Figure 2
Hypothesized evolutionary scenarios for explaining the origin of morphological variation among shallow-water morphotypes (represented here as ‘A’ and ‘B’) of Lake Trout from GBL, Canada. Shown are (a) an allopatric model of divergence, where morphotypes diverged in discrete refugia and then subsequently colonized GBL followed by the colonization of shallow-water habitats within each arm, (b) an ‘intra-lacustrine’ model of divergence, where the evolution of morphological variation occurred in situ soon after colonizing GBL; subsequently, discrete morphs dispersed to occupy the shallow-water habitats within each arm and (c) an ‘intra-arm’ model of divergence, where the evolution of morphological variation ensued in situ within each arm from a common ancestor within GBL (that is, parallel evolution of morphs across arms). Shown below each colonization map are the anticipated phylogenetic relationships.
