Download Population Genetics and Speciation

Population Genetics and Speciation
Vocabulary:
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Population Genetics: The study of evolution from a ____________________________ point of view
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_________________________________: Change in the allele frequencies of a population
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Gene Pool: the total genetic information available in a population
o
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In other words: all of the possible ________________________ (variations) that are present, for each gene,
within a population.
________________________ Frequency: the number of times an allele occurs in a gene pool
o Total # of a certain allele / total # of alleles (in the population)
Hardy Weinberg Genetic _______________________________ = 5 conditions/agents of evolutionary change
(change in the frequency of alleles)
1. Genetic mutations = _________________ in DNA
2. Gene Flow = flow of ___________________ between populations
a. ____________________________ = gene flow INTO a population
b. ____________________________ = gene flow OUT of a population
3. Genetic drift = a change in allele frequencies due to ________________________ events.
a. ____________________ populations are most susceptible to genetic drift
4. Random mating vs. nonrandom mating
a. __________________________ mating: mating that happens more by chance than by choice – it has less
effect on allele frequencies
i. Example: coral polyps disperse their sperm into ocean currents and will randomly contact
an egg.
b. Nonrandom mating: whenever individuals choose partners
c. Sexual selection: when certain traits increase an individual’s success with mating
5. Natural Selection
a. The ongoing process in nature where the presence or absence of certain factors in the
___________________________ “select” which traits/variations within a population are most successful
** Most traits are _________________________________________________ = many possible variations
Types of Natural Selection - 3 general graphing patterns:
1. Stabilizing selection: favors the __________________________________ traits
2. Disruptive selection: favors the __________________________________ traits (each end of the graph)
3. Directional selection: favors the formation of just ONE of the __________________________________ traits
Goldfish Population Activity:
Calculate the Allele Frequency
 Add up the total number of all alleles in your population of fish: ____________
o Brown fish = BB
o Orange fish = Bb
o Yellow fish = bb
 How many brown (B) alleles are in your population? _______________
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How many total alleles are in your population? ______________________
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Determine the allele frequency of (B) brown alleles: _________________
1. Gene Flow
a. Immigrate: 10 yellow fish move in from a neighboring pond
b. Emigrate: 5 brown fish move out to another pond
c. Recalculate the brown allele frequency: _______________________________
How does gene flow affect allele frequencies in a gene pool?
2. Genetic Drift
a. Perform a random act to your population
b. Recalculate the brown allele frequency: _______________________________
How does genetic drift affect allele frequencies in a gene pool?
3. Nonrandom mating:
a. If every fish in the population only wanted to mate with the brown fish (pretzels), how would that
change the allele frequencies over time?