Question

Passage A
The debate surrounding the sudden extinction of Pleistocene megafauna—including mammoths, mastodons, and saber-toothed cats—has long centered on the "overkill" hypothesis. Proponents of this view point to a compelling temporal correlation: the abrupt disappearance of these massive mammals closely tracks the global expansion of anatomically modern humans into new continents. As highly efficient apex predators equipped with sophisticated projectile weaponry, human hunters entered ecologically naive environments where megafauna had not co-evolved to recognize them as lethal threats. The sheer volume of fossil evidence showing weapon marks on megafaunal bones, combined with the rapid depletion of large-bodied species shortly after human arrival, underscores the catastrophic impact of human predation. While it is undeniable that the late Pleistocene epoch was marked by significant climatic turbulence, it is crucial to recognize that these environmental shifts were not entirely unprecedented; megafaunal species had successfully survived numerous similar glacial-interglacial cycles in the past. Consequently, climate change alone cannot account for the severity of the late Quaternary losses. However, the rapidly changing climate likely fragmented crucial habitats and reduced the overall carrying capacity of the environment, thereby placing animal populations under considerable ecological stress. This severe climatic destabilization left megafauna highly vulnerable to the sudden introduction of a novel, hyper-efficient predator, ultimately accelerating an extinction process that was driven fundamentally by human hunting pressure.

Passage B
For decades, the human overkill hypothesis dominated paleontological discussions of late Quaternary extinctions, often painting our ancestors as the sole architects of global ecological collapse. However, recent advancements in paleoclimatology and radiocarbon dating have increasingly challenged this human-centric narrative. High-resolution ice core samples and fossilized pollen data reveal that the end of the Pleistocene was characterized by violent, unprecedentedly rapid climatic oscillations. These dramatic temperature fluctuations profoundly reorganized vegetation patterns on a continental scale, effectively eliminating the expansive, nutrient-rich steppe-tundras upon which megafaunal herbivores heavily depended. Without sufficient forage to sustain their massive caloric requirements, large-bodied herbivores suffered catastrophic population declines. The structural collapse of the ecosystem was already in motion due to rising global temperatures and changing precipitation patterns. This trophic collapse subsequently decimated specialized predators. Importantly, the fossil record clearly indicates that many megafaunal populations were already severely bottlenecked and geographically isolated long before evidence of human arrival in those specific regions. Although archaeological sites do occasionally show evidence of human scavenging or opportunistic hunting of these large mammals, characterizing early humans as the primary cause of extinction vastly overestimates their population density and ecological impact. Instead, human hunting likely represented a terminal pressure—a final, localized blow to fragmented populations that were already doomed by irreversible habitat loss and extreme climatic stress.

Regarding the extinction of Pleistocene megafauna, the authors of both passages would most likely agree with which of the following statements? Select all that apply.