Escritura integrada TOEFL

📖 Texto de lectura

The extinction of the woolly mammoth has long been attributed to human hunting, but recent evidence suggests that climate change was the primary driver. First, the timing of mammoth extinction coincides with the end of the last Ice Age, when global temperatures rose rapidly. Paleoclimate data show that warming led to the replacement of open grasslands with dense forests and wetlands, shrinking the mammoth's preferred habitat. Second, genetic studies of ancient mammoth remains reveal a severe population bottleneck beginning around 20,000 years ago, well before humans reached North America. This decline correlates with a period of climatic instability, not with human activity. Third, archaeological evidence indicates that human hunting pressure was relatively low. Sparse kill sites and the absence of specialized hunting tools suggest that early humans did not rely on mammoths as a primary food source. Instead, the animals' low reproductive rates and sensitivity to environmental change made them vulnerable to habitat loss. Therefore, while humans may have delivered a final blow, the extinction was fundamentally a response to natural climatic shifts.

🎧 Conferencia de audio

The reading argues that climate change was the main cause of mammoth extinction, but this view is flawed. First, the timing argument is misleading. While warming did alter habitats, mammoths had survived previous interglacial periods with similar conditions. What was different this time was the arrival of highly efficient human hunters, who used coordinated drives and traps. Second, the genetic bottleneck cited in the reading actually supports human involvement. The population decline began when humans first entered Siberia, and the most rapid decline occurred after humans reached the Americas. Climate data alone cannot explain why mammoths persisted through earlier warm periods but vanished after human contact. Third, the archaeological evidence is incomplete. Many kill sites may have been destroyed by glacial retreat or sea-level rise, and early humans likely used organic tools that decayed. Moreover, even low hunting pressure could be devastating for a slow-reproducing species like the mammoth. Thus, the pattern of extinction aligns more closely with human expansion than with climate trends.