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  Minerals and Plants

  Research has shown that certain minerals are required by plants for normal growth and development. The soil is the source of these minerals, which are absorbed by the plant with the water from the soil. Even nitrogen, which is a gas in its elemental state, is normally absorbed from the soil as nitrate ions. Some soils are notoriously deficient in micro nutrients and are therefore unable to support most plant life. So-called serpentine soils, for example, are deficient in calcium, and only plants able to tolerate low levels of this mineral can survive. In modern agriculture, mineral depletion of soils is a major concern, since harvesting crops interrupts the recycling of nutrients back to the soil.

  研究表明，某些礦物質(zhì)是植物正常生長(zhǎng)發(fā)育所必需的。土壤是這些礦物質(zhì)的來(lái)源，它們通過(guò)水分被植物從土壤中吸收。即使是元素狀態(tài)為氣體的氮，也通常作為硝酸根離子從土壤中被吸收。眾所周知，一些土壤缺乏微量營(yíng)養(yǎng)素，因此大多數(shù)植物不能生長(zhǎng)。例如所謂的蛇紋巖土壤，由于缺乏鈣，只有那些能忍受如此低含量的鈣的植物才能夠存活。在現(xiàn)代農(nóng)業(yè)，土壤礦物質(zhì)枯竭是一個(gè)大問(wèn)題，因?yàn)槭崭钋f稼切斷了養(yǎng)分返回土壤的循環(huán)。

  Mineral deficiencies can often be detected by specific symptoms such as chlorosis (loss of chlorophyll resulting in yellow or white leaf tissue), necrosis (isolated dead patches), anthocyanin formation (development of deep red pigmentation of leaves or stem), stunted growth, and development of woody tissue in an herbaceous plant. Soils are most commonly deficient in nitrogen and phosphorus. Nitrogen-deficient plants exhibit many of the symptoms just described. Leaves develop chlorosis; stems are short and slender, and anthocyanin discoloration occurs on stems, petioles, and lower leaf surfaces. Phosphorus-deficient plants are often stunted, with leaves turning a characteristic dark green, often with the accumulation of anthocyanin. Typically, older leaves are affected first as the phosphorus is mobilized to young growing tissue. Iron deficiency is characterized by chlorosis between veins in young leaves.

  礦物質(zhì)缺乏通常可由特定的癥狀檢測(cè)出來(lái)，如褪綠(葉綠素?fù)p失導(dǎo)致黃葉或白葉的現(xiàn)象)、壞疽(孤立的壞死斑)、花青素的形成(形成深紅色葉片和莖色素沉積)、發(fā)育不良以及草本植物長(zhǎng)木質(zhì)組織。土壤最常缺乏的是氮和磷。氮缺乏植物表現(xiàn)出了剛才描述的許多癥狀：葉片黃化、莖短而細(xì)以及發(fā)生在莖、葉柄以及下葉表面的花青素變色。磷缺乏的植物往往發(fā)育不良，葉片變成特殊的深綠色，經(jīng)常伴隨著花青素的積累。由于磷流向新生的組織，通常較老的葉片首先受到影響。鐵缺乏癥的特點(diǎn)是嫩葉的葉脈之間萎黃。

  Much of the research on nutrient deficiencies is based on growing plants hydroponically, that is, in soilless liquid nutrient solutions. This technique allows researchers to create solutions that selectively omit certain nutrients and then observe the resulting effects on the plants. Hydroponics has applications beyond basic research, since it facilitates the growing of greenhouse vegetables during winter. Aeroponics, a technique in which plants are suspended and the roots misted with a nutrient solution, is another method for growing plants without soil.

  大多數(shù)關(guān)于營(yíng)養(yǎng)素缺乏癥的研究都基于水培法，即在無(wú)土營(yíng)養(yǎng)液中培養(yǎng)。這項(xiàng)技術(shù)允許研究人員創(chuàng)造缺乏某種營(yíng)養(yǎng)素的溶液，然后觀察對(duì)植物生長(zhǎng)造成的影響。水培法的應(yīng)用已經(jīng)超越了基礎(chǔ)研究，因?yàn)樗龠M(jìn)了溫室蔬菜在冬季的生長(zhǎng)。空氣培養(yǎng)法，一種把植物懸掛起來(lái)，將其根部噴上營(yíng)養(yǎng)液的技術(shù)，是另外一種無(wú)土栽培的方法。

  While mineral deficiencies can limit the growth of plants, an overabundance of certain minerals can be toxic and can also limit growth. Saline soils, which have high concentrations of sodium chloride and other salts, limit plant growth, and research continues to focus on developing salt-tolerant varieties of agricultural crops. Research has focused on the toxic effects of heavy metals such as lead, cadmium, mercury, and aluminum; however, even copper and zinc, which are essential elements, can become toxic in high concentrations. Although most plants cannot survive in these soils, certain plants have the ability to tolerate high levels of these minerals.

  雖然缺乏礦物質(zhì)會(huì)抑制植物生長(zhǎng)，但某些礦物質(zhì)過(guò)量可能會(huì)有毒，同樣也會(huì)抑制植物生長(zhǎng)。含有高濃度的氯化鈉和其他鹽類的鹽堿土壤抑制植物生長(zhǎng)，于是研究繼續(xù)集中開(kāi)發(fā)耐鹽農(nóng)作物品種。著重研究重金屬的毒性作用，如鉛、鎘、汞、鋁;然而即使是銅和鋅這樣的必需元素，如果濃度過(guò)高也會(huì)產(chǎn)生毒性。雖然大多數(shù)植物無(wú)法在這種土壤生存，某些植物卻能夠忍耐如此高含量的礦物質(zhì)。

  Scientists have known for some time that certain plants, called hyperaccumulators, can concentrate minerals at levels a hundredfold or greater than normal. A survey of known hyperaccumulators identified that 75 percent of them amassed nickel, cobalt, copper, zinc, manganese, lead, and cadmium are other minerals of choice. Hyperaccumulators run the entire range of the plant world. They may be herbs, shrubs, or trees. Many members of the mustard family, spurge family, legume family, and grass family are top hyperaccumulators. Many are found in tropical and subtropical areas of the world, where accumulation of high concentrations of metals may afford some protection against plant-eating insects and microbial pathogens.

  科學(xué)家早前就了解到，某些所謂的富集植物能夠比普通植物多集中100倍甚至更多的礦物質(zhì)。一項(xiàng)對(duì)已知富集植物的調(diào)查表明，它們中75%積聚了鎳，而鈷、銅、鋅、錳、鉛和鎘則是其他選擇性聚集的礦物質(zhì)。富集植物存在于整個(gè)世界范圍，它們可能是草本植物、灌木或樹(shù)。芥屬、大戟屬、豆科和禾本科植物中的許多成員都是靠前的富集植物。許多富集植物被發(fā)現(xiàn)于熱帶和亞熱帶，金屬可以為植物提供保護(hù)，對(duì)抗植食昆蟲(chóng)和細(xì)菌病原體。

  Only recently have investigators considered using these plants to clean up soil and waste sites that have been contaminated by toxic levels of heavy metals–an environmentally friendly approach known as phytoremediation. This scenario begins with the planting of hyperaccumulating species in the target area, such as an abandoned mine or an irrigation pond contaminated by runoff. Toxic minerals would first be absorbed by roots but later relocated to the stem and leaves. A harvest of the shoots would remove the toxic compounds off site to be burned or composted to recover the metal for industrial uses. After several years of cultivation and harvest, the site would be restored at a cost much lower than the price of excavation and reburial, the standard practice for remediation of contaminated soils. For examples, in field trials, the plant alpine pennycress removed zinc and cadmium from soils near a zinc smelter, and Indian mustard, native to Pakistan and India, has been effective in reducing levels of selenium salts by 50 percent in contaminated soils.

  直到最近研究者才考慮用這些植物來(lái)清理已經(jīng)被有毒重金屬污染的土壤和廢棄物物處理點(diǎn)——一種被稱為植物修復(fù)法的修復(fù)方法。這套方案首先從在目標(biāo)區(qū)域種植超積累物種開(kāi)始，如在廢棄礦井和被徑流污染的灌溉池塘。有毒礦物質(zhì)首先被根吸收，隨后被運(yùn)送至莖和葉。收割下來(lái)的枝葉將被焚燒以移除有毒化合物或被制成混合肥料回收金屬用于工業(yè)。經(jīng)過(guò)幾年的種植和收割，該污染點(diǎn)將被修復(fù)，而其造價(jià)遠(yuǎn)比修復(fù)污染土壤的標(biāo)準(zhǔn)做法——挖掘和填埋來(lái)得低。舉例來(lái)說(shuō)，在實(shí)地試驗(yàn)中，高山菥蓂從靠近一個(gè)鋅冶煉廠的土壤中去除了鋅和鎘，原產(chǎn)自巴基斯坦和印度的印度芥菜可以將染土壤中硒的水平有效地降低了50%。

  Paragraph 1: Research has shown that certain minerals are required by plants for normal growth and development. The soil is the source of these minerals, which are absorbed by the plant with the water from the soil. Even nitrogen, which is a gas in its elemental state, is normally absorbed from the soil as nitrate ions. Some soils are notoriously deficient in micro nutrients and are therefore unable to support most plant life. So-called serpentine soils, for example, are deficient in calcium, and only plants able to tolerate low levels of this mineral can survive. In modern agriculture, mineral depletion of soils is a major concern, since harvesting crops interrupts the recycling of nutrients back to the soil.

  1. According to paragraph 1, what is true of plants that can grow in serpentine soil?

  ○They absorb micronutrients unusually well.

  ○They require far less calcium than most plants do.

  ○They are able to absorb nitrogen in its elemental state.

  ○They are typically crops raised for food.

  Paragraph 2: Mineral deficiencies can often be detected by specific symptoms such as chlorosis (loss of chlorophyll resulting in yellow or white leaf tissue), necrosis (isolated dead patches), anthocyanin formation (development of deep red pigmentation of leaves or stem), stunted growth, and development of woody tissue in an herbaceous plant. Soils are most commonly deficient in nitrogen and phosphorus. Nitrogen-deficient plants exhibit many of the symptoms just described. Leaves develop chlorosis; stems are short and slender, and anthocyanin discoloration occurs on stems, petioles, and lower leaf surfaces. Phosphorus-deficient plants are often stunted, with leaves turning a characteristic dark green, often with the accumulation of anthocyanin. Typically, older leaves are affected first as the phosphorus is mobilized to young growing tissue. Iron deficiency is characterized by chlorosis between veins in young leaves.

  2. The word “exhibit” in the passage is closest in meaning to

  ○fight off

  ○show

  ○cause

  ○spread

  3. According to paragraph 2, which of the following symptoms occurs in phosphorus-deficient plants but not in plants deficient in nitrogen or iron?

  ○Chlorosis on leaves

  ○Change in leaf pigmentation to a dark shade of green

  ○Short, stunted appearance of stems

  ○Reddish pigmentation on the leaves or stem

  4. According to paragraph 2, a symptom of iron deficiency is the presence in young leaves of

  ○deep red discoloration between the veins

  ○white or yellow tissue between the veins

  ○dead spots between the veins

  ○characteristic dark green veins

  Paragraph 3: Much of the research on nutrient deficiencies is based on growing plants hydroponically, that is, in soilless liquid nutrient solutions. This technique allows researchers to create solutions that selectively omit certain nutrients and then observe the resulting effects on the plants. Hydroponics has applications beyond basic research, since it facilitates the growing of greenhouse vegetables during winter. Aeroponics, a technique in which plants are suspended and the roots misted with a nutrient solution, is another method for growing plants without soil.

  5. The word “facilitates” in the passage is closest in meaning to

  ○slows down

  ○affects

  ○makes easier

  ○focuses on

  6. According to paragraph 3, what is the advantage of hydroponics for research on nutrient deficiencies in plants?

  ○It allows researchers to control what nutrients a plant receives.

  ○It allows researchers to observe the growth of a large number of plants simultaneously.

  ○It is possible to directly observe the roots of plants.

  ○It is unnecessary to keep misting plants with nutrient solutions.

  7. The word “suspended” in the passage is closest in meaning to

  ○grown

  ○protected

  ○spread out

  ○hung

  Paragraph 5: Scientists have known for some time that certain plants, called hyperaccumulators, can concentrate minerals at levels a hundredfold or greater than normal. A survey of known hyperaccumulators identified that 75 percent of them amassed nickel, cobalt, copper, zinc, manganese, lead, and cadmium are other minerals of choice. Hyperaccumulators run the entire range of the plant world. They may be herbs, shrubs, or trees. Many members of the mustard family, spurge family, legume family, and grass family are top hyperaccumulators. Many are found in tropical and subtropical areas of the world, where accumulation of high concentrations of metals may afford some protection against plant-eating insects and microbial pathogens.

  8. Why does the author mention “herbs”, “shrubs”, and “trees”?

  ○To provide examples of plant types that cannot tolerate high levels of harmful minerals.

  ○To show why so many plants are hyperaccumulators.

  ○To help explain why hyperaccumulators can be found in so many different places.

  ○To emphasize that hyperaccumulators occur in a wide range of plant types.

  9. The word “afford” in the passage is closest in meaning to

  ○offer

  ○prevent

  ○increase

  ○remove

  Paragraph 6: Only recently have investigators considered using these plants to clean up soil and waste sites that have been contaminated by toxic levels of heavy metals–an environmentally friendly approach known as phytoremediation. This scenario begins with the planting of hyperaccumulating species in the target area, such as an abandoned mine or an irrigation pond contaminated by runoff. Toxic minerals would first be absorbed by roots but later relocated to the stem and leaves. A harvest of the shoots would remove the toxic compounds off site to be burned or composted to recover the metal for industrial uses. After several years of cultivation and harvest, the site would be restored at a cost much lower than the price of excavation and reburial, the standard practice for remediation of contaminated soils. For examples, in field trials, the plant alpine pennycress removed zinc and cadmium from soils near a zinc smelter, and Indian mustard, native to Pakistan and India, has been effective in reducing levels of selenium salts by 50 percent in contaminated soils.

  10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

  ○B(yǎng)efore considering phytoremediation, hyperaccumulating species of plants local to the target area must be identified.

  ○The investigation begins with an evaluation of toxic sites in the target area to determine the extent of contamination.

  ○The first step in phytoremediation is the planting of hyperaccumulating plants in the area to be cleaned up.

  ○Mines and irrigation ponds can be kept from becoming contaminated by planting hyperaccumulating species in targeted areas.

  11. It can be inferred from paragraph 6 that compared with standard practices for remediation of contaminated soils, phytoremediation

  ○does not allow for the use of the removed minerals for industrial purposes

  ○can be faster to implement

  ○is equally friendly to the environment

  ○is less suitable for soils that need to be used within a short period of time

  12. Why does the author mention “Indian mustard”?

  ○To warn about possible risks involved in phytoremediation

  ○To help illustrate the potential of phytoremediation

  ○To show that hyperaccumulating plants grow in many regions of the world

  ○To explain how zinc contamination can be reduced

  Paragraph 5: Scientists have known for some time that certain plants, called hyperaccumulators, can concentrate minerals at levels a hundredfold or greater than normal. ■A survey of known hyperaccumulators identified that 75 percent of them amassed nickel, cobalt, copper, zinc, manganese, lead, and cadmium are other minerals of choice. ■Hyperaccumulators run the entire range of the plant world. ■They may be herbs, shrubs, or trees. ■Many members of the mustard family, spurge family, legume family, and grass family are top hyperaccumulators. Many are found in tropical and subtropical areas of the world, where accumulation of high concentrations of metals may afford some protection against plant-eating insects and microbial pathogens.

  13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

  Certain minerals are more likely to be accumulated in large quantities than others.

  Where could the sentence best fit?

  14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

  Plants need to absorb certain minerals from the soil in adequate quantities for normal growth and development.

  ●

  ●

  ●

  Answer Choices

  ○Some plants are able to accumulate extremely high levels of certain minerals and thus can be used to clean up soils contaminated with toxic levels of these minerals.

  ○Though beneficial in lower levels, high levels of salts, other minerals, and heavy metals can be harmful to plants.

  ○When plants do not absorb sufficient amounts of essential minerals, characteristic abnormalities result.

  ○B(yǎng)ecause high concentrations of sodium chloride and other salts limit growth in most plants, much research has been done in an effort to develop salt-tolerant agricultural crops.

  ○Some plants can tolerate comparatively low levels of certain minerals, but such plants are of little use for recycling nutrients back into depleted soils.

  ○Mineral deficiencies in many plants can be cured by misting their roots with a nutrient solution or by transferring the plants to a soilless nutrient solution.

  參考答案：

  1.○2

  2.○2

  3.○2

  4.○2

  5.○3

  6.○1

  7.○4

  8.○4

  9.○1

  10.○3

  11.○4

  12.○2

  13.○1

  14. Some plants are able to

  Though beneficial in lower…

  When plants do not…

  The Origin of the Pacific Island People

  The greater Pacific region, traditionally called Oceania, consists of three cultural areas: Melanesia, Micronesia, and Polynesia. Melanesia, in the southwest Pacific, contains the large islands of New Guinea, the Solomons, Vanuatu, and New Caledonia. Micronesia, the area north of Melanesia, consists primarily of small scattered islands. Polynesia is the central Pacific area in the great triangle defined by Hawaii, Easter Island, and New Zealand. Before the arrival of Europeans, the islands in the two largest cultural areas, Polynesia and Micronesia, together contained a population estimated at 700,000.

  廣義的太平洋地區(qū)，傳統(tǒng)上被稱作大洋洲，由三塊文化區(qū)域組成：美拉尼西亞，密克羅尼西亞和波利尼西亞。美拉尼西亞在西南太平洋，包含了新幾內(nèi)亞島、所羅門(mén)、瓦努阿圖和新喀里多尼亞的廣大島嶼。密克羅尼西亞在美拉尼西亞的北邊，主要由一些分散的島嶼組成。波利尼西亞是太平洋中心地區(qū)，位于由夏威夷、復(fù)活節(jié)群島和新西蘭的三大島嶼組成的三角區(qū)域中。在歐洲人到來(lái)之前，最大的波利尼西亞和密克羅尼西亞島嶼群一共有差不多70萬(wàn)人口。

  Speculation on the origin of these Pacific islanders began as soon as outsiders encountered them, in the absence of solid linguistic, archaeological, and biological data, many fanciful and mutually exclusive theories were devised. Pacific islanders are variously thought to have come from North America, South America, Egypt, Israel, and India, as well as Southeast Asia. Many older theories implicitly deprecated the navigational abilities and overall cultural creativity of the Pacific islanders. For example, British anthropologists G. Elliot Smith and W. J. Perry assumed that only Egyptians would have been skilled enough to navigate and colonize the Pacific. They inferred that the Egyptians even crossed the Pacific to found the great civilizations of the New World (North and South America). In 1947 Norwegian adventurer Thor Heyerdahl drifted on a balsa-log raft westward with the winds and currents across the Pacific from South America to prove his theory that Pacific islanders were Native Americans (also called American Indians). Later Heyerdahl suggested that the Pacific was peopled by three migrations: by Native Americans from the Pacific Northwest of North America drifting to Hawaii, by Peruvians drifting to Easter Island, and by Melanesians. In 1969 he crossed the Atlantic in an Egyptian-style reed boat to prove Egyptian influences in the Americas. Contrary to these theorists, the overwhelming evidence of physical anthropology, linguistics, and archaeology shows that the Pacific islanders came from Southeast Asia and were skilled enough as navigators to sail against the prevailing winds and currents.

  對(duì)于太平洋群島居民起源的思索開(kāi)始于外來(lái)者和島民們接觸的最初，由于缺乏可靠的語(yǔ)言學(xué)、考古學(xué)和生物學(xué)資料，出現(xiàn)了很多奇異并且互斥的理論。之前太平洋島民曾被認(rèn)為來(lái)自北美洲、南美洲、埃及、以色列、印度以及東南亞。許多古老的理論含蓄地貶低了太平洋群島居民的航海能力和綜合文化創(chuàng)造力。比如說(shuō)，英國(guó)人類學(xué)家G. Elliot Smith 和W. J. Perry認(rèn)為只有埃及人才能熟練地航海和統(tǒng)治太平洋。他們推斷埃及人甚至曾經(jīng)穿越過(guò)太平洋去尋找新世界的文明(北美洲和南美洲)。1947年，挪威探險(xiǎn)家Thor Heyerdahl為了證明他的太平洋群島居民是美國(guó)本土居民(也被稱作美國(guó)印第安人)的理論，用一只帶有標(biāo)志的輕質(zhì)木筏，借助風(fēng)力和水流從南美洲漂流過(guò)了太平洋。后來(lái)Heyerdahl表明太平洋人來(lái)自三個(gè)移民群體：從北美洲西北部太平洋地區(qū)漂流到夏威夷的美國(guó)本土居民，從秘魯去往復(fù)活節(jié)島的漂流者，還有美拉尼西亞人。1969年，他駕駛一條埃及樣式的蘆葦船穿過(guò)大西洋，證明埃及人在美洲的影響。與這些理論相矛盾的是，有關(guān)物理人類學(xué)、語(yǔ)言學(xué)和考古學(xué)的權(quán)威證據(jù)表明，太平洋島居民來(lái)自東南亞，并且他們有足夠的能力來(lái)逆著風(fēng)和洋流航行。

  The basic cultural requirements for the successful colonization of the Pacific islands include the appropriate boat-building, sailing, and navigation skills to get to the islands in the first place, domesticated plants and gardening skills suited to often marginal conditions, and a varied inventory of fishing implements and techniques. It is now generally believed that these prerequisites originated with peoples speaking Austronesian languages (a group of several hundred related languages) and began to emerge in Southeast Asia by about 5000 B.C.E. The culture of that time, based on archaeology and linguistic reconstruction, is assumed to have had a broad inventory of cultivated plants including taro, yarns, banana, sugarcane, breadfruit, coconut, sago, and rice. Just as important, the culture also possessed the basic foundation for an effective maritime adaptation, including outrigger canoes and a variety of fishing techniques that could be effective for overseas voyaging.

  成功地將太平洋群島殖民地化需要的基礎(chǔ)文化條件包括：適當(dāng)?shù)脑齑⒑叫泻秃胶＜夹g(shù)以首先到達(dá)島嶼;適應(yīng)貧瘠條件的馴化植物和園藝技術(shù);各種各樣的捕魚(yú)器具和技術(shù)。現(xiàn)在普遍認(rèn)為這些先決條件是那些說(shuō)南島語(yǔ)(一個(gè)有幾百種親屬語(yǔ)種的語(yǔ)系)的人所帶來(lái)的，他們公元前5 000年前就出現(xiàn)在東南亞。通過(guò)考古學(xué)和語(yǔ)言學(xué)的重建發(fā)現(xiàn)，那個(gè)時(shí)候的文明擁有廣泛的植物儲(chǔ)存，包括芋頭、紗、香蕉、甘蔗、面包果、椰子、西米和稻米。同樣重要的是，當(dāng)時(shí)的社會(huì)也具備適應(yīng)海洋的基礎(chǔ)，包括桅桿船和各種各樣有利于越洋航行的捕魚(yú)技術(shù)。

  Contrary to the arguments of some that much of the pacific was settled by Polynesians accidentally marooned after being lost and adrift, it seems reasonable that this feat was accomplished by deliberate colonization expeditions that set out fully stocked with food and domesticated plants and animals. Detailed studies of the winds and currents using computer simulations suggest that drifting canoes would have been a most unlikely means of colonizing the Pacific. These expeditions were likely driven by population growth and political dynamics on the home islands, as well as the challenge and excitement of exploring unknown waters.

  與那個(gè)太平洋人很多都是波利尼西亞人偶然迷失并漂流而定居下來(lái)的說(shuō)法相反的是，這些功績(jī)是通過(guò)有意的殖民遠(yuǎn)征來(lái)實(shí)現(xiàn)的，他們那些準(zhǔn)備周詳，出發(fā)時(shí)滿載食物、已培育好的植物和以馴化的動(dòng)物。通過(guò)電腦模擬對(duì)風(fēng)向和洋流進(jìn)行的詳細(xì)研究表明，船只漂流是最不可能的殖民太平洋的途徑。遠(yuǎn)征可能是由本土的人口增長(zhǎng)、政治動(dòng)蕩以及探索未知水域的挑戰(zhàn)和興奮所驅(qū)動(dòng)的。

  Because all Polynesians, Micronesians, and many Melanesians speak Austronesian languages and grow crops derived from Southeast Asia, all these peoples most certainly derived from that region and not the New World or elsewhere. The undisputed pre-Columbian presence in Oceania of the sweet potato, which is a New World domesticate, has sometimes been used to support Heyerdahl’s “American Indians in the Pacific” theories. However, this is one plant out of a long list of Southeast Asian domesticates. As Patrick Kirch, an American anthropologist, points out, rather than being brought by rafting South Americans, sweet potatoes might just have easily been brought back by returning Polynesian navigators who could have reached the west coast of South America.

  因?yàn)樗械牟ɡ嵛鱽喨恕⒚芸肆_尼西亞人和很多美拉尼西亞人說(shuō)南島語(yǔ)，種植的莊稼起源于東南亞，所以所有的這些人最有可能來(lái)自那個(gè)地方，而不是新世界或者其他地方。甘薯，一種新世界的品種，在哥倫比亞發(fā)現(xiàn)美洲大陸前它就在大洋洲的出現(xiàn)，這是無(wú)可置疑的，這有時(shí)候被用來(lái)證明Heyerdahl的太平洋島民是美國(guó)印第安人的理論。然而，這是一種在東南亞培育的植物的長(zhǎng)名單之外的植物。正如美國(guó)人類學(xué)家Patrick Kirch所指出的，比起從南美漂流過(guò)來(lái)，甘薯更容易被那些到過(guò)南美的玻利尼西亞返航者攜帶來(lái)。

  Paragraph1: The greater Pacific region, traditionally called Oceania, consists of three cultural areas: Melanesia, Micronesia, and Polynesia. Melanesia, in the southwest Pacific, contains the large islands of New Guinea, the Solomons, Vanuatu, and New Caledonia. Micronesia, the area north of Melanesia, consists primarily of small scattered islands. Polynesia is the central Pacific area in the great triangle defined by Hawaii, Easter Island, and New Zealand. Before the arrival of Europeans, the islands in the two largest cultural areas, Polynesia and Micronesia, together contained a population estimated at 700,000.

  1. According to paragraph 1, all of the following are true statements about Melanesia, Micronesia, and Polynesia EXCEPT:

  ○ Collectively, these regions are traditionally known as Oceania.

  ○ These islands of Micronesia are small and spread out.

  ○ Hawaii, Easter Island, and New Zealand mark the boundaries of Polynesia.

  ○ Melanesia is situated to the north of Micronesia.

  Paragraph 2: Speculation on the origin of these Pacific islanders began as soon as outsiders encountered them, in the absence of solid linguistic, archaeological, and biological data, many fanciful and mutually exclusive theories were devised. Pacific islanders are variously thought to have come from North America, South America, Egypt, Israel, and India, as well as Southeast Asia. Many older theories implicitly deprecated the navigational abilities and overall cultural creativity of the Pacific islanders. For example, British anthropologists G. Elliot Smith and W. J. Perry assumed that only Egyptians would have been skilled enough to navigate and colonize the Pacific. They inferred that the Egyptians even crossed the Pacific to found the great civilizations of the New World (North and South America). In 1947 Norwegian adventurer Thor Heyerdahl drifted on a balsa-log raft westward with the winds and currents across the Pacific from South America to prove his theory that Pacific islanders were Native Americans (also called American Indians). Later Heyerdahl suggested that the Pacific was peopled by three migrations: by Native Americans from the Pacific Northwest of North America drifting to Hawaii, by Peruvians drifting to Easter Island, and by Melanesians. In 1969 he crossed the Atlantic in an Egyptian-style reed boat to prove Egyptian influences in the Americas. Contrary to these theorists, the overwhelming evidence of physical anthropology, linguistics, and archaeology shows that the Pacific islanders came from Southeast Asia and were skilled enough as navigators to sail against the prevailing winds and currents.

  2. By stating that the theories are “mutually exclusive” the author means that

  ○ if one of the theories is true, then all the others must be false

  ○ the differences between the theories are unimportant

  ○ taken together, the theories cover all possibilities

  ○ the theories support each other

  3. The word “overwhelming” in the passage is closest in meaning to

  ○ powerful

  ○ favorable

  ○ current

  ○ reasonable

  4. According to paragraph 2, which of the following led some early researchers to believe that the Pacific islanders originally came from Egypt?

  ○ Egyptians were known to have founded other great civilizations.

  ○ Sailors from other parts of the world were believed to lack the skills needed to travel across the ocean.

  ○ Linguistic, archaeological, and biological data connected the islands to Egypt.

  ○ Egyptian accounts claimed responsibility for colonizing the Pacific as well as the Americas.

  5. Which of the following can be inferred from paragraph 2 about early theories of where the first inhabitants of the Pacific islands came from?

  ○ They were generally based on solid evidence.

  ○ They tried to account for the origin of the characteristic features of the languages spoken by Pacific islanders.

  ○ They assumed that the peoples living in Southeast Asia did not have the skills needed to sail to the Pacific islands.

  ○ They questioned the ideas of G. Elliot Smith and W. J. Perry.

  Paragraph 3: The basic cultural requirements for the successful colonization of the Pacific islands include the appropriate boat-building, sailing, and navigation skills to get to the islands in the first place, domesticated plants and gardening skills suited to often marginal conditions, and a varied inventory of fishing implements and techniques. It is now generally believed that these prerequisites originated with peoples speaking Austronesian languages (a group of several hundred related languages) and began to emerge in Southeast Asia by about 5000 B.C.E. The culture of that time, based on archaeology and linguistic reconstruction, is assumed to have had a broad inventory of cultivated plants including taro, yarns, banana, sugarcane, breadfruit, coconut, sago, and rice. Just as important, the culture also possessed the basic foundation for an effective maritime adaptation, including outrigger canoes and a variety of fishing techniques that could be effective for overseas voyaging.來(lái)源：北京新航道托福培訓(xùn)

  6. The word “implements” in the passage is closest in meaning to

  ○ skills

  ○ tools

  ○ opportunities

  ○ practices

  7. All of the following are mentioned in paragraph 3 as required for successful colonization of the Pacific islands EXCEPT

  ○ knowledge of various Austronesian languages

  ○ a variety of fishing techniques

  ○ navigational skills

  ○ knowledge of plant cultivation

  8. In paragraph 3, why does the author provide information about the types of crops grown and boats used in Southeast Asia during the period around 5000 B. C. E.?

  ○ To evaluate the relative importance of agriculture and fishing to early Austronesian peoples

  ○ To illustrate the effectiveness of archaeological and linguistic methods in discovering details about life in ancient times

  ○ To contrast living conditions on the continent of Asia with living conditions on the Pacific islands

  ○ To demonstrate that people from this region had the skills and resources necessary to travel to and survive on the Pacific islands

  Paragraph 4: Contrary to the arguments of some that much of the pacific was settled by Polynesians accidentally marooned after being lost and adrift, it seems reasonable that this feat was accomplished by deliberate colonization expeditions that set out fully stocked with food and domesticated plants and animals. Detailed studies of the winds and currents using computer simulations suggest that drifting canoes would have been a most unlikely means of colonizing the Pacific. These expeditions were likely driven by population growth and political dynamics on the home islands, as well as the challenge and excitement of exploring unknown waters. Because all Polynesians, Micronesians, and many Melanesians speak Austronesian languages and grow crops derived from Southeast Asia, all these peoples most certainly derived from that region and not the New World or elsewhere. The undisputed pre-Columbian presence in Oceania of the sweet potato, which is a New World domesticate, has sometimes been used to support Heyerdahl’s “American Indians in the Pacific” theories. However, this is one plant out of a long list of Southeast Asian domesticates. As Patrick Kirch, an American anthropologist, points out, rather than being brought by rafting South Americans, sweet potatoes might just have easily been brought back by returning Polynesian navigators who could have reached the west coast of South America.

  9. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

  ○ Some people have argued that the Pacific was settled by traders who became lost while transporting domesticated plants and animals.

  ○ The original Polynesian settlers were probably marooned on the islands, but they may have been joined later by carefully prepared colonization expeditions.

  ○ Although it seems reasonable to believe that colonization expeditions would set out fully stocked, this is contradicted by much of the evidence.

  ○ The settlement of the Pacific islands was probably intentional and well planned rather than accidental as some people have proposed.

  10. The word “undisputed” in the passage is closest in meaning to

  ○ mysterious

  ○ unexpected

  ○ acknowledged

  ○ significant

  11. According to paragraph 4, which of the following is NOT an explanation for why a group of people might have wanted to colonize the Pacific islands?

  ○ As their numbers increased, they needed additional territory.

  ○ The winds and currents made the islands easy to reach.

  ○ The political situation at home made emigration desirable.

  ○ They found exploration challenging and exciting.

  12. Why does the author mention the views of “Patrick Kirch”?

  ○ To present evidence in favor of Heyerdahl’s idea about American Indians reaching Oceania

  ○ To emphasize the familiarity of Pacific islanders with crops from many different regions of the world

  ○ To indicate that supposed proof for Heyerdahl’s theory has an alternative explanation

  ○ To demonstrate that some of the same crops were cultivated in both South America and Oceania

  Paragraph 2: Speculation on the origin of these Pacific islanders began as soon as outsiders encountered them, in the absence of solid linguistic, archaeological, and biological data, many fanciful and mutually exclusive theories were devised. Pacific islanders are variously thought to have come from North America, South America, Egypt, Israel, and India, as well as Southeast Asia. ■Many older theories implicitly deprecated the navigational abilities and overall cultural creativity of the Pacific islanders. ■For example, British anthropologists G. Elliot Smith and W. J. Perry assumed that only Egyptians would have been skilled enough to navigate and colonize the Pacific. ■They inferred that the Egyptians even crossed the Pacific to found the great civilizations of the New World (North and South America). ■In 1947 Norwegian adventurer Thor Heyerdahl drifted on a balsa-log raft westward with the winds and currents across the Pacific from South America to prove his theory that Pacific islanders were Native Americans (also called American Indians). Later Heyerdahl suggested that the Pacific was peopled by three migrations: by Native Americans from the Pacific Northwest of North America drifting to Hawaii, by Peruvians drifting to Easter Island, and by Melanesians. In 1969 he crossed the Atlantic in an Egyptian-style reed boat to prove Egyptian influences in the Americas. Contrary to these theorists, the overwhelming evidence of physical anthropology, linguistics, and archaeology shows that the Pacific islanders came from Southeast Asia and were skilled enough as navigators to sail against the prevailing winds and currents.

  13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

  Later theories concentrate on journeys in the other direction.

  Where could the sentence best fit?

  Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

  Together, Melanesia, Micronesia, and Polynesia make up the region described as the Pacific islands, or Oceania.

  ●

  ●

  ●

  Answer Choices

  ○The first Europeans to reach the area assumed that the islands’ original inhabitants must have drifted to Oceania, perhaps from Egypt or the Americas.

  ○It is now believed that the process of colonization required a great deal of skill, determination, and planning and could not have happened by chance.

  ○Using linguistic and archaeological evidence, anthropologists have determined that the first Pacific islanders were Austronesian people from Southeast Asia.

  ○New evidence suggests that, rather than being isolated, Pacific islanders engaged in trade and social interaction with peoples living in Southeast Asia.

  ○Although early colonizers of the islands probably came from agriculture-based societies, they were obliged to adopt an economy based on fishing.

  ○Computer simulations of the winds and currents in the Pacific have shown that reaching the Pacific islands was probably much easier than previously thought.

  參考答案：

  1.○4

  2.○1

  3.○1

  4.○2

  5.○3

  6.○2

  7.○1

  8.○4

  9.○4

  10.○3

  11.○2

  12.○3

  13.○4

  14. The first Europeans to…

  It is now believed that…

  Using linguistic and…

  The Cambrian Explosion

  The geologic timescale is marked by significant geologic and biological events, including the origin of Earth about 4.6 billion years ago, the origin of life about 3.5 billion years ago, the origin of eukaryotic life-forms (living things that have cells with true nuclei) about 1.5 billion years ago, and the origin of animals about 0.6 billion years ago. The last event marks the beginning of the Cambrian period. Animals originated relatively late in the history of Earth—in only the last 10 percent of Earth’s history. During a geologically brief 100-million-year period, all modern animal groups (along with other animals that are now extinct) evolved. This rapid origin and diversification of animals is often referred to as “the Cambrian explosion.”

  地質(zhì)年代是由重大地質(zhì)事件和生物事件標(biāo)記的，包括46億年前地球的形成、35億年前生命的起源、15億年前真核生物(細(xì)胞中有真核的生命體)的起源以及6億年前動(dòng)物的起源;最近的一個(gè)事件標(biāo)志著寒武紀(jì)的開(kāi)始。動(dòng)物的起源相對(duì)處于地球歷史的晚期——僅存在于地球歷史時(shí)間的1∕10。在短暫的1億年地質(zhì)學(xué)周期中，所有現(xiàn)代動(dòng)物群(包括現(xiàn)在已經(jīng)滅絕的生物)進(jìn)化了。這次快速的動(dòng)物起源和分化常常被稱為“寒武紀(jì)大爆發(fā)”。

  Scientists have asked important questions about this explosion for more than a century. Why did it occur so late in the history of Earth? The origin of multicellular forms of life seems a relatively simple step compared to the origin of life itself. Why does the fossil record not document the series of evolutionary changes during the evolution of animals? Why did animal life evolve so quickly? Paleontologists continue to search the fossil record for answers to these questions.

  一個(gè)多世紀(jì)以來(lái)，科學(xué)家們對(duì)這次大爆發(fā)一直有疑惑。為什么它發(fā)生的得這么晚?多細(xì)胞生物的出現(xiàn)相對(duì)于生命的出現(xiàn)而言則是一次相對(duì)簡(jiǎn)單的進(jìn)化。為什么化石沒(méi)有記錄下動(dòng)物演化的一系列變化呢?為什么動(dòng)物生命進(jìn)化得如此迅速呢?古生物學(xué)家們?nèi)耘f在研究化石記錄以期回答這些問(wèn)題。

  One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft bodied and simply did not fossilize. Fossilization of soft-bodied animals is less likely than fossilization of hard-bodied animals, but it does occur. Conditions that promote fossilization of soft-bodied animals include very rapid covering by sediments that create an environment that discourages decomposition. In fact, fossil beds containing soft-bodied animals have been known for many years.

  關(guān)于這重要的1億年內(nèi)化石的缺失，有一種解釋是早期的動(dòng)物都是軟體動(dòng)物，它們很難形成化石。軟體動(dòng)物的化石比硬體動(dòng)物化石少見(jiàn)得多，但是也是存在的。促使軟體動(dòng)物成為化石的條件是沉積物的迅速覆蓋以形成一個(gè)抑制分解的環(huán)境。事實(shí)上，含有軟體動(dòng)物的化石層在很多年以前就已經(jīng)為人們所知了。

  The Ediacara fossil formation, which contains the oldest known animal fossils, consists exclusively of soft-bodied forms. Although named after a site in Australia, the Ediacara formation is worldwide in distribution and dates to Precambrian times. This 700-million-year-old formation gives few clues to the origins of modern animals, however, because paleontologists believe it represents an evolutionary experiment that failed. It contains no ancestors of modern animal groups.

  含有最古老的動(dòng)物化石的伊迪卡拉化石群就全部由軟體動(dòng)物化石組成。盡管伊迪卡拉是以澳大利亞的一處地名而命名，但是伊迪卡拉沉積層的分布卻遍及世界各地，并且可以追溯到前寒武紀(jì)時(shí)期。這些7億年前形成的地層為現(xiàn)代動(dòng)物的起源提供了一些新的線索。因?yàn)楣派飳W(xué)家們認(rèn)為它代表著一次失敗的進(jìn)化試驗(yàn)，其中并沒(méi)有包含任何現(xiàn)代動(dòng)物的祖先。

  A slightly younger fossil formation containing animal remains is the Tommotian formation, named after a locale in Russia. It dates to the very early Cambrian period, and it also contains only soft-bodied forms. At one time, the animals present in these fossil beds were assigned to various modern animal groups, but most paleontologists now agree that all Tommotian fossils represent unique body forms that arose in the early Cambrian period and disappeared before the end of the period, leaving no descendants in modern animal groups.

  以俄羅斯的一處地名而命名的Tommotian是一層包含動(dòng)物殘骸的較年輕的化石層。它形成于寒武紀(jì)的早期，并且同樣只含有軟體動(dòng)物化石。在一段時(shí)間內(nèi)，人們認(rèn)為這些化石中的動(dòng)物分化出了各種各樣的現(xiàn)代動(dòng)物。但是古生物學(xué)家們現(xiàn)在卻認(rèn)為，所有的Tommotian化石都僅代表在寒武紀(jì)初期出現(xiàn)但到寒武紀(jì)結(jié)束時(shí)就消失了的特別生物。所以它們沒(méi)有在現(xiàn)在動(dòng)物中留下后代。

  A third fossil formation containing both soft-bodied and hard-bodied animals provides evidence of the result of the Cambrian explosion. This fossil formation, called the Burgess Shale, is in Yoho National Park in the Canadian Rocky Mountains of British Columbia. Shortly after the Cambrian explosion, mud slides rapidly buried thousands of marine animals under conditions that favored fossilization. These fossil beds provide evidence of about 32 modern animal groups, plus about 20 other animal body forms that are so different from any modern animals that they cannot be assigned to any one of the modern groups. These unassignable animals include a large swimming predator called Anomalocaris and a soft-bodied animal called Wiwaxia, which ate detritus or algae. The Burgess Shale formation also has fossils of many extinct representatives of modern animal groups. For example, a well-known Burgess Shale animal called Sidneyia is a representative of a previously unknown group of arthropods (a category of animals that includes insects, spiders, mites, and crabs).

  第三種化石層既包含了軟體動(dòng)物也包含了硬體動(dòng)物，它為寒武紀(jì)大爆發(fā)提供了證據(jù)。這種叫做伯吉斯頁(yè)巖的化石群就在加拿大的大不列顛哥倫比亞石山上的約霍國(guó)家公園內(nèi)。在寒武紀(jì)大爆發(fā)后不久，滑落的泥土迅速掩埋了成千上萬(wàn)的海洋動(dòng)物，形成了極有利于化石形成的環(huán)境。這些化石層含有大約32種現(xiàn)代動(dòng)物，還有大約20種與現(xiàn)在動(dòng)物截然不同以至于不可能分類為任何一種現(xiàn)代動(dòng)物的其他動(dòng)物體。這些無(wú)法劃分的動(dòng)物包含一種叫做奇蝦的肉食動(dòng)物和一種叫做威瓦亞蟲(chóng)的以巖屑和藻類為食的軟體動(dòng)物。伯吉斯頁(yè)巖化石群也含有很多現(xiàn)在已經(jīng)滅絕了的動(dòng)物化石。例如伯吉斯頁(yè)巖化石群中的一種著名動(dòng)物，Sidneyia，就是一種典型的以前還不為人知的節(jié)肢動(dòng)物(一種動(dòng)物分類，它包括昆蟲(chóng)、蜘蛛、螨蟲(chóng)和螃蟹)。

  Fossil formations like the Burgess Shale show that evolution cannot always be thought of as a slow progression. The Cambrian explosion involved rapid evolutionary diversification, followed by the extinction of many unique animals. Why was this evolution so rapid? No one really knows. Many zoologists believe that it was because so many ecological niches were available with virtually no competition from existing species. Will zoologists ever know the evolutionary sequences in the Cambrian explosion? Perhaps another ancient fossil bed of soft-bodied animals from 600-million-year-old seas is awaiting discovery.

  像伯吉斯頁(yè)巖化石群這樣的化石層表明進(jìn)化不能總是被認(rèn)為是緩慢的過(guò)程。寒武紀(jì)大爆涉及到了快速的進(jìn)化分化，接著就是很多獨(dú)特動(dòng)物的滅絕。為什么這種進(jìn)化如此迅速呢?沒(méi)有人真正的明白。很多動(dòng)物學(xué)家認(rèn)為這是很多幾乎沒(méi)有任何競(jìng)爭(zhēng)性物種的環(huán)境使然。動(dòng)物學(xué)家們是否知道寒武紀(jì)大爆發(fā)的動(dòng)物的進(jìn)化順序呢?或許另一些含有來(lái)自于6億年前的海洋動(dòng)物的化石亟待發(fā)現(xiàn)。

  Paragraph 1: The geologic timescale is marked by significant geologic and biological events, including the origin of Earth about 4.6 billion years ago, the origin of life about 3.5 billion years ago, the origin of eukaryotic life-forms (living things that have cells with true nuclei) about 1.5 billion years ago, and the origin of animals about 0.6 billion years ago. The last event marks the beginning of the Cambrian period. Animals originated relatively late in the history of Earth—in only the last 10 percent of Earth’s history. During a geologically brief 100-million-year period, all modern animal groups (along with other animals that are now extinct) evolved. This rapid origin and diversification of animals is often referred to as “the Cambrian explosion.”

  1. The word “significant” in the passage is closest in meaning to

  ○ numerous

  ○ important

  ○ unexplained

  ○ sudden

  2. The word “relatively” in the passage is closest in meaning to

  ○ surprisingly

  ○ collectively

  ○ comparatively

  ○ characteristically

  3. The word “diversification” in the passage is closest in meaning to

  ○ emergence of many varieties

  ○ steady decline in number

  ○ gradual increase in body size

  ○ sudden disappearance

  Paragraph 2: Scientists have asked important questions about this explosion for more than a century. Why did it occur so late in the history of Earth? The origin of multicellular forms of life seems a relatively simple step compared to the origin of life itself. Why does the fossil record not document the series of evolutionary changes during the evolution of animals? Why did animal life evolve so quickly? Paleontologists continue to search the fossil record for answers to these questions.

  4. The period discussed in the passage is referred to as an “explosion” because it

  ○ occurred 0.6 billion years ago, late in Earth’s history

  ○ was characterized by the unusually fast evolution of many new life-forms

  ○ was characterized by widespread animal extinction

  ○ was characterized by violent volcanic eruptions

  5. According to Paragraph2, which of the following is NOT a question that paleontologists asked about the Cambrian explosion?

  ○ Why was the origin of life a simple step in Earth’s history?

  ○ Why did it take so long for multicellular organisms to develop?

  ○ Why did animal life evolve so rapidly?

  ○ Why does the fossil record lack evidence of animal evolution during that time?

  6. Which of the following best describes the relationship between paragraph 2 and paragraph 3?

  ○ Paragraph 2 puts forward several scientific claims, one of which is rejected in paragraph 3.

  ○ Paragraph 2 poses several questions, and paragraph 3 offers a possible answer to one of them.

  ○ Paragraph 2 presents outdated traditional views, while paragraph 3 presents the current scientific conclusions.

  ○ Paragraph 2 introduces a generalization that is illustrated by specific examples in paragraph 3.

  Paragraph 3: One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft bodied and simply did not fossilize. Fossilization of soft-bodied animals is less likely than fossilization of hard-bodied animals, but it does occur. Conditions that promote fossilization of soft-bodied animals include very rapid covering by sediments that create an environment that discourages decomposition. In fact, fossil beds containing soft-bodied animals have been known for many years.

  7. The word “promote” in the passage is closest in meaning to

  ○ complicate

  ○ prevent

  ○ encourage

  ○ affect

  Paragraph 4: The Ediacara fossil formation, which contains the oldest known animal fossils, consists exclusively of soft-bodied forms. Although named after a site in Australia, the Ediacara formation is worldwide in distribution and dates to Precambrian times. This 700-million-year-old formation gives few clues to the origins of modern animals, however, because paleontologists believe it represents an evolutionary experiment that failed. It contains no ancestors of modern animal groups.

  8. Which of the following is NOT mentioned in paragraph 4 as being true of the Ediacara formation?

  ○ It contains fossils that date back to the Precambrian period.

  ○ It contains only soft-bodied animal fossils.

  ○ It is located on a single site in Australia.

  ○ It does not contain any fossils of the ancestors of modern animals.

  Paragraph 5: A slightly younger fossil formation containing animal remains is the Tommotian formation, named after a locale in Russia. It dates to the very early Cambrian period, and it also contains only soft-bodied forms. At one time, the animals present in these fossil beds were assigned to various modern animal groups, but most paleontologists now agree that all Tommotian fossils represent unique body forms that arose in the early Cambrian period and disappeared before the end of the period, leaving no descendants in modern animal groups.

  9. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

  ○ The animals found in the Tommotian fossil bed were once thought to belong to a variety of modern animal groups, but now they are thought to have descended from a single group.

  ○ Animals in the Tommotian fossil beds were initially assigned to modern animal groups but are now thought to belong to groups that emerged and died out during the Cambrian period.

  ○ Though at first they thought otherwise, paleontologists now agree that the animals in the Tommotian have body forms from which modern animals have descended.

  ○ It is unclear whether the Tommotian fossils from the early Cambrian period represent unique body forms or whether they should be assigned to various modern animal groups.

  Paragraph 6: A third fossil formation containing both soft-bodied and hard-bodied animals provides evidence of the result of the Cambrian explosion. This fossil formation, called the Burgess Shale, is in Yoho National Park in the Canadian Rocky Mountains of British Columbia. Shortly after the Cambrian explosion, mud slides rapidly buried thousands of marine animals under conditions that favored fossilization. These fossil beds provide evidence of about 32 modern animal groups, plus about 20 other animal body forms that are so different from any modern animals that they cannot be assigned to any one of the modern groups. These unassignable animals include a large swimming predator called Anomalocaris and a soft-bodied animal called Wiwaxia, which ate detritus or algae. The Burgess Shale formation also has fossils of many extinct representatives of modern animal groups. For example, a well-known Burgess Shale animal called Sidneyia is a representative of a previously unknown group of arthropods (a category of animals that includes insects, spiders, mites, and crabs).

  10. Why does the author mention “Anomalocans” and “Wiwaxia”?

  ○ To contrast predators with animals that eat plants such as algae

  ○ To question the effects of rapid mud slides on fossilization

  ○ To suggest that much is still unknown about animals found in the Burgess Shale

  ○ To provide examples of fossils that cannot be assigned to a modern animal group

  11. “Sidneyia” is an example of

  ○ a relative of Anomalocaris and Wiwaxia

  ○ a previously unknown Burgess Shale animal

  ○ an extinct member of a currently existing category of animals

  ○ an animal that cannot be assigned to any modern animal group

  Paragraph 7: Fossil formations like the Burgess Shale show that evolution cannot always be thought of as a slow progression. The Cambrian explosion involved rapid evolutionary diversification, followed by the extinction of many unique animals. Why was this evolution so rapid? No one really knows. Many zoologists believe that it was because so many ecological niches were available with virtually no competition from existing species. Will zoologists ever know the evolutionary sequences in the Cambrian explosion? Perhaps another ancient fossil bed of soft-bodied animals from 600-million-year-old seas is awaiting discovery.

  12. What can be inferred from paragraph 7 about why the Cambrian explosion is so unusual?

  ○ It generated new ecological niches through the extinction of many unique animals.

  ○ It was a period of rapid evolution, and evolution is often thought of as a slow process.

  ○ It is a period whose evolutionary sequences are clearly marked.

  ○ It generated a very large number of ancient fossil beds containing soft-bodied animals.

  Paragraph 3: One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft bodied and simply did not fossilize. ■Fossilization of soft-bodied animals is less likely than fossilization of hard-bodied animals, but it does occur. ■Conditions that promote fossilization of soft-bodied animals include very rapid covering by sediments that create an environment that discourages decomposition. ■In fact, fossil beds containing soft-bodied animals have been known for many years. ■

  13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

  It is relatively rare because the fossilization of soft-bodied animals requires a special environment.

  Where could the sentence best fit?

  14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

  The term “Cambrian explosion” refers to the geologically brief period during which all modern animal groups evolved.

  ●

  ●

  ●

  Answer Choices

  ○Little is known about the stages of evolution during the Cambrian period, in part because early animals were soft bodied and could fossilize only under particular conditions.

  ○While animal fossils from before the Cambrian explosion have no modern descendants, many animals that evolved during the Cambrian explosion can be assigned to modern groups.

  ○The Cambrian period is significant because it marks the emergence of eukaryotic life-forms—organisms that have cells with true nuclei.

  ○The Ediacara fossil formation provides the most information about the Cambrian explosion, while the earlier, Tommotian and Burgess Shale formations give clues about Precambrian evolution.

  ○Zoologists are awaiting the discovery of a 600-million-year-old fossil formation in order to be able to form a theory of how animal evolution progressed.

  ○Although the reasons for the rapid evolution of animals during the Cambrian period are not known, one proposed explanation is an abundance of niches with a lack of competitors.

  參考答案：

  1. ○2

  2. ○3

  3. ○1

  4. ○2

  5. ○1

  6. ○2

  7. ○3

  8. ○3

  9. ○2

  10. ○4

  11. ○3

  12. ○2

  13. ○2

  14. Little is known about the…

  While animal fossils…

  Although the reasons for the…

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