北美托福机经英文版原文(2)

1. 英國工業發展時期灰蛾子和黑蛾子數量的增減。
核心觀點是：污染嚴重使樹木變黑，此時黑蛾子隱蔽效果變好；另一方面，灰蛾子被吃得多。這個理論涉及到一個科學家的實驗以及資料獲取，學術界關於這個還是有爭議的，所以作者使出殺手鐧：1965年英國通過環保法案以後，灰蛾子的數量又上來了，於是科學家的理論就從反方向得到證實。
辭彙題：detecting。
How did peppered moths change because of the Industrial Revolution?
The Industrial Revolution caused pepper moths to adapt to a darker color because of the soot and ash everywhere so that they could hide from predators better, which made the black to gray moth ratio pull towards black. After the Industrial Revolution was over however then the black peppered moths numbers started to decrease and the grayish peppered moths number began to increase. This is evidence of adaptation.
The English moth, Biston betularia, is a frequently cited example of observed evolution. In this moth there are two color morphs, light and dark (typica and carbonaria). H. Kettlewell found that dark moths constituted less than 2% of the population prior to 1848. Then, the frequency of the dark morph began to increase. By 1898, the 95% of the moths in Manchester and other highly industrialized areas were of the dark type, their frequency was less in rural areas. The moth population changed from mostly light colored moths to mostly dark colored moths. The moths' color was primarily determined by a single gene. So, the change in frequency of dark colored moths represented a change in the gene pool. This change was, by definition, evolution.
The increase in relative abundance of the dark type was due to natural selection. The late eighteen hundreds was the time of England 's industrial revolution. Soot from factories darkened the birch trees the moths landed on. Against a sooty background, birds could see the lighter colored moths better and ate more of them. As a result, more dark moths survived until reproductive age and left offspring. The greater number of offspring left by dark moths is what caused their increase in frequency. This is an example of natural selection.
Populations evolve, not individuals. In order to understand evolution, it is necessary to view populations as a collection of individuals, each harboring a different set of traits. A single organism is never typical of an entire population unless there is no variation within that population. Individual organisms do not evolve, they retain the same genes throughout their life. When a population is evolving, the ratio of different genetic types is changing -- each individual organism within a population does not change. For example, in the previous example, the frequency of black moths increased; the moths did not turn from light to gray to dark in concert.
2. 生物多樣性
從赤道到極地，生物的多樣性漸漸減弱。裏面談到海洋裏的對比不強烈，因為溫差只是在上面幾十米，下面都是一個樣的黑和冷，所以作者認為，海洋多樣性不是由光照和溫度產生的。另外一個問題是多食動物generalist和專食動物specialist的區別。作者是通過季節週期性變化，帶來食物供應量的變化，然後食物的限制造成兩種動物的不同這個方面來談。
3. 歐洲中世紀同業公會制度guild
先講大師master的出道過程，然後是整個行會的排他性。接著是行會和城邦政府怎麼樣由前提相互支持（壟斷）。後來政府看中壟斷的大麵包於是插手進來分一杯羹。
除了政府以外，另一個行會的強勁對手是城外不受法律約束，而且擁有廉價勞動力（農民工）的個體企業。後來行會競爭不過－因為成本拼不過，價格當然也拼不過。同時又遇到一些供應上的困難，所以結果怎麼樣就…。還有，他們自己本身也有矛盾，主要是master中有些很有野心，想要擴張，簡單說就是內憂外患。
辭彙題：inevitable，endorse，convince，give rise to，marginally，capacious。

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