BIO CHP 17

population

the variant forms in which genes exist

• no more than 2 for a given gene
• -one from the mother
• -one from the father

The sum total of alleles in a given population

a change in the frequency of allels in a gene pool

a change of allele frequencies within a population over a relatively short period of time.

these changes in alleele frequencies can said to have evolved

• -mutation
• -gene flow
• -genetic drift
• -sexual selection
• -natural selection

Permanent alteration in an organism's DNA


Some mutations are heritable, meaning they can be passed on from one generation to the next.

Movement of genes from one population to another


through migration: movement of individuals from one population into the territory of another

chance alternation of allele frequencies in a population

• has greatest effects on small populations
• -bottleneck effect
• -the founder effect

form of natural selection that can affect the frequency of alleles in a gene pool

occurs when differences in reproductive success arise becuse of differential success in mating

• Some individuals more successful than others in surviving
• -and hence reproducing
• -owing to traits that better adapt them to their environment

• the phrase "survival of the fittest" is misleading
• -implies that evolution works to produce generally superior being who would be successful competitors in any environment
• only has to do with relative reprouctive success of individuals in a given environment at a given time.

Stabilizing, directional, diruptive

• most common
• moves a given character in a population toward intermediate forms and hence tends to preserve the status quo

moves a given character toward one of its extreme forms

• moves a given character toward two extreme forms
• (rarest form)