population genetics- micorevoltuion

microevolution

small changed

does not create new species

how can gene frequencies in a population be changed

• mutations

• genetic drift

• gene flow

• non-random mating

• natural selection

Mutations… can be

source of gene variation:

• change in nucleotide base pairs

• rearrangement of genes on a chromosome

• change in chromsome number

Genetic drift (4)

frequencies change randomly:

• small population

• not advantage or disadvantage

• two types

type 1- founder effect

• a small group breaks away from the original to colonize a new territory

• new smaller gene pool

type 2- bottleneck effect

• natural disatser (or manmade) occurs that shrinks the population

• only certain genes make in through

• shrink/alter gene pool

gene flow (migration)

movement of genes from one population to another

non-random mating

choosing mates for traits you are looking for

natural selection

environment decides

five fingers

+thumb is natural selection