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