68 research outputs found
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Phenotypic Evolution: The Ongoing Synthesis
I explore the proposition that evolutionary biology is
currently in the midst of its greatest period of synthesis. This period,
which I call the Ongoing Synthesis, began in 1963 and continues at
the present time. I use analysis of citations, conduct, and content to
compare the Ongoing Synthesis to widely recognized periods of synthesis
in the nineteenth and twentieth centuries. To compare content,
I focus on phenotypic evolution and compare current efforts with
George Gaylord Simpsonâs struggle to understand evolution in deep
geological time. The essence of current effort is captured by the
question, What is the best model for phenotypic evolution? Although
many investigators are actively engaged in answering this question,
I single out two examples of my own collaborative work for emphasis
here. These two studies share three important characteristics: diagnosis
of evolutionary pattern using massive data sets, validation of
model parameter values using compilations of estimates (e.g., heritability,
stabilizing selection, distance to an intermediate optimum),
and identification of evolutionary process using alternative models
of stochastic evolution. Our primary findings (discovery of the blunderbuss
pattern and the result that rare bursts of evolution carry
lineages out of established adaptive zones) compare favorably with
important insights from the Modern Synthesis.This is the publisherâs final pdf. The published article is copyrighted by the University of Chicago Press and can be found at: http://www.press.uchicago.edu/ucp/journals/journal/an.html.Keywords: adaptive zone, adaptive radiation, blunderbuss pattern, quantum evolution, deep evolutionary tim
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Can the Fisher-Lande Process Account for Birds of Paradise and Other Sexual Radiations?
Models of the FisherâLande process (FLP) have been used successfully to explore many aspects of evolution by sexual selection. Despite this success, quantitative tests of these models using data from sexual radiations are rare. Consequently, we do not know whether realistic versions of the FLP can account for the extent and the rate of evolution of sexually selected traits. To answer this question, we generalize the basic FLP model of sexual coevolution and compare predictions of that basic model with patterns observed in an iconic sexual radiation, birds of paradise. Our model tracks the coevolution of male and female traits (two in each sex) while relaxing some restrictive assumptions. Using computer simulations, we evaluate the behavior of the model and confirm that it is an OrnsteinâUhlenbeck (OU) process. We also assess the ability of the FLP to account for the quantitative aspects of ornament evolution in the genus Paradisaea using published measurements of display traits and a phylogeny of the genus. Finally, we use the program OUwie to compare model fits to generic OU and Brownian motion processes and to estimate FLP parameters. We show that to explain the sexual radiation of the genus Paradisaea one must either invoke extremely weak stabilizing selection on female mating preferences or allow the preference optimum to undergo Brownian motion at a modest rate.Keywords: phenotypic tango, adaptive radiation, Brownian motion, OrnsteinâUhlenbeck (OU) process, sexual coevolution
Epistasis and Natural Selection Shape the Mutational Architecture of Complex Traits
The evolutionary trajectories of complex traits are constrained by levels of genetic variation as well as genetic correlations among traits. Because the ultimate source of all genetic variation is mutation, the distribution of mutations entering populations profoundly affects standing variation and genetic correlations. Here, we use an individual-based simulation model to investigate how natural selection and gene interactions (i.e., epistasis) shape the evolution of mutational processes affecting complex traits. We find that the presence of epistasis allows natural selection to mold the distribution of mutations, such that mutational effects align with the selection surface. Consequently, novel mutations tend to be more compatible with the current forces of selection acting on the population. These results suggest that in many cases mutational effects should be seen as an outcome of natural selection rather than as an unbiased source of genetic variation that is independent of other evolutionary processes
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Evolutionary biology for the 21st century
New theoretical and conceptual frameworks are required for evolutionary biology to capitalize on the wealth of data now becoming available from the study of genomes, phenotypes, and organisms - including humans - in their natural environments.Molecular and Cellular BiologyOrganismic and Evolutionary Biolog
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Evolutionary Biology for the 21st Century
We live in an exciting time for biology. Technological advances have made data collection easier and cheaper than we could ever have imagined just 10 years ago. We can now synthesize and analyze large data sets containing genomes, transcriptomes, proteomes, and multivariate phenotypes. At the same time, society's need for the results of biological research has never been greater. Solutions to many of the world's most pressing problemsâfeeding a global population, coping with climate change, preserving ecosystems and biodiversity, curing and preventing genetically based diseasesâwill rely heavily on biologists, collaborating across disciplines
The evolution of courtship behavior in New World salamanders with some comments on Old World salamanders
Data from: Can the Fisher-Lande process account for birds of paradise and other sexual radiations?
Models of the FisherâLande process (FLP) have been used successfully to explore many aspects of evolution by sexual selection. Despite this success, quantitative tests of these models using data from sexual radiations are rare. Consequently, we do not know whether realistic versions of the FLP can account for the extent and the rate of evolution of sexually selected traits. To answer this question, we generalize the basic FLP model of sexual coevolution and compare predictions of that basic model with patterns observed in an iconic sexual radiation, birds of paradise. Our model tracks the coevolution of male and female traits (two in each sex) while relaxing some restrictive assumptions. Using computer simulations, we evaluate the behavior of the model and confirm that it is an OrnsteinâUhlenbeck (OU) process. We also assess the ability of the FLP to account for the quantitative aspects of ornament evolution in the genus Paradisaea using published measurements of display traits and a phylogeny of the genus. Finally, we use the program OUwie to compare model fits to generic OU and Brownian motion processes and to estimate FLP parameters. We show that to explain the sexual radiation of the genus Paradisaea one must either invoke extremely weak stabilizing selection on female mating preferences or allow the preference optimum to undergo Brownian motion at a modest rate
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