COMMUNITY EVOLUTION IN GREATER ANTILLEAN ANOLIS LIZARDS - PHYLOGENETIC PATTERNS AND EXPERIMENTAL TESTS

Phylogenies can be useful not only as a means of examining evolutionar y hypotheses, but also as a source of hypotheses that can be tested us ing extant taxa. I illustrate this approach with examples from the stu dy of community evolution in Caribbean Anolis lizards. Phylogenetic an alyses indicate that not only are Anolis communities on Jamaica and Pu erto Rico convergent in structure, but they have attained their simila rity by evolving through a nearly identical sequence of ancestral comm unities. Examination of the pattern of community evolution suggests th at interspecific competition is the driving force behind anole adaptiv e radiation. This hypothesis can be tested by investigating whether an oles shift their habitat use in the presence of competitors and, if so , whether such shifts lead to morphological adaptation to the new habi tat. These hypotheses have been tested experimentally by introducing l izards onto small islands. Preliminary results indicate the existence of ecological interactions among sympatric anoles and that shifts in h abitat use are accompanied by microevolutionary changes in morphology.