Figure 2. Scatter plot of the proportion of oxic genes versus mass-specific metabolic rate.

Vertical axis is on a logarithmic scale. The solid line is a linear regression fit to the data. Symbol color indicates base-10 logarithmic body mass. Both simple rank correlation analysis (r_s = 0.52, p = 2.0 × 10^–8) and partial rank correlation analysis (r_s^p = 0.38, p = 4.3 × 10^–5), in which body mass is kept constant, indicate a positive association the proportion of oxic genes between the mass-specific rate.