The extinction of the woolly mammoth has long been attributed to overhunting by early humans. However, recent evidence suggests that climate change was the primary driver. First, the warming climate at the end of the Pleistocene reduced the mammoth’s habitat, as the open grasslands they depended on were replaced by forests and tundra. Pollen records from Siberia and Alaska show a dramatic shift in vegetation around 10,000 years ago, coinciding with mammoth decline. Second, mammoth bones found in human campsites are relatively rare, indicating that hunting was not a major factor. For example, at the famous Berelekh site in Siberia, only a small fraction of the thousands of bones show cut marks or other signs of human processing. Third, genetic studies of mammoth populations reveal a severe bottleneck—a sharp reduction in genetic diversity—that occurred well before human populations reached high densities in the Arctic. This bottleneck suggests that climate-induced habitat fragmentation stressed the populations, making them vulnerable to extinction even without human interference. Thus, the evidence strongly points to climate change as the primary cause of the woolly mammoth’s demise.
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The reading’s argument that climate change alone drove the woolly mammoth to extinction is problematic. While vegetation did shift, this was not a sudden event but a gradual process spanning thousands of years, during which mammoths had time to adapt and migrate. In fact, mammoths survived in refugia, such as islands like Wrangel Island, for thousands of years after the mainland climate changed—proving that climate alone was not sufficient to wipe them out. As for the scarcity of cut marks on bones, this is weak evidence: early humans often used mammoth bones for tools or fuel without leaving obvious butchery marks, and many kill sites may have been destroyed by glacial processes or sea-level rise. Moreover, the genetic bottleneck cited in the reading actually occurred around 1.2 million years ago, long before the end of the Pleistocene, and was likely due to natural population cycles or earlier environmental changes, not the final warming. The final extinction event on mainland Eurasia and North America coincides precisely with the expansion of human hunters who had advanced projectile weapons. Indeed, archaeological sites in North America, such as Clovis, show clear evidence of mammoth hunting, including projectile points embedded in bones. Therefore, while climate change may have stressed mammoth populations, human hunting was the decisive factor that pushed them over the edge.
📝 Instrucciones de escritura 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).
