7.4 Population Genetics Flashcards
What are mutations?
Random changes in an organism;s DNA sequence
What do mutations create in a population?
Genetic variation and provides new phenotypes that contribute to evolution by natural selection
What is genetic drift?
A random change in the frequency of a particular allele within a population
In what size populations is genetic drift more likely to occur?
Small populations
Describes what happens in a bottleneck event.
A large, varied population is drastically reduced by a natural disaster, famine, habitat destruction, overhunting, etc; alleles are lost from the gene pool
What are the two main types of genetic drift?
The founder effect and bottleneck effect
Describes what happens in the founder effect.
A random process that reduces genetic variation in a small population due to separation from a larger population; may result from migration and geological events that isolate populations
What is gene flow (migration)?
The movement of individuals and/or gametes in and out of a population (exchange of alleles)
What does gene flow do?
it introduces new genes into populations, which increases genetic variation and reduces differences between populations over time
What is the raw material for evolution?
Genetic variation
What does fitness depend on?
Specific environmental conditions
What is nonrandom mating?
A process that is not random and relies on sexual selection to select for advantageous traits in a mate
