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2.1.2猛兽灭绝 △
作者观点：猛兽灭绝跟人类有关。
第一段:
亚非在60000年灭绝了15%，澳洲在40000年前灭绝了80%。然后就说这是因为亚非等等的动物AND人类一起生活，慢慢人类的进步，比如狩猎工具的进步，然后比较有时间去慢慢适应，然后那些人类较晚的因为过去很少有人而且人类更加发达，然后就大规模灭绝。
第二段：
讲灭绝不会是因为气候引起的，如果是气候原因，A地和B地距离很近，但是动物灭绝时间却不一样。说如果是气候原因那么什么亚非周围的群岛以及澳洲周围的新西兰的大型猛兽没有同时灭绝。
第三段：
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. |
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