A major goal of evolutionary science is to understand how biological diversity is generated
and altered. Despite considerable advances, we still have limited insight into how phenotypic …

… 1994a; Jonsson and Skúlason 2000). An extreme case of morphological diversification is
seen in the four morphs of arctic charr in Thingvallavatn, a rift lake situated in the neovolcanic …

▪ Abstract Resource polymorphism in vertebrates is generally underappreciated as a
diversifying force and is probably more common than is currently recognized. Research across …

Four coexisting morphs or arctic charr, Salvelinus alpinus (L.), occur in the lake Thingvallavatn,
Iceland. They can be identified by their head morphology, which appears to he related to …

Le polymorphisme lié aux ressources serait une phase importante de la diversification et de
la spéciation chez les vertébrés. Des études sur des poissons vivant dans des lacs …

We studied the salmonid fish Arctic charr, Salvelinus alpinus, in a small and shallow
landlocked lake in NW Iceland. The lake is productive but die only fish present is Arctic charr. …

Discrete resource polymorphisms occur in various vertebrate species and probably occur
more frequently than is generally appreciated. They are manifested in a number of ways, …

Parasite communities of fishes are known to respond directly to the abiotic environment of
the host, for example, to water quality and water temperature. Biotic factors are also important …

Parallelism, the evolution of similar traits in populations diversifying in similar conditions,
provides strong evidence of adaptation by natural selection. Many studies of parallelism focus …

In 1987, a fjord in the Snæfellsnes peninsula, north-west Iceland, was dammed and a freshwater
lagoon formed. There is a large population of threespine stickleback in this lagoon. We …