Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Evolution II 1Chapter 22: The Nature of SpeciesWe will also cover some selected topics from Chapters 23 -- intro to claudisticsChapter 26-- Biological classification-- Domains vs kingdoms-- Intro to history of lifeEvolution II 2What is a species?Scientific naming of speciesScientific binomial – Carolus LinnaeusGenus + SpeciesHomo sapiens vs “humans”Acer rubrum vs “red maple”Writing ConventionsDefinition“A group of interbreeding organisms that are reproductively isolated”What is ‘reproductive isolation’?Biological classification system: DomainKingdom Phylum Class Order FamilyGenus SpeciesWhich of these is Acer rubrum?QuestionEvolution II 3What are some mechanisms of reproductive isolation?Pre-zygoticEcological (habitat)e.g., mountain rangesMechanicale.g. reproductive anatomyTemporale.g. mating seasonsBehaviorale.g., mating ritualsGameticgametes incompatible(many plants)e.g., frogs of Sierra Nevada foothillse.g., bowerbirds of AustraliaEvolution II 4Mechanisms of reproductive isolation, con’t.Post-zygoticHybrid inviability-- embryo / fetus does not develope.g., cattle and water buffaloHybrid infertility-- offspring is infertilee.g., colored and pied flycatchersMeet and hybridize in central and northern EuropeQuestionEvolution II 5The biological species concept has limitationsIf two species can hybridize, are they separate species?-- plants-- animalsShould all dogs be classified in the same species?Native: California Tiger Salamander Invasive: Adult Barred Tiger Salamander Hybrid: Appears to bemore fit then nativehttp://sciencemode.com/2007/09/20/california-barred-tiger-salamanders-interbreed-produce-hybrids/Evolution II 6How does geographic distribution relate to speciation?Allopatric speciation: geographic isolationmountains, rivers, islandsWhat evolutionary mechanisms can operate?Can Sympatric speciation occur?e.g., “blackbellied seedcracker”Less fit hybrids -‘reinforcement’Reinforcement amongEuropean flycatchersQuestionEvolution II 7HawthornAppleApple MaggotHow can we explain the origin of the apple maggot?Visit Martin G. Kelly’s site at http://www.sciencecases.org/maggot_fly/maggot_fly.aspEvolution II 8Under what conditions does ‘Adaptive Radiation’ occur?-A special case of disruptive evolutionDarwin’s Finches -- classic exampleCan occur regionally or globally-- rise of mammalsAdaptations reinforced by“Character Displacement’QuestionEvolution II 9Plotting macroevolutionWhat are some characteristicsof evolution that can be diagrammed?Gradualism vs ‘punctuated equilibrium’Stephen J Gould & Niles EldredgeWhat are possible mechanisms ofrapid speciation?-- polyploidy-- mutations to developmental genes-- geologic time vs ‘human’ timeEvolution II 10Plotting evolutionary relationships(from Chapter 23)The traditional “evolutionary tree” vs ClaudisticsClade= all organisms with“Shared derived characteristics”Evolution II 11Revisiting Classification… (from Chapter 26)Domains and Kingdoms Biological classification system:DomainKingdomPhylumClassOrder FamilyGenus SpeciesQuestionEvolution II 12Highlights of the History of Life(from Chapter 26)Advanced life forms have appearedLate in earth’s geologic history Origin of life ~ 3.8 byaEukaryotic cells ~ 1.7 byaMulticellular organisms ~ 1.2 byaHumans only ~ 1 myaOrigin of lifeMulticellularorganismsEvolution II 13The origin of major groupsof animalsThe ‘eras’The Cambrian explosionVertebrates InvertebratesAge of reptilesAge of mammalsInsects most successfulof them allEvolution II 14There have been many mass extinctions!Some small,Some