The extinction of the woolly mammoth, a species that roamed the Arctic regions until roughly 4,000 years ago, has long been attributed to overhunting by early human populations. This "overkill hypothesis" rests on three main arguments. First, archaeological sites across Siberia and North America contain mammoth bones with cut marks, alongside stone tools and spear points, indicating that humans actively hunted and butchered these animals. Second, the timing of mammoth extinctions correlates with human migration patterns; as humans spread into new territories, mammoth populations declined and vanished shortly thereafter. Third, mammoths had low reproductive rates—females gave birth to a single calf after a long gestation period—making their populations especially vulnerable to even modest levels of hunting pressure. Together, these points suggest that human predation was the primary driver of the mammoth's demise, rather than climate change or disease.
🎧 듣기 강의
The reading's overkill hypothesis is appealing, but it fails to withstand scrutiny. First, the so-called cut marks on mammoth bones are often ambiguous. Many of these marks could be the result of natural processes, such as trampling by other animals or abrasion from ice and sediment, not human butchering. In fact, recent microscopic analysis shows that several purported cut marks lack the characteristic V-shape of stone tools. Second, the timing argument is flawed. Radiocarbon dating reveals that some mammoth populations survived for thousands of years after humans arrived in their regions, while others disappeared before any human presence. This inconsistent pattern contradicts a simple cause-and-effect relationship with human migration. Third, the claim about low reproductive rates is misleading. Modern elephants, which have similar reproductive biology, have coexisted with human hunters for centuries without extinction. Moreover, mammoths likely had adaptive strategies, such as seasonal migration and grouping, that could mitigate hunting losses. Therefore, climate-driven habitat loss—specifically the shrinkage of steppe grasslands—more plausibly explains their decline.
📝 작문 지시 Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific points made in the reading passage.
📊 TOEFL Integrated Writing Rubric
Content Accuracy: Accurately capture the relationship between lecture and reading
Information Completeness: Cover all key counter-arguments from the lecture
Structure & Coherence: Logical organization and progression
Language Use: Grammar, vocabulary, expression accuracy
Scored 0-30 based on holistic scoring (original 0-5, scaled to 30).