Extended Data Fig. 7: Explanation of non-linearities in coccolithophore evolution.

a, Low-pass filter design for the delay between first appearance datum (FAD) and the beginning of the acme (BA) for E. huxleyi (blue line, lag of two eccentricity cycles) and another possible scenario for another species (red line, lag of one eccentricity cycle). The stepped green line represents E. huxleyi’s existence (0 = absence, 1 = presence). The blue and red curves in all panels are the output series of the 2 low-pass filters described in the Methods. The black curve in a represents coeval eccentricity values. b, c, Bode plots of the 1-cycle lag filter (red) and the 2-cycle lag filter (blue) for magnitude (b) and phase (c) (see Methods). Earth’s primary orbital periods are indicated by shading.