TPO 21
How might this result of genetic modification used to change genes and its attributes be perceived? It was noted promising a chunk of benefits in the reading. The sheer passage of merit to promote persistence of the natural unmodified trees does not necessarily account for it. Another seemingly plausible postulation--- that genetically modified tree could be more productive and hence more lucrative--- also is unpromising. Nor does the hypothesis that genetic modification would satisfy the desire of replacement of overexploited wild tree depict the probable subsequence.
Three other predictions offered by the lecturer, which attached on numerous grounds, seem more convincing.
One involves inherent flaws of genetic modification. Since modified genes aimed at one detrimental condition, an unexpected threat could destroy whole unified population. While wild trees are genetically various, by which ensure the survival of the species. That is, if partially jeopardized some other parts of the population would possibly have resistance developed.
A second foreground concerns the surcharge of transgenic seeds. Contrary to the reading, the professor implies that every single batch of genetically modified seed would be far more costly than the original seed and expenses tallying on every single time planting new trees.
A third prediction for
genetically modified trees pertains to the extra damage of natural trees rather than protecting them. Particularly, the modified species competed with the original ones for resources--- light, water, space--- violently, and consequently overwhelmed wild trees population.作者: 劫財劫色小白兔 时间: 2011-6-18 00:54:53
TPO 17
To be honest, as the professor mentioned, the reading's prediction of the reduction in bird population is not so far off the mark; yet it neglected to take into account indispensable new forces developing that in a sense, would not take yes for answer.
The author denotes as birds' habitats occupied by human beings, the number of birds would subsequently dwindle. But this statement hardly scratches the surface. The speaker, on the other hand, interprets while human activities destroying the natural habitats, they virtually craft new ones. Some species may be jeopardized, whereas others may thrive in the urban areas.
That future is not captured by description in the reading passage of agricultural expansion, nevertheless it arises elsewhere and it is inferred by the lecturer that the situation would be relieved with increasing productivity.
The listening retorts premise suggested in the reading concerning the toxic pesticides tainted the food chain of birds. Through the listening, the speaker renders the resolution that is originating less hazardous pesticides and pest resistant crops.