MICROEVOLUTION MICROEVOLUTION VS. VS. MACROEVOLUTION MACROEVOLUTION • Microevolution: survival through the inheritance of f avorable characteristics – mutations – selection • Macroevolution: progression of biodiversity through geological time – speciation – extinction
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MICROEVOLUTION VS. MACROEVOLUTION Microevolution: survival through the inheritance of favorable characteristicssurvival through the inheritance of favorable.
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MICROEVOLUTION MICROEVOLUTION VS. VS. MACROEVOLUTIONMACROEVOLUTION
• Microevolution: survival through the inheritance of favorable characteristics – mutations – selection
• Macroevolution: progression of biodiversity through geological time – speciation – extinction
• Large Population Size(laws of probability must apply)
• Isolation of Population(no immigration/emigration to/from other populations)
• NO MUTATIONS ALLOWED!• NO NATURAL SELECTION ! all traits must be selectively neutral• Mating Must Be RANDOM equal probabilities of mating btwn genotypes
IS HW EQUILIBRIUM IS HW EQUILIBRIUM POSSIBLE?POSSIBLE?
THE HARDY-WEINBERG THE HARDY-WEINBERG EQUATIONEQUATION
• Given one locus with two alleles (A,a) the frequency of either allele is described by a number from zero to one:
allele absent from pop freq = 0
same allele in all indiv in pop
freq = 1
WHAT IF BOTH ALLELES ARE WHAT IF BOTH ALLELES ARE PRESENT IN A POPULATION?PRESENT IN A POPULATION?• Frequency of both alleles is equal to
p + q = 1
[p = dominant allele (A)]
[q = recessive allele (a)]
• Knowing the frequency of one allele allows for the calculation of the other…
p = 1- q ; q = 1 - p
• If p+q=1,
then (p+q)2 = 1.
Expand it and get…
p 2 + 2pq + q2 = 1
WHAT DOES IT ALL MEAN WHAT DOES IT ALL MEAN GENOTYPICALLY?GENOTYPICALLY?
p2 = frequency of AA
2pq = frequency of Aa
q2 = frequency of aa
PROBLEM 1PROBLEM 1
• In pigs, the allele for black coat (b) is recessive to the allele for pink coat (B).
WHAT % OF PIGS ARE WHAT % OF PIGS ARE HETEROZYGOUS FOR PINK HETEROZYGOUS FOR PINK
COAT?COAT?
PROBLEM 2PROBLEM 2In a certain population of 1000 fruit flies, 640 have red eyes while the remainder have sepia eyes. The sepia eye trait is recessive to red eyes. How many individuals would you expect to be homozygous for red eye color?
PROBLEM 3PROBLEM 3
Phenylketonuria (PKU) is a human metabolic disorder that results in mental retardation if it is untreated in infancy. In the United States, one out of approximately 10,000 babies is born with the disorder. Approximately what percent of the population are heterozygous carriers of the recessive PKU allele?
IF 9% OF AN AFRICAN IF 9% OF AN AFRICAN POPULATION IS BORN POPULATION IS BORN
WITH A SEVERE FORM OF WITH A SEVERE FORM OF SICKLE-CELL ANEMIA (SS), SICKLE-CELL ANEMIA (SS),
WHAT PERCENTAGE OF WHAT PERCENTAGE OF THE POPULATION WILL BE THE POPULATION WILL BE
MORE RESISTANT TO MORE RESISTANT TO MALARIA BECAUSE THEY MALARIA BECAUSE THEY ARE HETEROZYGOUS(SS) ARE HETEROZYGOUS(SS)
FOR THE SICKLE-CELL FOR THE SICKLE-CELL GENE?GENE?