Viết tích hợp TOEFL

📖 Đoạn văn

The concept of 'de-extinction'—the process of bringing back extinct species through advanced genetic technologies—has gained significant attention in recent years. Proponents argue that de-extinction is a scientifically feasible and ethically commendable goal. First, advances in genetic engineering, particularly CRISPR technology, have made it possible to reconstruct the genomes of extinct species such as the woolly mammoth or the passenger pigeon. By inserting preserved DNA fragments into the genomes of closely related living species, scientists can create viable embryos, as demonstrated in preliminary experiments with the mammoth-elephant hybrid. Second, reintroducing these resurrected species into their former habitats could restore ecological balance. For example, woolly mammoths might help maintain Arctic grasslands by trampling snow and enabling grass growth, which would combat permafrost thaw and reduce carbon emissions. Third, de-extinction could provide valuable insights into evolutionary biology and genetics, allowing researchers to study how species adapt to environmental changes over time. Furthermore, the ethical argument that humans have a moral obligation to undo the harm they caused through extinction is compelling. Given these scientific, ecological, and ethical benefits, de-extinction should be pursued as a priority in conservation biology.

🎧 Bài giảng

The lecture challenges the optimistic view presented in the reading, arguing that de-extinction is neither scientifically practical nor ecologically beneficial. First, the genetic engineering claims are overstated. In reality, ancient DNA is often highly degraded, and complete genomes of extinct species are rarely, if ever, recovered. For instance, the woolly mammoth DNA fragments are fragmented, and researchers must rely on the genome of the Asian elephant, leading to a hybrid organism that is not a true mammoth. Moreover, even if viable embryos are produced, the survival rate is extremely low, and the process is prohibitively expensive, diverting funds from conserving living endangered species. Second, the ecological restoration argument is flawed. The ecosystems where these species once thrived have changed dramatically; climate conditions, plant communities, and predator-prey relationships are different today. Reintroducing a species like the mammoth into the Arctic tundra could disrupt current ecosystems, as they may compete with existing herbivores or fail to establish due to lack of suitable habitat. Third, the scientific and ethical justification ignores the suffering of individual animals. The cloning process involves high rates of miscarriage and health problems in surrogate mothers, raising serious animal welfare concerns. Additionally, focusing on de-extinction detracts from the urgent need to protect existing biodiversity, which is more cost-effective and immediately beneficial. Therefore, the lecture concludes that de-extinction is an unrealistic and misguided endeavor.