四月阅读机经 帝王蛾 考古求确认！！！

wsywsywsy

本月原始V1 【By liuzhaoroy】
　　主题是有关Monarch Butterfly迁徙的。三段，一屏左右。楼主严重失忆，只记得提到了墨西哥和美国的几个地名，milkweed等几个名词，在第三段还提到了chemical fingerprint。
　　考古+分析 【By 元叔】
　　※ 主题：
　　蝴蝶的迁移要经过几个generation才能完成;
　　西部的蝴蝶如何过冬 → 墨西哥的蝴蝶发现基因 → 为什么会在墨西哥 → 通过几代完成
　　※ 段意：
　　第一段：探究西部的蝴蝶如何过冬;
　　Monarch=帝王蝶，在洛基山脉有两种帝王蝶(这些蝴蝶最北到加拿大，原因是它们生长赖生存的植物，milkweed(乳草属植物)，最北就长到那)。两种→东、西，东边那种冬天去加洲过冬，西边那种怎么过冬一直是个迷(大意)。科学家想出了一种办法→在1930年，在它们的翅膀上安glue small tags，结果发现它们是跑到墨西哥过冬的。
　　第二段：他们为什么会在墨西哥过冬;
　　然而，大家猜想说，有几个debate，whether，具体的记不清了大约是它们怎么会跑那么远吧，反正这一段很短的。
　　第三段：毒素证明他们是通过几代完成的;
　　针对第二段的讲科学家的新发现，原来啊，在M某某里面有一种chemical，是保护它们不受天敌侵害的东西，他们就检测这种Chemical，因为milkweed中的一种化学物质，这种poison随着milkweed所在地的不同而有不同的特性，当milkweed被虫子吃了后，这种物质去到一个叫puna的器官，然后在虫子体内积淀下来。因此研究一只抓到的虫子身上所含有的这个物质的特性就知道他在哪里生活过。利用这个性质他们发现帝王蝶要过冬，飞来飞去的要花好几代才能来回一次。
　　※ 题目：
　　1)highlight的"footprint"加引号用意：
　　这个就是之前提过的在蝴蝶体内的特殊物质 所以该处认为是metaphor，我选E
　　2)还问蝴蝶迁徙是根据什么?
　　3)问第一段里面的研究需要什么作为保障之类的
　　5个选项都不是很明显，我就选了一个“需要很多和researcher不认识的人的配合”
　　4)1930年试验的成功主要是由于?
　　(在它们的翅膀上安了glue small tags，结果发现它们是跑到墨西哥过冬的)
　　5)成功研究落基山脉以东地区蝴蝶迁徙的 central reason 是?
　　个人答案：许多不同researchers 的合作。因为第二段讲chemical的时候提到了other researchers found。
　　※ 备注：
　　这道题目注意细节题，迁移过程和实验发现他们在墨西哥过冬;

peachjudy13

哈哈哈哈哈哈哈我又来了怎么办！！！！

开心的柠檬

4)1930年试验的成功主要是由于?
　　(在它们的翅膀上安了glue small tags，结果发现它们是跑到墨西哥过冬的)
　　5)成功研究落基山脉以东地区蝴蝶迁徙的 central reason 是?
　　个人答案：许多不同researchers 的合作。因为第二段讲chemical的时候提到了other researchers found。

第四题和第五题是一个问题，而且选项里面没有许多不同researchers 的合作，都是奇怪的选项，每个看着都不像，我选的是”天气条件不会有很大变化“

1)highlight的"footprint"加引号用意： 这个没有考！

考了个P3段的作用

先森，我累了

元叔厉害！！！！！！！！！！！！！！！！

开心的柠檬

元酥我又想起来一道题，问1870年时researchers知道什么。。选项很灵活，有点难，我感觉我选错了。。
另外我的帖子里又更新了一篇新阅读（刚想起来的=。=）

zondazz

元叔  挖坟挖到了这个  是不是这个啊  好像！
Brower has perfected a technique for tracking monarchs throughout the rest of the year, based on the butterflies' special relationship with milkweed plants. Monarchs lay their eggs on milkweed and, as larvae, eat the plants not only for nutrition but also for the toxins in the sap, which is poisonous to birds that prey on butterflies. The toxic compounds, known as cardiac glycosides, accumulate in larval tissues and persist after the larvae metamorphose into butterflies, making monarchs unpalatable to birds. "I've tasted the sap of the sandhill milkweed," says Brower, "and it's incredibly nauseating." Brower realized in the mid-1970s that he could use these poisons to understand monarch migration. The specific glycosides present in different species of milkweed vary from place to place, so analysis of a plant's glycosides can be used to determine its site of origin. Likewise, the glycosides in adult butterflies are a fingerprint of the plants on which the insects fed as larvae. "The light bulb went on," says Brower. His idea: If monarchs reflect the different arrays of glycosides in milkweeds, then he should be able to analyze butterfly glycosides and correlate individual insects with particular species of milkweed and with certain regions where the milkweed grew.
Traveling around the country, Brower trapped monarchs everywhere from the Great Lakes to Mexico and studied their glycosides. "We collected monarchs in the fall migration and established that over 90 percent fed on the northern milkweed pattern," he says. "Then we sampled the butterflies in Mexico and the ones along the Gulf Coast at the end of March and early April and, lo and behold, all of them had the same pattern. The same butterflies were going to Mexico and coming back in the spring."
Brower's work on glycosides helped to reveal the entire pattern of monarch migration. The first generation of monarch butterflies to return from Mexico stops along the Gulf Coast from Texas to Florida, where the insects lay eggs and die. The eggs hatch, and the new monarchs (with their distinctive southern milkweed fingerprint) head for the Great Lakes region. Later, the new generation of monarchs born around the Great Lakes flies to the East Coast, where they breed and die. Their offspring, fed on eastern milkweeds, then head south toward the Gulf Coast and on to Mexico, traveling as far as 90 miles per day and completing the great circle of monarch migration.