lesson plan – what is a dichotomous key? summary€¦ · key concept(s) • binomial nomenclature...

LessonPlan–WhatisaDichotomousKey?

SummaryScientistshaveidentifiedandclassifiedoveroneandahalfmillionspeciesofanimals,plants,fungi,andotherorganismsontheearth.Speciesareidentifiedbyscientistsallovertheworldbyauniformclassificationandnamingsystem.Adichotomouskeyisaprocessofidentifyinganorganismwithaseriesofsteps,eachcontainingtwoquestions.Theanswersleadyoualongapathuntiltheorganismisidentified.ContentAreaBiology,Botany,ZoologyGradeLevel3-5KeyConcept(s)•  Withwellover1.5millionspeciesoforganismsonearthdescribed,scientistsaround

theworldhavedevelopedauniformprocessofidentifyingandnamingspecies.•  Onespeciesmayhavemanydifferentcommonnamesbuteachspecieshasonly

onescientificname.

KeyConcept(s)•  Binomialnomenclaturegiveseachdescribednamedspeciesatwopartname;the

genusandspecies.•  Adichotomouskeyisaguideinwhichyouprogressthroughsteps,eachwithtwo

questions,untilyouidentifyanorganism.ObjectivesStudentswillbeableto:•  Describethedifferencebetweenacommonnameandascientificname.•  Understandthatscientistsortlivingthingsintogroupsforclassificationfromlarge

Kingdomsdowntoindividualspecies.•  Explainanddemonstratehowtouseadichotomouskey.

LessonPlan–WhatisaDichotomousKey?

NationalScienceEducationStandardorOceanLiteracyEssentialPrinciple

LearningGoals

UnifyingConceptsandProcesses1.Systems,order,andorganization

Typesandlevelsoforganizationprovideusefulwaysofthinkingabouttheworld.Typesoforganizationincludetheperiodictableofelementsandtheclassificationoforganisms.

LifeScienceC.1.Characteristicsoforganisms

Eachplantoranimalhasdifferentstructuresthatservedifferentfunctionsingrowth,survival,andreproduction.Forexample,humanshavedistinctbodystructuresforwalking,holding,seeing,andtalking.

Principle5(3-5,B.)Theoceansupportsagreatdiversityoflifeandecosystems.DiversityofLife

TheoceanprovidesmostofEarth’slivingspaceandsupportsagreatdiversityoflifefromthesurface,throughthewatercolumn,anddowntotheseafloor.

LessonPlan–WhatisaDichotomousKey?

Peoplehavemanynamesforthesamething.Whatwouldyoucallit?

PeoplehavemanynamesForthesamethings.Whatwouldyoucallit?

CarTruckTransportationAutomobileMotorVehicleVehicleBucketofBoltsPick-uptruck2015ToyotaTacomapick-uptruckFour-door2015ToyotaTacomapick-uptruck

ScientistsNeedtoSpeaktheSameLanguage!

•  Confusionoverwordsmaynotseemlikeabigdeal,butitcanbe!

Wearesinking!

GermanCoastGuard

Whatareyouthinking

about?

Nomenclature:Howscientistsnamelivingthingsbysortingintogroups.

•  Kingdom•  Phylum•  Class•  Order•  Family•  Genus•  Species

LEASTSimilar

MOSTSimilar

CarlLinnaeus,1758Createdthesystemofnaminglivingthings.Binominalnomenclature

Ursusarctos,Linnaeus,1758

Ursusmaritimus,Phipps,1774

YESorNO:Thekeytonaminglivingthingsisaskingtherightquestions!

•  Dichotomous(dīˈkätəməs)meansdividedintwoparts.

•  Whenyouuseadichotomouskey,youfollowapath.Eachchoicealongthepathhasonlytwoquestions.TheanswerisalwaysYESorNO.

1.  Doesithaveashell?

2.Doesithavetwoshellhalvesthatfittogether?3.Doesithavewings?4.Doesithave8legs?YES,itisaspider

YES,gotoquestion2NO,gotoquestion3

YES,itisaclam

YES,itisabutterflyNO,gotoquestion4

Let’sPractice!

Wewilldivideintogroups.Ihavefivebagswithsupplies.Howmanycanbeineachgroup?

Groups:3groupsof42groupsof3

Let’sPractice!1.  Isitananimal2.Doesithavefeathers3.Doesithavefins4.Doesithavegills5.Doesithaveablowhole

Yes,it’sawhale6.Doesithavealongtrunk

Yes,it’sanelephant7.Doesithaveleaves

Yes,it’saplant

Yes,goto2No,goto7

Yes,it’sabirdNo,goto3

Yes,goto4No,goto6

Yes,it’safishNo,goto5

Testyour‘Yes’and‘No’QuestioningSkills!

•  Askingtherightquestionsiskeytofiguringoutwhatthingsare.•  Wearegoingtoplayagame.•  Youwillhavethepictureofalivingthingtapedtoyourback.YOUcannot

lookatit.Yourclassmatescan.•  Youcanaskthemquestionsaboutwhatitis,BUTyoucanonlyaskYesor

Noquestions.

Let’sPracticeFirst!

•  Doesitliveinthewater?•  Doesitliveonland?•  Canitfly?•  Doesithavefur?•  Isitamammal?•  Isitwild?•  Canitbeapet?•  Isitadog?•  Isitacat?

MakeYourOwnDichotomousKey

•  Workingroupsoftwoormorepeople.•  Eachteamtakeapaperbag.•  Chooseatleastfiveitemsfromyourbag.Youcanusealloftheitemsif

youarefeelinginspired!•  Using“yes”or“no”questions,makeakeythatleadstotheidentification

ofeachoftheitemsyouselected.•  Usethepracticesheetfrombeforeasaguide.Therearealsoreal

identificationkeystoviewifyouneedideas.

1.  Isitananimal2.Doesithavefeathers3.Doesithavefins4.Doesithavegills5.Doesithaveablowhole6.DoesithavealongtrunkYes,it’sanelephant7.DoesithaveleavesYes,it’saplant

Yes,goto2No,goto7

Yes,it’sabirdNo,goto3

Yes,goto4No,goto6

Yes,it’safishNo,goto5

Yes,it’sawhale

1.  Isitananimal2.Doesithavefeathers3.Doesithavefins4.Doesithavegills5.DoesithaveablowholeYes,it’sawhale6.DoesithavealongtrunkYes,it’sanelephant7.DoesithaveleavesYes,it’saplant

1.  Isitananimal2.Doesithavefeathers3.Doesithavefins4.Doesithavegills5.DoesithaveablowholeYes,it’sawhale6.DoesithavealongtrunkYes,it’sanelephant7.DoesithaveleavesYes,it’saplant

1.  Isitananimal2.Doesithavefeathers3.Doesithavefins4.Doesithavegills5.DoesithaveablowholeYes,it’sawhale6.DoesithavealongtrunkYes,it’sanelephant7.DoesithaveleavesYes,it’saplant

Yes,goto2No,goto7

Yes,it’sabirdNo,goto3

Yes,goto4No,goto6Yes,it’safishNo,goto5

Yes,goto2No,goto7

Yes,it’sabirdNo,goto3

Yes,goto4No,goto6

Yes,it’safishNo,goto5

Yes,goto2No,goto7

Yes,it’sabirdNo,goto3

Yes,goto4No,goto6

Yes,it’safishNo,goto5

AcknowledgementsLessondevelopedbyDr.ChrisSimonielloforBayPointElementary.Standards-cross-referencingandformattingbyGrantCraig.Questions,comments,edits?ContactDr.Chris:chris.Simoniello@gcoos.org