b33 ppt mechanics of evolution ch 15.2
TRANSCRIPT
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Week 33Week 33
Ch. 15.2 pg 404Ch. 15.2 pg 404
Mechanics of EvolutionMechanics of EvolutionWhat’s behind the curtain?What’s behind the curtain?
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gene poolgene poolAll the genes (alleles) in a All the genes (alleles) in a
population population Darwin Award videoDarwin Award video
genegeneDNA segment that DNA segment that
controls protein controls protein production and cell production and cell cyclecycle
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allelic frequencyallelic frequency
The percentage of an allele The percentage of an allele
in the gene poolin the gene pool
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genetic equilibriumgenetic equilibrium
When the frequency of alleles When the frequency of alleles remains the same over generationsremains the same over generations
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genetic driftgenetic drift The change of allelic The change of allelic frequencies by unusual frequencies by unusual events, disrupting a events, disrupting a population’s genetic population’s genetic equilibriumequilibrium
ex. extra fingers and toes ex. extra fingers and toes due to inbreedingdue to inbreeding
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stabilizing selectionstabilizing selection
natural selection that favors natural selection that favors averageaverage individuals in a populationindividuals in a population
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directional selectiondirectional selection
natural selection that favors natural selection that favors individuals with an individuals with an extremeextreme variation variation of a traitof a trait
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disruptive selectiondisruptive selectionnatural selection that favors natural selection that favors
individuals with individuals with either extreme either extreme variationvariation of a trait, eliminating of a trait, eliminating intermediate phenotypesintermediate phenotypes
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speciationspeciation
Evolution of a new speciesEvolution of a new species
extinct
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geographic isolationgeographic isolation
Occurs whenever a physical barrier Occurs whenever a physical barrier divides a populationdivides a population
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reproductive isolationreproductive isolation
Occurs when Occurs when formerly interbreeding organisms formerly interbreeding organisms can no longer mate and produce fertile can no longer mate and produce fertile offspringoffspring, due to change in genetic material or , due to change in genetic material or behaviorbehavior
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polyploidypolyploidymultiple of the multiple of the
normal set (2n) normal set (2n) of chromosomes of chromosomes due to mistakes due to mistakes in mitosis or in mitosis or meiosismeiosis
Examples of Polyploid CropsTriploid (3n) crops: banana, apple, ginger, watermelon, citrus[11] Tetraploid (4n) crops: durum or macaroni wheat, maize, cotton,
potato, cabbage, leek, tobacco, peanutHexaploid (6n) crops: chrysanthemum, bread wheat, oat, kiwifruit Octaploid (8n) crops: strawberry, dahlia, pansies, sugar cane
Tetraploid (4n)
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gradualismgradualism
Idea that Idea that species species originate originate though a though a gradual gradual change of change of adaptatioadaptationsns
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punctuated equilibriumpunctuated equilibrium
Idea Idea speciation speciation occurs occurs relatively relatively quickly in quickly in rapid burstsrapid bursts with long with long periods of periods of genetic genetic equilibrium equilibrium in betweenin between
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adaptive radiationadaptive radiation
When an When an ancestral ancestral species species evolves into evolves into an array of an array of species to species to fit number fit number of diverse of diverse habitatshabitats
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divergent evolutiondivergent evolution
species that once were similar to an species that once were similar to an ancestral species diverge (become ancestral species diverge (become increasingly DIFFERENT)increasingly DIFFERENT)
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convergent evolutionconvergent evolution
When unrelated species evolve When unrelated species evolve similar traitssimilar traits
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Report on Report on an example of an example of
convergent evolutionconvergent evolutionand divergent evolutionand divergent evolution
oror
examples of examples of stablizing, directional, and disruptive stablizing, directional, and disruptive
selectionselection
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And now the quizAnd now the quiz
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1. ___________ selection1. ___________ selection
natural selection that favors natural selection that favors individuals with an individuals with an extremeextreme variation variation of a traitof a trait
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22 The change of allelic The change of allelic
frequencies by unusual frequencies by unusual events, disrupting a events, disrupting a population’s genetic population’s genetic equilibriumequilibrium
ex. extra fingers and toes ex. extra fingers and toes due to inbreedingdue to inbreeding
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3 _________ selection3 _________ selection
natural selection that favors natural selection that favors averageaverage individuals in a populationindividuals in a population
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4 _________ selection4 _________ selectionnatural selection that favors natural selection that favors
individuals with individuals with either extreme either extreme variationvariation of a trait, eliminating of a trait, eliminating intermediate phenotypesintermediate phenotypes
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5_________ isolation5_________ isolation
Occurs whenever a physical barrier Occurs whenever a physical barrier divides a populationdivides a population
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6________ isolation6________ isolation
Occurs when Occurs when formerly interbreeding organisms formerly interbreeding organisms can no longer mate and produce fertile can no longer mate and produce fertile offspringoffspring, due to change in , due to change in genetic materialgenetic material or or behaviorbehavior
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7 ____________ radiation7 ____________ radiation
When an When an ancestral ancestral species species evolves into evolves into an array of an array of species to species to fit number fit number of diverse of diverse habitatshabitats
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8 __________ evolution8 __________ evolution
The pattern of evolution in which species that The pattern of evolution in which species that once were similar to an ancestral species once were similar to an ancestral species diverge (become increasingly district)diverge (become increasingly district)
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9_________ evolution9_________ evolution
When unrelated species evolve When unrelated species evolve similar traitssimilar traits
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1010
Evolution of a new speciesEvolution of a new species
extinct
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11 _________ ________11 _________ ________
The percentage of an allele The percentage of an allele
in the gene poolin the gene pool
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12 ______ ______12 ______ ______
When the frequency of alleles When the frequency of alleles remains the same (equal) over remains the same (equal) over generationsgenerations
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13 13 multiple of the multiple of the
normal set (2n) normal set (2n) of chromosomes of chromosomes due to mistakes due to mistakes in mitosis or in mitosis or meiosismeiosis
ExamplesTriploid (3n) crops: banana, apple, ginger, watermelon, citrus[11] Tetraploid (4n) crops: durum or macaroni wheat, maize, cotton,
potato, cabbage, leek, tobacco, peanutHexaploid (6n) crops: chrysanthemum, bread wheat, oat, kiwifruit Octaploid (8n) crops: strawberry, dahlia, pansies, sugar cane
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1414
Idea that Idea that species species originate originate though a though a gradual gradual change of change of adaptatioadaptationsns
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1515All the genes (alleles) in a All the genes (alleles) in a
population population Darwin Award videoDarwin Award videoDNA segment that DNA segment that
controls protein controls protein production and cell production and cell cyclecycle
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16 16
Idea Idea speciation speciation occurs occurs relatively relatively quickly in quickly in rapid burstsrapid bursts with long with long periods of periods of genetic genetic equilibrium equilibrium in betweenin between