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Date:
Life Science Grade7
."_-Chapter7 GhangesOver Time
fnstructions: Completethe crosswordpuzzle.Use the clues to help identifythe words.
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2. scienlific'
: A well-testedconceptthat explainsa wide range of observations.
o.Pt#mrfossilformed
when mineratsreplaeeall or partof an organism.
structures:Bodypartsthatarestructurally
similarin relatedspecies.
Homotryu55.
selection: A processby which individualsthat are betteradaptedto their environmentare more likelyto
surviveand reproducethan othersof the same species.
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' The theorythat evolutionoccurs slowlybut steadily.
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An organismwhose cells containnuclei.
1 3 'The
, preservedremainsor traces of an organismthat lived in the past.
A group of organismsthat are physicallysimilarand can mate with each other and produceoffspringthat can
5 Q e i l e , ' , t 4 'also mate and reproduce.
nomenclature:The systemfor namingorganismsin which each organismis given a unique,two part
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scientificname.
1 7 . The scientificstudy of how livingthings are classifiea. - TaXon,ovny
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to surviveor reproduce
owsan organism
in its environment.
ciesfromEarth.
olveduringshortperiodsof rapidchange.
Down
ngs an organismneeds to live, grow, and reproduce.
rard part of an organismdissolves,leavingan empty space in
The comparisonof the strucluresof differentorganisms.
-*tst'^Y 7. comparative-:
tree diagram: A diagramthat shows how scientiststhink differentgroupsof organismsare related.
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A classificationgroupingthat consisGof a numberof similar,closelyrelatedspecies.
An organismwhose cells lack a nucleusand some other cell structures.
fossil: A type of fossil that providesevidenceof the activitiesof ancientorganisms.
genetic_:
Any differencebetweenindividualsof the same species.
sharedgroup.
characteristic:A characteristie-usuallya homologousstructure-shared by all organismsin a
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