又提出别人的两种观点，作者又一一反驳。counterargument一：根据fossil，P时代人类主要靠collect植物什么的过活，化石没有反映出人类hunting。作者反对，提出一句话：if hunting evidences are "small", then the collecting evidence are nonexistent. (这句话有考题，但有点忘了）；counterargument二：在那个时代人类捕猎水平不够，根本不可能造成那么多物种灭绝，说道要用rifle之类的才能造成，另外还说到，大动物如果被捕猎死的话，死相会有挣扎的痕迹，但是没有。最后作者还是把这个反对了下。
题目：
1. 主旨题：main purpose
答： 好像是一个theory并支持它。
2. 为什么第一个地方比第二个地方灭绝的百分比小？
答：因为那些猛兽有更多时间适应猎人的狩猎技巧。
3. 如果是气候引起的灭绝，会怎么样？
答：亚非周围的群岛以及澳洲周围的新西兰的大型猛兽同时灭绝
Martin (1968, 1984, 1990) has summarized the evidence for the world-wide
extinction of late Pleistocene megafauna.
In Africa and Asia 15–20 percent of the genera disappeared 80–60,000 years B.P.; in Australia 94 percent were lost from 40–15,000 years B.P.; North and South America experienced a 70–80 percent loss in the last 15,000 years, with an abrupt North American loss of mammoth, mastodon, ground sloth, and such dependent predators and scavengers as the saber toothed cat and (in much of its range) the condor 11,000 years ago. The horse and two subspecies of bison were gone by 9–8,000 years ago. This worldwide pattern correlates suspiciously with the chronology of human colonization leading to Paul Martin's hypothesis that extinction was directly or indirectly due to “overkill” by exceptionally competent hunter cultures. This model explains the light extinctions in Africa and Asia where modern humankind “grew up,” allowing gradual adaptation to humankind's accumulating proficiency as a superpredator; it explains the abrupt massive losses in Australia and the Americas—the only habitable continents that were colonized suddenly by advanced stone-aged humans. But the control cases for Martin's “experiment” are the large oceanic islands such as Madagascar and New Zealand; both were colonized within the last 1000 years, and both suffered a wave of extinctions at this time.
One wonders, if extinction was due to climatic change, why Madagascar extinctions were not coincident with those of Africa 220 miles off its coast, and those of Australia were not coincident with New Zealand extinctions; and why European and Ukrainian mammoths became extinct 13,000 years B.P. while in North America they survived another 2000 years. Previous great extinction waves had affected plants and small animals as well as large animals, but the late Pleistocene extinctions are concentrated on the large gregarious herding, or slow moving, animals—the ideal prey of human hunters. Such large genera are also the animals that are slower growing, have longer gestation (怀孕期) periods, require longer periods of maternal care, and live longer. Consequently they were more vulnerable to hunting pressure because reductions in biomass require more time to recover. The theory is bold—some say fanciful.
A counter argument is that there is little direct evidence of hunting; that Paleolithic peoples “probably” relied on plants. But if the fossil record of hunting is “small,” the fossil evidence of gathering (植物) is virtually non-existent.
A second counter argument is that there would not have been an incentive to overproduce in excess of immediate needs; that this occurs only in modern exchange economies. But this argument fails to recognize that in the absence of private property rights, there is no intertemporal （跨期的） incentive to avoid the kind of waste associated with large kills. What controls the slaughter of domestic cattle is the comparative value of dressed versus live beef. Since no one owned the mammoth, their harvest value (net of hunting cost) contrasted sharply with their zero live procreation （生产,生殖） value to the individual hunter.A third argument finds it incomprehensible that mere bands of men could have wiped out the great mammoth and two subspecies of bison. It takes a particularly skilled modern rifleman to stop a charging African elephant in time to prevent injury, and extant bison react quickly and violently when they sense danger.
Such observations may simply tell us that these particular subspecies have survived because they were selected for their successful defensive characteristics. We know nothing of the behavioral properties of extinct species which may have been far more approachable than their surviving relatives. While the African and Indian elephants are both members of the same genus, their fossil similarities fail to inform us that the Indian elephant is docile and easily trained for circus display, while the African elephant is not. No one has successfully domesticated the African zebra; in contrast, the Tarpan horse has been domesticated since ancient times (5000–2500 B.P.). Equus includes horses, asses and zebras—all behaviorally distinct animals.
In Africa, where humans evolved, prey animals and human hunting ability evolved together, so the animals evolved avoidance techniques. As humans migrated throughout the world and became more and more proficient at hunting, they encountered animals that had evolved without the presence of humans. Lacking the fear of humans that African animals had developed, animals outside of Africa were easy prey for human hunting techniques.作者: selma 时间: 2010-11-17 16:17
2.1.3 native species declines
第一段：
native species declines, 有人认为是因为nonnative species invade了，也有人认为是本地的一些环境改变，像污染之类的才是造成这个原因。然后给了个例子说某某湖的某鱼在另外一种鱼来invade之前数量已经decline了，原因是人们过度捕捞还有环境污染之类。
第二段：
说2个研究的人说，如果是nonnative species造成的，那如果把nonnative species拿掉的话，native species 就不会减少了(drive model)； 如果是本地环境变化造成的，那就算拿掉nonnative species 的话也会减少native species (passenger model)。 然后就分析了一个实验. 在本地的草中间引入两种外来的草。实验的结果是并没有发现本地的那种草被外来物种影响数量下降。
题目：
1. 问第一段的例子作用是什么
答： nonnative species invade不是造成native species下降的原因
2. 有题目问说这2试验的结果会justify以下哪个？
答：native plant的兴旺will not be impeded by外来species
3. 主旨题
答：Nonnative的入侵不是造成native species declines的原因，而是native species declines之后的结果作者: selma 时间: 2010-11-17 16:17
2.1.4 lepidoptera★更改答案（10/24日晚11点修改）
A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has proved surprisingly elusive despite considerable research. The common approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, has been unproductive in the case of lepidoptera. Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar populations have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may at least be regulated by an agent more intimately connected with the insect than are predatory birds or parasites.
Recent work suggests that this agent may be a virus. For many years, viral disease had been reported in declining populations of caterpillars, but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it. The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment. Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which, if protected from direct sun light, they may remain virulent for many years in the environment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, the crystals dissolve, releasing the virus to infect the insect’s cells. Late in the course of the infection, millions of new virus particles are formed and enclosed in polyhedron crystals. These crystals reenter the environment after the insect dies and decomposes, thus becoming available to infect other caterpillars.
One of the attractions of this hypothesis is its broad applicability. Remarkably, despite significant differences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight and eleven years. Nuclear polyhedrosis viral infection is one factor these disparate species share.
T-9-20:GWD-13-34:
Which of the following, if true, would most weaken the author’s conclusion in lines 25-30?
A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
E. Viral disease is typically observed in a large proportion of the lepidoptera population.
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T-9-21:GWD-13-35:
It can be inferred from the passage that the mortality caused by agents such as predatory birds or parasites was measured in an attempt to
A. develop an explanation for the existence of lepidoptera population cycles
B. identify behavioral factors in lepidoptera that affect survival rates
C. identify possible methods for controlling lepidoptera population growth
D. provide evidence that lepidoptera populations are self-regulating
E. determine the life stages of lepidoptera at which mortality rates are highest
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T-9-22:GWD-13-36:
The primary purpose of the passage is to
A. describe the development of new techniques that may help to determine the driving force behind population cycles in Lepidoptera
B. present evidence that refutes a particular theory about the driving force behind population cycles in Lepidoptera
C. present a hypothesis about the driving force behind population cycles in Lepidoptera
D. describe the fluctuating patterns of population cycles in Lepidoptera
E. question the idea that a single driving force is behind population cycles in Lepidoptera
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T-9-23:GWD-13-37:
According to the passage, before the discovery of new techniques for detecting viral DNA, population ecologists believed that viral diseases
A. were not widely prevalent among insect populations generally
B. affected only the caterpillar life stage of lepidoptera
C. were the driving force behind lepidoptera population cycles
D. attacked already declining caterpillar populations
E. infected birds and parasites that prey on various species of lepidoptera作者: selma 时间: 2010-11-17 16:17
1. 主旨
答：选阐述科学发现那个.（identify an explanation to some findings）
2. 有个题关于免疫力的貌似问：下列哪个选项能weaken专家关于免疫力的观点?
答：
Blaustein and his colleagues (1994) have looked at levels of photolyase, an enzyme that repairs UV damage to DNA by excising and replacing damaged thymidine residues), in amphibian eggs and oocytes. Levels of photolyase varied 80-fold among the tested species and correlates with the site of egg laying. Those eggs more exposed to the sun had higher levels of photolyase. These levels also correlated with whether or not the species was suffering population decline. The highest photolyase levels were in those species (such as the Pacific tree frog, Hyla regilla) whose populations were not seen to be in decline. The lowest levels were seen in those species (such as the Western toad, Bufo boreas, and the Cascades frog, Rana cascadae) whose populations had declined dramatically.
Blaustein and his colleagues tested whether or not UV-B could be a factor in lowering the hatching rate of amphibian eggs. At two field sites, they divided the eggs of each of three amphibian species into three groups (Figure 3.6). The first group developed without any sun filter. The second group developed under a filter that allowed UV-B to pass through. The third group developed under a filter that blocked UV-B from reaching the eggs. For Hyla regilla, the filters had no effect, and hatching success was excellent under all three conditions. For Rana cascadea and Bufo boreas, however, the UV-B blocking filter raised the percentage of eggs hatched from about 60% to close to 80%.作者: selma 时间: 2010-11-17 16:17
WHY BEETLES ARE GOOD ENVIRONMENTAL PROXIES
Beetle fossils are commonly preserved as disarticulated (脱节的) skeletal fragments (fig. 2) in organic sediments such as clays, peats （泥炭）, sands and silts (Porch & Elias, 2000). Beetles preserve well due to their robust nature and structural details can often be distinguished allowing them to be identified to species level. In most cases identification has revealed fossilised beetles to be extant species indicating a great degree of morphological（形态学的） constancy throughout the Quaternary（地质学第四季）. This constancy includes that of key characters, such as genitalia（生殖器）, used in the identification of species. As morphology does not appear to have evolved it is generally assumed that the physiological（生理学的） requirements of beetles have also remained constant.
Evidence to support this assumption exists in the fact that the composition of beetle communities has, like morphology, remained relatively constant throughout the Quaternary and that host-specific phytophagus species can be sometimes be found in association with macrofossils of their host plant. Due to this observed constancy and the ectothermic （变温的）nature of beetles – and thus their reliance on environmental conditions – beetle fossils can therefore make excellent indicators of paleoenvironment (古生物环境的).
HISTORY OF FOSSIL BEETLE PALEOENVIRONMENTAL RECONSTRUCTIONS
The first climate and environmental reconstruction using beetle fossils was published by Coope. Since this time beetle fossils have been increasingly used for reconstructing past environments and the associated climate. Initially this work was restricted to the United Kingdom but soon spread to continental Europe and North America. Since then the number of studies utilizing beetle remains to reconstruct the paleoenvironment has continued to increase, primarily in the Northern Hemisphere, but also in South America and recently there has been discussion of the potential for this research in Australia. In 2002 the first New Zealand study using beetle fossils to reconstruct paleoclimate and paleoenvironment was completed proving that this technique is usable in New Zealand and laying the groundwork for this study.
While the use of beetle fossils for paleoclimatic and paleoenvironmental reconstruction has increased over the last four decades it is still little used when compared to other biological proxies (代替物，指标), and in New Zealand palaeoenvironmental analysis is dominated by palynology (孢粉学) even though the flora of New Zealand is temperature-tolerant making quantification of palaeo climate difficult. Other methods of environmental and climatic reconstruction used in New Zealand are tree rings, phytoliths, aerosolic quartz influx, glacial equilibrium-line estimates, speleothems and diatoms
ADVANTAGES OF FOSSIL BEETLES OVER OTHER BIOLOGICAL PROXIES
Fossil beetle analysis has a number of advantages over other biological proxies such as pollen. Beetles are the most diverse group of organisms filling a large range of ecological roles and habitats from deserts to rainforests to the littoral（海滨的） zone. Beetles, and insects in general, respond rapidly to environmental change by dispersal（分散）, rather than undergoing speciation (物种形成), and fossils are generally identifiable to species level in contrast to New Zealand palynological studies where some genera (类,属) contain species with different ecological requirements, but with indistinguishable pollen. Predatory and scavenging beetles are able to take advantage of recently modified areas (along with pioneer plant species) before the trees and shrubs with similar climatic requirements. Trees and shrubs can therefore lag behind the actual period of climatic change and the resultant spread of beetles. This ability to rapidly respond to climatic change has also revealed short-term climate fluctuations that are not observed in the pollen record. Beetles fossils also avoid the problem of contamination of the local pollen rain (and hence local climate signal) by long-distance wind dispersed pollen.
Until the development of the Mutual Climatic Range (MCR) by Atkinson et. al. (1987) studies using beetle fossils were, like palynology, predominantly qualitative in nature. MCR is a method of quantifying paleoclimate and has further increased the usefulness of beetle fossils in reconstructing the past climate of the Quaternary. This quantitative method has enabled studies of beetle fossils to be compared to, or combined with, other proxy(有代表性的) data to provide a more complete paleo climatic and paleo environmental reconstruction.
MCR uses the modern distribution of a species found within a fossil beetle assemblage to construct a climate envelope for that species. This is based on the observation that the contemporary distribution of a beetle species is seen to measure its climatic tolerances. Only predators and scavengers are used to calculate MCR as the distribution of some herbivorous species may be limited by the range of a host plant rather than by direct climatic influences. The climate envelopes of all applicable species in the assemblage are overlapped to find the mutual intersection of the climatic ranges. This provides a quantitative measure of the paleoclimate at the time of the assemblage deposition. While providing a quantitative measure of temperature MCR has been found to underestimate maximum temperatures (TMAX) and overestimate minimum temperatures (TMIN) in extremely cold environments. TMIN can also be underestimated in areas with milder winters. However these errors can be corrected for using regression equations. Currently these equations have been calibrated for Europe and North American sites. The recent work by Marra(2002) has also formulated a method of establishing quantitative measures of paleoclimate for the smaller datasets normally extracted from New Zealand sites.
Herbivorous beetle species, while excluded from MCR analysis due to their potential relationship to host-plants, are extremely useful in paleoenvironmental reconstruction. Some phytophagus beetle species, such as some scolytids (bark beetles), are restricted in their distribution to certain species of trees. When discovered in a fossil assemblage these beetle species therefore indicate that the required host-plant was present at the study site at the time of deposition. The application of phytophagus beetle fossils for this purpose is possible in a New Zealand context as previously shown by Marra.作者: selma 时间: 2010-11-17 16:19
