Escritura integrada TOEFL

📖 Texto de lectura

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 extinction correlates more closely with climatic shifts than with human migration patterns. Radiocarbon dating shows that mammoth populations declined sharply during the Last Glacial Maximum (about 20,000 years ago), a period of extreme cold and aridity, well before humans reached major mammoth habitats in Siberia and North America. Second, genetic studies of ancient mammoth remains reveal a loss of genetic diversity just before extinction, indicating small, isolated populations that were vulnerable to environmental stress, not to hunting pressure. Finally, the geographic range of mammoths contracted to Arctic islands, such as Wrangel Island, where humans were absent until much later, yet mammoths still became extinct around 4,000 years ago. These islands experienced significant vegetation changes due to warming, reducing their food supply. Thus, climate-induced habitat loss and food scarcity, not human hunting, were the decisive factors in mammoth extinction.

🎧 Conferencia de audio

The reading's argument that climate change alone drove mammoth extinction is flawed. While climate shifts did occur, human hunting played a crucial role, especially in the final extinction events. First, the claim that mammoth decline began before human arrival ignores evidence that early humans, such as the Clovis culture, used sophisticated hunting techniques and may have caused rapid local extinctions even with small populations. In North America, for example, mammoth remains are found at kill sites with Clovis spear points, and the timing of their disappearance coincides with human expansion, not just with climate change. Second, the genetic diversity loss cited in the reading can be explained by overhunting: as humans reduced mammoth populations, survivors became isolated and inbred, a consequence of hunting, not a cause independent of it. Finally, the Wrangel Island case actually supports human involvement. Although humans were late to arrive, they did reach the island around 3,700 years ago, and mammoth extinction occurred shortly thereafter. Moreover, climate warming on the island was gradual, but the final extinction was abrupt, which is more consistent with a sudden human impact, such as hunting or habitat disturbance, than with slow climate change.