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 coincides with the rapid warming at the end of the last Ice Age, around 10,000 years ago. As temperatures rose, the open grasslands that mammoths depended on were replaced by dense forests and wetlands, reducing their food supply and habitat. Second, genetic studies on preserved mammoth remains show a significant loss of genetic diversity before their extinction, indicating small, isolated populations that were vulnerable to environmental stress rather than to hunting pressure. Finally, archaeological records reveal that human hunting of mammoths was relatively rare; most kill sites contain only a few bones, and the human population in the Arctic was sparse at the time. Therefore, the extinction is better explained by climate-induced habitat loss than by human overhunting.
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The reading presents a neat theory, but it overlooks critical evidence. First, while climate change did alter habitats, mammoths survived similar warming periods for millions of years. What changed 10,000 years ago was the arrival of highly skilled human hunters with advanced weapons. In fact, the spread of humans across Eurasia and North America correlates precisely with the timing of mammoth extinctions on each continent. Second, the genetic diversity loss mentioned actually supports the overhunting theory: as humans killed mammoths in large numbers, populations were fragmented and reduced, leading to inbreeding and loss of diversity. This is a consequence of hunting, not a cause of extinction. Third, the claim that hunting was rare is misleading. Archeologists have found mammoth kill sites with dozens of individuals, and butchery marks are common. Moreover, even low-level hunting by a growing human population could have pushed already stressed populations over the edge, especially since mammoths had slow reproductive rates. Thus, the reading’s arguments fail to undermine the strong link between human hunting and mammoth extinction.
📝 写作提示 Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific points made in the reading passage.
