such as "Introduction", "Conclusion"..etc
Darwin suggested that the action of natural selection can produce new
species, but 150 years after the publication of his famous book, On
the Origin of Species, debate still continues on the mechanisms of
speciation. New research finds sexual selection to greatly enlarge the
scope for adaptive speciation by triggering a positive feedback between
mate choice and ecological diversification that can eventually eliminate
gene flow between species.
By means of a mathematical model, former postdoctoral fellow at the
Santa Fe Institute and current postdoctoral fellow at the Institute of
Ecology and Evolution at the University of Bern in Switzerland, Sander
van Doorn and fellow colleagues demonstrate that disruptive ecological
selection favors the evolution of sexual preferences for ornaments that
signal local adaptation. Such preferences induce assortative mating with
respect to ecological characters and enhance the strength of disruptive
selection. The model predicts that species can split into specialized
ecotypes without the divergence of mating preferences, avoiding problems
that have plagued previous theoretical studies of speciation by sexual
This research study examining the origin of species through
ecological specialization and the simultaneous evolution of mating
preferences for locally adapted mates will be published in the November
26, 2009 issue of Science.
Findings suggest natural and sexual selection can work in concert to
achieve local adaptation and reproductive isolation, even in the
presence of substantial gene flow. Future research involves the
development of models to examine interactions between ecology and mate
choice that could help to explain how diversity arises and how
reproductive isolation between species evolves.
The ideas presented in the paper may soon be tested in the field in
crossbill birds, sticklebacks and other species where biologists are
currently investigating whether the attractiveness of mates does indeed
reflect adaptation to the local environment.
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