Population genetics

Genetic Variation

Sexual recombination - mixing genetic material, creating new combinations of alles

What creates new alleles

Genetic Mutation

What causes Genetic Variation?

Mutations, recombination, and gene flow

How does Genetic Variation Influence Evolution?

Direct source of evolutionary change

Environments role on Genetic Variation

No direct effect on DNA Sequence

Phenotypic Variation

Differences in observable traits

What causes Phenotypic Variation?

Genes, environment, or both

Phenotypic Variation influence on evolution

Natural selection acts on phenotypes

Environments role on Phenotypic Variation.

Strong influence on many traits

Mechanisms of Evolution. Mutations

Random change in DNA

Mutation Effects on Population

Creates new genetic variation, the original and only source of all new alleles

Mechanisms of Evolution. Non-random mating

Individuals choose mates based on certain traits or mate within a specific group

Non-random mating effects on population

Changes genotype frequencies, not allele frequencies, and increases homozygosity

Mechanism of Evolution. Natural selection

Individuals with more favorable traits survive and reproduce more (than those who do not)

Natural Selection effects on Population

Causes adaptive evolution (alleles that improve fitness increase), changes allele frequencies in a non-random way

Mechanisms of Evolution. Genetic drift

Random changes in allele frequencies due to chance events

Genetic Drift Effects on Population

Stronger in small populations, can cause alleles to be lost or fixed by chance

Mechanisms of Evolution. Gene flow

Movement of alleles between populations

Gene Flow effect on population

Reduces differences between populations

Equation to Find allele frequency

p+q=1

Equation to find Genotype frequency

p²+2pq+q²