托福听力背景知识：重塑更新世

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　　Introduction：

　　Pleistocene rewilding

　　更新世绝大多数动、植物属种与 2012 年的物种相似。显著特征为气候变冷、有冰期与间冰期的明显交替。人类也在这一时期出现。更新世的植物开始同现代的植物相似,被子植物特别是落叶的种类在温和的和较冷的区域中迅速繁殖。那时,猛犸、骆驼、马、巨型河狸、狼和短面熊等适应寒冷气候的动物,在整个冰期都生活在亚洲、欧洲和美洲大陆。更新世晚期,距今约 2 万年前,现代人类经白令海峡进入美洲。

　　Background information：

　　Pleistocene rewilding is the advocacy ofthe reintroduction of descendants of Pleistocene megafauna, or their closeecological equivalents. An extension of the conservation practice of rewilding,which involves reintroducing species to areas where they became extinct inrecent history (hundreds of years ago or less).

　　Toward the end of the Pleistocene era(roughly 13,000 to 10,000 years ago), nearly all megafauna of South, Central,North America and Europe dwindled toward extinction. With the loss of largeherbivores and predator species, niches important for ecosystem functioningwere left unoccupied. In the words of the biologist Tim Flannery, "eversince the extinction of the megafauna 13,000 years ago, the continent has had aseriously unbalanced fauna". This means, for example, that the managers ofnational parks in North America have to resort to culling to keep thepopulation of ungulates under control.

　　Paul S. Martin (originator of thePleistocene overkill hypothesis) states that present ecological communities inNorth America do not function appropriately in the absence of megafauna,because much of the native flora and fauna evolved under the influence of largemammals.

　　Knowledge points：

　　1. 重塑更新世是指将更新世的巨型动物或者在生态上和他们相等地位的动物再次引入。具体的活动包括在物种灭绝地区重新引入物种。

　　2. 在更新世的末期,几乎南美,北美和欧洲所有的巨型动物都逐步走向灭绝。随着大型食草动物和食肉动物的灭绝,生态功能的一些重要机制空闲。

　　Vocabulary prediction：

　　Vertebrate 脊椎动物

　　Fauna 动物群

　　Cheetah 非洲猎豹

　　Conceivable 可想到的

　　Test Point – TPO22L3

　　So here’s the biologists’idea. Take aselect group of animals, megafauna from places like Africa and Asia, andintroduce them into other ecosystems similar to their current homes, beginningin the United States. They call their plan Pleistocene rewilding.

　　Now, the advocates of Pleistocene rewildingcite two main goals. One is to help prevent the extinction of some endangeredmegafauna by providing new refuges, new habitats for them. The other is torestore some of the evolutionary and ecological potential that has been lost inNorth America. What do I mean by restore evolutionary potential? Well as youknow the evolution of any species is largely influenced by its interactionswith other species. So during the Pleistocene epoch... let’s take the now extinctAmerican cheetah, for instance. We believe it played a pivotal role in theevolution of the pronghorn antelope, the antelope’s amazing speed, to be exact,because natural selection would favor those antelope that could outrun acheetah. When the American cheetahs disappeared, their influence on theevolution of pronghorn and presumably on other prey animals stopped. So it isconceivable that the pronghorn antelope would have continued to evolve, getfaster maybe, if the cheetahs were still around. That’s what’s meant byevolutionary potential. Importing African cheetahs to the western United Statescould, in theory, put the pronghorn back onto its ...uh, natural evolutionarytrajectory according to these biologists.

　　Knowledge points

　　1.在非洲亚洲选一组动物,把它们引入到和它们本身生活环境类似的生态系统,比如到美国。这个计划叫做重塑更新世。

　　2.科学家给重塑更新世这项计划制定了两个目标:一是帮助阻止大型动物的灭绝,二是修复在北美丢失的生态趋势。

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