Bio Ch 23

Front 1

microcvolution

Back 1

The change in allele frequencies in a population over generations.

Front 2

three main mechanisms
that can cause allele frequency change:

Back 2

natural selection.
genetic drift (chance events that alter allele frequencies), and gene flow (the transfer ofalleles between populations)

Front 3

geographic variation

Back 3

differences in the
genetic composition of separate populations.

Front 4

cline

Back 4

a
graded change in a character along a geographic axis

Front 5

mutation

Back 5

a change in
the nucleotide sequence of an organism's DNA

Front 6

point mutation

Back 6

A change of as little as one base in a gene.

Front 7

genetic drift

Back 7

Chance events can also cause allele frequencies to fluctuate unpredictably from one generation to the next, especially
in small population

Front 8

founder effect

Back 8

When a few individuals become isolated from a larger population,
this smaller group may establish a new population
whose gene pool differs from the source population;

Front 9

bottleneck effect

Back 9

A sudden change in the environment, such as a fire or flood,
may drastically reduce the size ofa population. Asevere drop in
population size can cause the ____________.

Front 10

gene flow

Back 10

the transfer of alleles into or out of a population
due to the movement of fertile individuals or their gametes.