Non Random Mating

Inbreeding

Mating between relatives

Genetic Drift ( Inbreeding )

This would increase due to genetic drift in small populations

Self-fertilization (selfing)

Many flowering plants contain both male and female organs and self-pollinate

Homozygous Parents

Parents that self-fertilize produce all homozygous offspring

Heterozygous Parents

Parents that self-fertilize produce homozygous and heterozygous offspring in a 1:2:1 ratio

Inbreeding Effects ( generational )

Increases frequency of homozygotes and reduces frequency of heterozygotes

Inbreeding and Evolution

Inbreeding does not cause evolution, yet it can speed the rate of evolutionary change

Natural Selection and Inbreeding

Increases rate at which natural selection eliminates recessive deleterious alleles (that lower fitness) from a population

Allele Frequencies ( Inbreeding )

Allele frequencies do not change in population as a whole

Genotype Frequencies ( Inbreeding )

Changes genotype frequencies, not allele frequencies

Inbreeding Depression

- Decline in average fitness

- takes place when homozygosity increases and heterozygosity decreases in population

Sexual Selection

Another form of nonrandom mating where females choose certain males, and/or males compete among themselves to secure mates

Impact of Sexual Selection

Different from inbreeding, does lead to change in allele frequencies in population and increases fitness (a form of Natual Selection )