【正文】 ered both the most and the least stable munities. ○ They are stable because they recover quickly after major disturbances. ○ They are the most resilient munities because they change the least over time. Paragraph 5: Even the kind of stability defined as simple lack of change is not always associated with maximum diversity. At least in temperate zones, maximum diversity is often found in midsuccessional stages, not in the climax munity. Once a redwood forest matures, for example, the kinds of species and the number of individuals growing on the forest floor are reduced. In general, diversity, by itself, does not ensure stability. Mathematical models of ecosystems likewise suggest that diversity does not guarantee ecosystem stability—just the opposite, in fact. A more plicated system is, in general, more likely than a simple system to break down. (A fifteenspeed racing bicycle is more likely to break down than a child’s tricycle.) （推理題，邏輯 推理） 7. Which of the following can be inferred from paragraph 5 about redwood forests? ○ They bee less stable as they mature. ○ They support many species when they reach climax. ○ They are found in temperate zones. ○ They have reduced diversity during midsuccessional stages. THE LONGTERM STABILITY OF ECOSYSTEMS Paragraph 4: The question of ecosystem stability is plicated, however. The first problem is that ecologists do not all agree what “stability” means. Stability can be defined as simply lack of change. In that case, the climax munity would be considered the most stable, since, by definition, it changes the least over time. Alternatively, stability can be defined as the speed with which an ecosystem returns to a particular form following a major disturbance, such as a fire. This kind of stability is also called resilience. In that case, climax munities would be the most fragile and the least stable, since they can require hundreds of years to return to the climax state. （推理題） 6. According to paragraph 4, which of the following is true of climax munities? ○ They are more resilient than pioneer munities. ○ They can be considered both the most and the least stable munities. ○ They are stable because they recover quickly after major disturbances. ○ They are the most resilient munities because they change the least over time. Paragraph 5: Even the kind of stability defined as simple lack of change is not always associated with maximum diversity. At least in temperate zones, maximum diversity is often found in midsuccessional stages, not in the climax munity. Once a redwood forest matures, for example, the kinds of species and the number of individuals growing on the forest floor are reduced. In general, diversity, by itself, does not ensure stability. Mathematical models of ecosystems likewise suggest that diversity does not guarantee ecosystem stability—just the opposite, in fact. A more plicated system is, in general, more likely than a simple system to break down. (A fifteenspeed racing bicycle is more likely to break down than a child’s tricycle.) （推理題，邏輯推理） 7. Which of the following can be inferred from paragraph 5 about redwood forests? ○ They bee less stable as they mature. ○ They support many species when they reach climax. ○ They are found in temperate zones. ○ They have reduced diversity during midsuccessional stages. DEER POPULATIONS OF THE PUGET SOUND Paragraph 2: Nearly any kind of plant of the forest understory can be part of a deer39。 also snow and wind bring down leafy branches of cedar, hemlock, red alder, and other arboreal fodder. 2. It can be inferred from the discussion in paragraph 2 that winter conditions ○ Cause some deer to hibernate ○ Make food unavailable in the highlands for deer ○ Make it easier for deer to locate understory plants ○ Prevent deer from migrating during the winter Paragraph 4： Reduction in numbers of game should have boded ill for their survival in later times. A worsening of the plight of deer was to be expected as settlers encroached on the land, logging, burning, and clearing, eventually replacing a wilderness landscape with roads, cities, towns, and factories. No doubt the numbers of deer declined still further. Recall the fate of the Columbian whitetail