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Jonathan B. Losos – One of the best experts on this subject based on the ideXlab platform.
Ecological Opportunity and Adaptive RadiationAnnual Review of Ecology Evolution and Systematics, 2016Co-Authors: James T. Stroud, Jonathan B. LososAbstract:
The process of Adaptive Radiation—the proliferation of species from a single ancestor and diversification into many ecologically different forms—has been of great interest to evolutionary biologists since Darwin. Since the middle of the last century, ecological opportunity has been invoked as a potential key to understanding when and how Adaptive Radiation occurs. Interest in the topic of ecological opportunity has accelerated as research on Adaptive Radiation has experienced a resurgence, fueled in part by advances in phylogenetic approaches to studying evolutionary diversification. Nonetheless, what the term actually means, much less how it mechanistically leads to Adaptive diversification, is currently debated; whether the term has any predictive value or is a heuristic useful only for post hoc explanation also remains unclear. Recent recognition that evolutionary change can occur rapidly and on a timescale commensurate with ecological processes suggests that it is time to synthesize ecological and evo…
Adaptive Radiation, Ecological Opportunity, and Evolutionary DeterminismThe American Naturalist, 2010Co-Authors: Jonathan B. LososAbstract:
Abstract: Adaptive Radiation refers to diversification from an ancestral species that produces descendants adapted to use a great variety of distinct ecological niches. In this review, I examine two aspects of Adaptive Radiation: first, that it results from ecological opportunity and, second, that it is deterministic in terms of its outcome and evolutionary trajectory. Ecological opportunity is usually a prerequisite for Adaptive Radiation, although in some cases, Radiation can occur in the absence of preexisting opportunity. Nonetheless, many clades fail to radiate although seemingly in the presence of ecological opportunity; until methods are developed to identify and quantify ecological opportunity, the concept will have little predictive utility in understanding a priori when a clade might be expected to radiate. Although predicted by theory, replicated Adaptive Radiations occur only rarely, usually in closely related and poorly dispersing taxa found in the same region on islands or in lakes. Continge…
lizards in an evolutionary tree ecology and Adaptive Radiation of anoles, 2009Co-Authors: Jonathan B. LososAbstract:
Adaptive Radiation, which results when a single ancestral species gives rise to many descendants, each adapted to a different part of the environment, is possibly the single most important source of biological diversity in the living world. One of the best-studied examples involves Caribbean Anolis lizards. With about 400 species, Anolis has played an important role in the development of ecological theory and has become a model system exemplifying the integration of ecological, evolutionary, and behavioral studies to understand evolutionary diversification. This major work, written by one of the best-known investigators of Anolis, reviews and synthesizes an immense literature. Jonathan B. Losos illustrates how different scientific approaches to the questions of adaptation and diversification can be integrated and examines evolutionary and ecological questions of interest to a broad range of biologists.
Dolph Schluter – One of the best experts on this subject based on the ideXlab platform.
ecological character displacement in Adaptive RadiationThe American Naturalist, 2000Co-Authors: Dolph SchluterAbstract:
abstract: I give an overview of the observational and experimental evidence for ecological character displacement in Adaptive Radiation. Sixty‐one published cases of character displacement involving closely related species (congeners) make up the observational data set. All cases involve divergence, even though parallel and convergent displacement are theoretically possible. Character ratios in sympatry were greatest when displacement was symmetric (mean 1.54) and least when asymmetric (mean 1.29), perhaps because the most symmetric resource distributions are also the broadest. Carnivores are vastly overrepresented in the data compared with other trophic groups, with herbivores the next most common category. I consider five hypotheses to explain this pattern, including the possibility that the likelihood of divergence via competition depends on position in food webs. Overall, the quality and completeness of observational data has improved in recent years, as judged by the extent to which individual cases …
Introduction to the Symposium: Species Interactions and Adaptive RadiationThe American Naturalist, 2000Co-Authors: Dolph SchluterAbstract:
The purpose of this supplement is to explore the effects of interactions between species on the evolution of diversity, with an emphasis on lineages undergoing Adaptive Radiation. By “Adaptive Radiation,” I mean the relatively rapid proliferation of new species from a single ancestor accompanied by expansion to new resources and environments and by divergence in phenotypic traits used to exploit those environments. The process may have many causes, but here we focus on the role of interactions between members of the diversifying lineage. Adaptive Radiation is a good place to center an inquiry into the evolutionary consequences of species interactions because so much of ecological diversity, perhaps even most of it, has arisen by Adaptive Radiation. Species interactions, especially competition, have also been regarded as important causes of phenotypic differentiation in Adaptive Radiation. Finally, interactions play an important role in several ecological theories of speciation, especially sympatric speciation.
the ecology of Adaptive Radiation, 2000Co-Authors: Dolph SchluterAbstract:
1. The origins of ecological diversity 2. Detecting Adaptive Radiation 3. The progress of Adaptive Radiation 4. The ecological theory of Adaptive Radiation 5. Divergent natural selection between environments 6. Divergence and species interactions 7. Ecological opportunity speciation 8. The ecological basis of speciation 9. Divergence along genetic lines of least resistance 10. The ecology of Adaptive Radiation
Ole Seehausen – One of the best experts on this subject based on the ideXlab platform.
The coincidence of ecological opportunity with hybridization explains rapid Adaptive Radiation in Lake Mweru cichlid fishesNature Communications, 2019Co-Authors: Joana I. Meier, Catherine E. Wagner, Rike B. Stelkens, Domino A. Joyce, Salome Mwaiko, Numel Phiri, Ulrich K. Schliewen, Oliver Selz, Cyprian Katongo, Ole SeehausenAbstract:
The process of Adaptive Radiation was classically hypothesized to require isolation of a lineage from its source (no gene flow) and from related species (no competition). Alternatively, hybridization between species may generate genetic variation that facilitates Adaptive Radiation. Here we study haplochromine cichlid assemblages in two African Great Lakes to test these hypotheses. Greater biotic isolation (fewer lineages) predicts fewer constraints by competition and hence more ecological opportunity in Lake Bangweulu, whereas opportunity for hybridization predicts increased genetic potential in Lake Mweru. In Lake Bangweulu, we find no evidence for hybridization but also no Adaptive Radiation. We show that the Bangweulu lineages also colonized Lake Mweru, where they hybridized with Congolese lineages and then underwent multiple Adaptive Radiations that are strikingly complementary in ecology and morphology. Our data suggest that the presence of several related lineages does not necessarily prevent Adaptive Radiation, although it constrains the trajectories of morphological diversification. It might instead facilitate Adaptive Radiation when hybridization generates genetic variation, without which Radiation may start much later, progress more slowly or never occur. Recent studies have suggested that hybridization can facilitate Adaptive Radiations. Here, the authors show that opportunity for hybridization differentiates Lake Mweru, where cichlids radiated, and Lake Bangweulu, where cichlids did not radiate despite ecological opportunity in both lakes.
A Combinatorial View on Speciation and Adaptive RadiationTrends in Ecology and Evolution, 2019Co-Authors: David Alexander Marques, Joana I. Meier, Ole SeehausenAbstract:
Speciation is often thought of as a slow process due to the waiting times for mutations that cause incompatibilities, and permit ecological differentiation or assortative mating. Cases of rapid speciation and particularly cases of rapid Adaptive Radiation into multiple sympatric species have remained somewhat mysterious. We review recent findings from speciation genomics that reveal an emerging commonality among such cases: reassembly of old genetic variation into new combinations facilitating rapid speciation and Adaptive Radiation. The polymorphisms in old variants frequently originated from hybridization at some point in the past. We discuss why old variants are particularly good fuel for rapid speciation, and hypothesize that variation in access to such old variants might contribute to the large variation in speciation rates observed in nature.
Upward Adaptive Radiation Cascades: Predator Diversification Induced by Prey DiversificationTrends in Ecology and Evolution, 2017Co-Authors: Jakob Brodersen, David M. Post, Ole SeehausenAbstract:
The value of biodiversity is widely appreciated, but we are only beginning to understand the interplay of processes that generate biodiversity and their consequences for coevolutionary interactions. Whereas predator–prey coevolution is most often analyzed in the context of evolutionary arms races, much less has been written about how predators are affected by, and respond to, evolutionary diversification in their prey. We hypothesize here that Adaptive Radiation of prey may lead to diversification and potentially speciation in predators, a process that we call an upwards Adaptive Radiation cascade. In this paper we lay out the conceptual basis for upwards Adaptive Radiation cascades, explore evidence for such cascades, and finally advocate for intensified research.