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!6.1 Genes Populations and Evolution

•A

population is all the members of a single species

occupying a particular area at the same time.

•Diversity

exists among members of a population.

•Population

genetics is the study of this diversity in terms

of allele differences.

§Evaluates the diversity of a

population by studying genotype and phenotype frequencies over time

•In the 1930s, population geneticists

began to describe variations in a pop based on alleles

•Microevolution pertains

to evolutionary changes within a population.

§All

the alleles of a gene make up the gene pool of

the population.

§The

gene pool can be described in terms of:

•Genotype frequencies

•Allele frequencies

•Allele Frequencies

§The

proportion of each allele within a population’s gene pool.

§Frequencies

of the dominant and recessive allele must add up to 1.

•This relationship is described by

the expression p

+ q = 1

•p is the frequency of one allele and q is the frequency of the other

§Microevolution

involves a change in these allele frequencies within populations over time.

•If the gene frequencies do not

change over time, microevolution has not occurred.

•The

Hardy-Weinberg Equalibrium states

that Allele frequencies in a population

will remain constant assuming:

•No

Mutations

•No

Gene Flow

•Random

Mating

•No

Genetic Drift

•No

Selection