Showing papers by "Jonathan B. Losos published in 2008"
TL;DR: A review of case studies indicates that ecological and phylogenetic similarities often are not related, and ecologists should not assume that phylogenetic niche conservatism exists, but rather should empirically examine the extent to which it occurs.
Abstract: Ecologists are increasingly adopting an evolutionary perspective, and in recent years, the idea that closely related species are ecologically similar has become widespread. In this regard, phylogenetic signal must be distinguished from phylogenetic niche conservatism. Phylogenetic niche conservatism results when closely related species are more ecologically similar that would be expected based on their phylogenetic relationships; its occurrence suggests that some process is constraining divergence among closely related species. In contrast, phylogenetic signal refers to the situation in which ecological similarity between species is related to phylogenetic relatedness; this is the expected outcome of Brownian motion divergence and thus is necessary, but not sufficient, evidence for the existence of phylogenetic niche conservatism. Although many workers consider phylogenetic niche conservatism to be common, a review of case studies indicates that ecological and phylogenetic similarities often are not related. Consequently, ecologists should not assume that phylogenetic niche conservatism exists, but rather should empirically examine the extent to which it occurs.
1,363 citations
TL;DR: Analysis of microsatellite variation supports the hypothesis that lizards from disparate native-range sources, identified using mtDNA haplotypes, form genetically admixed introduced populations of the lizard Anolis sagrei.
Abstract: Molecular genetic analyses show that introduced populations undergoing biological invasions often bring together individuals from genetically disparate native-range source populations, which can elevate genotypic variation if these individuals interbreed. Differential admixture among multiple native-range sources explains mitochondrial haplotypic diversity within and differentiation among invasive populations of the lizard Anolis sagrei. Our examination of microsatellite variation supports the hypothesis that lizards from disparate native-range sources, identified using mtDNA haplotypes, form genetically admixed introduced populations. Furthermore, within-population genotypic diversity increases with the number of sources and among-population genotypic differentiation reflects disparity in their native-range sources. If adaptive genetic variation is similarly restructured, then the ability of invasive species to adapt to new conditions may be enhanced.
143 citations
TL;DR: A new model system for the integration of development, evolution, and ecology, the lizard genus Anolis, a diverse group of lizards whose ecology and evolution is well understood, and whose genome has recently been sequenced is introduced.
Abstract: Vertebrate developmental biologists typi- cally rely on a limited number of model organisms to understand the evolutionary bases of morphological change. Unfortunately, a typical model system for squa- mates (lizards and snakes) has not yet been developed leaving many fundamental questions about morphologi- cal evolution unaddressed. New model systems would ideally include clades, rather than single species, that are amenable to both laboratory studies of development and field-based analyses of ecology and evolution. Com- bining an understanding of development with an under- standing of ecology and evolution within and between closely related species has the potential to create a seam- less understanding of how genetic variation underlies eco- logically and evolutionarily relevant variation within pop- ulations and between species. Here we briefly introduce a new model system for the integration of development, evolution, and ecology, the lizard genus Anolis, a diverse group of lizards whose ecology and evolution is well understood, and whose genome has recently been se- quenced. We present a developmental staging series for Anolis lizards that can act as a baseline for later com- parative and experimental studies within this genus. J.
136 citations
TL;DR: Comparisons of patterns and rates of morphological evolution found that rates and extent of diversification were comparable, but Anolis adaptive radiation is not an island phenomenon; in independent colonizations of both island and mainland habitats, island anoles have evolved shorter limbs and better-developed toe pads.
Abstract: Many of the classic examples of adaptive radiation, including Caribbean Anolis lizards, are found on islands. However, Anolis also exhibits substantial species richness and ecomorphological disparity on mainland Central and South America. We compared patterns and rates of morphological evolution to investigate whether, in fact, island Anolis are exceptionally diverse relative to their mainland counterparts. Quite the contrary, we found that rates and extent of diversification were comparable—Anolis adaptive radiation is not an island phenomenon. However, mainland and Caribbean anoles occupy different parts of morphological space; in independent colonizations of both island and mainland habitats, island anoles have evolved shorter limbs and better-developed toe pads. These patterns suggest that the two areas are on different evolutionary trajectories. The ecological causes of these differences are unknown, but may relate to differences in predation or competition among mainland and island communities.
126 citations
TL;DR: Rates of morphological evolution are higher in both the Mascarene and Seychelles archipelagos compared to rates on Madagascar, suggesting that ecological opportunity is an important factor in diversification of day gecko species.
Abstract: We examine the effects of ecological opportunity and geographic area on rates of species accumulation and morphological evolution following archipelago colonization in day geckos (genus Phelsuma) in the Indian Ocean. Using a newly generated molecular phylogeny for the genus, we present evidence that these geckos likely originated on Madagascar, whereas colonization of three archipelagos in the Indian Ocean, the Seychelles, Mascarene, and Comoros Islands has produced three independent monophyletic radiations. We find that rates of species accumulation are not elevated following colonization but are roughly equivalent on all three isolated archipelagos and on the larger island of Madagascar. However, rates of species accumulation have slowed through time on Madagascar. Rates of morphological evolution are higher in both the Mascarene and Seychelles archipelagos compared to rates on Madagascar. This negative relationship between rate of morphological evolution and island area suggests that ecological opportunity is an important factor in diversification of day gecko species.
112 citations
01 Jan 2008
TL;DR: Poles were captured and raised with approval of theInstitutional Animal Care and Use Committee of the University of Geor -gia and the institution's institutional animal care and use committee.
Abstract: Acknowledgments. NW e thank Daniel van Dijk, Alina Ruiz, and mem-bers of the University of Geor gia 2006 Herpetology class for field andlab assistance. T adpoles were captured and raised with approval of theInstitutional Animal Care and Use Committee of the University of Geor -gia.L
68 citations
TL;DR: Variation among ecomorphs indicates that foraging behaviour is related to habitat use, although the specific environmental factors driving foraging divergence are unclear.
39 citations
38 citations