Escritura integrada TOEFL

📖 Texto de lectura

The extinction of the woolly mammoth has long been attributed to human overhunting. However, a closer examination of the fossil record and environmental data suggests that climate change was the primary driver. First, the timing of mammoth extinctions correlates more strongly with periods of rapid climate warming than with human expansion. For instance, populations on Wrangel Island survived until 4,000 years ago, long after humans arrived, but disappeared shortly after a dramatic shift in vegetation. Second, mammoths were highly specialized grazers, dependent on vast expanses of steppe-tundra. As the climate warmed, this habitat was replaced by forest and peatland, shrinking their food supply. Isotopic analyses of mammoth bones from the late Pleistocene show a marked decline in nutritional quality, indicating starvation rather than hunting pressure. Third, human hunting was not intensive enough to drive such a widespread species to extinction. Archaeological sites from the era contain few mammoth remains, and early human populations were sparse, with weapons that were often ineffective against such large prey. Therefore, the evidence strongly supports climate-induced habitat loss as the main cause of the mammoth’s demise.

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The reading’s argument is flawed. First, while Wrangel Island mammoths did survive late, their extinction at 4,000 years ago actually coincides with the arrival of humans on the island, not just climate shifts. Paleobotanical data show that the vegetation change was gradual, not abrupt, and mammoths had adapted to mixed diets. Second, the claim about habitat loss is overstated. Mammoths were not exclusively steppe grazers; dental microwear studies reveal they consumed a variety of plants, including sedges and shrubs, which were abundant in warmer periods. Moreover, isotopic evidence of starvation can be explained by other factors, such as disease or volcanic ash poisoning, not solely food shortage. Third, the archaeological record is biased. Many coastal sites where humans hunted are now submerged, so we lack evidence of hunting. Additionally, early humans used sophisticated techniques like drives and pitfalls, which would not leave many skeletal remains. In fact, spear points and butchery marks on mammoth bones at several sites prove that hunting occurred. Thus, the reading ignores the synergistic effect of climate and hunting, but human predation was likely the decisive factor that pushed already stressed populations over the edge.