Fig. 4. Comparison of quantitative model of morphological diversity with data from 660 extant species of medusae. (A) Black circles, morphological data; solid blue curve, 0.5 Hz swimming frequency model; solid red curve, 1 Hz model; solid green curve, 2 Hz model. Broken red curve, model prediction in the absence of stopping vortex formation at 1 Hz. (B) Black circles, morphological data; solid blue curve, morphospace limit corresponding to an order of magnitude increase (10 times) in the physiologically available force F_M for the model with 0.5 Hz swimming frequency; solid green curve, morphospace limit corresponding to an order of magnitude decrease (0.1 times) in the physiologically available force F_M for the model with 2 Hz swimming frequency; red curve, 1 Hz model corresponding to average physiological data. f_CRIT, critical fitness ratio.