GB1 Ch. 23 - Population Genetics

gene pool

All the alleles of all the genes in a certain population

Hardy-Weinberg Principle

All the alleles of all the genes in a certain population.

states that genotype frequencies in a large population do not change from generation to generation in the absence of evolutionary processes

Hardy-Weinberg Equilibrium

observed frequencies conform to the Hardy–Weinberg predictions

genetic bottleneck

sudden reduction in the diversity of alleles in a population

founder effect

change in allele frequencies that occurs when a new population is established

sampling error

statistics

allele frequencies of a chosen subset of a population (the sample) are different from those in the total population, by chance

genetic drift

change in allele frequencies in a population that is due to chance

gene flow

movement of alleles between populations

mutation

random production of new alleles

point mutation

change in a single base pair in DNA

chromosome-level mutation

change in the number or composition of chromosomes

lateral (horizontal) gene transfer

transfer of genetic information from one species to another, rather than from parent to offspring

sexual polymorphism

When a population has more than two genders

sexual dimorphism

Any trait that differs between males and females.

territory

actively defended area where the owner has exclusive or semi-exclusive use

intersexual selection

A type of sexual selection in which an individual of one sex choses a particular individual of the other sex for mating (often occurs through female choice).

intrasexual selection

A type of sexual selection driven by competition among members of one sex (usually male–male) for an opportunity to mate.

frequency-dependent selection

when certain alleles are favored when they are rare, but not when they are common

heterozygote advantage

occurs when heterozygous individuals have higher fitness than homozygous individuals do

purifying selection

When deleterious alleles decline in frequency

directional selection

change average value of trait

stabilizing selection

reduce variation of trait

disruptive selection

increase variation in trait

balancing selection

maintain variation in trait

genetic variation

the number and relative frequency of alleles that are present in a particular population

ecological selection

type of natural selection that favors individuals with heritable traits that enhance their ability to survive and reproduce in a certain environment