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Yourwebbrowser(Safari7)isoutofdate.Formoresecurity,comfortand thebestexperienceonthissite: Updateyourbrowser Ignore Activityapply A DA P T I V E RA D I AT I O N Howdospeciesrespondtoenvironmentalpressures? OVERVIEW Studentsanalyzecharacteristicsofsixpterosaurstodeterminetheroleof adaptiveradiationintheirevolutionfromacommonancestor. Forthecompleteactivitywithmediaresources,visit: http://www.nationalgeographic.org/activity/adaptive-radiation/ Program DIRECTIO NS 1.Discussconvergentanddivergentevolution. Reviewthedifferencebetweenconvergenceanddivergence.Ontheboard, sketchpathscomingtogether(convergence)andonepathsplittingintwo directions(divergence).Tellstudentsthataspartofevolution,speciescan convergeanddivergeovertime.Justasspeciesthatarenotcloselyrelated— suchasbirds,bats,andpterosaurs—canovertimedevelopcharacteristicssuch aswingstohelpthemsurvive,speciescanalsodiverge.Anewspeciesof pterosaurcanbreakofffromapopulation,asnewfeaturesevolvethatset speciesapartfromoneanother.Allowstudentstoaskanyquestions.Then explainthat,inthisactivity,studentswillexplorewhathappensaspartof divergentevolution.Thentheywillusepresentationsoftwaretocreatea summaryslideabouthowdivergentevolutionrelatestopterosaurs. 1of7 2.Analyzepterosaurskullstructure. Dividestudentsintopairs.Giveeachpairthetwo-pagePterosaurSpecies handout.Havethemglanceatthepicturesofthepterosaurheadsbriefly.Ask: Whatdoyounoticeabouttheheads?Acceptavarietyofideasanddescriptions, andguidestudentstothesimplerealizationthattheseanimalsarebothvery similarandverydifferent.Askstudentstorelatethecharacteristicsoftheskulls toeachanimal'slikelyfoodandhabitat.Notethatthebeaksvary;somehave teeth,arepointed,areduck-like,orarerounded.Guidestudentstorecognize thatdifferentmouthsenableaccesstodifferentfoods;notethatTapejaracould likelyscoopfromastreamandPterodaustrowouldhavehadafoodfiltering ability,whilethetoothedpterosaurswerelikelyabletotearatpreyor vegetation.Thisvariationinformistheresultofenvironmentalselection,where animalshaveovertimeadaptedtodifferentenvironmentalconditions,including foodsources. 3.Determinehowcloselyrelatedthepterosaursare. Nexthavestudentsdeterminehowcloselythesedifferentanimalsarerelated, bythinkingaboutwhethertheseanimalsseemtohaveevolvedfromacommon ancestor,orwhethertheyaremoredistantlyrelated.Havestudentscompare descriptionsoftheskeletalstructureoftheshoulders,wings,andtailinthe Anatomycolumn.Ask:Whatcharacteristicsdothepterosaurshaveincommon? (Thefirstfourhavethesamefixedshoulder,longpalm,andnotail;the differenceisinthewingspan.Thelasttwohavenotailandashorttail, respectively.) 4.Analyzeimagesfromthegalleryforcommoncharacteristics. Showstudentsthesiximagesinthegallery,andhavethemlookcloselyatthe wings.Ask:Whatcharacteristicdoalloftheseshare?(Studentsshouldrecallthat allsixhaveanelongatedfourthfinger.)What'sthefunctionofthislongfinger? (Withthemembraneattached,thepterosaurscouldextendtheirwingstoglide andfly.)Explainthatthisisakeycharacteristicthatshowsacommonancestry 2of7 amongpterosaurs. 5.Considerthedifferencesamongthegalleryimages. Havestudentsdiscusswiththeirpartnershowtheymightgroupthese pterosaurs.Guidestudentstoseethatallbutoneoftheanimalscanbeplaced inonegroupwithfixedshoulder,longpalm,andeithernotailorashorttail. Thesefivelivedfrom160millionyearsago(mya)to71mya.Thisgroup, however,hasatremendousvarietyinskullform,andtheylivedmuchlaterthan Dimorphodonfrom200mya,withitslooseshoulder,shortpalm,andlongtail. 6.Considerthegeographyofadaptiveradiation. Explainthatadaptiveradiationisatermthatdescribeswhenmanyorganisms resultingfromoneearlierancestoraresubjectedtodifferentenvironmental selectionastheyspreadoverabroadarea.Havestudentslookinthehabitat columnatthegeographicdistributionofthesepterosaurs.Ask:What environmentalpressuresmayhaveresultedinthesepterosaursspreadingacross severalcontinents?PointoutthatbecauseofPangaea,thepositionofthe continentsvariedoverthetimethatpterosaurslived,soconsiderthatdistances traveled,thoughfar,werenotasfarasapresent-dayglobewouldrepresent. 7.Summarizeideasabouttherelationshipbetweenthesixpterosaurs. Havepartnersworktogetheronacomputertodevelopapresentationslide explainingadaptiveradiationusingpterosaursasanexample.Havestudents includeatleastthreekeyideasaboutadaptiveradiationandtherelationships amongthesixpterosaurs.Allowstudentstousetheinformationinthechart,the imagegallery,andnotesfromthediscussionasreference. InformalAssessment Assessstudents'completedpresentationslidesbasedonwhatpointstheychose toincludeontheslideandhowtheydescribesimilaritiesanddifferences betweenthesixpterosaurs.Studentscanrefertothesimilaritiesofthesix pterosaurs'bodystructurestoillustratetheircloseevolutionaryrelationshipand 3of7 thedifferencesintheirskullstructuretoillustratetheirdivergentevolutionand adaptiveradiation. ExtendingtheLearning Havestudentsrevisittheimagesofthesixpterosaursbeforewatchingthefilm FlyingMonsters3D.Askthemtoconsidertheirownquestionsthatmaybe answeredinthefilm,suchas"WhydoesTapejarahavesuchalargehead crest?"Asstudentswatchthefilm,havethemnotedifferenthypothesesforwhy pterosaursmayhavedevelopeddifferently. O BJECTIVES Subjects&Disciplines Science Biologicalandlifesciences Ecology Paleontology LearningObjectives Studentswill: analyzecharacteristicsofspeciestodeterminehowcloselyrelatedtheyare explainthemeaningof TeachingApproach Learning-for-use TeachingMethods 4of7 Discussions Informationorganization Visualinstruction SkillsSummary Thisactivitytargetsthefollowingskills: CriticalThinkingSkills Analyzing Applying Understanding NationalStandards,Principles,and Practices N AT I O N A L S C I E N C E E DU C AT I O N S TA N DA RDS •(9-12)StandardA-2: Understandingsaboutscientificinquiry •(9-12)StandardC-3: Biologicalevolution PREPARATIO N WhatYou’llNeed M AT E RI A LS YO U P RO V I DE Paper 5of7 Pens RE Q U I RE D T E C H N O LO G Y InternetAccess:Optional TechSetup:1computerpersmallgroup,Presentationsoftware,Projector Plug-Ins:Flash P H Y S I C A L S PA C E Classroom G RO U P I N G Large-groupinstruction Small-groupinstruction RE S O U RC E S P RO V I DE D: H A N DO U T S & W O RK S H E E T S PterosaurSpecies RE S O U RC E S P RO V I DE D: I M A G E S PterosaursGallery BACKGRO U ND & VO CABU L ARY BackgroundInformation Theearlierpterosaurshadlongtailsandflightmembranes,calleduropatagia, connectingthetailswiththehindlegs.Thisarrangementgavethepterosaurs stabilityinflight,butitalsomeantthattheycouldn’twalkverywell.Accordingto thefossilrecord,theseearlypterosaursvariedrelativelylittleintheirdesigns: size,teeth,andheadcrests.ThissituationchangedoncethePterodactyloids 6of7 evolvedinthemiddleJurassicPeriod.Theseanimalshadnotailsandthusno membraneconnectingtothehindlegs.Theycouldthereforewalkmuchbetter. Inaddition,theirwingstructure,thoughitmadeflightmoreunstable,alsomade itmoremaneuverable.Consequently,thePterodactyloidswereabletobemore flexibleintheirlifestylechoices,andtheyevolvedtofillmanymorenichesthan theirforebearerscould.Pterosaurdesignstookoffinmanydirections,leading toastunningvarietyofanimals. PriorKnowledge ["evolution","classification","convergentevolution"] RecommendedPriorActivities ExploringVertebrateClassification Vocabulary Term Partof classificationnoun evolution Definition Speech noun groupingbasedonphysicalandgenetic characteristics. changeinheritabletraitsofapopulationovertime. ForFurtherExploration Websites NationalGeographicEntertainment:FlyingMonsters3D ©1996–2017NationalGeographicSociety.Allrightsreserved. 7of7