Selection and Evolution with a Deck of Cards

Table 1 Summary statistics from class data for the standard exercise and the inclusion of random environmental effects. Data are from a class of 32 students

Gen 0 trait avg.	Gen 1 trait avg.	h ²	Gen 1 post-seln avg.	S	Gen 2 trait avg.	R
Standard exercise
13.41	13.41	1.00^a	11.08	−2.33	11.08	−2.33
With random environmental effects
13.34	13.34	0.40^a	16.21	2.86	14.67	1.33

^aSee Fig. 2a and b, respectively, for actual class data. Note that the inclusion of random environmental effects need not change the average trait value across generations; however, the heritability is drastically reduced leading to a dampened response to selection

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