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Proc Biol Sci. Jan 22, 2003; 270(1511): 215–224.
PMCID: PMC1691226
The phenomenology of niche evolution via quantitative traits in a 'black-hole' sink.
R D Holt, R Gomulkiewicz, and M Barfield
Department of Zoology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA.
R D Holt: rdholt/at/zoo.ufl.edu
Abstract
Previous studies of adaptive evolution in sink habitats (in which isolated populations of a species cannot persist deterministically) have highlighted the importance of demographic constraints in slowing such evolution, and of immigration in facilitating adaptation. These studies have relied upon either single-locus models or deterministic quantitative genetic formulations. We use individual-based simulations to examine adaptive evolution in a 'black-hole' sink environment where fitness is governed by a polygenic character. The simulations track both the number of individuals and their multi-locus genotypes, and incorporate, in a natural manner, both demographic and genetic stochastic processes. In agreement with previous studies, our findings reveal the central parts played by demographic constraints and immigration in adaptation within a sink (adaptation is more difficult in environments with low absolute fitness, and higher immigration can accelerate adaptation). A novel finding is that there is a 'punctuational' pattern in adaptive evolution in sink environments. Populations typically stay maladapted for a long time, and then rapidly shift into a relatively adapted state, in which persistence no longer depends upon recurrent immigration.
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Articles from Proceedings of the Royal Society B: Biological Sciences are provided here courtesy of
The Royal Society