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lecture Notes speciesa speciation • now1speciescansplit9becomemultiple species .answeredbyErnstMayr species .biological speciesconcept - groupoforganismsthatbreedw/ eachothertoproducefertileoffspring .- issuesWItheIMUPt
:_
animalsofdiff species occasionallyproducefertileoffspring ..Asexualorganismsbacteria ) clonethemselvesacannotreproducew/anyotherorg .• orgsin1Population0 breedw/thoseintheandpopulation , butcanWIthe3rdpopulation _ - ☒ Gies .l othernotions
:
- speciesarepopulation oforgs thataresimilar inappearance a behavior ..speciesaredefinedby geneticsimilarity ./ solves asexualissue ) • ecological speciesconcept - definesspeciesbynowtheyinteractw/theenvironment .- 0fundamentalnotionofWhatspeciesis!Speciation .allopatric - 1 species split into separatepopulations byabarrierthatcannotbecrossed .• Oncethepopulationissplit , groupscanevolveinto speciesblcdifferentmutations↑92populations experian .diffenvironment → Naturalselection .Closed barrier - parapatria - 1 specieslivesacross diff .environments .Natural selectionfavorsadaptationsacancausespeciation .- MMM blocked ifmigrationacrossspeciesrange occurs .0PMBarritt .sympatric - ↑ controversial .speciescan ÷in2tomakesubpopulationsthat0interactw/eachother .
3.2 HOMO10949Phylogeny phylogeny - .interredrelationshipbtwmultiple species .• 2Methodstoidentify ."¥ comparativeanatomy - comp .Multiple speciesusingtheseobservationsto dldllll relatedness .living afossil species .the↑similarities .thecloser theyareevolutionary .Greaterthesimilarities , closerthey are ."¥ comparativegenetics - comparesDNAsequenceoflivingorganisms .Reconstructingancestors
HOMO1094
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1Mistake of sharedancestrybtwpair of traits , orgents , in diff .Species .- evolutionofspecifictrait .Ex
:
fins , wings , arms .Bohlstructure ..convergentevolution _ .similartraitsevolvingseparately ..analogus _ comparableincertainrespects .3.3Dating .Radioactivedecay - estimatefossil age isotopes - atomsWI diff #ofprotonsallneutrons .
allisotopesarestable .• radiative - unstableatoms • decay _ aatoms ejectparticles or electromagneticradiation .Happensrepeatedlyuntilstable .~ Whencarbon -14decays
:1
neuron = proton + electron .Onlyprotonremains .~ ' hlife - 42atomsdecay ina timeperiod .• Carbondating _ .producedbycosmicrayshittingupperatmosphere .- look@howmuchradioactivecarbon -14leftina deadorganism ~ estimationoftimeof death ."¥ limitations
:
onlygivesrangeofdatesover 100 yrs , afterUOKyrs , 0longergivesreliabledates .• otherradioactivedating
:
uraniumapotassiumelements
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