Интегрированное письмо TOEFL

📖 Текст для чтения

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 population declines correlates closely with the rapid warming at the end of the last Ice Age, around 10,000 years ago. As temperatures rose, the vast steppe grasslands that mammoths depended on were replaced by dense forests and wetlands, reducing their primary food source. Second, genetic studies of mammoth remains show a sharp drop in genetic diversity just before extinction, which is typically a sign of habitat fragmentation rather than sudden hunting pressure. If humans had caused a rapid kill-off, we would expect a more abrupt loss of individuals without the prolonged period of low diversity. Third, archaeological evidence indicates that human hunting of mammoths was relatively rare. Most human settlements from that era contain bones of smaller game like deer and rabbits, not mammoths. Moreover, human populations in Siberia and North America were too sparse to have hunted mammoths to extinction over such a vast range. Therefore, while humans may have delivered the final blow, the primary cause was environmental change that shrank and degraded mammoth habitats.

🎧 Лекция

The reading’s argument that climate change was the main cause of mammoth extinction is not convincing. First, while climate warming did reduce some grassland, mammoths had survived previous interglacial warm periods, such as the Eemian, without going extinct. What was different in the late Pleistocene was the arrival of highly skilled human hunters with advanced weapons like spears and projectiles. Second, the low genetic diversity observed in late mammoth populations actually supports human overhunting: when a species is driven into small, isolated refuges by hunters, genetic diversity drops due to inbreeding, just as seen in modern endangered species that are overhunted. Third, the archaeological record is biased because mammoth bones are large and may have been transported or processed differently, while smaller animal bones are more likely to be preserved at camp sites. In fact, several kill sites with mammoth remains and butchering tools have been found, and the number of such sites may be underestimated due to rising sea levels that flooded coastal hunting grounds. Thus, human hunting, not climate, played the decisive role.