more than words

60

OriginofSpecies&ContinentFormation

A

ThefactthattherewasonceaPangeansupercontinent,aPanthalassa

Ocean,andaTethysOcean,hasprofoundimplicationsfortheevolution

onsiderationswereunknowntothe

scientistsofthe19thcentury—makingtheirscientificdeductionvenmore

ndependentlyofeachother,CharlesDarwinandhis

youngcontemporaryAlfredRuslWallacereachedtheconclusionthatlife

elaterwroteinMyLifeofhisown

inspiration:

B

Whydosomespeciesdieandsomelive?Theanswerwasclearlythaton

eeffectsofdiathemosthealthy

escaped;fromenemiesthestrongest,theswiftestorthemostcunningfrom

faminethebesthunters…thenitsuddenlyflashedonmethatthislf-acting

processwouldimprovetherace,becauineverygenerationtheinferior

wouldinevitablybekilledoffandthesuperiorwouldremain,thatis,the

fittest

wouldsurvive.

C

B

othDarwin

’

sandWallace

’

sideasaboutnaturallectionhadbeeninfluenced

conclusions,however,hadbeenthedirectresultoftheirpersonalobrvation

ofanimalsandplantsinwidelyparatedgeographiclocations:Darwinfrom

hixperiencesduringthevoyageoftheBeagle,andparticularlyduringthe

ship

’

svisittotheGalapagosIslandsintheEastPaci

ficin1835;Wallaceduring

hisyearsoftravelintheAmazonBasinand

intheIndonesia-AustralianArchipelagoin

the1850s.

D

Darwinhadbeendocumentinghisideason

naturallectionformanyyearswhenhe

receivedapaperonthislfsamesubject

61

fromWallace,whoaskedforDarwin

’

sopinionandhelpingettingitpublished.

InJuly1858,r,clofriendsofDarwin,presd

Darwintoprenthisconclusionssothathewouldnotlopriorityto

ingoverthehastilycalledbutnowhistoric

meetingoftheLinneanSocietyinLondon,LyellandHookerexplainedtothe

distinguishedmembershow

“

thetwogentlemen

”

(whowereabnt:Wallace

wasabroadandDarwinchonottoattend),had

“

independentlyandunknown

tooneanother,conceivedthesameveryingenioustheory,

”

E

BothDarwinandWallacehadrealizedthattheanomalousdistribution

ofspeciesinparticularregionshadprofoundevolutionarysignificance.

Subquently,Darwinspenttherestofhisdaysinalmosttotalclusion

rast,Wallace

appliedhimlftothescienceofbiogeography,thestudyofthepatternand

distributionofspecies,anditssignificance,resultinginthepublicationofa

massivetwo-volumeworktheGeographicalDistributionofAnimalsin1876.

F

Wallacewasagentleandmodestman,butalsopersistentandquietly

tyearsworkinginthemostarduouspossibleclimatesand

terrains,particularlyintheMalayarchipelago,hemadepatientanddetailed

zoologicalobrvationsandcollectedhugenumberofspecimensformuums

ultofhisworkwas

theconclusionthatthereisadistinctfaunalboundary,called

“

Wallace

’

sline,

“

betweenanAsianrealmofanimalsinJava,BorneoandthePhilipionesand

ncethisboundary

podadifficultquestion:HowonEarthdidplantsandanimalswithaclear

affinitytotheNorthernHemispheremeetwiththeirSouthernHemispheric

counterpartsalongsuchadistinctMalaysiandemarcationzone?Wallacewas

uncertainaboutdemarcationononeparticularisland-Celebes,acuriously

llyheassignedits

flora-faunatotheAustraliansideoftheline,butlaterhetransferredittothe

62

eknowthereasonforhisdilemma.200MYAEastand

WestCelebeswereislandswiththeirownnaturalhistorylyingonopposite

answertothemainquestionisthatWallace

’

sLinecategorizesLaurasia-

derivedflora-fauna(theAsian)andGondwana-derivedflora-fauna(the

Australian),

closureoftheTethysOceantodayismanifestedbytheongoingcollisionof

Australia/NewGuineawithIndochina/Indonesiaandthecontinuingclosureof

theMediterraneanSea—aremnantoftheWesternTethysOcean.

G

Inhisoriginofcontinentsandoceans,Wegenerquotedatlengthfrom

Wallace

’

ingtoWegener

’

s

reading,WallacehadidentifiedthreecleardivisionsofAustraliananimals,

ehad

shownthatanimalslongestablishedinsouthwesternAustraliahadanaf

finity

withanimalsinSouthAfrica,Madagascar,India,andCeylon,butdidnothave

anaf

ealsoshowedthatAustralianmarsupials

63

andmonotremesareclearlyrelatedto

thoinSouthAmerica,theMoluccas,

andvariousPacificislands,andthatnone

thisandrelateddata,Wegenerconcludedthatthethenbroadlyaccepted

“

landbridge

”

theorycouldnotaccountforthisdistributionofanimalsandthat

onlyhistheoryofcontinentaldriftcouldexplainit.

H

ThetheorythatWegenerdismisdinpreferencetohisownpropodthat

plantsandanimalshadoncemigratedacrossnow-submergedintercontinental

1885,oneofEurope

’

sleadinggeologists,EduardSuess,

theorizedthatastherigidEarthcools,itsuppercrustshrinksandwrinkleslike

estedthattheplanet

’

sasand

oceansnowfillthewrinklesbetweenonce-contiguousplateaus.

I

Today,weknowthatweliveonadynamicEarthwithshifting,collidingand

paratingtectonicplates,nota

“

witheringskin

”

,andthemaindebateinthe

cussionnowconcerns

“

dispersalism

”

versus

“

vicarianism:unrestrictedradiationofspeciesontheonehandandthe

sionisashort-term

phenomenon—thedailyorasonalmigrationofspeciesandtheirradiation

tothelimitsoftheirnaturalenvironmentonanextensiveandcontinuous

anevolution,however,dependsupontheparationand

isolationofavarietyofspecieswithintheconfinesofnaturalbarriersinthe

formofislands,lakes,orshallowas

—topographicalfeaturesthattakealong

timetodevelop.

64

Questions1-5

.................................................................................

Utheinformationinthepassagetomatchthepeople(listedA-E)withopinionsor

heappropriatelettersA-Einboxes1-5onyouranswersheet.

NByoumayuanylettermorethanonce

ASuess

B

Wallace

C

DarwinandWallace

D

Wegener

E

LyellandHooker

1

PersuadeDarwintopublishhisscienti

ficfindings

2

Depictedphysicalfeatureofearth

’

scrust.

3

Introducedcontinentaldrifttheory.

4

Publishedworksaboutwildlifedistributionindifferentregion.

5

Evolutionofspeciesisbadonlectionbynature.

Questions6-8

.................................................................................

ThereadingPassagehasnineparagraphsA-I.

Whichparagraphcontainsthefollowinginformation?

WritethecorrectletterA-I,inboxes6-8onyouranswersheet.

6

Bestadaptableanimalsurvivedontheplanet.

7

BoundarycalledWallace

’

slinefoundbetweenAsiaandAustralia.

8

AnimalrelevanceexistsbetweenAustraliaandAfrica.

65

Questions9-13

...............................................................................

Summary

CompletethefollowingsummaryoftheparagraphsofReadingPassage,usingnomore

ouranswersinboxes9-13

onyouranswersheet.

Wegenerfoundthatcontinentaldriftinsteadof“landbridge”theorycouldexplain

strangespecies’heory,vegetationandwildlife

9

r,EduardSuesscomparedthewrinkleofcrust

to10

swellknownthatwearelivingonaconstant

mobile11

tinbiogeographyare

switchedtoconcernsbetweentwoterms:“12

”and“13”