Evolution Lab 1: Process of Genetic Drift/Natural Selection Visualized Through Beans. By Team "TomTom" aka Punyanith, Najib, JungSoo, and John

Team "TomTom" produced a hypothesis that we proceeded to test using the beans at our disposal. As the generations progress, if the allele frequencies become less varied (and move toward one allele) then natural selection has occurred. If the variation between the allele frequencies is consistently random, genetic drift instead has happened. After entering the laboratory and viewing the 4 different beans (differing in size, structure and texture) we predicted that the allele frequency change would gear toward the pinto beans, since they are the biggest and easiest to pick out of the cup.

Figure 1.

Figure 1. Our team divided 50 beans randomly in half, with four different alleles possible to produce the first generation. We continued the lab procedure to produce ten generations of Population A.

Figure 2.

Figure 2. Our team divided 50 beans randomly in half, with four different alleles possible to produce the first generation. We continued the lab procedure to produce ten generations of Population B.

As you can see, Figure 1. and Figure 2. had very similar results; we can strongly state that our hypothesis was supported: the allele frequency, by the tenth generation had very little variance meaning natural selection has occurred. This agrees with the prediction we came up with previously, the Pinto beans became the dominant allele by the end of the generations because the size, shape and mass made it the easiest to pick even though we picked randomly. The allele frequencies shifted greatly toward one allele which eliminates any change of genetic drift being a possibility.

	Population A
Beans	Expectation	Observed	o - e	(o-e)^2	(o-e)^2/e	sum of (o-e)^2/e
Pinto	13	50	37	1369	105.3	142.3
Round	12	0	12	144	12
Black	13	0	13	169	13
White	12	0	12	144	12
	Population B
Beans	Expectation	Observed	o - e	(o-e)^2	(o-e)^2/e	sum of (o-e)^2/e
Pinto	12	48	36	1296	108	144
Round	13	0	13	169	13
Black	12	1	11	121	11
White	13	1	12	144	12

Table 1. Displays the calculations used to find the chi-squared value based on our data from Population A and B.

Degrees of Freedom: 4-1 = 3

We used p = .05 for our chi-squared and 3 for our degrees of freedom, we know that our chi-squared value needs to be less than 7.82 to fail to reject the null hypothesis. Since both of the chi-squared values are tremendously larger than this value(expected and observed allele frequencies were not close at all) we can safely reject the null hypothesis. Essentially, generation 1 is the expected values while generation 10 is the observed.