Evolution 3-microevolution

Localized group of individuals that are capable of interbreeding and producing fertile offspring

All of the genes in a population at any one time

Modern synthesis was born from

Existence of two or more distinct morphs each represented in a population in high enough frequencies to be readily noticeable

Calculate the frequency of alleles

Hardy-Weinberg Theorem

Change in DNA nucleotide sequence; corresponding change in mRNA may alter protein synthesis

Random fluctuation in gene pool (especially important in small populations)

Sudden event dramatically reduces population size. Sudden event dramatically reduces population size, future variations

Isolated group starts new population with no further gene glow from source population. Some populations are not able to interact with the rest of the group

Consequence of the bottleneck & founder effects: artificial selection

Genetic input from other populations

Mean proportion of loci that are heterozygous; used to help measure genetic diversity for the population

Gene pool differences among populations

graded variation in a trait parallels environmental gradient

wild plants from different altitudes were grown in controlled conditions

three ways natural selection can alter variation in a population

favors intermediate variants by acting against both extremes

favors individuals on both extremes of phenotypic range

natural selection that favors individuals at one end of the phenotypic range

natural selection for mating success; may produce

distinct male vs female adult phenotypes (secondary sex characteristics)

direct competition for potential mates. Mate choice; one sex usually females are choosy in selecting their mates

Maintains stable frequencies of multiple phenotypic forms

success of one phenoypic morph declines when it becomes too common in the population