是考试中非常重要的一部分，考生们想要提高自己的托福阅读成绩首先是要大量的做题。今天托福阅读plant Colonization的原文试题以及答案，希望考生们可以认真答题，多读多练，这样才可以在考试中取得好成绩。
托福阅读原文
【1】Colonization is one way in which plants can change the ecology of a site. Colonization is a process with two components: invasion and survival. The rate at which a site is colonized by plants depends on both the rate at which individual organisms (seeds, spores, immature or mature individuals) arrive at the site and their success at becoming established and surviving. Success in colonization depends to a great extent on there being a site available for colonization—a safe site where disturbance by fire or by cutting down of trees has either removed competing species or reduced levels of competition and other negative interactions to a level at which the invading species can become established. For a given rate of invasion, colonization of a moist, fertile site is likely to be much more rapid than that of a dry, infertile site because of poor survival on the latter. A fertile, plowed field is rapidly invaded by a large variety of weeds, whereas a neighboring construction site from which the soil has beencompacted or removed to expose a coarse, infertile parent material may remain virtually free of vegetation for many months or even years despite receiving the same input of seeds as the plowed field.
【2】Both the rate of invasion and the rate of extinction vary greatly among different plant species. Pioneer species—those that occur only in the earliest stages of colonization—tend to have high rates of invasion because they produce very large numbers of reproductive propagules (seeds, spores, and so on) and because they have an efficient means of dispersal (normally, wind).
【3】If colonizers produce short-lived reproductive propagules, then they must produce very large numbers unless they have an efficient means of dispersal to suitable new habitats. Many plants depend on wind for dispersal and produce abundant quantities of small, relatively short-lived seeds to compensate for the fact that wind is not always a reliable means of reaching the appropriate type of habitat. Alternative strategies have evolved in some plants, such as those that produce fewer but larger seeds that are dispersed to suitable sites by birds or small mammals or those that produce long-lived seeds. Many forest plants seem to exhibit the latter adaptation, and viable seeds of pioneer species can be found in large numbers on some forest floors. For example, as many as 1,125 viable seeds per square meter were found in a 100-year-old Douglas fir/western hemlock forest in coastal British Columbia. Nearly all the seeds that had germinated from this seed bank were from pioneer species. The rapid colonization ofsuch sites after disturbance is undoubtedly in part a reflection of the large seed bank on the forest floor.
【4】An adaptation that is well developed in colonizing species is a high degree of variation in germination (the beginning of a seed's growth). Seeds of a given species exhibit a wide range of germination dates, increasing the probability that at least some of the seeds will germinate during a period of favorable environmental conditions. This is particularly important for species that colonize an environment where there is no existing vegetation to ameliorate climatic extremes and in which there may be great climatic diversity.
【5】Species succession in plant communities, i.e., the temporal sequence of appearance and disappearance of species is dependent on events occurring at different stages in the life history of a species. Variation in rates of invasion and growth plays an important role in determining patterns of succession, especially secondary succession. The species that are first to colonize a site are those that produce abundant seed that is distributed successfully to new sites. Such species generally grow rapidly and quickly dominate new sites, excluding other species with lower invasion and growth rates. The first community that occupies a disturbed area therefore may be composed of species with the highest rate of invasion, whereas the community of the subsequent stage may consist of plants with similar survival rates but lower invasion rates.
托福阅读试题
1.According to paragraph 1, how does disturbance of a site influence its colonization by a plant species?
A.Disturbance reduces or eliminates competition by other species.
B.Disturbance increases negative interactions with other organisms on the site.
C.Disturbance prevents a plant species from colonizing a new site.
D.Disturbance reduces the fertility of a site.
2.The word "virtually" in the passage (paragraph 1) is closest in meaning to
A.almost totally.
B.unusually.
C.consistently.
D.unnaturally.
3.Why does the author mention a plowed field and a construction site in the passage?
A.To argue that sites that have been affected by human activity tend to be colonized slowly.
B.To illustrate the kind of sites that may be invaded by weeds.
C.To contrast sites in terms of their suitability for colonization.
D.To explain that exposing or compacting the soil results in successful colonization.
4.The word "despite"(paragraph 1) in the passage is closest in meaning to
A.without.
B.almost never.
C.even though.
D.perhaps.
5.Which of the sentences below best expresses the essential information in the highlighted sentence in the passage (paragraph 2)? Incorrect choices change the meaning in important ways or leave out essential information.
A.The seeds of pioneer species are usually carried by the wind to fertile sites, where they reproduce very efficiently.
B.Pioneer species are successful invaders because they produce lots of seeds that are dispersed effectively.
C.Pioneer species produce their largest numbers of propagules during the earliest stages of their colonization.
D.Pioneer species reproduce very quickly and efficiently because they produce very large number of seeds.
6.What can be inferred from paragraph 3 about the reason that large seeds are dispersed by birds or small animals rather than by wind?
A.Large seeds are easier for birds and animals to see than are the small seeds dispersed by the wind.
B.Large seeds are too heavy for the wind to disperse.
C.Large seeds cannot be eaten by birds and animals.
D.Large seeds are short-lived and thus require a more efficient means of dispersal than small seeds do.
7.The phrase "the latter adaptation" in the passage (paragraph 3) refers to
A.producing fewer seeds.
B.producing larger seeds.
C.dispersal by birds and small mammals.
D.producing long-lived seeds.
8.The word "viable" in the passage (paragraph 3) is closest in meaning to
A.able to survive.
B.individual.
C.large.
D.remaining.
9.The example of the 100-year-old Douglas fir/western hemlock forest in paragraph to illustrates which of the following ideas?
A.It is uncommon for older seed to germinate.
B.Pioneer species tend to prefer forest floors for colonization purposes.
C.Long-lived seeds of pioneer species can successfully germinate over long periods of time.
D.Coastal British Columbia is particularly suited for pioneer species to develop.
10.According to paragraph 4, how do plants manage to germinate in areas with great climatic diversity and climatic extremes?
A.By producing seeds only during favorable climatic conditions.
B.By generating large numbers of seeds.
C.By colonizing only those areas where other plants have survived.
D.By producing seeds that have a wide range of germination dates.
11.The word "abundant〃 in the passage (paragraph 5) is closest in meaning to
A.new.
B.improved.
C.suitable.
D.plentiful.
12.According to paragraph 5, which of the following determines the sequence in which plant species will colonize a site?
A.The extent of growth of a species on a prior site before it begins to colonize a secondary site.
B.The differences in invasion and growth rates across species.
C.The degree of fertility of a site.
D.The kind of disturbance that the site has undergone.
13. Look at the four squares [■] that indicate where the following sentence could be added to the passage. Where does the sentence best fit? They require relatively little protection or nutrients.
Species succession in plant communities, i.e., the temporal sequence of appearance and disappearance of species is dependent on events occurring at different stages in the life history of a species.■【A】Variation in rates of invasion and growth plays an important role in determining patterns of succession, especially secondary succession.■【B】The species that are first to colonize a site are those that produce abundant seed that is distributed successfully to new sites.■【C】Such species generally grow rapidly and quickly dominate new sites, excluding other species with lower invasion and growth rates. The first community that occupies a disturbed area therefore may be composed of species with the highest rate of invasion, whereas the community of the subsequent stage may consist of plants with similar survival rates but lower invasion rates.■【D】
14. Prose Summary
The ecology of a site is changed through its colonization by new plants that arrive and grow there.
A.The species that first colonize a disturbed site are typically ones that produce a large number of efficiently dispersed seeds.
B.Plants that cannot successfully compete with other species can invade and colonize a site only if it is fertile and moist, such as a plowed field.
C.Pioneer species arrive at a site first but have lower survival rates than do species that arrive later.
D.Producing seeds that germinate at various times over long periods allows some plants to colonize sites that only occasionally present the right conditions for growth.
E.Large, long-lived seeds tend to result in large seed banks with short germination periods requiring favorable environmental conditions for development.
F.The successive appearance and disappearance of species on a site is a result of variation in species' rates of invasion, growth, and survival.
托福阅读答案
1.第1段第4句话，通过火灾和砍伐的干涉要么消除竞争对手要么降低竞争的强度。
2.virtually表示"实际上，几乎", 程度上对应almost totally。
3.第一段第5、6句话，肥沃的土地植物入侵的速度快，反之亦然。
4.despite 尽管，对应even though 尽管/即使。
5.原句强调了先锋物种入侵速度快的两个原因，一是能够产生大量可繁殖的种子，二是拥有有效的传播途径。原句和fertile sites没有关系，A错;C没有提到种子的繁殖力; D没有提到传播途径，只有B满足原句的条件。
6.第3段第2，3句：小种子通常靠风传播，大种子由鸟和动物实现传播。
7.the latter adaptation，后一种适应性，段落开头讲的是短命种子，所以后一种适应性是指长命种子。
8.viable，有生命力的，对应A。
9.该例子的前一句话为观点句, 例子是为了说明观点，即长命种子在森林地面上很繁荣。
10.该段的第1句话，发芽时间的变化。
11.abundant，表示"丰富的"，对应D。
12.该段第二句话，succession 对应colonize a site。
13.they指代species. 原句说该物种的生存要求很低，就意味着他们更能存活，原句接下去可能阐述该物种如何靠着该优势来侵占土地繁殖。
14.A选项: 对应第2段的核心意思，第2句话;
B选项: 原文中没有明确说明的信息;
C选项: 违背原文意思，第三段最后一句;
D选项: 对应第4段的核心意思;
E选项: requiring favorable environmental conditions for development是原文中没有明确说明的信息;
F选项: 对应第5段的核心意思。
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