2023考研英語閱讀滴定進食
Drip-feeding
滴定進食
Ecology raids the techniques of chemistry
生態學里應用上了化學技術。
Time to change restaurant
該換家館子了。
BIOLOGISTS are sometimes accused of physics envyand there is truth in this accusation.
生物學家們常常被認為非常嫉妒研究物理學的人。
The essential fuzziness of biological systems can never be captured by the precise,mathematically based experiments of something like the Large Hadron Collider.
他們永遠不可能通過像大型強子加速碰撞那樣精確、量化的實驗來揭示生物學里的一些關鍵性的奧秘。
Between physics and biology on the spectrum of fuzziness, though, lies chemistry.
但是在這種奧秘的兩極物理學和生物學之間還有化學。
And a group of researchers led by CarolynNersesian of the University of Sydney has just borrowed one of chemistrys most eleganttechniques, titration, to answer a pressing ecological question: how do animals choosewhere to feed?
最近由悉尼大學的卡洛琳涅爾謝相帶領的一組研究人員借用化學里一種非常精妙的技術滴定法來解決一個迫待回答的問題：動物們如何選擇覓食場所。
Titration, to remind those who dozed through their chemistry lessons, is a way of workingout the concentration of a substance in a solution.
滴定法是一種計算溶質在溶液中的濃度的方法。
A reagent of known concentration is dripped into the unknown solution in the presenceof an appropriate indicator molecule.
在某種特定的指示分子的參與下，將一種已知濃度的溶液滴到未知溶液中。
When the tipping point comes, and all of the unknown reagent has reacted, the solutionchanges colour.
當滴定終點到來時，所有的未知溶液全都完成了化學反應，溶液的顏色就會發生變化。
The unknown concentration can then be calculated from the amount of known reagentused.
然后未知溶液的濃度就可以通過被消耗掉的已知溶液的體積計算出來。
In Dr Nersesians titration the litmus was a species called the brushtail possum. The tworeagents were predators and poisons.
涅爾謝相博士的滴定實驗中的石蕊指示劑是一種叫帚尾袋貂的動物。那兩種溶液是獵食者和有毒物。
In the wild, possums feed mainly on eucalyptus trees.
在野生環境下，袋貂主要以桉樹葉為食。
Feeding in trees this way also keeps them safe from ground-based predators, such as foxes.
生活在樹上也能讓它們安全地遠離地面上的那些獵食者例如狐貍。
They frequently have to shift from tree to tree in search of non-poisonous leaves, though,because a tree that is being browsed starts manufacturing toxins.
但是他們還得經常從一棵樹上換到另一棵樹上去尋找那些沒有毒的葉子。因為一顆樹如果被它們吃久了就會自動分泌毒素。
Dr Nersesian reasoned that there is probably a measurable point at which a plant becomesso toxic that possums prefer to take their chances with the predators on the groundand sherealised this was a perfect opportunity to do an ecological titration.
涅爾謝相博士認為可能當植物中的毒素達到一個量值的時候，袋貂會選擇冒著被獵食的風險，然后她就意識到這是一個應用生態滴定法絕好的機會。
As she reports in the Journal of Animal Ecology, she attempted to imitate the distinctionbetween trees and ground by giving eight possums the opportunity to feed in either of twoenclosures.
她發表在動物生態學報上報告中寫道：她通過給8只袋貂兩種桉樹來選擇覓食來模擬樹上和地面的區別。
In one, cover was created with eucalyptus branches and light levels were kept low,mimicking an arboreal habitat.
一棵桉樹上，有特意放置的桉樹枝來遮擋，光照強度也很低，模擬出適合樹棲動物習性的環境。
Here, the food was sometimes spiked with cineolea poison often found in eucalyptusleaves.
但是，這種樹上的葉子有時含有桉樹腦桉樹葉中常見的毒素。
In the other enclosure, the food was always untarnished.
另一棵桉樹上，葉子總是無毒的，但是，沒有樹枝的遮擋。
However, no cover was provided and fox scent, in the form of faeces and urine, wasscattered liberally around, mimicking conditions on the ground.
而且通過將一些狐貍的蹤跡，例如狐貍的臉譜尿液隨意四散在周圍，來模擬地面環境。
To start with, when the level of cineole was low, possums preferred the first enclosure.
開始桉樹腦的濃度很低，袋貂都喜歡第一棵桉樹。
But as the drip of the titration went up, from 0% to 1% to 2% to 5% and ultimately to 10%of the food being cineole, their behaviour changed.
但是隨著滴定程度的上升，食物中的桉樹腦含量從0%到1%到2%到5% 到最終的10%，它們的行為開始出現變化。
It was not quite the sudden shift from litmus red to blue of an acid being neutralised by analkali, but it was not far off.
雖然不是完全像酸溶液完全被堿溶液中和時石蕊試劑突然從紅變藍那樣迅速，但是也差不太多。
When the food was toxin-free, the possums spent an average of 40 minutes of every houreating safely under treelike cover and only 20 minutes in the risky, ground-like enclosure,and that scarcely changed for 1% and 2% cineole.
當葉子無毒時，袋貂們每小時用平均40分鐘的時間在樹枝狀的遮蔽物下安全的進食。而在危險的類地面的桉樹上只待20分鐘，這時的桉樹腦含量變化在1%到2%之間。
The switch began at 5%, and by the time the cineole level had reached 10% the ratio oftime the animals spent in the two enclosures had reversed itselfpresumably reflecting,though this remains to be tested, the point at which they change trees in the wild.
分界點出現在5%，當桉樹腦含量達到10%，這些小動物們呆在這兩顆桉樹上的時間比完全顛倒過來了這大致上能反映在野外環境下它們換樹進食時的毒素量值，當然這還有待驗證。
Though foxes are of recent introduction in Australia, many marsupial predators, now extinct,were present before the arrival of man in both his Aboriginal and his European forms, so theecological system of plants, herbivores and carnivores in the eucalyptus forests wouldprobably not have been that different in the evolutionary past.
雖然狐貍是很晚才被引進到澳大利亞的，但是在原始人或者歐洲人到來之前還有很多其他的有袋動物的獵食者。所以桉樹林生態系統中的那些植物，素食動物肉食動物，與進化史中較早的生態系統相比，差別可能也沒有那么大。
A neat illustration, then, of co-evolution between three different parts of anecosystemand of the value, even in biology, of precise measurement.
這樣一來生態系統中的三個不同角色的協同進化的一張清晰的圖表呈現出來。在生物學里也能進行精確的量化計算，這種嘗試的價值是巨大的。
詞語解釋
1.behaviour n.行為;舉止
Such behaviour is beneath contempt.
這種行為令人不齒。
2.accusation n.控告;指控
His father was under an accusation then.
他父親當時受到控告。
3.experiment n.試驗;實驗
The researchers are repeating the experiment on rats.
研究人員用老鼠反覆做該試驗。
4.elegant a.優雅的;雅致的
He strolled about, looking very debonair in his elegant new suit.
他穿了一身講究的新衣服逛來逛去，顯得頗為愜意。
5.chemistry n.化學
I prefer chemistry to physics.
我喜歡化學甚于物理。
Drip-feeding
滴定進食
Ecology raids the techniques of chemistry
生態學里應用上了化學技術。
Time to change restaurant
該換家館子了。
BIOLOGISTS are sometimes accused of physics envyand there is truth in this accusation.
生物學家們常常被認為非常嫉妒研究物理學的人。
The essential fuzziness of biological systems can never be captured by the precise,mathematically based experiments of something like the Large Hadron Collider.
他們永遠不可能通過像大型強子加速碰撞那樣精確、量化的實驗來揭示生物學里的一些關鍵性的奧秘。
Between physics and biology on the spectrum of fuzziness, though, lies chemistry.
但是在這種奧秘的兩極物理學和生物學之間還有化學。
And a group of researchers led by CarolynNersesian of the University of Sydney has just borrowed one of chemistrys most eleganttechniques, titration, to answer a pressing ecological question: how do animals choosewhere to feed?
最近由悉尼大學的卡洛琳涅爾謝相帶領的一組研究人員借用化學里一種非常精妙的技術滴定法來解決一個迫待回答的問題：動物們如何選擇覓食場所。
Titration, to remind those who dozed through their chemistry lessons, is a way of workingout the concentration of a substance in a solution.
滴定法是一種計算溶質在溶液中的濃度的方法。
A reagent of known concentration is dripped into the unknown solution in the presenceof an appropriate indicator molecule.
在某種特定的指示分子的參與下，將一種已知濃度的溶液滴到未知溶液中。
When the tipping point comes, and all of the unknown reagent has reacted, the solutionchanges colour.
當滴定終點到來時，所有的未知溶液全都完成了化學反應，溶液的顏色就會發生變化。
The unknown concentration can then be calculated from the amount of known reagentused.
然后未知溶液的濃度就可以通過被消耗掉的已知溶液的體積計算出來。
In Dr Nersesians titration the litmus was a species called the brushtail possum. The tworeagents were predators and poisons.
涅爾謝相博士的滴定實驗中的石蕊指示劑是一種叫帚尾袋貂的動物。那兩種溶液是獵食者和有毒物。
In the wild, possums feed mainly on eucalyptus trees.
在野生環境下，袋貂主要以桉樹葉為食。
Feeding in trees this way also keeps them safe from ground-based predators, such as foxes.
生活在樹上也能讓它們安全地遠離地面上的那些獵食者例如狐貍。
They frequently have to shift from tree to tree in search of non-poisonous leaves, though,because a tree that is being browsed starts manufacturing toxins.
但是他們還得經常從一棵樹上換到另一棵樹上去尋找那些沒有毒的葉子。因為一顆樹如果被它們吃久了就會自動分泌毒素。
Dr Nersesian reasoned that there is probably a measurable point at which a plant becomesso toxic that possums prefer to take their chances with the predators on the groundand sherealised this was a perfect opportunity to do an ecological titration.
涅爾謝相博士認為可能當植物中的毒素達到一個量值的時候，袋貂會選擇冒著被獵食的風險，然后她就意識到這是一個應用生態滴定法絕好的機會。
As she reports in the Journal of Animal Ecology, she attempted to imitate the distinctionbetween trees and ground by giving eight possums the opportunity to feed in either of twoenclosures.
她發表在動物生態學報上報告中寫道：她通過給8只袋貂兩種桉樹來選擇覓食來模擬樹上和地面的區別。
In one, cover was created with eucalyptus branches and light levels were kept low,mimicking an arboreal habitat.
一棵桉樹上，有特意放置的桉樹枝來遮擋，光照強度也很低，模擬出適合樹棲動物習性的環境。
Here, the food was sometimes spiked with cineolea poison often found in eucalyptusleaves.
但是，這種樹上的葉子有時含有桉樹腦桉樹葉中常見的毒素。
In the other enclosure, the food was always untarnished.
另一棵桉樹上，葉子總是無毒的，但是，沒有樹枝的遮擋。
However, no cover was provided and fox scent, in the form of faeces and urine, wasscattered liberally around, mimicking conditions on the ground.
而且通過將一些狐貍的蹤跡，例如狐貍的臉譜尿液隨意四散在周圍，來模擬地面環境。
To start with, when the level of cineole was low, possums preferred the first enclosure.
開始桉樹腦的濃度很低，袋貂都喜歡第一棵桉樹。
But as the drip of the titration went up, from 0% to 1% to 2% to 5% and ultimately to 10%of the food being cineole, their behaviour changed.
但是隨著滴定程度的上升，食物中的桉樹腦含量從0%到1%到2%到5% 到最終的10%，它們的行為開始出現變化。
It was not quite the sudden shift from litmus red to blue of an acid being neutralised by analkali, but it was not far off.
雖然不是完全像酸溶液完全被堿溶液中和時石蕊試劑突然從紅變藍那樣迅速，但是也差不太多。
When the food was toxin-free, the possums spent an average of 40 minutes of every houreating safely under treelike cover and only 20 minutes in the risky, ground-like enclosure,and that scarcely changed for 1% and 2% cineole.
當葉子無毒時，袋貂們每小時用平均40分鐘的時間在樹枝狀的遮蔽物下安全的進食。而在危險的類地面的桉樹上只待20分鐘，這時的桉樹腦含量變化在1%到2%之間。
The switch began at 5%, and by the time the cineole level had reached 10% the ratio oftime the animals spent in the two enclosures had reversed itselfpresumably reflecting,though this remains to be tested, the point at which they change trees in the wild.
分界點出現在5%，當桉樹腦含量達到10%，這些小動物們呆在這兩顆桉樹上的時間比完全顛倒過來了這大致上能反映在野外環境下它們換樹進食時的毒素量值，當然這還有待驗證。
Though foxes are of recent introduction in Australia, many marsupial predators, now extinct,were present before the arrival of man in both his Aboriginal and his European forms, so theecological system of plants, herbivores and carnivores in the eucalyptus forests wouldprobably not have been that different in the evolutionary past.
雖然狐貍是很晚才被引進到澳大利亞的，但是在原始人或者歐洲人到來之前還有很多其他的有袋動物的獵食者。所以桉樹林生態系統中的那些植物，素食動物肉食動物，與進化史中較早的生態系統相比，差別可能也沒有那么大。
A neat illustration, then, of co-evolution between three different parts of anecosystemand of the value, even in biology, of precise measurement.
這樣一來生態系統中的三個不同角色的協同進化的一張清晰的圖表呈現出來。在生物學里也能進行精確的量化計算，這種嘗試的價值是巨大的。
詞語解釋
1.behaviour n.行為;舉止
Such behaviour is beneath contempt.
這種行為令人不齒。
2.accusation n.控告;指控
His father was under an accusation then.
他父親當時受到控告。
3.experiment n.試驗;實驗
The researchers are repeating the experiment on rats.
研究人員用老鼠反覆做該試驗。
4.elegant a.優雅的;雅致的
He strolled about, looking very debonair in his elegant new suit.
他穿了一身講究的新衣服逛來逛去，顯得頗為愜意。
5.chemistry n.化學
I prefer chemistry to physics.
我喜歡化學甚于物理。
