托福综合写作

📖 阅读文章

The extinction of the woolly mammoth has long been attributed to overhunting by early human populations. Proponents of this theory argue that human hunters, equipped with advanced tools and cooperative strategies, systematically drove mammoths to extinction. First, archaeological evidence shows a strong correlation between the arrival of humans in North America and the decline of mammoth populations. Sites such as Clovis, New Mexico, contain mammoth bones with spear points embedded, indicating direct hunting. Second, mammoths had low reproductive rates, making them vulnerable to even modest levels of hunting pressure; a 10% increase in adult mortality could outpace birth rates. Third, other large megafauna, such as saber-toothed cats and giant ground sloths, also vanished shortly after human arrival, suggesting a broad pattern of human-induced extinction across species. Thus, the overhunting hypothesis remains the most parsimonious explanation for the mammoth’s demise.

🎧 听力讲座

The lecture challenges the overhunting theory, offering alternative explanations. First, while human hunting is documented, the scale was likely insufficient. Modern hunter-gatherer societies rarely rely on large game as a staple, and mammoth populations were sparse; even with efficient hunting, the number of kills needed to drive extinction would have been enormous—far beyond what Clovis sites reveal. Second, climate change at the end of the Pleistocene was far more disruptive. Rising temperatures altered vegetation, shrinking the grasslands that mammoths depended on. Pollen records show a rapid shift from open steppe to forest, reducing food availability and fragmenting habitats. Third, the extinction of other megafauna did not coincide perfectly with human arrival; for instance, some species disappeared thousands of years before humans reached certain regions. Additionally, diseases introduced by humans or domesticated animals could have ravaged isolated populations, a factor the reading ignores. Therefore, the lecture argues that a combination of climate and ecological pressures, not human hunting alone, best explains the mammoth’s extinction.