Showing papers by "Jonathan B. Losos published in 1994"
TL;DR: The hypothesis that interspecific competition has been the driving force behind the evolutionary radiation of Anolis lizards in the Caribbean is examined by examining the four lines of evidence supported by this hypothesis.
Abstract: Two approaches characterize the study of evolutionary ecology. Prospective studies investigate how present-day ecological processes may lead to evolutionary change; retrospective studies ask how present-day ecological conditions can be understood as the outcome of historical events. I argue that the most appropriate test of an evolutionary ecological hypothesis requires an integration of these approaches. I illustrate this approach by examining the hypothesis that interspecific competition has been the driving force behind the evolutionary radiation of Anolis lizards in the Caribbean. This hypothesis is supported by four lines of evidence: 1. Anole communities are structured by competition; 2. Populations alter resource use in the presence of congeners; 3. Microevolutionary adaptation occurs in response to resource shifts; and 4. Macroevolutionary patterns are consistent with interspecific competition as the driving force behind anole adaptive radiation.
210 citations
TL;DR: This article examined populations of two species of Anolis lizards that evolved in the species-rich communities of Cuba and are now widespread in the Bahamas and found that none of the populations appears to have differentiated from its ancestral "ecomorph" type toward a more generalized morphology.
Abstract: Interspecific interactions affect habitat use and subsequent morphological adaptation in Anolis lizards. We examined populations of two species of Anolis lizards that evolved in the species-rich communities of Cuba and are now widespread in the Bahamas. Because the species occupy islands in the Bahamas that vary in the number of lizard species present and other characteristics, we predicted that directional selection should have led to morphological differentiation. In particular, we expected that populations on one-species islands should have evolved toward a generalist morphology because of the lack of competitors. Divergence in both species has been adaptive; populations that use wider perches have longer legs. Nonetheless, these differences are relatively minor, and none of the populations appears to have differentiated from its ancestral "ecomorph" type toward a more generalized morphology. This stasis mirrors a trend observed in the radiation of Caribbean anoles, which exhibits repeated instances of evolutionary specialization, but few or no cases of reversion to a more generalized condition. The explanation for this directionality of evolution is not obvious but probably involves the tendency of specialized species to continue using and further adapting the niches for which they are specialized even as conditions change.
117 citations
TL;DR: An alternative to using an available taxonomy as if it were a phylogeny or ignoring phylogeny is to turn the question on its head and ask whether the results of the analysis are accurate, as yet unexplored.
Abstract: using an available taxonomy as if it were a phylogeny or ignoring phylogeny alto? gether. Ahistorical (=nonphylogenetic) analyses have a high probability of being inaccurate (Felsenstein, 1985; Grafen, 1989; Martins and Garland, 1991). Using taxon? omies is perhaps less risky, but many avail? able taxonomies probably poorly reflect phylogeny and do not resolve the rela? tionships among taxa within a category (e.g., genus, family). An alternative, as yet unexplored pos? sibility is to turn the question on its head and ask whether the results of the statis?
93 citations
70 citations