The concept of 'de-extinction'—the process of resurrecting extinct species through genetic engineering—has gained traction among scientists. Proponents argue that bringing back species like the woolly mammoth or the passenger pigeon could restore damaged ecosystems, advance scientific knowledge, and correct past human mistakes. However, a more pragmatic view suggests that de-extinction is not only impractical but also ethically and ecologically problematic. First, the technology is prohibitively expensive and inefficient. Current gene-editing tools, such as CRISPR, require intact DNA, but most extinct species' DNA is fragmented and degraded. For example, the woolly mammoth specimens found in permafrost yield only small, damaged sequences, making it nearly impossible to reconstruct a full genome. Even if a hybrid embryo were created, the success rate of implantation and live birth would be extremely low, requiring hundreds of failed attempts. Second, de-extinction diverts critical funding and attention from conserving living species. Conservation budgets are already insufficient to protect endangered habitats and animals. Spending millions on reviving one species would mean fewer resources for preventing extinction of many existing species, which are more likely to survive and contribute to biodiversity. Third, reintroducing extinct species could disrupt current ecosystems. These species evolved in environments that have since changed dramatically due to climate change, human development, and invasive species. For instance, releasing a woolly mammoth into the Arctic tundra might alter vegetation patterns, but it could also outcompete native herbivores or introduce novel diseases, causing unforeseen ecological harm. Given these practical and ecological drawbacks, de-extinction should remain a speculative venture, not a conservation priority.
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🎯 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。
Now listen to a lecture on the same topic. The professor challenges the reading's arguments. First, you claim that de-extinction is too expensive and inefficient, but this ignores the rapid pace of biotechnological advancement. CRISPR and other gene-editing tools are becoming cheaper and more precise every year. The cost of sequencing a genome has dropped from millions to a few thousand dollars in the past two decades. Moreover, scientists have already successfully edited the genomes of elephants to include mammoth traits, such as cold-resistant hair and fat layers. These 'mammoth-like' embryos, though not yet brought to term, demonstrate that technical hurdles are surmountable. The inefficiency you mention is a temporary issue, not a permanent flaw—just as IVF was once experimental but now is routine. Second, you argue that de-extinction diverts funds from existing conservation. However, de-extinction projects often attract novel funding sources, such as private investors and crowdfunding, that would not otherwise go to traditional conservation. For example, the 'Revive and Restore' project has raised millions from tech entrepreneurs who are not typical donors to wildlife causes. This additional money does not compete with but supplements existing budgets. Furthermore, the biotechnological tools developed for de-extinction, like gene banking and genetic rescue, are directly applicable to saving endangered species, thus enhancing conservation rather than undermining it. Third, you worry about ecological disruption, but this assumes we would release resurrected species without careful planning. In reality, de-extinction would follow a rigorous 'soft release' protocol, similar to species reintroduction programs. Scientists would first study the target ecosystem, use computer models to predict impacts, and start with small, controlled populations in fenced reserves. Moreover, the ecological niches of many extinct species, like the passenger pigeon, which once shaped forest structure, are now vacant. Their reintroduction could restore ecosystem functions that have been lost for over a century, benefiting native species. The risk of disruption is manageable and often lower than the risk of continuing to lose today's keystone species.
📝 写作提示 Summarize the points made in the lecture, being sure to explain how they cast doubt on the specific points made in the reading passage.
