Evolution in Littorina: ecology matters
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
Also appears in:Philippart, C.J.M.; Van Raaphorst, W. (Ed.) (2003). Structuring Factors of Shallow Marine Coastal Communities, part II. Journal of Sea Research, 49(2). Elsevier Science: Amsterdam. 81-155 pp., more
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| Keywords |
Biological phenomena > Evolution
Biological speciation
Ecotypes
Evolution > Speciation
Gastropods
Speciation
Topographic features > Landforms > Coastal landforms > Rocky shores
Gastropoda [WoRMS]; Littorina saxatilis (Olivi, 1792) [WoRMS]
Marine/Coastal |
| Abstract |
Organisms of marine rocky shores are exposed to physical stress from abiotic factors, such as temperature, salinity and wave action. These factors vary over compressed temporal and spatial scales, producing an exceedingly heterogeneous habitat with steep gradients of selection, and it seems likely that this has a strong influence on the evolution of populations of rocky shore organisms. With the periwinkles (genus Littorina) as a model group, I review strategies for coping with small-scale heterogeneous environments and what implications these strategies have on the evolution of these species. Some species ofLittorina have long-lived pelagic larvae and sites of various habitats are thus recruited from a common gene pool. This largely prevents local adaptation but minor adjustments are possible through a plastic phenotype. Other species of the genus are directly developing with no larval dispersal and among these there is evidence of strong local adaptation forming distinct ecotypes in contrasting habitats by parallel evolution. In at least one of the directly developing species (L. saxatilis) divergent selection among ecotypes has resulted in partial reproductive barriers that further impede gene flow among ecotypes. Furthermore, convergent evolution among species has produced superficially similar morphs in different habitats. Ecotype formation, ecological reproductive barriers and convergence among species all indicate that ecological processes are critical for evolution of Littorina species. |
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