General Biology - Allele Frequencies and Evolution

Flashcards covering key vocabulary and concepts related to allele frequencies, Hardy-Weinberg equilibrium, and factors affecting evolution in populations.

Allele

Alternate forms of a gene at each locus.

Homozygous

Having two identical alleles for a gene (AA or aa).

Heterozygous

Having two different alleles for a gene (Aa).

Mendel's Law of Segregation

The alleles for a heritable character segregate during gamete formation and end up in different gametes.

Gene Pool

All alleles of all genes in a population at any one time.

Fixed Allele

All individuals in a gene pool are homozygous for the same allele.

Allele Frequency

Proportion of a specific allele in a population.

Genotype Frequency

The proportion of a specific genotype (AA, Aa, aa) in a population.

Hardy-Weinberg Equations

Equations used to calculate allele (p + q = 1) and genotypic (p^2 + 2pq + q^2 = 1) frequencies in a population.

Genetic Drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

Founder Effect

A few individuals colonize a new habitat; the gene pool on the new population probably has only some of the alleles that were in the original population.

Bottleneck Effect

A chance event or catastrophe can reduce the genetic variability within a population.

Natural Selection

Differential survival and reproduction of individuals due to differences in phenotype.

Stabilizing Selection

Natural selection that favors intermediate variants by acting against extreme phenotypes.

Directional Selection

Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.

Diversifying Selection

Natural selection that favors extreme over intermediate phenotypes.