Chapter 24Overview: The “Mystery of Mysteries”Slide 3Slide 4Slide 5LE 24-2Concept 24.1: The biological species concept emphasizes reproductive isolationThe Biological Species ConceptLE 24-3Reproductive IsolationSlide 11Slide 12LE 24-4aSlide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22LE 24-4aaSlide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30LE 24-4abLimitations of the Biological Species ConceptOther Definitions of SpeciesConcept 24.2: Speciation can take place with or without geographic separationLE 24-5Allopatric (“Other Country”) SpeciationLE 24-6Slide 38LE 24-7aLE 24-7bSympatric (“Same Country”) SpeciationPolyploidyLE 24-8Slide 44LE 24-9Habitat Differentiation and Sexual SelectionLE 24-10Allopatric and Sympatric Speciation: A SummaryAdaptive RadiationSlide 50Slide 51LE 24-12Studying the Genetics of SpeciationThe Tempo of SpeciationLE 24-13Concept 24.3: Macroevolutionary changes can accumulate through many speciation eventsEvolutionary NoveltiesSlide 58LE 24-14Evolution of the Genes That Control DevelopmentChanges in Rate and TimingLE 24-15aSlide 63LE 24-15bSlide 65LE 24-16Slide 67Slide 68Changes in Spatial PatternSlide 70LE 24-18Slide 72LE 24-19Evolution Is Not Goal OrientedLE 24-20Slide 76Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsPowerPoint Lectures for Biology, Seventh EditionNeil Campbell and Jane ReeceLectures by Chris RomeroChapter 24Chapter 24The Origin of SpeciesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsOverview: The “Mystery of Mysteries”•In the Galápagos Islands Darwin discovered plants and animals found nowhere else on EarthVideo: Video: GalápagosGalápagos Tortoise TortoiseCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Speciation, the origin of new species, is at the focal point of evolutionary theory •Evolutionary theory must explain how new species originate and how populations evolve•Microevolution consists of adaptations that evolve within a population, confined to one gene pool•Macroevolution refers to evolutionary change above the species levelCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Two basic patterns of evolutionary change:– Anagenesis (phyletic evolution) transforms one species into another–Cladogenesis (branching evolution) is the splitting of a gene pool, giving rise to one or more new speciesAnimation: MacroevolutionAnimation: MacroevolutionLE 24-2LE 24-2AnagenesisCladogenesisCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsConcept 24.1: The biological species concept emphasizes reproductive isolation•Species is a Latin word meaning “kind” or “appearance”Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsThe Biological Species Concept•Members of a biological species are reproductively compatible, at least potentially; they cannot interbreed with other populations.LE 24-3LE 24-3Similarity between different species.Diversity within a species.Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsReproductive Isolation•Reproductive isolation is the existence of biological factors (barriers) that impede two species from producing viable, fertile hybrids•Two types of barriers: prezygotic and postzygoticCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Prezygotic barriers impede mating or hinder fertilization if mating does occur:–Habitat isolation–Temporal isolation–Behavioral isolation–Mechanical isolation–Gametic isolationCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Habitat isolation: Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriersLE 24-4aLE 24-4aPrezygotic barriers impede mating or hinder fertilization if mating does occurPostzygotic barriers prevent a hybrid zygote fromdeveloping into a viable, fertile adultREDUCED HYBRIDVIABILITYREDUCED HYBRIDFERTILITYHYBRID BREAKDOWNHABITAT ISOLATIONTEMPORAL ISOLATIONBEHAVIORAL ISOLATIONMECHANICAL ISOLATIONGAMETIC ISOLATIONReducedhybridviabilityFertilizationViable,fertileoffspringReducedhybridfertilityHybridbreakdownMatingattemptGameticisolationFertilizationMechanicalisolationBehavioralisolationTemporalisolationHabitatisolationIndividualsofdifferentspeciesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Temporal isolation: Species that breed at different times of the day, different seasons, or different years cannot mix their gametesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Behavioral isolation: Courtship rituals and other behaviors unique to a species are effective barriersCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Mechanical isolation: Morphological differences can prevent successful matingCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Gametic isolation: Sperm of one species may not be able to fertilize eggs of another speciesVideo: Blue-footed Boobies Courtship RitualVideo: Blue-footed Boobies Courtship RitualVideo: Giraffe Courtship RitualVideo: Giraffe Courtship RitualVideo: Albatross Courtship RitualVideo: Albatross Courtship RitualCopyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsLE 24-4aaLE 24-4aaPrezygotic barriers impede mating or hinder fertilization if mating does occurHABITAT ISOLATIONTEMPORAL ISOLATIONBEHAVIORAL ISOLATIONMECHANICAL ISOLATIONGAMETIC ISOLATIONMatingattemptGameticisolationFertilizationMechanicalisolationBehavioralisolationTemporalisolationHabitatisolationIndividualsofdifferentspeciesCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Postzygotic barriers prevent the hybrid zygote from developing into a viable, fertile adult:–Reduced hybrid viability–Reduced hybrid fertility–Hybrid breakdownCopyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings•Reduced hybrid viability: Genes of the different parent species may interact