GRE閱讀題目解析:昆蟲幫助蘇鐵傳粉

　　GRE閱讀題目解析:昆蟲幫助蘇鐵傳粉

　　P3

　　Experiments show that insects can function as pollinators of cycads, rare, palmlike tropical plants. Furthermore, cycads removed from their native habitats - and therefore from insects native to those habitats - are usually infertile. Nevertheless, anecdotal reports of wind pollination in cycads cannot be ignored. The structure of cycads male cones is quite consistent with the wind dispersal of pollen, clouds of which are released from some of the larger cones. The male cone of Cycas circinalis, for example, sheds almost 100 cubic centimeters of pollen, most of which is probably dispersed by wind. Furthermore, the structure of most female cycad cones seems inconsistent with direct pollination by wind. Only in the Cycas genus are the females' ovules accessible to airborne pollen, since only in this genus are the ovules surrounded by a loose aggregation of megasporophylls rather than by a tight cone. (141 words)

　　For the following question, consider each of the choices separately and select all that apply

　　6. The passage suggests that which of the following is true of the structure of cycad cones?

　　(A) The structure of cycad cones provides conclusive evidence in favor of one particular explanation of cycad pollination.

　　(B) The structure of male cycad cones rules out a possible mechanism for cycad pollination that is suggested by the structure of most female cycad cones.

　　(C) The structure of male cycad cones is consistent with a certain means of cycad pollination, but that means is inconsistent with the structure of most female cycad cones.

　　7. The evidence in favor of insect pollination of cycads presented in the second sentence would be more convincing if which of the following were also true?

　　(A) Only a small variety of cycad species can be successfully transplanted.

　　(B) Cycads can sometimes be pollinated by means other than wind or insects.

　　(C) Insects indigenous to regions to which cycads are transplanted sometimes feed on cycads.

　　(D) Winds in the areas to which cycads are usually transplanted are similar to winds in cycads' native habitats.

　　(E) The transplantation of cycads from one region to another usually involves the accidental removal and introduction of insects as well.

　　P3

　　1

　　Experiments show that insects can function as pollinators of cycads, rare, palmlike tropical plants.

　　實驗顯示昆蟲可以幫助蘇鐵傳粉，后者是一種稀有的，手掌形狀的熱帶植物。

　　cycad 蘇鐵，俗稱鐵樹

　　2

　　Furthermore, cycads removed from their native habitats - and therefore from insects native to those habitats - are usually infertile.

　　此外，離開了原棲息地的蘇鐵 —— 所以是被昆蟲帶過去的 —— 往往無法結(jié)果。

　　3

　　Nevertheless, anecdotal reports of wind pollination in cycads cannot be ignored.

　　然而，一些關(guān)于蘇鐵風(fēng)媒傳粉的好玩報告不可忽略。

　　4

　　The structure of cycads male cones is quite consistent with the wind dispersal of pollen, clouds of which are released from some of the larger cones.

　　蘇鐵雄球花的結(jié)構(gòu)，相當(dāng)符合花粉隨風(fēng)散落的模式，較大的雄球花會釋放出花粉云。

　　5

　　The male cone of Cycas circinalis, for example, sheds almost 100 cubic centimeters of pollen, most of which is probably dispersed by wind.

　　比如說卷圈蘇鐵的雄球花，所釋放的 100 立方厘米花粉，大部分可能是通過風(fēng)散布的。

　　6

　　Furthermore, the structure of most female cycad cones seems inconsistent with direct pollination by wind.

　　另外，多數(shù)蘇鐵的雌球花似乎不配合直接的風(fēng)媒傳粉。

　　7

　　Only in the Cycas genus are the females' ovules accessible to airborne pollen, since only in this genus are the ovules surrounded by a loose aggregation of megasporophylls rather than by a tight cone. (141 words)

　　只有 Cycas 屬雌球花的胚珠能夠接觸到風(fēng)攜帶的花粉，因為只有這個屬的胚珠被大孢子葉叢松散地包圍，而非緊湊的雌球花。

　　For the following question, consider each of the choices separately and select all that apply

　　6. The passage suggests that which of the following is true of the structure of cycad cones?

　　(A) The structure of cycad cones provides conclusive evidence in favor of one particular explanation of cycad pollination.

　　(B) The structure of male cycad cones rules out a possible mechanism for cycad pollination that is suggested by the structure of most female cycad cones.

　　(C) The structure of male cycad cones is consistent with a certain means of cycad pollination, but that means is inconsistent with the structure of most female cycad cones.

　　選 C

　　A 錯在 conclusive 和 one，證據(jù)有兩個：

　　首先開篇就告訴我們，昆蟲可以給蘇鐵傳粉;

　　另外，句 5：

　　The male cone of Cycas circinalis, for example, sheds almost 100 cubic centimeters of pollen, most of which is probably dispersed by wind.

　　從 probably 也能暗示我們受粉的方式未必是 in favor of one particular explanation 的。

　　B

　　說反了也說錯了。

　　文中告訴我們，雄球花 male cone 是配合風(fēng)媒傳粉的 quite consistent，而雌球花 female cone 是鬧別扭的 seems inconsistent with direct pollination by wind ;

　　即便 B 把雌雄換位，仍然不成立，seems 拒絕了一種方式，不代表拒絕所有的方式，起碼文章中就提到蟲可以牽線。

　　rule out 排除，根除，防止

　　C

　　正確，分別在句 4、6：

　　The structure of cycads male cones is quite consistent with the wind dispersal of pollen, clouds of which are released from some of the larger cones.

　　...

　　Furthermore, the structure of most female cycad cones seems inconsistent with direct pollination by wind.

　　7. The evidence in favor of insect pollination of cycads presented in the second sentence would be more convincing if which of the following were also true?

　　(A) Only a small variety of cycad species can be successfully transplanted.

　　(B) Cycads can sometimes be pollinated by means other than wind or insects.

　　(C) Insects indigenous to regions to which cycads are transplanted sometimes feed on cycads.

　　(D) Winds in the areas to which cycads are usually transplanted are similar to winds in cycads' native habitats.

　　(E) The transplantation of cycads from one region to another usually involves the accidental removal and introduction of insects as well.

　　選 D

　　再看一遍句 2：

　　Furthermore, cycads removed from their native habitats - and therefore from insects native to those habitats - are usually infertile.

　　理一理思路：

　　蘇鐵作為一種植物，首先它得有一部分能夠正常生育，否則它早就滅絕了;

　　而蟲幫助授粉的蘇鐵，多數(shù)不育;

　　結(jié)合后文提到的風(fēng)媒傳粉，我們有理由猜測，風(fēng)媒傳粉的蘇鐵，與能夠正常生育的蘇鐵，重合度比較高。

　　綜上，看選項：

　　A 只有很少幾種蘇鐵可以被成功移植。無法判斷是能夠移植的種類少，還是數(shù)量少，還是其他別的原因，比如 D 提示的原因。

　　B 除了風(fēng)和蟲，蘇鐵還有其他方式授粉。無關(guān)項，它不能幫我們解釋句 2 提出的 fact 。

　　C 遷居的蘇鐵，被當(dāng)?shù)匾恍┫x吃了?？赡苷_但不夠嚴(yán)謹(jǐn)，首先你得確保蟲能吃光這個外來物種(你看看那個圖片，難度很高的)，另外，不育和被吃光來不及生育是兩碼事，有 tiny 可能正確，但不夠嚴(yán)謹(jǐn)。

　　D 通常蘇鐵成功遷居的地區(qū)，有著和原棲息地相似的風(fēng)。正確項。根據(jù)我們上面的推測，盡管蟲也能讓蘇鐵授粉，但風(fēng)媒傳粉顯然對蘇鐵來說更靠譜。有相似的風(fēng)，就能通過風(fēng)煤傳粉，也就能成功生育，而昆蟲攜帶的蘇鐵，因為當(dāng)?shù)氐娘L(fēng)不適合蘇鐵授粉，都沒有結(jié)果。

　　E 蘇鐵的遷居，可能伴隨著某種蟲的去來?？赡苷_，但無關(guān)，它無法解釋句 2 提出的，為什么蟲帶走的蘇鐵不育。