The data in Fig. 21.2b show that the variation in beak depth is heritable (genetic), and the variations in Fig. 21.2a show that there is natural selection for these traits year-after year. Finally, the combination of these two show that individuals who are better adapted in one year will contribute more offspring with their genes to the next generation.
Work Step by Step
Just use the list from the answer for Ch. 21 Summary 1, which comes from the first part of the chapter, and link each item in the list with something in the data from Fig. 21.2.