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 known as the Bølling-Allerød interstadial (around 14,000 years ago), when temperatures rose rapidly and vegetation shifted from productive grasslands to less nutritious forests and tundra. This habitat loss would have reduced the carrying capacity for mammoths, leading to population crashes even without human pressure. Second, genetic studies of ancient mammoth remains show a significant loss of genetic diversity well before the arrival of large human populations in their main habitats, such as Wrangel Island. This bottleneck indicates that environmental stress, not hunting, was already causing population decline. Third, archaeological evidence reveals that early human hunters primarily targeted smaller, more manageable prey like reindeer and horses, and that mammoth bones found at kill sites are often scavenged rather than hunted. Thus, the pattern of extinction aligns more with ecological change than with human predation.

🎧 Listening Lecture

The reading’s argument that climate change alone drove mammoth extinction is flawed. While it is true that warming altered habitats, similar climatic shifts had occurred multiple times in the previous 100,000 years, yet mammoths survived those changes. This suggests that climate alone was not sufficient to cause extinction. Regarding the genetic diversity claim, the loss of diversity mentioned in the reading actually reflects a population that was already in decline, but it does not identify the cause. In fact, human hunting can also lead to population bottlenecks, especially when hunters selectively target large, mature individuals—exactly what we see in mammoth remains. Moreover, the archaeological evidence is misinterpreted. Recent finds at sites like Clovis, New Mexico, show mammoth bones with embedded projectile points and cut marks consistent with hunting, not scavenging. Additionally, the claim that hunters preferred smaller prey is based on limited site data; in many regions, mammoth bones dominate the faunal assemblages. Finally, the timing argument is weak: human populations expanded into mammoth habitats precisely during the Bølling-Allerød, so both factors overlapped. Given that the mammoth had survived past warm periods but not the combination of warming and new, efficient predators, human hunting likely played a decisive role.