How Populations Evolve (Quiz 2)

alleles

Versions of a gene that underly the variability within a population.

genotype

The combination of alleles of a certain gene.

phenotype

The observable characteristics of an organism, influenced by genotype.

population genetics

The study of alleles and how frequent they are in a population.

gene pool

The number of each allele that exists in a population.

allele frequency

The percentage of each allele in the population.

genetic drift

Random changes in allele frequencies in a population.

assortive mating

A mating pattern where individuals with similar phenotypes mate with each other.

bottleneck effect

A sharp reduction in the size of a population due to environmental events.

founder effect

Reduced genetic diversity that results when a population is descended from a small number of ancestors.

natural selection

The process whereby organisms better adapted to their environment tend to survive and produce more offspring.

Harvey-Weinberg equilibrium

A population in which the allele frequency does not change between generations.

dominant alleles

Alleles that take precedence over recessive alleles.

recessive alleles

Alleles that are masked by dominant alleles.

mutation

A change in the DNA sequence that can contribute to evolution.

migration

The movement of individuals into or out of a population, affecting allele frequencies.

evolving population

A population in which the allele frequency changes between generations.

non-evolving population

A population at Harvey-Weinberg equilibrium where allele frequencies remain constant.

dark color allele (D)

A dominant allele that results in dark fur in mice.

light color allele (d)

A recessive allele that results in light fur in mice.

pocket mouse

A species used as an example to study evolution and allele frequencies.

allele frequency change

Indicates that a population is evolving.

allele frequency stability

Indicates that a population is at Harvey-Weinberg equilibrium.

Mutations

Copy errors in genes that are passed on to offspring, which can introduce new alleles into a population.

Small population

A population size that can lead to more rapid evolution due to increased effects of genetic drift and reduced genetic diversity.

Evolution

The change in the heritable characteristics of biological populations over successive generations.

Random mating

A mating system in which all individuals have an equal chance of mating with any other individual in the population.

Large population

A population size that tends to maintain genetic diversity and is less affected by genetic drift.

Changes in allele frequency

Changes in allele frequency due to mutations, migration, genetic drift, and natural selection are fundamental processes in evolution.