The document provides instructions for using a dichotomous key to identify different types of beetles. It explains that a dichotomous key uses specific characteristics to classify unknown organisms by comparing them to known organisms through a series of choices. The key then guides the user to choose between pairs of descriptions based on beetle characteristics like antennae, body shape, color, etc. until identifying the beetle's common and scientific name.

1. How can you identify a beetle?
A dichotomouskeyisone of the toolsscientistsuse toidentifyan
unknownorganismand classifyitintoa group.To use a dichotomous
key,a scientistexaminesspecificcharacteristicsof the unknownorganism
and comparesthemto characteristicsof knownorganisms.
Learn It
Sortingobjectsoreventsintogroupsbasedon
commonfeaturesiscalledclassifying.When
classifying,selectone feature thatissharedby
some membersof the group,butnot by all.
Place those membersthatshare the feature ina
subgroup.Youcan classifyobjectsorevents
intosmallerandsmallersubgroupsbasedon
characteristics.
Try It
1 Use the dichotomouskeytoidentifybeetle
A. Choose betweenthe firstpairof
descriptions.Followthe instructionsforthe
nextchoice.Notice thateachdescription
eitherendsinthe name of the beetle or
instructsyouto go on to another setof
choices.
2 Inyour Science Journal,recordthe identity
of the beetle usingbothitscommonname
and scientificname.
3 Repeatsteps1 and 2 for beetlesB,C,andD.
Apply It
4 Thinkaboutthe choicesineach stepof the
dichotomouskey.Whatconclusioncanbe

2. made if you arrive at a step and neither
choice seemscorrect?
5 Predictwhetheradichotomouskeywill
workif you start at a locationotherthanthe
firstdescription.Supportyourreasoning.
6 KeyConcept Howdid the
dichotomouskeyhelpyouclassify
the unknownbeetles?
DichotomousKey
1A.
1B.
The beetle haslong,thinantennae.Go
to 5.
The beetle doesnothave long,thin
antennae.Goto 2.
2A.
2B.
The beetle hasshortantennae that
branch.Go to 3.
The beetle doesnothave shortantennae
that branch.It is a stag beetle, Lucanus
cervus.
3A.
3B.
The beetle hasa triangularstructure
betweenwingcoversandupperbody.
It isa Japanese beetle, Popillia japonica.
The beetle doesnothave a triangular
structure.Go to 4.

3. 4A.
4B.
The beetle hasa wide,roundedbody.
It isa June bug, Cotinisnitida.
The beetle doesnothave a wide,
roundedbody.Itisa deathwatchbeetle,
Xestobiumrufovillosum.
5A.
5B.
The beetle hasa distinctseparation
betweenbody parts.Goto 6.
The beetle hasnodistinctseparation
betweenbodyparts.Itisa firefly,
Photinuspyralis.
6A.
6B.
The beetle hasa black,gray,and white
bodywithtwoblack eyespots.Itisan
eyedclickbeetle, Alausoculatis.
The beetle hasa dull brownbodywith
lightstripes.Itisa clickbeetle,
Chalcolepidiuslimbatus.
From: iScience Grade 7, Davis County Edition. Page 729.