Radiating on Oceanic Islands: Patterns and Processes of Speciation in the Land Snail Genus Theba (Risso 1826)

Island radiations have played a major role in shaping our current understanding of allopatric, sympatric and parapatric speciation. However, the fact that species divergence correlates with island size emphasizes the importance of geographic isolation (allopatry) in speciation. Based on molecular and morphological data, we investigated the diversification of the land snail genus Theba on the two Canary Islands of Lanzarote and Fuerteventura. Due to the geological history of both islands, this study system provides ideal conditions to investigate the interplay of biogeography, dispersal ability and differentiation in generating species diversity. Our analyses demonstrated extensive cryptic diversification of Theba on these islands, probably driven mainly by non-adaptive allopatric differentiation and secondary gene flow. In a few cases, we observed a complete absence of gene flow among sympatrically distributed forms suggesting an advanced stage of speciation. On the Jandía peninsula genome scans suggested genotype-environment associations and potentially adaptive diversification of two closely related Theba species to different ecological environments. We found support for the idea that genetic differentiation was enhanced by divergent selection in different environments. The diversification of Theba on both islands is therefore best explained by a mixture of non-adaptive and adaptive speciation, promoted by ecological and geomorphological factors

Operational Systems

Oriented Architectures (SOA) are valued more and more by companies in all industries and sizes. This paper explains SOA briefly and presents approaches for migrating to an SOA in ‘real life’. We will discuss how SOA design methods and proven software reengineering technology can be combined in order to support a company’s SOA adoption roadmap. 1. SOA Service Oriented Architecture (SOA) is a business-centric IT architectural approach that supports integrating business as linked, repeatable business tasks, or services. Web Services provide a standardized, cost-effective implementation of such services (but this is not mandatory for an SOA). The services that a company wants to expose (internally or to the market) must be commonly understood by the business and the IT departments (see central ‘layer ’ in Figure 1). Then the business requirements can be implemented with a view to services, which also form major elements of the business processes to support: The services are invoked where they are required in the process; they can also be accessed directly from consumers (e.g. via a portal)