The extinction of the woolly mammoth has long been attributed to human overhunting. However, recent evidence suggests that climate change was the primary driver. First, the warming period at the end of the Pleistocene drastically reduced the mammoth’s grassland habitat. As forests and tundra expanded, the open steppe where mammoths thrived shrank, leading to population fragmentation and decline. Second, climate-driven changes in vegetation reduced the nutritional quality of available plants. Fossilized dung and plant remains show that late-surviving mammoth populations subsisted on woody plants and mosses, which are less digestible and lower in protein than the grasses they preferred. This dietary stress would have lowered fertility and increased calf mortality. Third, the timing of mammoth extinctions correlates more closely with climate events than with human arrival. On islands like Wrangel and St. Paul, mammoths survived for thousands of years after humans arrived, but disappeared soon after abrupt climate shifts altered their environments. Therefore, while hunting may have contributed locally, the overarching cause of the woolly mammoth’s extinction was climate-driven habitat and dietary change.
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The reading’s argument that climate change caused woolly mammoth extinction is not convincing. First, habitat reduction alone cannot explain extinction because mammoths were highly adaptable. Fossil evidence shows they could survive in varied environments, including forested and tundra regions, and they migrated over vast distances. The loss of open grassland would not have been fatal, as other large herbivores like bison and horses also adapted to changing habitats. Second, the claim about dietary stress is weak. Studies of mammoth tooth wear and isotopic analyses reveal that late populations consumed a mix of grasses, sedges, and even some woody plants, but their overall diet remained sufficiently nutritious. Moreover, modern elephants, close relatives, can thrive on lower-quality forage, suggesting mammoths had similar physiological resilience. Third, the timing argument actually supports human hunting. On Wrangel Island, mammoths survived until about 4,000 years ago, but archaeological evidence indicates humans arrived there only a few centuries before their final disappearance. On St. Paul Island, mammoths vanished around 5,600 years ago, coinciding with the arrival of sea hunters. In contrast, climate shifts on these islands occurred over millennia, providing ample time for adaptation. Thus, the sudden extinction after human appearance points to overhunting, not gradual climate change.
📝 Hướng dẫn viết 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).
