Evolutionary branching and sympatric speciation caused by different types of ecological interactions

Doebeli M & Dieckmann U (2000). Evolutionary branching and sympatric speciation caused by different types of ecological interactions. The American Naturalist 156 (s4): s77-s101. DOI:10.1086/303417.

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Abstract

Evolutionary branching occurs when frequency-dependent selection splits a phenotypically monomorphic population into two distinct phenotypic clusters. A prerequisite for evolutionary branching is that directional selection drives the population toward a fitness minimum in phenotype space. This article demonstrates that selection regimes leading to evolutionary branching readily arise from a wide variety of different ecological interactions within and between species. We use classical ecological models for symmetric and asymmetric competition, for mutualism, and for predator-prey interactions to describe evolving populations with continuously varying characters. For these models, we investigate the ecological and evolutionary conditions that allow for evolutionary branching and establish that branching is a generic and robust phenomenon. Evolutionary branching becomes a model for sympatric speciation when population genetics and mating mechanisms are incorporated into ecological models. In sexual populations with random mating, the continual production of intermediate phenotypes from two incipient branches prevents evolutionary branching. In contrast, when mating is assortative for the ecological characters under study, evolutionary branching is possible in sexual populations and can lead to speciation. Therefore, we also study the evolution of assortative mating as a quantitative character. We show that evolution under branching conditions selects for assortativeness and thus allows sexual populations to escape from fitness minima. We conclude that evolutionary branching offers a general basis for understanding adaptive speciation and radiation under a wide range of different ecological conditions.

Item Type: Article
Uncontrolled Keywords: Adaptive dynamics; Evolutionary branching; Sympatric speciation; Competition; Mutualism; Predation; Quantitative genetics
Research Programs: Adaptive Dynamics Network (ADN)
Bibliographic Reference: The American Naturalist; 156(S4):S77-S101 (October 2000)
Depositing User: IIASA Import
Date Deposited: 15 Jan 2016 02:11
Last Modified: 07 Sep 2016 11:54
URI: http://pure.iiasa.ac.at/5955

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