The concept a surface describing fitness as a function of a set of phenotypic traits (one version of the "adaptive landscape"), has a long history in evolutionary theory [ 46, 47], and variants of this idea have recently been presented as unifying concepts in evolutionary biology [ 48, 49].
When plotting the fitness surface for the major canonical which represents the eigenvectors with the strongest positive (m1) eigenvalue, the surfaces were saddles with peaks at the extremes of the m1 axis for both courtship duration and spermatophore attachment, again suggestive of disruptive selection along these axes.
Powell had spoken of this as being the competition where he could "go lower than 9.7", but doubts began to surface about his fitness when he withdrew from the Diamond League meeting at Crystal Palace two weeks before the start of the world championships.
One approximation uses the average curvature of the fitness surface at the parental phenotype.
Most air breathing fish are facultative air breathers that avoid the energetic cost of rising to the surface and the fitness cost of exposure to surface predators.
As no strong signature of curvature in the fitness surface has been found for either virus, we assume that Q is approximately one.
Within these bounds, the fundamental niche is a fitness surface that describes the relationship between ambient temperature and other traits that contribute to survival, reproduction, and growth of the population.
The relative height of this surface represents the fitness of an organism with a particular genotype.
Recently, we developed biologically realistic models of the diploid fitness surface at a nonneutral microsatellite (Haasl and Payseur 2013).
This indicates a change in the shape of the fitness surface from saddle shaped to dome shaped [ 34, 35].
