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SI Bio 211
11.26.07
Population Genetics
1. _______POPULATION__________________________, not individuals, change
genetically over time.
2. The sum total of genes in a population is called the ____GENE_________
__POOL___________.
3. The ______GENE ____________ _____FREQUENCY__________________ is how often
an allele at a single locus occurs in a population.
4. _____GENE FLOW_____________ is the movement of alleles over time between
populations.
5. State the Hardy-Weinberg equation:
P2+2pq+q2 = 1
6. Hardy-Weinberg equilibrium means that no ____EVOLUTION___________________
is occurring.
7. What are the 5 assumptions HW?
No mutation, No migration, No selection, Random mating and infinitely large
population.
8. When does microevolution occur?
Natural selection accumulates and maintains favorable mutations and
genotypes in a population. If the environment changes, natural selection
responds by favoring genotypes and mutations adapted to the new
environment. The favorable mutations and genotypes accumulate and
gradually leading to microevolution.
9. Contrast founder effect, bottleneck, and genetic drift.
Genetic drift - random change in allele frequency
Founder effect- a small population from a main population moves to another
environment and starts a new population. Due to limited gene variation of the
small population, the population will have limited gene variation.
Bottleneck effect- a population passes through a selection barrier and only
certain genes and alleles pass through and the genetic variation of the
population would be very small. The limited genetic component might lead to
fixation of the allele in the population.
10. What do p and q represent?
P and q represent allele frequencies of two alleles in a population.
SI Bio 211
11.26.07
Population Genetics
11. A ____SMALL_____________________ population is more likely to go through
genetic drift.
12. For gene flow to occur, _____MIGRATION__________________ must occur between
populations.
13. __NATURAL____________ _____SELECTION_____________ is the most powerful
evolutionary mechanism.
14. Why does allele fixation occur?
Allele fixation occur when only individuals with certain alleles are present in a
population and individuals in a population can mate with individual with the same
alleles.
15. What is significant about sickle cell anemia?
It demonstrates heterozygote advantage. The heterozygotes for sickle-cell allele have
selective advantage over malaria. The heterozygotes are better adapted to survive
than normal homozygotes or sickle-cell homozygous.
16. What does selection act upon?
INDIVIDUALS
17. Draw graphs representing directional, diversifying, and stabilizing selection.