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?

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

allelic frequencyallelic frequency

The percentage of an allele The percentage of an allele

in the gene poolin the gene pool

genetic equilibriumgenetic equilibrium

When the frequency of alleles When the frequency of alleles remains the same over generationsremains the same over generations

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

stabilizing selectionstabilizing selection

natural selection that favors natural selection that favors averageaverage individuals in a populationindividuals in a population

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

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

speciationspeciation

Evolution of a new speciesEvolution of a new species

extinct

geographic isolationgeographic isolation

Occurs whenever a physical barrier Occurs whenever a physical barrier divides a populationdivides a population

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

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)

gradualismgradualism

Idea that Idea that species species originate originate though a though a gradual gradual change of change of adaptatioadaptationsns

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

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

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)

convergent evolutionconvergent evolution

When unrelated species evolve When unrelated species evolve similar traitssimilar traits

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

And now the quizAnd now the quiz

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

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

3 _________ selection3 _________ selection

natural selection that favors natural selection that favors averageaverage individuals in a populationindividuals in a population

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

5_________ isolation5_________ isolation

Occurs whenever a physical barrier Occurs whenever a physical barrier divides a populationdivides a population

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

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

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)

9_________ evolution9_________ evolution

When unrelated species evolve When unrelated species evolve similar traitssimilar traits

1010

Evolution of a new speciesEvolution of a new species

extinct

11 _________ ________11 _________ ________

The percentage of an allele The percentage of an allele

in the gene poolin the gene pool

12 ______ ______12 ______ ______

When the frequency of alleles When the frequency of alleles remains the same (equal) over remains the same (equal) over generationsgenerations

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

1414

Idea that Idea that species species originate originate though a though a gradual gradual change of change of adaptatioadaptationsns

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

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