The extinction of the megafauna—large animals such as mammoths, giant sloths, and saber-toothed cats—at the end of the Pleistocene epoch has long puzzled scientists. While many theories exist, the most compelling explanation is overhunting by early humans. First, archaeological sites across North America and Eurasia show clear evidence of human hunting of these animals, including spear points embedded in bones and butchery marks. Second, the timing of extinction closely correlates with human migration patterns. For example, megafauna disappeared from North America shortly after the arrival of Clovis hunters around 13,000 years ago, while in Australia, extinction followed human colonization by thousands of years. Third, megafauna species were particularly vulnerable to hunting pressure due to their slow reproductive rates and large body sizes, which made them easy targets. In contrast, climate change at the end of the Ice Age was a gradual process that had occurred many times before without causing such selective extinctions. Therefore, human predation, not climate, was the primary driver of these prehistoric losses.
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The reading's argument that humans caused megafauna extinction is flawed. First, while some archaeological evidence shows hunting, the number of kill sites is remarkably small. If humans had driven these animals to extinction, we would expect far more widespread evidence of mass hunting, but in many regions, no such sites exist at all. Second, the timing argument is not as clear-cut as the reading suggests. In North America, some megafauna populations survived until much later, overlapping with humans for thousands of years, which undermines the idea of rapid overkill. In other areas, extinctions occurred long after human arrival, indicating that other factors were at work. Third, the reading ignores the role of climate change. Recent studies of ancient DNA and sediment cores show that dramatic warming and vegetation shifts at the end of the Pleistocene reduced the habitats and food sources for large herbivores, leading to cascading effects on predators. Similar climate-driven extinctions occurred during earlier interglacial periods without human involvement. Thus, while hunting may have contributed locally, climate change was the dominant factor in the global megafauna collapse.
📝 Инструкция по письму 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).
