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The Phenomenology of Niche Evolution via Quantitative Traits in a 'Black-Hole' Sink
R. D. Holt, R. Gomulkiewicz and M. Barfield
Proceedings: Biological Sciences
Vol. 270, No. 1511 (Jan. 22, 2003), pp. 215-224
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/3558765
Page Count: 10
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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.
Proceedings: Biological Sciences © 2003 Royal Society