Distribution of beak depths in the breeding population of medium ground finches (Geospiza fortis) on the island of Daphne Major in 1976 (white bars) and of the survivors of the 1977 drought (black bars). The means of the two populations are indicated by the carets.
Download the educator guide PDF, which includes questions to guide a class discussion on the graph characteristics and what the data show. The finch presentation PowerPoint is an alternative approach to teaching this data point. Use this presentation to guide students through discussing the components of the graph.
Figure 5 from:
Rosemary B. Grant and Peter R. Grant. What Darwin's Finches Can Teach Us about the Evolutionary Origin and Regulation of Biodiversity. BioScience. 2003. 53: 965–975.