Blackwell Publishing

The evidence for evolution - How can evolution be observed?


House sparrows show variation in size

House sparrows also vary in size from place to place; house sparrows are generally larger in the north and smaller toward the southwest. The figure opposite shows a general picture of geographic variation in size in the North American house sparrow.

Figure: size of male house sparrows in North America. Size is measured as a principal component of score, derived from skeletal measurements. The score of 8 is the for the largest birds, the score of 1 is the smallest. From Gould and Johnston (1972)

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