GRE阅读练习：生物学家探究人手进化之谜.docxVIP

Word文档下载后（可任意编辑） 第 第 PAGE 1 页 共 NUMPAGES 1 页 GRE阅读练习：生物学家探究人手进化之谜 GRE阅读训练：GRE阅读练习：生物学家探究人手进化之谜 GRE考试精品课程指导  THE appendage at the end of a human beings arm is a strange organ.  与人类手臂相连的手掌是一个奇特的部位，也是人类唯 一因不同用途而拥有不同名称的部位。  It is the only one that has different names, depending on what it is being used for. Employ it to hold something, and it is called a hand. Employ it to hit someone, and it is called a fist.  拿物体，我们称之为手;攻击人，我们称之为拳头。  That second use, though, is almost unknown in other primates.  而几乎所有的灵长类动物极少使用拳头攻击。  Most primate hands are long of palm and finger, short of thumb, and suited for climbing.  大多数灵长类动物的手是手掌宽大、手指较长和大拇指较短，这一结构有利于攀爬。  Human hands have short palms, short fingers and long thumbs, which are not.  人类的手是手掌短小、手指适中和大拇指较长，这一结构不利于攀爬，  These proportions do, though, make it possible to grip things in two ways that other apes hands cannot manage well.  然而，手的这种比例结构使得人类比其它灵长类动物更擅长于抓取物体，抓取有两种方式，  One is by using what is known as a precision grip, in which an object is held between the pads of the finger tips and the pad of the thumb.  一是精确握法，使用大拇指指尖与其它手指指尖抓紧一物体;  The other is by means of a power grip, in which all the fingers and the thumb are wrapped around what is being grasped.  另一种方式是力量握法，包括大拇指在内的所有手指把一物体紧紧包住。  These two grips are crucial to Homo sapienss characteristic tool-crafting skills, and it has thus long been thought that the widespread use of tools by humanitys ancestors was the driving force behind the modern hands proportions.  以上两种握法是智人在使用工具上的关键特征，因此，长期以来人们认为人类的祖先广泛使用工具是驱使人类手部结构进化的推动力。  No doubt that was important. But a study just published in the Journal of Experimental Biology by Michael Morgan and David Carrier of the University of Utah has shown that the exact geometry of the hand is probably the result of its destructive rather than its constructive power.  毋庸置疑，广泛使用工具对人手的进化起到了重要的作用，但是，由犹他大学的生物学家迈克尔摩根与戴维卡里尔合作完成，并在最近刊登在《实验生物学杂志》的一篇论文里写道，人类手部的精