Biology Notes
Biology: Dr. Hensley / Mrs. Ingram
2016
Evolution of Populations Gene Pool – All of the alleles in a population
Relative Frequency – How often an allele occurs in a gene pool (%)
Single Gene Trait – One gene = few phenotypes
Polygenic Trait – Many genes = many possible phenotypes: such as height, eye
color, hair color, skin color
Directional Selection – Depends on the fitness of a species. When the
individuals at one end of the curve have better fitness, the curve will shift in
that direction.
Stabilizing Selection – Individuals at the center of the curve are more fit
those at the ends. The curve will narrow at the center.
than
Average
is best
Disruptive Selection – Individuals at the ends of the curve are more fit
at the center of the curve.
than
Genetic Drift – When population changes because of some chance or accident
Founder Effect – When migration to a new place causes an allele
change
This is an example of Founder Effect
frequency