2016年5月7日新
5月7日新SAT阅读考试真题原文分析第三篇双篇文章，，难度是整个阅读考试里最难的，第一篇是林肯的一个讲话，第二篇讲的是civic government，双篇题考察了四个，其他题目都是单篇题目。
引自：《Decoding a Flower's Message》-- Elsa Young steadt
Texas gourd vines unfurl their large,flared blossoms in the dim hours before sunrise. Until they close at noon,their yellow petals and mild, squashy aroma attract bees that gather nectar andshuttle pollen from flower to flower. But “when you advertise [to pollinators],youadvertise in an open communication network,” sayschemical ecologist IanBaldwin of the Max Planck Institute for Chemical Ecologyin Germany. “You attract not just the good guys, butyou also attract the bad guys.” For a Texas gourd plant(Cucurbita pepo variety texana), striped cucumber beetles(Acalymmavittatum) areamong the very bad guys. They chew up pollen and petals, defecatein the flowersand transmit the dreaded bacterial wilt disease, an infection that can reducean entire plant to a heap of collapsed tissue in mere days.
The gourd vine’s problem—how to attract enough pollinators but not too many beetles—is a specific case of a floraldilemma that biologists first noticedmany decades ago. In 1879, Austrian botanist Anton Kerner von Marilaunpublished a treatise titled The Protective Means of Flowers against UnbiddenGuests, in which he described glands and sticky hairs that seemed to help keepharmful insects at bay. But a century later, scientists had still barely begunto consider the contribution of aflower’s scent tothose interactions; to do so would require a convergence offield work,chemistry and molecular biology. “We’re just beginning to train the type of biologists who can use thosetools,” Baldwin says. The resulting experiments havebegun to reveal the many ways that floral fragrances maymanipulate animalbehavior.
In one recent study, published in the Februaryissue of Ecology, Nina Theis and Lynn Adler took on the specific problem of theTexas gourd. Its main pollinators are honey bees (Apismellifera) andspecialized squash bees (Peponapis pruinosa), which respond to its floralscent. The aroma includes 10 compounds, but the most abundant—and the only one thatlures squash bees into traps—is 1,4-dimethoxybenzene.
In one recent study, published in the Februaryissue of Ecology, Nina Theis and Lynn Adler took on the specific problem of theTexas gourd. Its main pollinators are honey bees (Apismellifera) andspecialized squash bees (Peponapis pruinosa), which respond to its floralscent. The aroma includes 10 compounds, but the most abundant—and the only one thatlures squash bees into traps—is 1,4-dimethoxybenzene.