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NAU BIO 435C - exam_2_ eview

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Review sheet for Exam 2 Spring 2018Species and speciation – Chapter 14Disadvantage: Polymorphic characters are not usedAdvantage: 5 species diagnosed at onceAllopatric- speciation takes place in populations that are geographically isolated from one anotherVicariance model- similarly sized populationsBarrierEX:Shrimp and the panama canalHybrid zoneSelective gradientEX: anthoxanthum odoratum, tolerance to heavy metalsSympatric- populations diverge into new species in the same locationWhat drives species to split if not geographical barrier or hybrid zone?EX: Apple maggot fly- breeding times vary-different fruiting times of host treesReproductive isolation: tolerance vs aggressionPeripheral isolate model- GENETIC DRIFT/founder effect is largePeripheral isolate model: Progenitor-derivative pairRed spruce- derivative speciesHybrid zone- gene flow b/w diverging pops exists along the clineSelective disadvantages of hybrid individualsIn hybrid zones, hybrid individuals have a superiority over nonhybridsSoil in hybid zone is a uniqueWhen Individuals live in one of a series of populations that are connected to one another- salamanderHabitat, ecological specialization, dietary analysisMidas, high bodied/short, likes living at bottom of lakesArrow, low bodied, likes foraging in open waterBoth mate w/ their own species so reproductive isolation existsDifferent fruiting times of their hosts/ difference in selective conditionsDifferent mating timesPrezygotic- timing is off, behavoiral isolation, sperm is not transferred, egg is not fertilizedSex chromosomes--- reproductive isolation (XX)(XY)interactionsExamples of possible short answer/essay:Peripheral isolate model: Progenitor-derivative pairRed spruce- derivative speciesLUCA was not the first living thingThe last universal common ancestor (LUCA).First mass extinction wiped out some 50% of all life on earthReview sheet for Exam 2 Spring 2018This exam will cover Chapters 14, 4, 5, 11, 12 (Species and Speciation, Phylogeny and Evolutionary History, Origin of Life, Major Transitions)Species and speciation – Chapter 14-Ecological species conceptspecies defined by a cluster of individuals that occupy the same niche. - What is the phenetic species concept?uses the clustering of individuals or populations in phenotype space to draw species boundaries between clusters. The vertical and horizontal axes may each represent a single phenotypic trait or multiple phenotypic traits.- What is the phylogenetic species concept?species defined by one or more derived characters/traits unique to the species. Disadvantage: Polymorphic characters are not usedAdvantage: 5 species diagnosed at once- What is the biological species concept?uses the presence or absence of gene flow among populations to delineate species boundaries.- What are the strengths and weakness of each of the above species concepts?- What are the three basic modes of speciation? How do they differ from each other? Allopatric- speciation takes place in populations that are geographically isolated from one anotherVicariance model- similarly sized populationsperipheral isolate model- unequal populations (island)BarrierEX:Shrimp and the panama canal Parapatric- incipient species- diverging populations on the path to speciation, have distributions tht abut one anotherHybrid zoneSelective gradientEX: anthoxanthum odoratum, tolerance to heavy metalsSympatric- populations diverge into new species in the same locationWhat drives species to split if not geographical barrier or hybrid zone?-resource competition/reproductive isolation/diet analysis EX: Apple maggot fly- breeding times vary-different fruiting times of host trees- Be able to provide examples of each of the basic modes of speciation?- Knowlton et al. (1993) describe how the formation of the Isthmus of Panama impacted the evolution of shrimp from the genus Alpheus. What evidence is presented to show this as an alloptric speciation event(s)?Reproductive isolation: tolerance vs aggressionTolerance decreased, aggression increased--- more reproductive isolation as a function of time separatedPeripheral isolate model- GENETIC DRIFT/founder effect is large - What evidence is presented to support the claim that red and black spruce for a progenitor-derivative species pair?Peripheral isolate model: Progenitor-derivative pairRed spruce- derivative species black spruce- progenitor speciesprogenitor species doesn’t change while derivative changes a lotblack spruce- high genetic diversity, broader geographic distributionred spruce has no unique mitochondrial haplotypesred spruce evolved from black spruce from a geographically isolated population - What is a cline? How does that affect the concept/process of parapatric speciation?Spatial gradient in frequency of phenotypes or genotypes/// formed when populations have different selective conditions- How does a hybrid zone affect the process of parapatric speciation?Hybrid zone- gene flow b/w diverging pops exists along the cline- What determines the breadth of a hybrid zone? In this context, understand the implications of Han Wang and colleagues study of big sagebrush (Artemisia tridentata) and the different methods they used to determine the strength of the hybrid populations.Selective disadvantages of hybrid individuals In hybrid zones, hybrid individuals have a superiority over nonhybridsSoil in hybid zone is a unique selection may have favpred hybrids- What is a ring species? Give an example from your text.When Individuals live in one of a series of populations that are connected to one another- salamander- Sympatric speciation: understand and be able to describe this process in relation to the two species of cichlids in Lake Apoyo, Nicaragua (Barluenga et al. 2006). In what ways do these two species differ? How is it thought that they came to be separate species (what led to their divergence)? Habitat, ecological specialization, dietary analysis Midas, high bodied/short, likes living at bottom of lakesArrow, low bodied, likes foraging in open waterBoth mate w/ their own species so reproductive isolation exists- You should understand process and factors that have led to the divergence of apple maggot flies on cultivated apples versus hawthorn trees.Different fruiting times of their hosts/ difference in selective conditionsDifferent mating times- Know the differences between prezygotic and postzygotic reproductive isolating mechanisms. Give examples of each type. Prezygotic- timing is off,


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