The concept of 'de-extinction'—bringing extinct species back to life through genetic engineering—has gained traction among scientists. Proponents argue that it could restore lost biodiversity and even combat climate change. Three main benefits are often cited. First, resurrecting keystone species like the woolly mammoth could help restore Arctic grasslands, which would reflect more sunlight and slow permafrost thawing, thereby reducing greenhouse gas emissions. Second, de-extinction offers a scientific safety net: if a modern species goes extinct, we could revive it using preserved DNA, thus preventing irreversible loss of genetic diversity. Third, the process would drive technological innovation in gene editing, benefiting medicine and conservation. For example, techniques developed for de-extinction could improve gene therapies for genetic diseases or help save endangered species with low genetic diversity. These arguments suggest that de-extinction is a practical and ethical tool for environmental management.
🎧 听力讲座
🎯 模拟考试环境：先点「播放讲座」听完内容，再作答。听力原文默认隐藏。
The lecture challenges the reading's optimistic view of de-extinction, arguing that its purported benefits are exaggerated and often impractical. First, the claim about woolly mammoths restoring Arctic grasslands is flawed. The reading assumes that mammoths could recreate the Pleistocene ecosystem, but modern Arctic conditions—such as higher temperatures, altered soil chemistry, and invasive species—are fundamentally different. Even if mammoths were introduced, they might not survive, let alone restore grasslands, and the carbon feedback effects are highly uncertain. Second, the idea of a 'safety net' is misleading. DNA degrades over time, and for species extinct for centuries, the recovered DNA is often fragmented, making it impossible to reconstruct a full genome. Even for recently extinct species like the passenger pigeon, the lack of living relatives to serve as surrogates complicates implantation. Third, the technological spin-off argument ignores the massive costs and opportunity costs. Funding de-extinction research would divert resources from proven conservation efforts, which protect existing habitats and species. Moreover, gene-editing tools like CRISPR are already advanced; focusing on de-extinction would not necessarily yield faster medical breakthroughs than direct research on human diseases. Thus, the lecture concludes that de-extinction is a costly distraction, not a solution.
📝 คำแนะนำการเขียน 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).
