為了幫助大家在備考雅思的時候能夠練習到更多的真題材料，下面小編給大家?guī)硌潘奸喿x真題精選:orientatin of birds，望喜歡！

雅思閱讀真題精選:orientatin of birds

Migration of Birds

Orientation andNavigation

A .Factors in a bird'senvironment select for the expression of migratory behavior, leading to theevolution of a migratory pattern or, on the other hand, to the loss ofmigratory abilities. Factors in the environment function to provide direct,proximal stimulation for the physiological preparation for migration. Factorsin the environment also provide information that allows birds to navigateduring migratory passage. Navigation requires knowing three things: currentlocation, destination, and the direction to travel to get from the currentlocation to the destination. Humans eventually learned to use both the sun andthe stars to obtain this information. Recently we invented more precisesatellite-based technologies that have made these celestial cues fordetermining geographic positions superfluous and developed electronic aids tonavigation that allow orientation without reference to the natural environment.Birds have successfully navigated for eons using environmental information.

B .Birds are not alone in their ability to navigatelong distances. Fish, mammals, and even insects make migratory journeys. Butthe clarion honking of geese moving in huge skeins across the vault of theheavens, the twittering of migrants filtering down out of the night sky, theflocks of newly arrived birds filling woodlands, fields, and mudflats makes usmost aware of the seasonal movements of birds and fills us with awe and wonderas to how such a magnificent event can be accomplished season after season,year after year, with such unerring precision.

C .Of the three kinds of information necessary fornavigation, we know something about the environmental cues that birds use to orienttheir migratory flight in the proper direction. On the other hand, there alsois well-supported experimental evidence that birds use neither the positions ofthe sun or the stars to know where they are or where they are to go. It hasbeen shown, however, that birds must learn both the location of the winteringarea as well as the location of the breeding area in order to navigateproperly, but we have no idea what information they are learning. Nor do weknow what cues birds use to know the location of their migratory destinationwhen they are in their wintering locale, often thousands of miles away. Therecapture of banded birds at the same places along the route of the migratoryjourney in subsequent years suggests that some species also learn the locationof traditional stop-over sites, but how they do that remains a mystery.

Vector Navigation

D.European Starlings passthrough Holland on their migration from Sweden, Finland, and northwesternRussia to their wintering grounds on the channel coast of France and thesouthern British Isles. Perdeck transported thousands of starlings from TheHague to Switzerland, releasing these banded birds in a geographic location inwhich the population had never had any previous experience. The subsequentrecapture of many of these banded birds demonstrated that the adults, which hadpreviously made the migratory flight, knew they had been displaced and returnedto their normal wintering range by flying a direction approximately ninetydegrees to their usual southwesterly course. The juveniles, which had nevermade the trip before, in contrast, continued to fly southwest and wererecaptured on the Iberian peninsula. These first-year birds "knew"what direction to fly, but did not recognize they had been displaced, thusending up in an atypical wintering range. In subsequent years these now adultbirds returned to again winter in Spain and Portugal. Coupled with anotherdisplacement of starlings to the Barcelona coast in Spain, Perdeck concludedthat the proper direction of the migratory flight was innate, that is,inherited in their DNA, since the naive juveniles could fly that direction, andthat the birds were also genetically programmed to fly a set distance. This isthe same vector or dead-reckoning navigation program Lindberg used to fly fromNew York to Paris by maintaining a given compass direction (or directions) fora predetermined time (i.e., distance). But this study demonstrated that thisnavigation system is modified by experience, since adults knew they were not inHolland any longer and knew that in order to get to their normal winteringgrounds they needed to fly a direction that they had never flown before! Theseresults are truly amazing. And we don't know how they did it.

E.Displacement studies in the Western Hemisphere usingseveral species of buntings also demonstrated that birds recognized they hadbeen moved and could fly appropriate, yet unique, routes to return to theirnormal range. Yet adult Hooded Crows transported latitudinally by over 600 km fromwintering grounds in the eastern Baltic to northwestern Germany failed torecognize this displacement. In the spring they oriented properly but migratedto Sweden, west of their normal breeding range. This species used vectornavigation, but did not know the location of its traditional destination. Sinceit is generally accepted that migratory behavior evolved independently againand again in different bird populations, a single explanation to fit all casesperhaps should not be expected.

Orientation Cues

F .Most of theeffort applied to understanding how birds make a migratory flight has beendirected toward environmental cues that birds use to maintain a particularflight direction. These cues are landmarks on the Earth's surface, the magneticlines of flux that longitudinally encircle the Earth, both the sun and thestars in the celestial sphere arching over the Earth, and perhaps prevailingwind direction and odors.

Landmarks are useful as a primarynavigation reference only if the bird has been there before. For cranes, swans,and geese that migrate in family groups, young of the year could learn thegeographic map for their migratory journey from their parents. But most birdsdo not migrate in family flocks, and on their initial flight south to thewintering range or back north in the spring must use other cues. Yet birds areaware of the landscape over which they are crossing and appear to use landmarksfor orientation purposes. Radar images of migrating birds subject to a strongcrosswind were seen to drift off course, except for flocks migrating parallelto a major river. These birds used the river as a reference to shift theirorientation and correct for drift in order to maintain the proper ground track.That major geographic features like Point Pelee jutting into Lake Erie or CapeMay at the tip of New Jersey are meccas for bird-watchers only reflects thefact that migrating birds recognize these peninsulas during their migration.Migrating hawks seeking updrafts along the north shore of Lake Superior or theridges of the Appalachians must pay attention to the terrain below them inorder to take advantage of the energetic savings afforded by these topographicstructures.

G.Since humans learned to use celestialcues, it was only natural that studies were undertaken to demonstrate thatbirds could use them as well. Soon after the end of the Second World War,Gustav Kramer showed that migratory European Starlings oriented to the azimuthof the sun when he used mirrors to shift the sun's image by ninety degrees inthe laboratory and obtained a corresponding shift in the birds' orientation.Furthermore, since the birds would maintain a constant direction even thoughthe sun traversed from east to west during the day, the compensation for thismovement demonstrated that the birds were keeping time. They knew whatorientation to the sun was appropriate at 9 a.m. They knew what different anglewas appropriate at noon, and again at 4 p.m. It has been recently shown thatmelatonin secretions from the light-sensitive pineal gland on the top of thebird's brain are involved in this response. Not only starlings but homingpigeons, penguins, waterfowl, and many species of perching birds have beenshown to use solar orientation. Even nocturnal migrants take directionalinformation from the sun. European Robins and Savannah Sparrows that wereprevented from seeing the setting sun did not orient under the stars as well asbirds that were allowed to see the sun set. Birds can detect polarized lightfrom sunlight's penetration through the atmosphere, and it has beenhypothesized that the pattern of polarized light in the evening sky is theprimary cue that provides a reference for their orientation.

Using the artificial night sky provided byplanetariums demonstrated that nocturnal migrants respond to star patterns.(quite analogous to Kramer's work on solar orientation, Franz Sauerdemonstrated that if the planetarium sky is shifted, the birds make acorresponding shift in their orientation azimuth. Steve Emlen was able to showthat the orientation was not dependent upon a single star, like Polaris, but tothe general sky pattern. As he would turn off more and more stars so that theywere no longer being projected in the planetarium, the bird's orientationbecame poorer and poorer. While the proper direction for orientation at a giventime is probably innate, Emlen was able to show that knowing the location of"north" must be learned. When young birds were raised under aplanetarium sky in which Betelgeuse, a star in Orion of the southern sky, wasprojected to the celestial north pole, the birds oriented as if Betelgeuse was"north" when they were later placed under the normally orientatednight sky, even though in reality it was south!

H.Radar studies have shown that birds domigrate above cloud decks where landmarks are not visible, under overcast skieswhere celestial cues are not visible, and even within cloud layers whereneither set of cues is available. The nomadic horsemen of the steppes of Asiaused the response of lodestones to the Earth's magnetic field to find theirway, and the hypothesis that migrating birds might do the same was suggested asearly as the middle of the nineteenth century. Yet it was not until themid-twentieth century that Merkel and Wiltschko demonstrated in a laboratoryenvironment devoid of any other cues that European Robins would change theirorientation in response to shifts in an artificial magnetic field that was asweak as the Earth's natural field. Although iron-containing magnetite crystalsare associated with the nervous system in homing pigeons, Northern Bobwhite,and several species of perching birds, it is unknown whether they areassociated with the sensory receptor for the geomagnetic cue. An alternatehypothesis for the sensory receptor suggests that response of visual pigmentsin the eye to electromagnetic energy is the basis for geomagnetic orientation.It has been shown, however, that previous exposure to celestial orientationcues enhances the ability of a bird to respond more appropriately when onlygeomagnetic cues are available.

Radar observations indicate that birdswill decrease their air speed when their ground speed is augmented by a strongtail wind. We also know that birds can sense wind direction as gusts rufflingthe feathers stimulate sensory receptors located in the skin around the base ofthe feather. Since there are characteristic patterns of wind circulation aroundhigh and low pressure centers at the altitude most birds migrate, it has beenhypothesized that birds could use these prevailing wind directions as anorientation cue. However, there presently is no experimental support for thishypothesis.

I.The sense of smell in birds wasconsidered for a long time to be poorly developed, but more recent evidencesuggests that some species can discriminate odors quite well. If the olfactorynerves of homing pigeons are cut, the birds do not return to their home loft aswell as birds whose olfactory nerves were left intact. A similar experiment hasdemonstrated that European Starlings with severed olfactory nerves returnedless often than unaffected control birds even at distances as great as 240 kmfrom their home roosts. And even more interesting, when these starlingsreturned to the nesting area the following spring, the starlings withnonfunctioning olfactory nerves returned at a significantly lower frequencythan the other starlings.

J.Considering the array of demonstratedand suggested cues that birds might use in their orientation, it is clear thatthey rely upon a suite of cues rather than a single cue. For a migrating birdthis redundancy is critical, since not all sources of orientation informationare equally available at a given time, nor are all sources of informationequally useful in a given situation.

Questions 1—8

The passage on the previous pages has eight sections labeled A-J

Which section mentions the following?

Write the correct letter A-Jin boxes1—8 on your answersheet.

1. The possible conclusion for migrating birds.

2. A description of olfactory nerves about birds’sdistance.

3. A description of Latitude about several species.

4. Insights from studies how young birds finddirection.

5. The ways birds can use for navigation.

6. Classes of animals for migratory movements.

7. The elements that birds have to navigation.

8. The birds use different cues to cope with weather.

Questions 9—11

Choose THREE letters A-F

Write your answers in boxes 9—11 on your answer sheet.

The list below gives some ways of regarding navigation.

Which THREE ways are mentioned by the writer of the text?

A. a exercise for young adult activity

B. Latitude for wintering ground

C. Physical surrounding

D. Weather cues

E. Satellite-based technologies

F. Places destination when they are in winter

Questions 12—14

Do the following statements agree with the information given in thepassage?

In boxes 12—14 on your answer sheet, write

TRUE ifthe statement agrees with the information

FALSE ifthe statement contradicts the information

NOT GIVEN if thereis no information on this

12. Birds’ migratory flight is affected by using natural environment.

13. Fish, mammals and insects are not in their ability to makemigratory journeys.

14. Birds use cues to find their destination thousands of miles away.

雅思閱讀需要特別注意的問題有哪些

總述篇：

雅思考試里的閱讀部分答題時間1個小時，要求完成3篇文章共40個題目的解答，總計約3000詞。其文章內(nèi)容廣泛，涉及動物學、人類學、管理、自然環(huán)境、醫(yī)療衛(wèi)生等十個學科， 題目類型包括Headings 、true/false/not given、Short-answer questions、Summary 、Multiple Choice;Matching 、Sentence Completion、diagram/flowchart/table completion 等10種。除了平時刻苦做題外，考試當天還需要留意哪些注意事項呢?現(xiàn)在就從應考和心理兩個方面簡單談一談。

技巧篇：

一、 發(fā)揮筆的作用：

雅思考試與托福不同，仍舊是傳統(tǒng)的筆紙答題方式，更符合中國考生的閱讀習慣。在閱讀考試過程中，考生最好筆不離手，做好各種標記。在讀文章時，記號可以起到突出重要內(nèi)容，加深記憶的作用。

當需要在文章定位一些非特殊印刷體的關(guān)鍵詞時，筆可以指引讀者的視線，一方面可以加快閱讀速度，同時又可以防止漏掉文中的重要信息。解題時用筆可以加快速度，比如，考生在審題時圈出關(guān)鍵詞，就可以果斷定位原文，同樣，用筆還可以排除無關(guān)選項，進一步縮小范圍提高正確率。

二、 正確填涂答題卡

和聽力部分不同，閱讀考試是沒有留出時間讓考生將答案抄謄到答題卡上。所以，各位烤鴨一定要將答案直接寫在答題卡上，以免浪費時間。各位烤鴨可以做1道，涂1道。也可以在做完整篇文章后，將答案一起抄謄。最怕的是四十個答案全部寫在了卷子上而沒有時間謄，一旦考試時間截止，你的這次考試閱讀成績就是零，因為雅思根本不批改你的試卷而只以答題卡上的答案來計分。

不過注意一定要對應題號，千萬不要張冠李戴。需要提醒的是，true/false/not given這樣的題目，寫答案的時候盡量寫完整的單詞，如true,最好不要用T來代替。

另外，答題卡上千萬不能留空。雅思閱讀的評分標準是答錯題不倒扣分，所以，即使不確定答案交卷前也一定要蒙一個答案，尤其是有選項的題目。MBA的考試中有句名言，題目做不出來是個人技術(shù)問題，沒人怪你;不會做空在那里不填，是情商問題!

三、 先易后難把題挑

從節(jié)省時間的角度來說，考生最好遵循由易到難的原則。3篇文章里，選擇你最熟悉的內(nèi)容、學科開始做起。人們對于自己熟悉的內(nèi)容總會有著天生的親切和輕松，更容易正常發(fā)揮。同1篇文章里，題目也要先易后難。

通常來講，填空類別的題目通常最簡單，如：table/chart/diagram, summary, sentence completion, short answer questions等，可以先做。選擇類的通常都較難，例如：T/F/NG, List of headings, Which paragraph contains the following information等，可以放到后面做。因為這些題目絕大多數(shù)是細節(jié)型考題。在做完類似headings 這樣的題型后，考生對于文章的結(jié)構(gòu)和大一都有比較清晰地了解，在這個基礎上再完成細節(jié)題定位會更加準確，節(jié)約時間且提高正確率。

雅思閱讀必知的高頻關(guān)系詞

雅思閱讀高頻關(guān)系詞1.表轉(zhuǎn)折：

but, however, yet, in fact, on the other hand;

A, but B: 否定A而肯定B，則A，B兩部分內(nèi)容是相反的。

例如：Computerized data storage and electronic mail were to have heralded the paper less office. But, contrary to expectations, paper consumption throughout the world shows no sign of abating .

解釋：paper less 表示負向，則but后no sign of abating 表示正向，所以abating是表示負向的詞。

總結(jié)：此種方法有利于在不認識單詞的前提下讀懂句子意思，很有幫助，但一定要練習，而且要敏感。

練習：The marginal costs of generating electricity from nuclear energy may be tiny, but , as the technology now stands, huge and uncertain costs are involved in building the power stations, dealing with spent fuel, and decommissioning.

雅思閱讀高頻關(guān)系詞2.表讓步：

(1)although：although A, B:盡管有A，B還是出現(xiàn)了(A，B互不影響)若A是正，那B就是負的。

例如：Although the world regards Asia as the focus of an economic and industrial miracle, without adequate supplies of food, Lampe says, chaos could easily result in many countries.

解釋：miracle奇跡，表正向,則but后的chaos是一個表負向的詞。

(2)while：五個含義：

A. although：雖然，盡管

B. as long as：只要

C. whereas, but：表轉(zhuǎn)折

D.when：當。。。的時候

E. n. 表一段時間

例如：While ducks offer many advantages over hens, they must be given greater quality of food, especially if regular eggs are desired.

解釋：原文在本段之前講鴨子的好，在本段之后講它的不好。

(3)Albeit：盡管，雖然

例如：Albeit true but not now.

雅思閱讀高頻關(guān)系詞3.表并列：A and B

A...and B...

(1) 并列雙方性質(zhì)相同;

(2) 當A、B都比較復雜時，應該從最后一項找起，根據(jù)B的形式到前文找到A

例如：The modern city consists of monstrous edifices and of dark, narrow streets full of petrol fumes and toxic gases, torn by the noise of the taxicabs, lorries and buses, and thronged ceaselessly by great crowds.

解釋：此句話中共有四個and ,第一個and 并列of 結(jié)構(gòu)，第二個and 并列fumes和toxic,第三個and并列taxicabs, lorries 和buses, 第四個and并列full of …, torn by… 和thronged…

雅思閱讀高頻關(guān)系詞4.表遞進：沒有轉(zhuǎn)折的意思，后項承接上文。

A furthermore B

A moreover B

A besides B

A為正向，B 仍為正向。

雅思閱讀高頻關(guān)系詞5.表順序或過程：

(1) first, then, next, later on, finally

(2) 1st, 2nd, 3rd…

(3) in the first place, in the second place…

(4) before…, after…

(5) once, until, as soon as,…

雅思閱讀高頻關(guān)系詞6.特殊的關(guān)鍵詞：人名，地名，時間，數(shù)字，生詞(這是最好的定位標準，多以A---A形式重現(xiàn))

雅思閱讀高頻關(guān)系詞7.比較級：類比

對比

(1) as…as, like 類比

(2) more…than, unlike 對比

(3) 不同的時間導致強的對比關(guān)系

例如：一段講1840年,…

1919年.。。

二段講2003年出現(xiàn)了A++(生詞)…

問題是，2003年人們有了A++, 1840年的時候人們沒有什么?

(4) 不同的地點導致強對比關(guān)系

例如：In Australia, only,….

In Asia, many, A(生詞)

問題是，Australia缺什么?

雅思閱讀高頻關(guān)系詞8.例如：A for example = ：=—— B

A是理論，B是解釋

雅思閱讀高頻關(guān)系詞9.因果關(guān)系：

(1) 大因果關(guān)系/分句間因果關(guān)系(即：原因、結(jié)果是兩句話)

because, in that, as, since, for, so(that), therefore, thus, hence, as a result

(2) 小因果關(guān)系/句內(nèi)因果關(guān)系(在一句話中，通過v.來表達)

例如：Increased air temperature brought about higher sea levels.

Cause, lead to, result in/ from, contribute to, pose, help, create, affect, influence, attribute to.

Attribute A to B, 把A歸因于B (因為B所以A)

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