結(jié)課真題原文1-40有答案foundational and keystone species

1、2015-kls-12-FoundationalandKeystoneTheharmonypresentinanyecologicalsystemsontheofdifferenttypesspecies, each specificroleor setofroles.Althoughtosome extentallspeciesinimportantways,scientistsarenowlearningaboutvotalpartsplayedby,what2015-kls-12-FoundationalandKeystoneTheharmonypresentinanyecologica

2、lsystemsontheofdifferenttypesspecies, each specificroleor setofroles.Althoughtosome extentallspeciesinimportantways,scientistsarenowlearningaboutvotalpartsplayedby,whatarecalledfoundationalandkeystoneerestingly,thelatterrepresentonlyafractionoftheoverallanimalpopulationwithinanecosystemwhiletheforme

3、rcanmakeupsignificantportionofit.Inbothcases,though,theirremovaloftenassivechangesifnotthecompletedestructionof,theirecosystems.Effortstoconservethesespeciescurrentlybasedon thenew started,bettheypreventthestartofadominotwould,Foundationalspeciesarethebackbonesofthesystemstheyinhabit.Thesespeciesref

4、erredtoasprimaryproducers,ttheygenerate alargeamountof abundanceotherspeciesrequiretoost cases, theyare atype ofionionaryanimal.Coral,whichtendstogrowinlargecolonies,isoftenedtoas le.Eventuallyagroupofcolonieswillformacoralreef,whichcansustainaecosystemaroundit.Thereefcontainstheskeletalremainsofcor

5、alatitsbottomandcoralonthetop.Numerousanimals,includingtonandsponges,hedand herock-likebottom.At thetop, the eractswithforms ofiontoregulatethelevelsofnutrientsandhewater.Therearenfour thousandtypesoftliveonor aroundmostcoralreefs.Fishrelyon hereefforprotection.Themorecolorfulspeciesofcoralprovideex

6、cellentforfish,aswell.Obviously,withoutitsfoundationalspecies,anecosystemwouldKeystonespeciesplaylessapparentbutequallyimportantroles.Thenamecomesthekeystones hebuildingofstonearchways.Thekeystonereceivestheamountof reof allthehearch,but,ifitisremoved,thearch willcollapse.thesameway,researchisnowsho

7、wing,certainspecieswithinecosystems,althoughtheysmallerinnumbersandnmostoftheotherspeciespresent,actlike 和 說講這兩種數(shù)量關(guān)係的目的是？Ke 的錯(cuò)。然後就提出A mptionUrchin increasekelpdecrease。 a mption kelp XX 和厄爾尼諾的 Urchin二三段的關(guān)係，有可能是因?yàn)槭颤N病的 而導(dǎo)致 kelp 的減少。不過，因?yàn)?Urchinincrease而導(dǎo)致 kelpdecreasesupport的例子。U 減少，K 就自然增加。單字contenti

8、onThesespeciesarebeingcategorizedasredatorsorengineers,dependingonrelationshipswiththevariousspeciesaroundthem.Thesecategoriesarenotabsolute,andanimalsaremoved fromonetotheotherThesespeciesarebeingcategorizedasredatorsorengineers,dependingonrelationshipswiththevariousspeciesaroundthem.Thesecategorie

9、sarenotabsolute,andanimalsaremoved fromonetotheotheras newfactscometohecaseofpredatorkeystonespecies,therearefourtpreyonandotheranimals.Also,theherbivoresusuallyhavenoothernaturalecosystem.Theseaotterisnowconsideredbymanyscientiststobeakeystonebecauseitcontrolsthenumberofseaurchins,whichhavefewredat

10、ors.Bothcanbefoundaroundkelpforests,whichhewarmpartsoftheworldsoceans.kelpisan lant,itsrootsarenotusedforthecollectionofnutrients.Instead,are there toanchor theplant.As soonas enough sea urchins chewed onthe roots, whichare fragile,thekelpwouldberemovedfromtheecosystem.Iftheseaotterweretodisappear,u

11、rchinswouldquicklygrowin numberanddestroyalltheEngineerkeystonespeciesahebalanceinecosystemsindifferentways. Althoughbearstendtoliveinforests,theybringinimportantofnutrientsfromandsea-basedecosystems. Thebearscapturelargesalmonfromthewaterandtakeotheforesttoeatthem.Thisdistributeslargeamountsofhefor

12、mofbearmatteraswellasuneatenportionsofsalmon.Theproteineventuallysupportsheeitherasafoodsourceforsmaller animalsorthe ion.Anothertplaysasimilar tofbearsisthebeaver.Throughtheconstructionofdams,beaversconvert opondsand marshes.Thenew urnsupportsavarietyoffish,whichturnprovidesadependablesourceoffoodf

13、orthebeavers.Theremovalofbeaversfrom ecosystemwouldalsoremovetheitdepends1.The wordhepassageis eaning(C) e(D) 2.Accordingtoparagraph1,foundationalspeciesare presentonlyincertaincloseto complete(D) helargest3.Thewordhepassagecouldbestbereplaced(C) (D) 4.Thewordcoralhepassagerefers5.Whichofthebelowbes

14、texpressestheessentialhe(C) (D) 4.Thewordcoralhepassagerefers5.Whichofthebelowbestexpressestheessentialhehepassage?Incorrectchangethemeaninginimportantwaysorleaveessential(A) Thefoundationaleobviousoncethesystemhas(B) Ecosystemswillnotcollapseasthefoundationalspeciesdonot(C) Itistthesystemwouldfalla

15、part ifitdid veitsfoundational(D) Withoutthecollapse,thefoundationalspeciesarenothe6.Theauthormentionsarchesinparagraph3inorder(A) helpunderstandwhatkeystonespecies(B) provideanleofanecological(C) showtheproblemsfoundational(D) heroleofatypeofanimal7.Whichofthefollowingcanbeinferredfromparagraph3abo

16、utkeystoneTheirroleshavebeenunderstoodforalongTheyarerelatedtoalargenumberofTheyarenowseenaslessimportantinTheyarethe subjectsofongoing8.The phrase hesamehepassagecouldbestbereplaced 9.ItisNOTtrueaccordingtoparagraph tseatseadamagekelpeatkeystone (D)livenear(D)livenear10.Accordingtoparagraph5,whicho

17、fthefollowingistrueabout(A)Theyarepredatorkeystone(B) Theyhesameareasas(C)Theyusuallyeatfishfrom(D)Theycanarge,strong11.Lookatthefoursquares tindicatewherethefollowingsentence11.Lookatthefoursquares tindicatewherethefollowingsentencecanbeaddedtoThetliveontheWestCoastofmericaareoftencitedasanWherewouldthesentencebest12.Directions:Ecologicalsystemsrequirethecontributionsofvariousspeciestypes.theymatchingtheappropriate