Crossing fitness valleys during the evolution of limpet homing behaviour

Abstract

Abstract:Evolution is often considered a gradual hill-climbing process, slowly increasing the fitness of organisms. Here I investigate evolution of homing behaviour in simulated intertidal limpets. While the simulation of homing is only a possible mechanism by which homing may have evolved, the process allows an investigation of how evolution may occur over different fitness landscapes. With some fitness landscapes, in order to evolve path integration as a homing mechanism, a temporary reduction in an organism's fitness was required -since high developmental costs occurred before successful homing strategies evolved. Simple hill-climbing algorithms, therefore, only rarely resulted in the evolution of a functional homing behaviour. The inclusion of trail-following greatly increases the frequency of success of evolution of a path integration strategy. Initially an emergent homing behaviour is formed combining path integration with trail-following. This also demonstrates evolution through exaptation, since in the simulation, the original role of trail-following is likely to be unrelated to homing. Analysis of the fitness landscapes of homing in the presence of trail-following behaviour shows a high variability of fitness, which results in the formation of 'stepping-stones' of high fitness across fitness valleys. By using these steppingstones, simple hill-climbing algorithms can reach the global maximum fitness value.© Versita Sp. z o.o.

Snails and their trails: the multiple functions of trail‐following in gastropods

“…A novel way of studying trail-following is to model movements and trail-following via computerized simulations (e.g. Stafford et al, 2007;Stafford, 2010). The objective is to build a model system that resembles reality as closely as possible by incorporating data from the natural environment.…”

Systems Biology as a Research Program for Intelligent Design

“…It is beyond the scope of this paper to survey the various pathways to optimization and good design available to evolution; for example, there have been various proposals of how to cross the "fitness valleys" between different local fitness maxima, including "annealing" (random shake-ups of the environment) and fortuitous combination of two or more separate functions [83]. It is a historical fact, however, that evolutionary theory has tended to lead to the expectation of bad design, junk, and sub-optimality, while those following the intelligent design perspective of Harvey have tended to look for a purpose for every little element of living things.…”