healthiest with the best genes—they selectively remove genetic variation. This would accelerate diversity loss, even if overall population numbers remained stable initially. Therefore, the evidence points to human overhunting as the primary cause, with climate change playing only a minor role.