Ring species as bridges between microevolution and speciation |
| |
Authors: | Irwin Darren E Irwin Jessica H Price Trevor D |
| |
Institution: | (1) Present address: Department of Ecology, Section of Animal Ecology, Lund University, Ecology Building, S-223 62 Lund, Sweden;(2) Present address: Department of Ecology, Section of Animal Ecology, Lund University, Ecology Building, S-223 62 Lund, Sweden;(3) Department of Biology 0116, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA |
| |
Abstract: | A demonstration of how small changes can lead to species-level differences is provided by ring species, in which two reproductively isolated forms are connected by a chain of intermediate populations. We review proposed cases of ring species and the insights they provide into speciation. Ring species have been viewed both as illustrations of the history of divergence of two species from their common ancestor and as demonstrations that speciation can occur in spite of gene flow between the diverging forms. Theoretical models predict that speciation with gene flow can occur when there is divergent ecological selection, and geographical differentiation increases the likelihood of speciation. Thus ring species are ideal systems for research into the role of both ecological and geographical differentiation in speciation, but few examples have been studied in detail. The Greenish warbler is a ring species in which two northward expansions around the Tibetan plateau have been accompanied by parallel evolution in morphology, ecology, and song length and complexity. However, songs have diverged in structure, resulting in a lack of recognition where the reproductively isolated forms come into contact in Siberia. Our analysis suggests that these differences could have arisen even with gene flow, and that parallel rather than divergent ecological changes have led to divergence in sexually selected traits and subsequent speciation. |
| |
Keywords: | circular overlap gene flow Greenish warbler Phylloscopus trochiloides ring species sexual selection song speciation |
本文献已被 SpringerLink 等数据库收录! |
|