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1、 出国留学考试申请|职业求职招聘家园-尚友社区 http:/ 尚友社区 http:/ 标题：标题：动物灭绝动物灭绝 尚友论坛尚友论坛【GMAT 专区专区】 【尚友学堂尚友学堂 GMAT 公开课公开课】 【GMAT 机经专区】机经专区】 【GMAT 资料下载区】资料下载区】 【GMAT 黄历查询黄历查询】 1.1.主题思路主题思路 大型动物的灭绝可能：大型动物的灭绝可能：人类原因或者气候原因 排除气候原因和化石原因 人类原因 2. 2. 段落大意：段落大意： 第一段：科学家分析气候造成大型动物灭绝元一案。第一段：科学家分析气候造成大型动物灭绝元一案。 P 时期大动物灭绝很快，最早在亚非，接着到澳
2、洲和美洲（都有具体年份说明的，比如 15000 年前），好奇怪。为什么呢？学者 A 说是因为人类活动。因为这些时间都对应着相应地区的人类频繁活动。 为了进一步说明：为了进一步说明： 1）灭绝的都是那种又大又笨的，容易被人抓到 2）亚非的大动物灭绝的不如澳美的 drastically，是因为人类是突然到澳美洲的，大动物都来不及反应。 第二段：证明科学家观点气候不是原因；还是是人类造成了物种减少。第二段：证明科学家观点气候不是原因；还是是人类造成了物种减少。 出国留学考试申请|职业求职招聘家园-尚友社区 http:/ 尚友社区 http:/ 顺承上文，继续支持 A（没有问道问题，没记得很多）不过有
3、说道，历史上如果由 CLIMATE 造成的物种灭绝都是更 大范围，而且大物种，小物种一起灭绝的，但这个 P 时段的灭绝只涉及大物种，所以还是认为还是人类干涉而不是气候。 第三段：人类活动造成了动物灭绝第三段：人类活动造成了动物灭绝 但是这个解释又两个 counterargument，(但最后还是被作者反对掉了，说明作者是支持 A 的） 1）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
4、are nonexistent. (这句话有考题，但有点忘了） 2）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（没仔细看了）。 3. 3. 注意点：注意点： 1）化石和气候对大型动物的灭绝的论证具体特点 2）各大洲这种动物存在的不同特点 4. 4. 题目题目 1）问道亚非动物灭绝的为什么比澳美缓慢 2）问 If hunting evidence are small, then the collecting evidence is nonexiste
5、nt.这句话被作者拿来做什么用?我选不能用来作为反驳人类活动造成 m 动物灭绝这个理论的理由 3）问作者对第二个 counterargument(即人类狩猎技术不够好)的反驳暗指下列哪件事? 我选更新世动物的防御能力较现存动物低第二个 counterargument 是说古时候人类狩猎技巧不高明，所以应该 很难将动物的灭绝归因于人类。 但是作者驳斥说， 并不需要高超的狩猎用具 （用于捕捉现在的大型动物， 如大象）就可以捕捉到 m 动物，因为动物的防御能力并不如现在的大象等，所以自然也不需要高超的狩猎工具。 5. 5. 引申引申 【参考文献】Pleistocene megafauna 更新世动物
6、 In broad usage, the Holocene extinction event includes the notable disappearance of large mammals, known as megafauna, by the end of the last glacial period 9,000 to 13,000 years ago. Such disappearances have been considered as either a response to climate change, a result of the proliferation of m
7、odern humans, or both. These extinctions, occurring near the PleistoceneHolocene boundary, are sometimes referred to as the Quaternary extinction event or Ice Age extinction event. However the Holocene extinction event continues through the events of the past several millennia and includes the prese
8、nt time. 出国留学考试申请|职业求职招聘家园-尚友社区 http:/ 尚友社区 http:/ These species appear to have died off as humans expanded out of Africa and Eurasia, the only continents that still retain a diversity of megafauna comparable to what was lost. Three theories have been given for these extinctions: hunting by the spre
9、ading humans, climatic change, and spreading disease. A combination of those explanations is also possible. Human Hunting This hypothesis was proposed 40 years ago by Paul S. Martin。This theory holds Pleistocene humans responsible for the megafaunal extinction. One variant, often referred to as over
10、kill, portrays humans as hunting the megafauna to extinction within a relatively short period of time. Some of the direct evidence for this includes: fossils of megafauna found in conjunction with human remains, embedded arrows and tool cut marks found in megafaunal bones, and cave paintings that de
11、pict such hunting. Biogeographical evidence is also suggestive; the areas of the world where humans evolved currently have more of their Pleistocene megafaunal diversity (the elephants and rhinos of Asia and Africa) compared to other areas such as Australia, the Americas, Madagascar and New Zealand,
12、 areas where early humans were non-existent. Based on this evidence, a picture arises of the megafauna of Asia and Africa evolving with humans, learning to be wary of them, and in other parts of the world the wildlife appearing ecologically naive and easier to hunt. This is particularly true of isla
13、nd fauna, which display a dangerous lack of fear of humans. The most convincing evidence of his theory is that 80% of the North American large mammal species disappeared within 1000 years of the arrival of humans on the Western Hemisphere continents. World wide extinctions seem to follow the migrati
14、on of humans and to be most severe where humans arrived most recently and least severe where humans were originally Africa (see figure at right). This suggests that in Africa, where humans evolved, prey animals and human hunting ability evolved together, so the animals evolved avoidance techniques.
15、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. It a
16、lso suggests that this is independent of climate change.Circumstantially, the close correlation in time between the appearance of humans in an area and extinction there provides weight to this theory. This is perhaps the strongest evidence, as it is almost impossible that it could be coincidental when science has so m
