托福阅读背景知识：水藻(Seaweed)

 　　在2014年4月19日的托福阅读考试中有这样一道题：水藻在海中的分布、作用以及影响水藻纵横分布的因素，主要讲一个颜色纵向分布。

　　针对这道托福考题，新东方富亦聪老师来为大家普及一下关于水藻的背景知识，这样有助于考生在面对这类题目时方便作答，同时富亦聪老师也为您指导解答这类题目的小技巧。

　　托福阅读真题再现：

　　Characteristics of seaweed plants

　　海草

　　第一段大概就在说这个海里面的东东和陆地植物有点不一样，但还是有叶绿素的，貌似还有其他神马的。。

　　第二段有图， 就讲这些东东要领队在在诸如石头啊什么的东西上面。说他们的类似于stem一类的东西可以达到35metres，(这里有题)还说因为这种植物不需要通过根部transportation，从ground里面吸收营养和水分，所以这个根部roots和一般的陆地植物根部不一样的(有题，问为什么他们不一样，有个选项是：因为他们不需要像leaves一样有运送水分和营养的功能，还有个选项说这个植物不需要ground的水分和营养)。。

　　第三段讲如果植物遇到storm的话，他们貌似会抓得更紧(有题：问遇到storm的时候这个哪门)。然后又讲说这个植物在某种情况下会die。

　　第四段说这个植物在海里的情况，说有三种颜色：green, blue, 和red。说是按深浅来的，只要在某Z的区域内，阳光都能照到，然后都可以活。

　　第五段讲这种植物可以给很多生物提供shelter。然后可以作为很多动物的food，还有一个功能，我也记不清了。然后下面有一道题问下列哪个不是这个植物可以为其他生物做的(有个选项貌似说是提供construction materials。我就选的这个。)题目：

　　海草为什么会被 植物学家特别划分出来?因为它有叶绿素会进行光合作用;为什么storm有可能造成海草死亡，因为它的根脱落。

　　海草跟陆上植物叶子或根作用有何不同?海草的叶子不储存水分(不确定)。

　　海草的根不吸收水份及营养。

　　新东方富亦聪解析如何解答这类考题：

　　本文主旨明确，结构清晰，围绕seaweed展开陈述。每段首句为topic sentence的可能性较高。做题时需注意记录笔记，对于结构化阅读及最后一题的解答有很大好处。

　　水藻(Seaweed)相关背景：

　　Seaweed, any red, green, or brown marine¹ algae² that grow on seashores. They are anchored to the sea bottom or to some solid structure by rootlike holdfasts that perform the sole function of attachment³ and do not extract nutrients⁴ as do the roots of higher plants.

　　Seaweeds often form dense⁵ growths on rocky shores or accumulations in shallow water. Many show a well-established zonation along the margins⁶ of the seas, where the depth of the water is 50 metres (about 165 feet) or less. The types of seaweed growing near the high-water mark, where plants are often exposed to air, differ from those growing at lower levels, where there is little or no exposure. Fucus, Macrocystis, Nereocystis, and Laminaria are widely distributed in colder zones and are absent from tropical waters.

　　Brown algae commonly found as seaweeds include kelps and Fucus. Among the kelps are the largest algae; certain species of Macrocystis and Nereocystis of the Pacific and Antarctic regions exceed 33 metres (100 feet) in length. Laminaria, another kelp, is abundant along both Pacific and Atlantic coasts. Gulfweed (Sargassum;) is common as free-floating masses in the Gulf⁷ Stream and the Sargasso Sea.

　　Red alga seaweeds include dulse (Rhodymenia), Gelidium, Chondrus, and laver (Porphyra). Various species of Chondrus (see Irish moss) carpet the lower half of the zone exposed at low tide along rocky coasts of the Atlantic.

　　Ulva species, commonly called sea lettuce⁸, are among the relatively⁹ few green algal seaweeds.

　　Structure

　　Seaweeds' appearance somewhat resembles non-arboreal terrestrial plants.

　　· thallus: the algal body

　　· lamina or blade: a flattened¹⁰ structure that is somewhat leaf-like· sorus: a spore¹¹ cluster

　　· on Fucus, air bladder: a floatation-assisting organ on the blade· on kelp, float: a floatation-assisting organ between the lamina and stipe· stipe: a stem-like structure, may be absent· holdfast: a specialized¹² basal structure providing attachment to a surface, often a rock or another alga· haptera: a finger-like extension of the holdfast anchoring to a benthic substrateThe stipe and blade are collectively known as the frond¹³.

　　Ecology

　　Two specific environmental requirements dominate seaweed ecology. These are the presence of seawater (or at least brackish¹⁴ water) and the presence of light sufficient to drive photosynthesis¹⁵. Another common requirement is a firm attachment point. As a result, seaweeds most commonly inhabit the littoral¹⁶ zone and within that zone more frequently on rocky shores than on sand or shingle¹⁷. Seaweeds occupy a wide range of ecological¹⁸ niches²⁰. The highest elevation²¹ is only wetted by the tops of sea spray, the lowest is several meters deep. In some areas, littoral seaweeds can extend several miles out to sea. The limiting factor in such cases is sunlight availability. The deepest living seaweeds are some species of red algae.

　　A number of species such as Sargassum have adapted to a fully²² planktonic²³ niche¹⁹ and are free-floating, depending on gas-filled sacs to maintain an acceptable depth.

　　Others have adapted to live in tidal rock pools. In this habitat seaweeds must withstand rapidly changing temperature andsalinity and even occasional drying.

 

1 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

2 algae   

n.水藻，海藻

参考例句：

• Most algae live in water.多数藻类生长在水中。
• Algae grow and spread quickly in the lake.湖中水藻滋蔓。

3 attachment   

n.附属物，附件；依恋；依附

参考例句：

• She has a great attachment to her sister.她十分依恋她的姐姐。
• She's on attachment to the Ministry of Defense.她现在隶属于国防部。

4 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

5 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

6 margins   

边( margin的名词复数 )； 利润； 页边空白； 差数

参考例句：

• They have always had to make do with relatively small profit margins. 他们不得不经常设法应付较少的利润额。
• To create more space between the navigation items, add left and right margins to the links. 在每个项目间留更多的空隙，加左或者右的margins来定义链接。

7 gulf   

n.海湾；深渊，鸿沟；分歧，隔阂

参考例句：

• The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
• There is a gulf between the two cities.这两座城市间有个海湾。

8 lettuce   

n.莴苣；生菜

参考例句：

• Get some lettuce and tomatoes so I can make a salad.买些莴苣和西红柿，我好做色拉。
• The lettuce is crisp and cold.莴苣松脆爽口。

9 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

10 flattened   

[医]（水）平扁的，弄平的

参考例句：

• She flattened her nose and lips against the window. 她把鼻子和嘴唇紧贴着窗户。
• I flattened myself against the wall to let them pass. 我身体紧靠着墙让他们通过。

11 spore   

n.(无花植物借以繁殖的)孢子，芽胞

参考例句：

• A spore can quickly spread and form a mould.一个孢子能迅速蔓延并形成霉。
• The cation penetrates the spore.这种阳离子能透入孢子。

12 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

13 frond   

n.棕榈类植物的叶子

参考例句：

• The weavers made a hat from palm fronds.织工用棕榈叶织成了一顶帽子。
• The village hut was thatched with palm fronds.乡村小屋用棕榈叶作顶。

14 brackish   

adj.混有盐的；咸的

参考例句：

• Brackish waters generally support only a small range of faunas.咸水水域通常只能存活为数不多的几种动物。
• The factory has several shallow pools of brackish water.工厂有几个浅的咸水池。

15 photosynthesis   

n.光合作用

参考例句：

• In apple trees photosynthesis occurs almost exclusively in the leaves.苹果树的光合作用几乎只发生在叶内。
• Chloroplasts are the structures in which photosynthesis happens.叶绿体就是光合作用发生的地方。

16 littoral   

adj.海岸的；湖岸的；n.沿（海）岸地区

参考例句：

• We should produce the littoral advantage well.我们应该把海滨的优势很好地发挥出来。
• The reservoir sandstone was believed to have been deposited in a littoral environment.储集层砂岩就被认为是近海环境的沉积。

17 shingle   

n.木瓦板；小招牌(尤指医生或律师挂的营业招牌)；v.用木瓦板盖（屋顶）；把（女子头发）剪短

参考例句：

• He scraped away the dirt,and exposed a pine shingle.他刨去泥土，下面露出一块松木瓦块。
• He hung out his grandfather's shingle.他挂出了祖父的行医招牌。

18 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

19 niche   

n.壁龛；合适的职务(环境、位置等)

参考例句：

• Madeleine placed it carefully in the rocky niche. 玛德琳小心翼翼地把它放在岩石壁龛里。
• The really talented among women would always make their own niche.妇女中真正有才能的人总是各得其所。

20 niches   

壁龛( niche的名词复数 )； 合适的位置[工作等]； （产品的）商机； 生态位（一个生物所占据的生境的最小单位）

参考例句：

• Some larvae extend the galleries to form niches. 许多幼虫将坑道延伸扩大成壁龛。
• In his view differences in adaptation are insufficient to create niches commensurate in number and kind. 按照他的观点，适应的差异不足以在数量上和种类上形成同量的小生境。

21 elevation   

n.高度；海拔；高地；上升；提高

参考例句：

• The house is at an elevation of 2,000 metres.那幢房子位于海拔两千米的高处。
• His elevation to the position of General Manager was announced yesterday.昨天宣布他晋升总经理职位。

22 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

23 planktonic   

[医] 浮游生物的

参考例句：

• Warmer Winters: Are Planktonic Algal Populations in Sweden's Largest Lakes Affected? 暖冬：瑞典最大湖泊的浮游藻类种群是否受到影响？
• They eat planktonic crustaceans and fish larvae. 以浮游的甲壳动物和鱼类幼体为食。