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QTscienceadventures
chapterthree
theendofthedinosaurs
wheelridingbacktoschool
fromafieldtriptoamuseum
theturterrenosaurswasamazingsaidbobbywheelsbestfriend
itwasscarywhillsaidhelookedataphoto
hedtakenofthedinosaurrskeletonwithhisphone
andthenglanceattheirhomework
doyouknowtheanswertonumberfive
whydiddinosaursdisappear
heaskedbobbyletsanswerthesequestionsbeforeweforgeteverythingorbeforeifallasleepbusesmakemetired
welltrytofocusontheworksheet
butsoonhiseyeswereclosedinhisheadwasbobbingupanddownwitheverybumpintheroad
whenwillowopenhiseyes
hewasntonthebus
anymore
hewasinanaircraft
flyingslowlyoverastrangelandscape
QTisphonespoke
scientiststhinktheworldlookedlikethisinthelattriasic
theperiodfromabouttwohundredandfiftytotwohundredmillionyearsago
hh well
whllsaid
thisairshipiscarryingusthroughtime
scientiststalkaboutearthshistory
usingaspecialscalecalledgeologictimeseethatdisplay
ittellsuswhatperiodoftimewereseeingpertsthinkdinosaururslikethoseoverthereappearedduringthetriassic
butletratravelforwardintothenextperiod
dinosaursthrivedqtshinealightup
thecontrolstakingoverthedisplaychangedasthesceneryoutsideshimmerredandtransformed
sothisisthejurassicwillask
yes
itlasteduntilaboutonehundredandfiftymillionyearsago
somedinosaursbecamegianticasyoucanseeletsgetforwardintothenextperiod
thecretatiousattheendofthecreticious
seventypercentofthespeciesonearthdied
includingmostdinosaurs
wellnotitwelearnthatatthemuseum
butwhatmadethemdisappear
well
scientistshavesometheories
buttheycantprovethemoneclueisanunusuallayerofrock
foundallovertheworld
itsaboutsixtyfivemillionyearsold
andcontainsalotofaradium
anelementthatsusuallyrareonearthsurface
itsnormallylocateddeepinsidetheplanetorinspace
insomeasteroids
thislayerofrockledtotwopopulartheoriesaboutwhatcausedtheextinction
QTannouncedherewearetheendofthecretatioussixtyfivemillionyearsago
theskywasdark
theywerehoveringoverafieldofvolcancanos
theressomuch
lovawillsaidweareoverindia
QTsaid
somescientistsbelievethesevolcaninoscontributedtotheextinction
becausetheycouldhavebroughtaradiumtoearthsurfaceinlava
thevolcanoesmighthavereleasedenoughashandgaseswhichthenblewaroundthewholeplanettocreateagreenhouseeffecttrappingheatintheatmosphere
awarmerclimatewouldhavemadeithardformanyspeciestosurvive
wow
wellwhispererwatchingadinosaurfleefromtheglowinghotrock
butthereisanotherpossibilityletmetransportustoanotherpartoftheplanet
QTsaid
theoceanappearedonthephonescreen
andtheworldwentpitchblack
whenitbecamelightagain
theiraircraftwashoveringhighoverabodyofwater
qtcontinuedsomescientiststhinkahugeasteroididabouttenkilometersacrosshitearthnearmexicosixtyfivemillionyearsago
agiantrockflewwthroughtheiriryielldisthattheasteroidyes
scientistsareprettysureithitearth
buttheycanonlyguesswhathappenednexttheaircraftshockastheasterooidcrashedintoearth
QTwentontheasteroidmighthavecreatedahugefireball
andthentssunameseashotpiecesoftheasteroididfellbacktoearth
theycouldhavestartedwildfiresworldwide
soatfirstthetemperatureoftheworldwouldhaveincreasedtheairraraftlewclosertotheground
alongshshorewillstareatthedestructioncausedbytheasteroid
howlongtothistakenooneknows
exactlymaybeweeksormonthsafterthefiresdustfromtheexplosion
mighthavelokedlightfromreachingearthsurface
inthefollowingyears
plants
whichneedlighttomakefoodwouldhavedied
thenplanteatingdinosaurswouldhavestarvedanddied
andthenthemedieatingdinosaurswouldhavestarvedanddied
toohowdoweknowthatweask
wecanguesswhenspecieslived
basedontheirfossilsandwhatlayerofrock
wefindthosefosslsinthespeciesthatwentextinct
dontappearinrocksformedaftersixtyfivemillionyearsago
wellthoughtabouteverything
QThadsaidwithscientistsararcer
whetherthevolcanoesortheasteroidcausedthedinosaurextinction
itspossible
bothcontributedthereareotherfactorsandtheoriestoo
QTrepliedforinstancesomepeoplethinkmammalsaid
somanydinosaureggs
thedinosaurscouldntsurvive
andwerenotsure
whetherdinosaursdied
suddenlytheycouldhavebeendyingoff
graduallybeforethevolcanoesorasteroidbecameaproblem
QTpaused
andthesceneryoutsidebegantotransform
wewejujumpedfororjustafewyearsseeallthoseanimals
manymammals
frogs
crcodilles
andevensomespeciesofdinosaurssurvivedtheextinction
butwedontknowwhywellremembertheferociouslookingtorenosaursatthemuseum
andshutreddidsomedinosaurrsurviveintomoderntimes
wellscientistsareprettysurebirdsevolvedfromdinosaurs
sotechnicallytheyaredinosaurs
andmoderncrocodillesarentdinosaurs
buttheyareverysimilartothecrocoddilesthatwerealivesixtyfivemillionyearsago
QTsaid
suddenlysomethingroseoutofthewater
itdrawanappshotinthetailoftheaircraft
nowellshuthiseyesexpectingthecrocodile
ilethatpulthemunderwater
theaircraftshoot
andthenwasstillwellpeakedandrealizethatthebushaddroghtittoastopinfrontoftheschoolwakeup
bobbysaid
ihopeyouhadanicenap
ihadthestrangerstreamaboutdinosaurs
idontthinkilleverforgetthestuff
ilearnedtoday
wellsaid
littlefox