Chapter 12 Bivariate spaceship model

Chapter 12 (Part A)  

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Figure 12.1 Bivariate evolution on a Gaussian adaptive landscape, the spaceship model. The adaptive landscape is shown in red: the ellipse represents the equivalent 50% confidence region, with eigenvectors shown as dashed lines. Stabilizing selection of equal magnitude acts on each trait: (omega + P)11 = (omega + P)22 = 50. G-matrices (represented as 95% confidence ellipses) are shown in blue. In each case, the genetic variance of both traits is 0.4. Evolutionary trajectories of the bivariate trait mean are shown in black, with arrows at regular intervals of elapsed generations. (a) rg = 0, rs = 0. Each evolutionary trajectory is 500 generations in duration, with arrowheads every 50 generations. (b) rg =0.9, rs = 0. Each evolutionary trajectory is 1500 generations in duration, with arrowheads every 300 generations. (c) rg = 0, rs = 0.9. Each evolutionary trajectory is 500 generation in duration, with arrowheads every 50 generations. (d) rg = 0.9, rs = 0.8. Each evolutionary trajectory is 700 generations in duration, with arrowheads every 50 generations.