2013年12月1日托福阅读真题解析.doc

2013年12月1日托福阅读解析 第一篇 TOPIC 的保护 植物为了防止被食草动物吃掉而发展出许多structure method, physical比如叶子很硬，含硅,或者的形状。这点 method，它们可以分泌一种化学物质避免被吃因为吃了以后就不再生长了。芥末科植物，分泌油，虫子有害健康，所以不吃。但是却吃，因为它们进化了植物也会出现进化在进化过程中不同生物的互相影响：coevolution。有一种monarch butterfly，吃milk family plant，它能吸收植物里的化学物质，让自己变得有毒颜色鲜艳colorful，鸟慢慢记住这个颜色蝴蝶不能吃，昆虫也常常用color警告捕食者自己有毒。）然后说色彩鲜艳的动物一般有毒是动物不是植物），所以会避免吃它们。但是也发生了进化。 ：属生物学话题，生物的保护方式。生物学托福阅读最稳定的考察话题，也一般都是每次托福考试中相对较简单的文章，因其所谈内容大多会很多动植物的举例，是同学在阅读时更容易理解本文也不例外。生物学的重要性，强烈建议广大考生在托福复习期间找到生物学Biology相关的一些教科书或介绍性一下，会发现内容都在托福阅读中有闪现。 Plant defense against herbivory Plant defense against herbivory or host-plant resistance (HPR) describes a range of adaptations evolved by plants which improve their survival and reproduction by reducing the impact of herbivores. Plants can sense being touched, and they can use several strategies to defend against damage caused by herbivores. Many plants produce secondary metabolites, known as allelochemicals, that influence the behavior, growth, or survival of herbivores. These chemical defenses can act as repellents or toxins to herbivores, or reduce plant digestibility. Other defensive strategies used by plants include escaping or avoiding herbivores in time or in place, for example by growing in a location where plants are not easily found or accessed by herbivores, or by changing seasonal growth patterns. Another approach diverts herbivores toward eating non-essential parts, or enhances the ability of a plant to recover from the damage caused by herbivory. Some plants encourage the presence of natural enemies of herbivores, which in turn protect the plant. Each type of defense can be either constitutive (always present in the plant), or induced (produced in reaction to damage or stress caused by herbivores). Historically, insects have been the most significant herbivores, and the evolution of land plants is closely associated with the evolution of insects. While most plant defenses are directed against insects, other defenses have evolved that are aimed at vert