*take out your hw to be stamped* · • review hw & “evidence for evolution” video • 15.2...

WarmUp1/18-1/19

*Takeoutyourhwtobestamped*

1.  Takeoutyourlaptopandnotes2.  LogintoGoogleClassroom

3.  Waitformetopostthe15.1QuickQuiz

Agenda•  Warmup-QuickQuiz•  Reviewhw&“EvidenceforEvolution”video•  15.2Notes:MechanismsofEvolution•  Ch15QuizletLive•  Chapter14/15TaskCards

Homework:Chapter15worksheet

**Ch14/15ExamWed/Thurs**Quizletandlistofthingstostudyisonwebsite!!!!!!!!!!!

15.2MechanismsofEvolution

Canindividualsevolve?

•  Populations,notindividuals,evolve.•  Naturalselectionactsonarangeofphenotypesinapopulation

•  Genepool:allallelesinapopulation’sgenes

AllelicFrequency&GeneticEquilibrium

•  Allelicfrequency:%ofanyspecificalleleinagenepool

•  Geneticequilibrium:frequencyofallelesinapopulationremainsthesameovergenerations

Howcanthegenepoolchange?

•  Mutationthatcausesusefulvariation-->becomespartofapopulation’sgenepool

•  Geneticdrift:alterationofallelicfrequencybychanceevents

•  Geneflow:Movementofindividualsinandoutofapopulation Wouldthesethingsaffectalarge populationorasmallpopulationmore?

https://youtu.be/W0TM4LQmoZY

NaturalSelectionActsonVariation

•  Stabilizingselection-favorsaverageindividualsinapopulation

•  Directionalselection-favorsoneoftheextremevariationsofatrait

•  Disruptiveselection-individualswitheitherextremeofatraitisfavored

https://youtu.be/64JUJdZdDQo

Speciation•  Whenmembersofapopulationcannolongerinterbreed(reproductiveisolation)– Geneticsorbehavioral

•  Geographicisolation:physicalbarrierdividespopulation

SpeciationRates

•  Gradualism:Gradualchangeofadaptationsoverlongperiodoftime

•  Punctuatedequilibrium:Speciationcanoccurinquickbursts,withlongperiodsofgeneticequilibriuminbetween

PatternsofEvolution•  Divergentevolution:speciesthatwereoncesimilartoancestralspeciesdiverge,eventuallyresultinginanewspecies.–  EXAMPLE:Adaptiveradiation-ancestralspeciesevolvesintoanarrayofspeciestofitanumberofdiverse

Example:Hawaiianhoneycreepers

PatternsofEvolution

•  Convergentevolution:Distantlyrelatedorganismsevolvesimilartraits

•  CanresultinAnalogousstructures-structuressimilarinfunctionbutnocommonancestor

Exampleofanalogousstructure: