第十三週

4-5http://tw.youtube.com/watch?v=LFG-aLidT8s演化基因工具箱
http://tw.youtube.com/watch?v=I-g9_zINZ0A 生物多樣性專家提出了肉與生質燃料的問題?人類不斷破壞環境,並大量使用不能再生的能源,且破壞了生物多樣性.少吃肉,並不用人類食物取
代飼料,這樣不斷能養活很多人,更能使人類對動物的暴力.


(P84 5-2 第三小節四,五段)
In a temperate grassland, winters are bitterly cold, summers are hot and duy, and annual precipitation is fairly sparse and falls unevenloy through the year(Figure 5-12, center graph). Becaause the aboveground parts of most of the grasses die and decompose eachyear, organic matter accumulates to produce a deep,fertile soil This soil is held in place by a thick network of interwined roots of drought-tolerant grasses unlessthe topsoil is plowed up, which exposes it to be blownaway by high winds found inthese biomes The natural grasses are also adapted to fires that burn the plantparts above the ground but do not harm the roots fromwhich new garss can grow. Two types of temperate grasslands are the tall-grasspariries and short-grass prairies (Figure 5-12, centerphoto) of the midwestern and western United Statesand Canada. Here winds blow almost continuously, andevaporation is rapid, ofter leading tofires in the summerand fall. This combination of winds (CoreCase Study) and fire helops maintain such grasslsndsby hindering tree rowth. Figure 2 on p. S49 inSupplement 11 shows some components and food-webinteractions in a temperate tall-grass prairie ecosystemin North America.
在溫帶草原,冬天非常的冷,夏天熱又乾,年雨量相當地稀少而且變率高.氣候圖表顯示在熱帶、溫帶、寒帶草原年溫度與年雨量的典型變動.最上方的圖顯示：牛羚牧場在肯亞馬塞馬拉國家公園的大草原上.中間那個圖顯示：野花盛開在美國溫帶草原接近東方冰河公園.底圖顯示：極地苔原上的北美馴鹿在阿拉斯加及地野生動物保護區.因為還活著部分的草,每年大多草死掉和分解,有機物質累積並製造養分在深層肥沃的土壤,這些土壤是藉著耐旱草的纏繞跟形成的厚網才能支撐住,除非表土被犁耕.犁耕過的土壤藉由強風吹散而發現了這些生物社會.自然的草也能適應地表上的草被燃燒,但不會損傷到根,而再從這些損傷的根長出新的草.美國中西部、美國西部和加拿大的溫帶草原有分高大草原和矮草原兩種形式.這裡的風幾乎都吹連續不斷,且蒸發快,通常導致火災在夏天和秋天.這些風和火的結合妨礙樹木成長,幫助這類草地維持.在第二章顯示了高大草原生態系的成分和食物網在北美區.

(P90 第五小節第一,二段)
Mountains Play ImpprtantEcological Roles 山扮演重要角色
Some of the world's most spectacular environments arehigh on mountains (Figure 5-17), which cover aboutone-fourth of the earth's land surface (Figure 5-8).Mountains are places where dramatic changes in altitude,climate, soil, and vegetation take place over avery short distance (Figure 5-9,left). About 17% (1.2 billon) of the world's people livein mountains or on their edges, and 4 billon people(60% of the world's population) depend on mountainsfpr all or some of their water. Because of the steepslopes, mountain soils are easily eroded when the vegetationholding them in place is removed by naturaldisturbances (such as landslides and avalanches) or humanactivities (such as timber cutting and agriculture).Many freestanding mountains are islands of biodiversitysurrounded by a sea of lower-elevation landscapestransformed by human activities.世界上一些最壯觀的環境在高山區上（圖5-17 ），其中包括大約四分之一的地球陸地表面（圖5-8 ） 。 山是短距離發生了緯度，氣候，土壤，植被急劇變化的地方（圖5-9 ，左） 。約17 ％ （ 1.2億）的世界人口生活在山區或其邊緣， 4億人（佔60 ％的世界人口）依靠山區的全部或部分的水。由於陡坡，當植被在自然干擾（如滑坡和崩塌）或人類活動（如木材切割和農業）的地方,山區土壤很容易被侵蝕。許多獨立的山是生物多樣性的島嶼並環繞在因人類活動所轉變的低海拔景觀.