Population Genetics  Population- a group of members of the same species living in a given area  Ex. –People in CR Metro Area –Oak trees at Rock Island –Bass at Pleasant Creek

Population Genetics  Variation of Traits in a Population  Individuals are different  When graphed, forms a bell curve  More individuals have a similar value  Less individuals have extreme values  Ex. Height of Students

Population Genetics  Causes of Variation  Mutation –Random change in a gene passed to offspring  Recombination –Reshuffling genes in diploid cell (independent assortment, crossing over)  Random pairing of gametes

Population Genetics  Gene pool- common group of genes shared by members of a population

Population Genetics  Allele frequency- –Number of times an allele is present compared to the number of times other alleles for the same trait are present –Calculate by dividing the number of alleles for one trait by the total number of alleles

Calculate  Example –Say an allele for a dark moth color (D) may be found in 15 of 60 alleles –The allele for a light moth color (d) may be found in 45 of 60 alleles.  What is the frequency of the alleles of the gene pool?

Hardy Weinberg  Principle that states that the frequency of alleles does not change unless acted upon by outside forces.  p 2 + 2pq + q 2 = 1  p represents one allele  q represents the other allele

Population Genetics  Adaptations cause changes in the gene frequency within a population