Impact of environmental change on evolutionary processes

Abstract

The present work addresses the problem of adaptation to changing environments. Under

the fitness landscape theory, the impact of a seasonal as well as a finite unidirectional envi- ronmental change on the levels of adaptation and, most importantly, on the repeatability of

the evolutionary process are explored. The implementation of time-varying fitness landscapes,

sometimes dubbed seascapes, allows a concomitantly investigation of the two major contingen- cies of the effect of a mutation: environmental conditions and interaction among loci, better

known as epistasis in biological sciences. Fitness landscapes and the population dynamics ap- plied correspond both to stochastic processes, as it is common in the evolutionary paradigm,

as well as to complex systems, so that results are obtained from Monte Carlo simulations. Evolutionary trajectories are recorded as temporal series of genotypes, from which a statistical analysis is performed. Alternatively, a scenario of sustained environmental change is studied analytically. Departing from the standard hypothesis of Gaussian selection and mutation, the

stationary state of the phenotypic evolution of a very large population is found, and the de- clining population paradigm is explored in terms of the critical rate of environmental change.

In this quantitative genetics model, the presence of linear plasticity manifests an interesting property. Despite the undeniable benefits to the mean population fitness, development also incurs a cost in terms of the recovery time from disturbances.