Gene Pool and Allele Frequency

Gene Pool: The total variety of genes and alleles present within a population at a given point in time.

Allele Frequency: How common an allele is in a population (e.g. B:b = 10:6).

Example:

Gene Pool = Only Short-Necked Giraffes

A New Long-Necked Comes Along (Immigration)

He Adds New Genes/Alleles To The Gene Pool

Now The Giraffes Can Reach The Trees

Yay!

EVOLUTION

...Or They Would've Turned Into Cows

This evolution would increase the population of giraffes because there is more food for them to eat (tree leaves) and less competition with other animals for grass.