Painted 0.- 10- -05- Blunt 1070 1980 1900 10 Dry yoar wat yoar Diy yaar Maan beak dopth of paronts (mm) Figure 21.2 Evidence that natural saloction alters boak shape in the modium ground finch, Goosplza fortis, a. In dry years, when onty large, Iough seds are aailahie, the mean beak depth increases. (The y-axis meures beak shape relative lo the zvenge beak shape acrus all years,) In wet years, when muny small seds are zailable, mean beak depth deceases. A. Beak depth is inheriled from parents to ofspring. 00 (uau) uudyo p udep g

Painted 0.- 10- -05- Blunt 1070 1980 1900 10 Dry yoar wat yoar Diy yaar Maan beak dopth of paronts (mm) Figure 21.2 Evidence that natural saloction alters boak shape in the modium ground finch, Goosplza fortis, a. In dry years, when onty large, Iough seds are aailahie, the mean beak depth increases. (The y-axis meures beak shape relative lo the zvenge beak shape acrus all years,) In wet years, when muny small seds are zailable, mean beak depth deceases. A. Beak depth is inheriled from parents to ofspring. 00 (uau) uudyo p udep g