沃邦獨家|3月亞太SAT考情速遞(附全部真題+詳解)


來源:   時間:2019-03-11 15:26:17

\
風雷驚蟄戶,細雨萬物蘇~今晨3月9號開考的這場是2019年的第一場新SAT考試,也是自改革后全球范圍第36場新SAT考試,即亞洲第14場考試(School Day和補考除外)。在剛剛過去的一年里8月北美場次的重復舊題,10亞洲場次成績延遲,12月整體評分嚴苛等等事件使得CB飽受爭議,然而這一切并沒有撼動SAT這門考試的地位,在官方給出的2018年度考試報告里全球考試人數增長到250萬(2017年170萬)。與此同時帶來的還有分數上更大的競爭壓力,以及寒假里高漲的備考熱情。
 
常規意義上這是多數學生的SAT首考,但是也有不少學生打算在本次二戰分手,甚至不乏極個別學神1550還刷分…這一切都說明學生的考試規劃愈發提前,培訓機構經驗逐步積累沉淀,美本標化考試生態日趨穩定成熟。在這樣的大背景下,勤奮和成績自然會更成正比,努力與出分也是水到渠成的事情,也讓我們更加期待這次考試同學們的表現!一如既往,沃邦以為學生提供最為優質的送考服務為理念,整理最全面的考試資料為習慣,傳遞最快速的考情回顧為目標,又一次派出專業教師團隊趕赴多地親臨考試,希望為大家帶來最新鮮及時的新SAT考試動態~
 

SAT考試概述

 
本場考試再次重復了北美School Day3月6號的原題,所以亞洲場次會大趨勢上重復使用北美考題,好在時間相隔很短,所以并不影響總體上的考試公平性。題目整體呈現出的難度正常,而且與2018年12月亞太場次在閱讀部分的結構順序上保持驚人的一致,相信做過或考過這場的學生應該感覺上并不陌生。但在評分標準的預估方面仍舊要看大家的表現和CB最后的評定,極有可能語法部分的curve繼續去年下半年的嚴苛。
 
\
 

各科回憶

閱讀部分

閱讀第 1 篇文章概述
小說是比較當代的經典劇情,極其類似于1708北美場次的那篇,女主人公作為學生接到教授要找她約談的消息后,十分擔心自己的表現顧慮課程是否會因此結束,課上還不小心打翻了儀器,在教授的嚴格而細心關懷下清理完畢就更加重了對此事的焦慮,課后劇情大反轉,跟教授談及自己之所以學生物的理想是當科學家,反而得到了教授暑期推薦去實驗室工作的機會。
  
閱讀第 2 篇文章概述
這篇文章討論了君主統治產生的根源以及如何去避免,表達了對于在美國有可能產生新的君主統治的擔心。
 
因閱讀第2篇難度較大,故附上全文翻譯。
先生們,有兩種激情對人類的事務有著強大的影響。這些是野心和貪婪,對權力和金錢的愛。單獨地說,每一種都有巨大的力量促使人們采取行動;但是,在許多人的心目中,當他們因為同一目標而結合在一起時,就會產生最強烈的影響。要在這些人眼前樹立一個榮耀的職位,同時又要成為一個有利益的地方,他們就會千方百計地去得到它。正是大量這樣的地方使英國政府如此狂暴。對他們的斗爭是所有這些派別的真正根源,這些派別永遠在分裂國家,分散議會的注意力,有時使國家陷入毫無結果和有害的戰爭,并常常迫使它屈從于不光彩的和平條件。
 
有什么樣的人會在陰謀集團的喧囂、激烈的爭論、無休止的互相謾罵、把最優秀的人物撕成碎片的過程中,為這種有利的優勢而奮斗呢? 智慧溫和的人,喜愛和平與美好秩序的人,配得信托的人,這些都不會有。那將是勇敢和暴力的人,在他們自私的追求中有強烈的激情和不知疲倦的活動。這些人要闖入你的政府,成為你的統治者。而這些人也會被他們所期望的幸福所誤導,因為他們被擊敗了的競爭對手具有同樣的精神,出于同樣的動機,將永遠竭力使他們的政府陷于困境,阻撓他們的措施,使人民憎惡他們。
 
除此之外,先生們,雖然我們開始的時候薪水還算過得去,但我們會發現,這種情況不會持續太久。提出的擴大措施永遠不會缺少理由;而且總會有一群人給統治者更多的東西,這樣統治者就可以回報給他們更多。因此,正如所有歷史告訴我們的那樣,在每一個國家和王國,統治者和被統治者之間一直存在著一種持續不斷的戰爭;一個努力獲得更多的支持,另一個付出更少。僅這一點就引發了巨大的動蕩,真正的內戰,最終不是推翻了君主的統治就是奴役了人民。總的來說,統治的權力是有其道理的,我們看到王室們的收入不斷增加,我們看到他們從不感到滿足,而且總是想要更多。人民對稅收的壓迫越不滿,君主就越需要錢來分配給他的黨羽,用來鎮壓一切抵抗,把這些錢變成隨心所欲掠奪的軍費。黨羽中很少有一個不愿意效法法老的,如果他能的話,他就先得百姓的銀子,再得他們的田地,然后使他們和他們的子孫永遠作奴仆。有人會說,我們并不打算立王。這一點我知道。但是人類有一種天生的傾向,那就是國王統治。國王統治有時能使他們擺脫貴族的統治。他們寧愿有一個暴君,也不愿有五百人在他們的階級之上。它更多地表現出公民之間的平等;他們喜歡這一點。因此,我擔心,也許是太擔心了,這些國家中的任何一個,在未來的時代,都可能以君主政體告終。但是,我認為,如果在我們所提議的制度中,我們不通過使我們的榮譽職位成為有利可圖的地方來播下爭論、派別和騷亂的種子,這場災難可能會被拖延很久。如果我們這樣做了,我擔心,雖然我們一開始使用的是幾個人,而不是一個人,但隨著時間的推移,這個數字將被保留下來;它只會滋養國王的出現(就像那位來自弗吉尼亞的可敬的先生非常恰當地表達的那樣),國王會更快地建立在我們之上。
  
閱讀第 3 篇文章概述
科學文章生物類,這篇文章主要講的是克羅地亞在地中海上兩個島嶼的蜥蜴進化關系,從PK島引入到PM島的五只蜥蜴在短短的36年內不斷繁衍進化,由昆蟲食性轉變為植物食性,因此在身形骨架,嘴部撕咬能力以及腸道消化系統,甚至在領地意識上對比起祖先都發生了驚人改變和“進化”。
  
閱讀第 4 篇文章概述
第四篇是典型的社會科學科研型文章,主要的研究問題是文字描述和事物的熟悉度(familarity vs. strangeness)是否會影響我們對貨幣和商品的價值判斷。
 
也即是假如我們對物品/錢幣比較熟悉,我們會認為它們比我們不熟悉(或復雜語言描述)的東西價值高,盡管它們的客觀價值是一樣的。
 
作者上來就說我們很多economic decision都做不到絕對客觀,會受一些主觀因素影響(比如對世界的內在認知以及我們的舒適度等等等)。這是心理學行為學最常見的話題,就是我們的行為決定到底有多少是理性成分有多少是主觀成分。人往往做不到絕對理性,但很多經濟學行為學模型卻不得不假定我們大體是理性的。老師上課在提到類似話題都會做相應介紹。
 
實驗過程也相對簡單,兩步:
 
第一步,兩組人給了兩種不同的一美金錢幣,一個是華盛頓為頭像(古老),一個是女權主義者Susan B Anthony為頭像(新),受試對象普遍認為前者的價值高于后者。作者還進一步用少見的杰弗遜為頭像的兩美元和兩張熟悉的兩張一美元對比,結果沒有差異。
 
第二步,兩組人去購買同種商品,一組人看到的文字描述清晰,一組人看到文字描述很不清晰閱讀難度有挑戰性。結果大家認為第一組商品價值高。
  
閱讀第 5 篇文章概述
P1
作者認為RNA可以幫助找到生命的起源。之前人們一直依賴DNA和Protein,但是現在RNA的出現會讓科學研究有重大的突破。DNA和Protein是互相依賴的,所以科學家很難知道到底哪個先出現。RNA可以幫助跳過這個難題,因為RNA可以起三個作用:第一,可以儲存信息;第二,可以復制配對;第三,可以起到催化作用。
 
P2
作者反對RNA的重要性。主要基于兩點:第一,RNA沒有足夠的時間進化;第二,RNA可能不會在那么早存在。
作者提到一個科學家做的實驗,提到起催化劑其實是酶的作用。
 
閱讀第 5 篇題目
43題:主旨題
選RNA很重要,能引導出credible theory
 
44題: 詞匯
carry的意思,選contain
 
45獨立取證題
問DNA和蛋白質研究中的問題
 
46詞匯題 
isolate的意思
 
47題 48關聯取證題
問allign experiment中能得出U這種酶具有什么樣的特點
特點是不會改變,因為它是core,可以被當做“fossil”來看
 
49事實細節題
問最早的酶是什么?
 
50雙篇關系 
問兩篇主旨不同點
 
51雙篇關系
問第二篇文章作者最不同意第一篇文章作者哪個觀點
 
52雙篇關系
問兩篇文章作者分別如何看待RNA
 

語法部分


本次文法總體簡單,沒有需要驗證或者陷阱題型。篇章題難度較低,基于前后句就可以解決。難點或相對比較需要注意的陷阱只有兩個:besides和furthermore的區分+and結構的主謂一致
  
語法第 1 篇文章概述
Dickens takes the stage
 
狄更斯不光是有名的作者 他本身也是個表演者 狄更斯可以很好的表演出自己出自己的作品 主要講述他的成就。本篇文章語法題較簡單,第一二題是簡單的句子鏈接和代詞,只要保證不run-on和代詞指代精確,就不會有任何問題。篇章題沒有難度。同時,考察了不太常見的破折號表示轉折的用法
  
語法第 2 篇文章概述
Fritz Pollard Beyond the Gridiron
 
Fritz Pollard是著名運動員,退役后從事各種業務很成功,但是他一直致力于幫助黑人找到職業生涯。
 
本篇文章題目較簡單,唯一難題在于學生區分邏輯連接詞besides和furthermore的區別。
  
語法第 3 篇文章概述
Why we still need mapmkers
 
地圖現在都是衛星和電子版,所以有人質疑制作地圖的人員和手藝就不重要了。但是作者強調mapmaker還有很多的重要的地方,比如見證歷史的改變和文化的傳承。
 
本篇文章語法題占據一半,出現了全套唯一句子順序題,難題簡單。
  
語法第 4 篇文章概述
The art of a cat’s lap
 
講貓和牛奶從而引發了關于貓科動物飲水的習慣,解讀了舌頭的形狀以及速度等等。
 
本篇文章題目注意run-on,出現了全套唯一圖表題,而且題干沒有陷阱,難度簡單。
 

數學部分

 總體概述
第三部分數學部分較為簡單。
 
難題回顧:
第三部分
二元一次方程解方程應用題:18塊錢賣Tshirt可以賣60件,每降一塊錢,多賣10件,問總共最多賺多少錢?
 
兩個長方體體積求比例,第一個長寬高分別是15 yard ,3yard 6 inches;另一個體積是2 cubic feet,求兩個長方體體積比例(1 yard=3 feet,1foot=12inches)
 
第四部分
題目題干略長,知識點難度不大,計算量小,部分應用題有很多讀題陷阱,較易出錯
 
易錯題回顧:
 
1科學家培養細菌, 每天的Beginning 都是前一天beginning 的2倍,the beginning of the first day is 20,what is the amount at the beginning of the sixth day?
 
2.統計抽樣,newspaper 做了一個調研,樣本是從a list of voters in the town抽的,問對應的population是什么
A.voters who receive the newspaperB.voters who participate in the poll
c.voters in the state
d.voters in the town
 
3.mean times of shopping at grocery store in a city is 91, margin of error, 3,in another city,the mean times is 95, margon of error,4,問那個城市的人均購物次數高
 
\
  
1. Looking out across Los Angeles from Mt. Wilson Observatory at night, the hills and mountains look like islands in a sea of light. It was here that Edwin Hubble first proved our universe was expanding at a rapid pace. From this vantage point you can still make out the major constellations, but drive into the light bubble and suddenly the cosmos feels awfully far away. The city shines so bright it blocks out the stars, a phenomenon known as "skyglow."
 
2. Light seeps into the sky from stadiums, malls, parking lots, offices and billboards. But streetlights, with their harsh bulbs, are the worst offenders. . . .
 
3. We intuitively assume that more lights mean less crime. Indeed, police are often taught that, second to more cops, good lighting is the best crime deterrent.
 
4. Yet decades of research show there's no scientific reason to believe that darker streets are inherently more dangerous. And, increasingly, researchers are finding that excess light is toxic for both humans and wildlife.
 
5. In one study, published July 28 in the Journal of Epidemiology and Community Health, researchers examined 14 years of data from 62 local authorities across England and Wales, hunting for crime and collision trends among agencies that reduced their lighting.
 
6. But the health researchers found no link between collisions and lighting despite studying about 14,500 miles of roadways where streetlights were dimmed, lighted for only part of the night or shut off entirely. They also examined lighting's effect on crime and similarly found no increase in burglary, auto theft, robbery, violence or sexual assault in areas where lighting policy had changed.
 
7. The scientists published a companion study based on surveys of 520 people living in darkened areas. Many residents said they didn't even notice the dimming, let alone feel threatened by an uptick in crime.
 
8. Other studies back up these results. In 1998, for example, Chicago tried to fight crime with a three-phase plan that included upgrading 175,000 streetlights, as well as lights in transit stations and alleys around the city. The city kept experimental control areas unchanged and found that crime consistently increased in both the well-lighted and the control areas. Illinois criminal justice officials concluded that strolling down a dark alley was no more dangerous than doing so in a well-lighted one.
 
9. All this should make taxpayers uneasy. Last week, the Cities at Night project released a report estimating that the European Union alone spends about $7 billion annually to power streetlights.
 
10. But there's something much more troubling than wasted money about losing the night. A growing body of biological research suggests that nighttime lighting messes with the circadian rhythms of humans and other animals, wreaking havoc on everything from sleep patterns to DNA repair.
 
11. Studies have shown that nighttime light exposure is a risk factor for some cancers, diabetes, heart disease and obesity. As scientists continue to gather evidence, the American Medical Assn. has already recommended that cities reduce light pollution and that people avoid staring at electronic screens after dark.
 
12. LEDs are of particular concern. Cities around the world are converting from traditional yellow sodium-vapor lamps, which cast their light in a narrow range, to broad-spectrum LED streetlights. Los Angeles has installed 165,000 LEDs in recent years, slashing streetlight energy use by 60% and netting $8 million in energy savings annually.
 
13. The problem is that these bright lamps increase skyglow by emitting more blue light than the older technology. They also could have unintended effects on wildlife. Artificial lights can disrupt navigation, mating and feeding among the many nocturnal animals that share our cities.
 
14. A University of Bristol study published this month showed that certain moths can't perform evasive maneuvers against predatory bats under LEDs. And recent research in New Zealand shows some insects are 48% more attracted to the new LEDs than they were to the old-fashioned lights. The researchers worry that widespread use of the new technology will create a "white-light night" that intensifies light pollution's pressure on ecosystems.
 
15. The psychological loss is less measurable. . . .
 
16. What happens when people grow up without stars? Do they lose their connection to the cosmos that our ancestors tracked so carefully, night after night?
 
\
  

附錄

 
閱讀第 1 篇文章原文
I scanned my mind for what this could be about. Had I left a supply closet or fridge unlocked? Had I open centrifuged one of the specimens she’d asked me to look at when it was supposed to be closed centrifuged? Had she glanced over my should erat my class notes and seen the list of embarrassing questions only I seemed to have and which I’d scribbled under the heading Things to Look Up Later? I’d been so careful around her so far, hoping to make up for all the times I raised my hand and revealed how little I knew, all the times she caught me pretty much fondling the equipment —the elegant pipettes, the test tube racks that kept everything snug and in place, the magical autoclave incinerating all evidence of use and making everything perfect over and over again. It could’ve been any or all of these things: she was so smart that I was certain she’d put these observations together and conclude, long before I figured it out, that though I was eager and good at keeping contamination at bay, I wasn’t cut out for the hard sciences. I wrote her back, composing my e-mail in a word processing program first to make sure the green squiggly line of grammar impropriety didn’t show up under every clause, and confirmed I could meet with her Monday at noon, right after class. She wrote back a cryptic, That will be more than fine.
 
The three hours of that week’s lab class felt like a goodbye. I stacked each petridish as if it were the last time I’d be allowed to handle those delicate circles of glass. I swished saline solution for longer than was needed, looked at the agar coating the bottom of plates as if its nutrients were intended for me and were about to be withheld. When a question popped into my head, I kept my hand down and didn’t even bother to write it in my notebook.
 
I watched Professor Kaufmann for clues all class but saw nothing, though she’d already proven herself good at masking frustration with kindness. You could drop an
entire tray of beakers, and she would smile and in a too-high voice say, That’s OK! I sometimes thought I was the only one in the class who saw through her, could tell how very upset she was at all that shattered glass on the floor: I knew it from the way she’d say Hmmm as she accosted the student culprit with a broom and stood over them, pointing out a missed shard here, a tiny speck there. She’d wait until they put the broom away before noticing another piece, then instruct them to go back to the closet and bring the broom again.
 
I approached her lab bench once everyone had left. She was scribbling something on some graph paper, and I glanced at what she wrote once I was closer. Whatever it was, it was in German—probably not a good sign—and it was underneath a series of equations that meant nothing to me and which were in no way related to our class.
 
—Liz! she said. Oh, super! Come here, please!
 
She stood and let me have her seat. I sat there for a good minute, watched her keep working as if she hadn’t just asked me to sit down. Her pen dug into the paper and I wondered if she had two brains—wondered if there were a way I could split my own mind like that, be in one place but let my mind hang out wherever it wanted. She slapped the pen down on her notebook, and without even apologizing for the awkward three or so minutes we’d been right next to each other but not speaking, she said, Thank you for staying after class. I see you’re eager to know what this is about.
 
—Yes, I said. I tried to keep my back straight; I found trying to maintain good posture more painful than just slouching. Even seated on her high stool, I was still looking up at her. I said, Is everything okay?
 
—Yes, of course. Thank you for asking.
 
I figured then that I should stop talking lest I incriminate myself, but she smiled at me and nodded as if I’d kept speaking, as if I was saying something at that very moment.
 
—Yes, so, sh—Yes, so, she said. You are enjoying the lab so far?
 
—I love it, I blurted out. It’s my favorite class this semester.
 
—Super! she said. That’s super.
 
She nodded some more. After a few additional seconds of painful silence and sustained eye contact she asked, Are you interested in becoming a research scientist?
 
I thought I wanted to be a doctor, but that didn’t seem like the right answer.
 
—Yes, I said. I am.
 
—Good, super. Because there is something you should do then, a program.
 
She slipped a hand beneath her pad of graph paper and slid out a glossy folder. I closed my eyes, not wanting to look at it: here it was, the remedial program for students needing extra help, forced in front of me like that list of campus resources I’d printed out last semester as my only hope. The folder was white with a crimson stripe down the front of it, a gold logo embossed at its center.
 
—This is connected to my research group. It’s a summer position at our field laboratory off the coast of Santa Barbara, in California. You would be perfect for it.
 
閱讀第 2 篇文章原文
Sir, there are two passions which have a powerful influence in the affairs of men. These are ambition and avarice; the love of power and the love of money. Separately, each of these has great force in prompting men to action; but, when united in view of the same object, they have, in many minds, the most violent effects. Place before the eyes of such men a post of honor, that shall, at the same time, be a place of profit, and they will move heaven and earth to obtain it. The vast number of such places it is that renders the British Government so tempestuous. The struggles for them are the true source of all those factions which are perpetually dividing the nation, distracting its councils, hurrying it sometimes into fruitless and mischievous wars, and often compelling a submission to dishonorable terms of peace.
 
And of what kind are the men that will strive for this profitable pre-eminence, through all the bustle of cabal, the heat of contention, the infinite mutual abuse of parties, tearing to pieces the best of characters? It will not be the wise and moderate, the lovers of peace and good order, the men fittest for the trust. It will be the bold and the violent, the men of strong passions and indefatigable activity in their selfish pursuits. These will thrust themselves into your government, and be your rulers. And these, too, will be mistaken in the expected happiness of their situation, for their vanquished competitors, of the same spirit, and from the same motives, will perpetually be endeavoring to distress their administration, thwart their measures, and render them odious to the people.
 
Besides these evils, sir, though we may set out in the beginning with moderate salaries, we shall find that such will not be of long continuance. Reasons will never be wanting for proposed augmentations; and there will always be a party for giving more to the rulers, that the rulers may be able, in return, to give more to them. Hence, as all history informs us, there has been in every state and kingdom a constant kind of warfare between the governing and the governed; the one striving to obtain more for its support, and the other to pay less. And this has alone occasioned great convulsions, actual civil wars, ending either in dethroning of the princes or enslaving of the people. Generally, indeed, the ruling power carries its point, and we see the revenues of princes constantly increasing, and we see that they are never satisfied, but always in want of more. The more the people are discontented with the oppression of taxes, the greater need the prince has of money to distribute among his partisans, and pay the troops that are to suppress all resistance, and enable him to plunder at pleasure. There is scarce a king in a hundred, who would not, if he could, follow the example of Pharaoh, - get first all the people's money, then all their lands, and then make them and their children servants forever. It will be said that we do not propose to establish kings. I know it. But there is a natural inclination in mankind to kingly government. It sometimes relieves them from aristocratic domination. They had rather have one tyrant than five hundred. It gives more of the appearance of equality among citizens; and that they like. I am apprehensive, therefore, - perhaps too apprehensive, - that the government of these States may, in future times, end in a monarchy. But this catastrophe, I think, may be long delayed, if in our proposed system we do not sow the seeds of contention, faction, and tumult, by making our posts of honor places of profit. If we do, I fear that, though we employ at first a number and not a single person, the number will, in time, be set aside; it will only nourish the foetus of a king (as the honorable gentleman from Virginia very aptly expressed it), and a king will the sooner be set over us.
  
閱讀第 3 篇文章原文
There are two small islets off the Croatian coast called Pod Kopiste and Pod Mrcaru. In 1971 a population of common Mediterranean lizards, Podarcis sicula, which mainly eat insects, was present on Pod Kopiste but there were none on Pod Mrcaru. In that year experimenters transported five pairs of Podarcis sicula from Pod Kopiste and released them on Pod Mrcaru. Then, in 2008, another group of mainly Belgian scientists, associated with Anthony Herrel, visited the islands to see what had happened.
 
They found a flourishing population of lizards on Pod Mrcaru, which DNA analysis confirmed were indeed Podarcis sicula. These are presumed to have descended from the original five pairs that were transported. Herrel and his colleagues made observations on the descendants of the transported lizards,
and compared them with lizards living on the original ancestral island. There were marked differences.
 
The scientists made the probably justified assumption that the lizards on the ancestral island, Pod Kopiste, were unchanged representatives of the ancestral lizards of thirty-six years before. In other words, they presumed they were comparing the evolved lizards of Pod Mrcaru with their unevolved ‘ancestors’ (meaning their contemporaries but of ancestral type) on Pod Kopiste. Even if this presumption is wrong – even if, for example, the lizards of Pod Kopiste have been evolving just as fast as the lizards of Pod Mrcaru – we are still observing evolutionary divergence in nature, over a timescale of decades: the sort of timescale that humans can observe within one lifetime.
 
And what were the differences between the two island populations, differences that had taken a mere thirty-seven years or so to evolve?* Well, the Pod Mrcaru lizards – the ‘evolved’ population – had significantly larger heads than the ‘original’ Pod Kopiste population: longer, wider and taller heads. This translates into a markedly greater bite force. A change of this kind typically goes with a shift to a more vegetarian diet and, sure enough, the lizards of Pod Mrcaru eat significantly more plant material than the ‘ancestral’ type on Pod Kopiste. From the almost exclusive diet of insects (arthropods, in the terms of the graph opposite) still enjoyed by the modern Pod Kopiste population, the lizards on Pod Mrcaru had shifted to a largely vegetarian diet, especially in summer.
 
Why would an animal need a stronger bite when shifting to a vegetarian diet? Because plant, but not animal, cell walls are stiffened by cellulose. Herbivorous mammals like horses, cattle and elephants have great millstone-like teeth for grinding cellulose, quite different from the shearing teeth of carnivores and the needly teeth of insectivores. And they have massive jaw muscles, and correspondingly robust skulls
for the muscle attachments (think of the stout midline crest along the top of a gorilla’s skull).*
 
Vegetarians also have characteristic peculiarities of the gut. Animals generally can’t digest cellulose without the aid of bacteria or other micro-organisms, and many vertebrates set aside a blind alley in the gut called the caecum, which houses such bacteria and acts as a fermentation chamber (our appendix is a vestige of the larger caecum in our more vegetarian ancestors). The caecum, and other parts of the gut, can become quite elaborate in specialist herbivores. Carnivores usually have simpler guts than herbivores, and smaller too. Among the complications that become inserted in herbivore guts are things called caecal valves. Valves are incomplete partitions, sometimes muscular, which can serve to regulate or slow down the flow of material through the gut, or simply increase the surface area of the interior of the caecum. The picture on the left shows the caecum cut open in a related species of lizard which eats a lot of plant material. The valve is indicated by the arrow. Now, the fascinating thing is that, although caecal valves don’t normally occur in Podarcis sicula and are rare in the family to which it belongs, those valves have actually started to evolve in the population of P. sicula on Pod Mrcaru, the population that has, for only the past thirty-seven years, been evolving towards herbivory. The investigators discovered other evolutionary changes in the lizards of Pod Mrcaru. The population density increased, and the lizards ceased to defend territories in the way that the ‘ancestral’ population on Pod Kopiste did.
 
I should repeat that the only thing that is really exceptional about this whole story, and the reason I am telling it here, is that it all happened so extremely rapidly, in a matter of a few decades: evolution before our very eyes.
 
閱讀第 4 篇文章原文
Princeton psychologist Daniel Oppenheimer and his New York University colleague Adam Alter believe that many of the economic decisions we make have little to do with objective value. Market choices have much more to do with the brain’s basic internal perception of the world and the way those perceptions shape our feelings of comfort and ease. In this view, even currency has no clear and absolute value within one national economy. Regardless of those numbers on bills and coins, money derives its true value at least in part from the individual mind. In a series of experiments, these two psychologists have been studying the marketplace cues that trigger psychological comfort or discomfort, and thus shape us as economic beings. They’ve found that our economic behavior is driven by the same fluency heuristic at work in the Moses illusion.
 
The basic idea is that it’s human nature to get anxious and wary when the world is strange or challenging. We’re more at ease around the familiar and comprehensible. Think back to the avalanche fatalities described in the introduction. Most of them happened in places familiar to the victims. That’s a version of the fluency bias, which is probably deep-wired from the days when the world was much more threatening. But the cues that signal us to be on guard in the modern social world—including the financial world—may not be obvious. Indeed, they may be almost undetectable at times. It’s these nuanced signals that the psychologists have been exploring in the lab.
 
Here’s an example of their work. Oppenheimer and Alter asked a group of volunteers to estimate how much of various commodities they could buy with a dollar. They were ordinary things like paper clips and gumballs and paper napkins. Some of the volunteers were given a regular old dollar bill, with George Washington on it, while others were given less familiar currency of the same value: a Susan B. Anthony $1 coin, for example. Invariably, the volunteers believed that the familiar old dollar bill was worth more—that it had more buying power—than the unusual currency.
 
That’s not logical, of course. But it was not a fluke. They got the same result when they gave some people a rare $2 bill and others two singles. It’s not as though people never see a $2 bill, and it does have Thomas Jefferson on it, after all. But just the slight unfamiliarity of the denomination was enough to make people devalue it. Why would this be? Oppenheimer and Alter believe this irrational behavior is rooted in our most fundamental mental processes: The world is full of stimuli of various kinds, some more familiar than others, and the brain is tuned to process the familiar ones rapidly, effortlessly, and intuitively. More difficult or alien cues require more mental work, more plodding deliberation; the brain switches to its more cautious and calculating style to be on the safe side. We intuitively know that familiar $1 bills are valuable items, but the dollar coin is an unknown commodity—and the difference shows just how hard it is for us to know the “value of a dollar.”
 
This is humbling to know. But there’s more. The psychologists wanted to see if the same cognitive bent shapes our perceptions and attitudes toward goods themselves, and they decided to use the typeface manipulation to find out. In this experiment, they gave everyone the same currency—the familiar dollar bill—but they made the commodities more or less accessible. Some of the “consumers” purchased the gumballs and paper clips from a form that was printed in a clear black font, while others had to select from a form printed in the difficult-to-read gray script—basically the same manipulation described before. The idea was to make the strangeness as subtle as possible, to reduce it to basic perception. Even at this most fundamental level, the differences shaped economic judgment: volunteers in the study consistently rated identical goods as less valuable when they came in an unfamiliar, cognitively challenging form.  
  
閱讀第 5 篇文章原文
P2
Before there was life on Earth, there were molecules. A primordial soup. At some point a few specialized molecules began replicating. This self-replication, scientists agree, kick-started a biochemical process that would lead to the first organisms. But exactly how that happened -- how those molecules began replicating -- has been one of science's enduring mysteries.
 
Now, research from UNC School of Medicine biochemist Charles Carter, PhD, appearing in the September 13 issue of the Journal of Biological Chemistry, offers an intriguing new view on how life began. Carter's work is based on lab experiments during which his team recreated ancient protein enzymes that likely played a vital role in helping create life on Earth. Carter's finding flies in the face of the widely-held theory that Ribonucleic Acid (RNA) self-replicated without the aid of simple proteins and eventually led to life as we know it.
 
In the early 1980s, researchers found that ribozymes -- RNA enzymes -- act as catalysts. It was evidence that RNA can be both the blueprints and the chemical catalysts that put those blueprints into action. This finding led to the "RNA World" hypothesis, which posits that RNA alone triggered the rise of life from a sea of molecules.
 
But for the hypothesis to be correct, ancient RNA catalysts would have had to copy multiple sets of RNA blueprints nearly as accurately as do modern-day enzymes. That's a hard sell; scientists calculate that it would take much longer than the age of the universe for randomly generated RNA molecules to evolve sufficiently to achieve the modern level of sophistication. Given Earth's age of 4.5 billion years, living systems run entirely by RNA could not have reproduced and evolved either fast or accurately enough to give rise to the vast biological complexity on Earth today.
 
"The RNA world hypothesis is extremely unlikely," said Carter. "It would take forever."
 
Moreover, there's no proof that such ribozymes even existed billions of years ago. To buttress the RNA World hypothesis, scientists use 21st century technology to create ribozymes that serve as catalysts. "But most of those synthetic ribozymes," Carter said, "bear little resemblance to anything anyone has ever isolated from a living system."
 
Carter, who has been an expert in ancient biochemistry for four decades, took a different approach. His experiments are deeply embedded in consensus biology.
 
Our genetic code is translated by two super-families of modern-day enzymes. Carter's research team created and superimposed digital three-dimensional versions of the two super-families to see how their structures aligned. Carter found that all the enzymes have virtually identical cores that can be extracted to produce "molecular fossils" he calls Urzymes -- Ur meaning earliest or original. The other parts, he said, are variations that were introduced later, as evolution unfolded.
 
These two Urzymes are as close as scientists have gotten to the actual ancient enzymes that would have populated Earth billions of years ago.
 
"Once we identified the core part of the enzyme, we cloned it and expressed it," Carter said. "Then we wanted to see if we could stabilize it and determine if it had any biochemical activity." They could and it did.
 
Both Urzymes are very good at accelerating the two reactions necessary to translate the genetic code.
 
"Our results suggest that there were very active protein enzymes very early in the generation of life, before there were organisms," Carter said. "And those enzymes were very much like the Urzymes we've made."
 
The finding also suggests that Urzymes evolved from even simpler ancestors -- tiny proteins called peptides. And over time those peptides co-evolved with RNA to give rise to more complex life forms.
 
In this "Peptide-RNA World" scenario, RNA would have contained the instructions for life while peptides would have accelerated key chemical reactions to carry out those instructions.
 
"To think that these two Urzymes might have launched protein synthesis before there was life on Earth is totally electrifying," Carter said. "I can't imagine a much more exciting result to be working on, if one is interested in the origin of life."
 
The study leaves open the question of exactly how those primitive systems managed to replicate themselves -- something neither the RNA World hypothesis nor the Peptide-RNA World theory can yet explain. Carter, though, is extending his research to include polymerases -- enzymes that actually assemble the RNA molecule. Finding an Urzyme that serves that purpose would help answer that question.

\
\
 
本文系沃邦教育 SAT 教研組老師原創,文章發布 6 小時之內暫不接受任何形式轉載,違者必究!文章發布滿 6 小時以后,轉載請經授權后再操作。


延伸閱讀

SAT語法成績難提高?做到這5點分數輕松提

美本申請 | SAT和GPA不平衡怎么辦?

從中美高考的差異來看,為何越來越多人選擇備考SAT?

熱點關注

校區地址
近期出分情況
快三中奖概率计算公式