7.4 Population Genetics
Notes
Evolution can be measured as a change in allele frequencies in a population's gene pool.
- A gene pool is all the alleles in a population.
- Mutation creates new alleles.
- Gene flow is the movement of alleles between populations when individuals migrate.
- Genetic drift is random change in allele frequencies, strongest in small populations. The bottleneck effect (a disaster shrinks a population) and the founder effect (a few individuals start a new population) are examples.
- Hardy-Weinberg equilibrium: allele frequencies stay the same only if there is no mutation, no migration, a very large population, random mating, and no natural selection.
Practice
A hurricane randomly kills 90% of a lizard population on an island, leaving a few survivors whose alleles happen to differ from the original group. This is:
A random disaster drastically shrank the population, changing allele frequencies by chance.
Which condition is required for a population to stay in Hardy-Weinberg equilibrium?
Random mating is one of the five conditions; the others would cause change.
Pollen from one population of sunflowers is blown to another population, adding new alleles. This is:
Gene flow moves alleles between populations.
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