Fig. 3: High population; effect plots of trends in nestling tarsus (a) and telomere lengths (c) during artificial selection for larger tarsus length in parents. The artificial selection ended after cohort 4 was born. The effect of selection category (0 : no parents selected (unselected), 0.5 : one parent selected, and1 : both parents selected) on tarsus (b) and telomere length (d) is shown.