However, many of these concepts can be demonstrated in a very basic way. In this activity, beans of two different colors are used to represent two alleles of a single gene that controls a single trait, such as a gene that controls for eye color. This is a fairly simplistic demonstration that does not take into account dominance, linkage, or other complexities of genetics, but its simplicity will give students an appreciation for how the genetic makeup of a population can be altered over time by seemingly minor forces. Terminology Several terms are used to explain differences in populations and how populations change over time. These terms should be used when the students write their reports at the end of the experiments.
Gene frequency represents how often an allele occurs in a population.
The number of alleles for a particular trait is divided by the total number of genes in the sample of the population you are counting. Evolution is a change in a population s gene frequencies over time. Evolutionary forces are processes that can change gene frequencies. Breeding population describes the part of the population likely to interbreed. An entire species can be considered a breeding population because, theoretically, all members of a species can interbreed.