The Coupling Between Evolutionary and Population Dynamics

Project description

Evolution is generally a much slower process than that of population dynamics. Evolutionary change usually takes place on the time scale of thousands or millions of years, whereas population densities change rapidly, often from one year or season to the next. The difference in time scales leads to a natural separation of the processes in evolutionary and population dynamic models. When population dynamics are in focus, species are considered constant and are not allowed to evolve. In models of evolutionary (adaptive) dynamics populations are commonly assumed to be at ecological equilibrium. Nevertheless, evolution is driven by population interactions, environmental conditions, and more precisely the realised fecundity and mortality of individuals - the very same processes which drive population dynamics. Therefore, it seems inappropriate to totally separate the two processes.

Ecological interactions are known to have a large influence on population fluctuations, e.g. in the case of predator-prey cycles. Variable densities gives variable interaction strengths and consequently variable selection on the interacting populations. The way populations fluctuate due to their ecological interactions gives patterns of fluctuating selection pressures, which determines the direction and speed of long term evolutionary change. Evolution, in turn, changes population interactions, which closes the feedback loop between population and evolutionary dynamics.

The idea of this project is to explore the possible interactions between the evolutionary and ecological time scales, preferably without a total merging of the two. This will be done in the context of the adaptive dynamics theoretical framework and with appropriate approximations of stochastic population dynamics.

Members

Jörgen Ripa

Related publications

Address: Theoretical Ecology, Ecology Building, 223 62 Lund , Sweden
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