首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Plant and Animal Life of the Pacific Islands P1: The Pacific Islands region covers 32 million square kilometers and is one of th
Plant and Animal Life of the Pacific Islands P1: The Pacific Islands region covers 32 million square kilometers and is one of th
admin
2018-10-18
90
问题
Plant and Animal Life of the Pacific Islands
P1: The Pacific Islands region covers 32 million square kilometers and is one of the richest, most complex terrestrial and marine ecosystems on Earth. Some islands that used to be parts of continents still carry some small plant and animal remnants of their earlier biota, providing clear examples of evolution and interesting patterns of colonization, adaptation, and speciation. Cn the contrary, some other islands arose due to volcanic activity or reef growth, which usually subside over time due to erosion and changing sea levels. When islands emerge, they undergo the process of ecological succession as species colonize the island. Only those species with ways of spreading to these islands were able to undertake the long journeys, and the various factors at play resulted in diverse combinations of new "colonists" on the islands. One estimate is that the distribution of plants was 75 percent due to being transported by birds, 23 percent by floating, and 2 percent by wind.
P2: Four major factors account for the fact that the plants and animals on Oceanic islands largely migrate from west to east. The size and fertility of the territory of certain islands is the first determining factor. That is, the larger the islands are, the wider the range of species they are able to support. Second, the further east the islands are, generally the less the diversity of species found there, largely because the eastern islands tended to be smaller, more scattered, and remote, as evidenced by the easterly decline in species diversity of birds and coral fish. It is estimated that there were over 550 species of birds in New Guinea, 127 in the Solomon Islands, 54 in Fiji, and 17 in the Society Islands. From the west across the Pacific, the Bismarck Archipelago and the Solomon Islands have more than 90 families of shore fish , Fiji has 50 families, and the Society Islands have 30. Third, the latitude of the islands also influenced the biotic mix, as those islands in relatively cooler latitudes, notably New Zealand, were unsuited to supporting some of the tropical plants with which Pacific islands are generally associated.
P3: The fourth factor that has influenced species distribution and the shaping of Pacific ecosystems was wind. There are strong prevailing winds throughout the Pacific Ocean, which has been known for centuries due to scientific development. Those in the northern hemisphere are called "North-easterlies", while their counterparts of the southern hemisphere are known as "south-easterlies." Further south, beginning from approximately thirty degrees south, the winds are mostly from the west. Therefore, on nearly every single island of large scale exists an ecological difference between its windward and leeward sides. Apart from the wind action itself on plants and soils, wind has a major effect on rain distribution. The Big Island of Hawaii offers a prime example; one can leave Kona on the leeward side in brilliant sunshine and drive across to the windward side where the city of Hilo is blanketed in mist and rain.
P4: The long geological isolation of the Pacific islands and their particular climatic conditions have combined to create a unique and spectacular ecosystem. New species cannot immigrate via land, and instead must arrive via air, water, or wind. As a result, organisms with high dispersal capabilities, such as plants and birds, are much more common on islands than are poorly dispersing taxa like mammals. Since immigration of predators and competitors is limited, many species of flightless and ground-nesting birds are able to persist in these new niches. This results in a high occurrence of endemism, where species are unique to a localized area. Besides, endemism is often the result of adaptive radiation, when a single species colonizes an area and rapidly diversifies to fill all of the available niches. These endemic species derived form adaptive radiation are often small in number, unused to serious predation, limited in range, and therefore vulnerable to disruption.
P1: The Pacific Islands region covers 32 million square kilometers and is one of the richest, most complex terrestrial and marine ecosystems on Earth. ■ Some islands that used to be parts of continents still carry some small plant and animal remnants of their earlier biota, providing clear examples of evolution and interesting patterns of colonization, adaptation, and speciation. ■ On the contrary, some other islands arose due to volcanic activity or reef growth, which usually subside over time due to erosion and changing sea levels. ■ When islands emerge, they undergo the process of ecological succession as species colonize the island. ■ Only those species with ways of spreading to these islands were able to undertake the long journeys, and the various factors at play resulted in diverse combinations of new "colonists" on the islands. One estimate is that the distribution of plants was 75 percent due to being transported by birds, 23 percent by floating, and 2 percent by wind.
Look at the four squares [■] that indicate where the following sentence could be added to the passage.
When varied ecosystems are present, they can be explained as resulting in part from the process that formed the islands.
Where would the sentence best fit?
Click on a square [■] to add the sentence to the passage.
选项
答案
A
解析
【句子插入题】空前提到太平洋岛屿是地球上陆地和海洋生态系统最丰富的综合体之一。插入句说不同的生态系统是因为岛屿形成的过程。后面就说有些岛屿曾经是大陆的一部分,仍然携带一些早期植物和动物的残余,而其他一些是由火山活动或礁石增长而产生的。
转载请注明原文地址:https://kaotiyun.com/show/M5fO777K
0
托福(TOEFL)
相关试题推荐
Completethenotesbelow.WriteNOMORETHANTWOWORDSforeachanswer.TheroleofsleepinhumansandanimalsImportanceofsl
Completethenotesbelow.WriteONEWORDONLYforeachanswer.EffectsofurbanenvironmentsonanimalsIntroductionRecenturba
ChooseTWOletters,A-E.WhichTWOsubjectsdidMartinalikebestbeforegoingtouniversity?AArtBHistoryCFrenchDEnglish
Whothinksthefollowing?AKatyaBPeterCbothKatyaandPeterTheInternetcreatesnewgapsbetweenrichandpoor.
HowtoMakePersonalControlofOne’sHealth【L31】________shouldtakechargeoftheirhealth.Thesinglegreatestthreattoheal
HowtoMakePersonalControlofOne’sHealth【L31】________shouldtakechargeoftheirhealth.Thesinglegreatestthreattoheal
A、Bygreatlyincreasingtheocean’sdepthinsomeareas.B、Bycreatinglargewavesonthesurfaceoftheocean.C、Bycausingmud
A、TheMoonhasnowaterB、TheMoon’smaterialscamefromEarth’scoreC、TheMoon’scorediffersfromitssurfaceD、TheMooncont
AstronomyWhatdideighteenth-centuryastronomershaveincommonwithastronomerstoday?
随机试题
某地利用调查表对抽取的2000人进行了高血压的行为危险因素监测和血压的测定。其中180人自报高血压而且测量结果也显示为高血压,40人血压测量结果显示为高血压而自报常,20人自报高血压而测量结果正常。某市开展的行为危险因素监测采用如下方法:每个月随机抽取
具有支撑气管作用的重要软骨
大量不保留灌肠禁用于
采用静力压桩法施工时,选用压桩设备的设计承载力宜大于压桩阻力的()。
《建设工程质量管理条例》规定,建设单位将工程发包给不具有相应资质等级单位的,责令改正,处以()的罚款。
金融期货合约是约定在未来时间以事先协定价格买卖某种金融工具的标准化合约,标准化的条款包括()。Ⅰ.标的资产Ⅱ.交易单位Ⅲ.交割时间Ⅳ.交易价格
下列各项,()不属于企业期间费用。
公安机关预防、制止和惩治违法犯罪活动的任务主要包括( )。
AlthoughTomwasawarethatitwouldbe(i)______todisplayannoyancepubliclyatthesalesconference,hecouldnot(ii)______
A、Thinkingbeforespeaking.B、Adoptingempathyduringcommunication.C、Focusingonthepresent.D、Listeningattentively.C讲座中提到,
最新回复
(
0
)