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section11.4 new.notebook
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Thursday, February 27
Bell Work:
Would a population of 10 individuals or 100 individuals be more vulnerable to genetic drift? Why?
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Hardy­Weinberg equilibrium­ Populations that meet the 5 conditions and are not evolving.
The genotype frequency remains the same when a population is in Hardy­Weinberg equilibrium.
a. Very large population
b. No emigration or immigration
c. No mutations
d. Random mating
e. No natural selection
Rarely occurs in real populations, but is still important because:
1. Learn more about how the population is evolving.
2. Gives a framework for testing the factors that can lead to evolution.
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Equation:
p2 + 2pq + q2 =1 and p+q=1
q2= frequency of homozygous recessive genotype
q= frequency of recessive allele
p= frequency of dominant allele
p2 = frequency of homozygous dominant genotype
2pq= frequency of heterozygous genotype
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Hardy­Weinberg equation can be used in simple dominant­
recessive systems.
The actual genotype frequencies must be known.
If the frequencies do not match the predicted frequencies the population is evolving.
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Genetic Drift­ allele frequencies can change due to chance alone.
Gene Flow­ Movement of alleles from one population to another changes the allele frequencies in the population.
Mutation­ New alleles can form through mutations. Create genetic variation needed for evolution.
Sexual Selection­ certain traits may improve mating success. Alleles for these traits increase in frequency.
Natural Selection­ certain traits may be an advantage for survival. Alleles for these traits increase in frequency.
Genotype frequencies
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section11.4 new.notebook
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Friday, February 28
Bell Work:
Complete the problem below.
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