Graham Bell
- Published in print:
- 2007
- Published Online:
- May 2008
- ISBN:
- 9780198569725
- eISBN:
- 9780191717741
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198569725.003.0010
- Subject:
- Biology, Evolutionary Biology / Genetics
Selection is often generated by interaction with other organisms: neighbours, partners, or antagonists. The force and direction of selection in these social contexts is very generally influenced by ...
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Selection is often generated by interaction with other organisms: neighbours, partners, or antagonists. The force and direction of selection in these social contexts is very generally influenced by the density and composition of the population. It may result in some degree of cooperation or helpfulness, rather than unrestricted competition among individuals. The first section here is called Selection within a single uniform population: density-dependent selection and details density regulation; density-dependent fitness; the principle of frugality; resource competition in continuous culture; r-K selection; r-K selection experiments; and selection in seasonal environments. The second section is called Selection within a single diverse population: frequency-dependent selection and describes GxG; frequency-dependent fitness; and also frequency-dependence in complex environments. The third section is about social behaviour and describes the phenotypic theory of aggression and exploitation; cross-feeding; selfish cooperation; the prisoners' dilemmas; intransitive social interactions; and time-lagged social interactions. The final section is called Kin selection and group selection and describes kin selection; kin proximity and kin choice; spite; group selection in structured populations; productivity and diversity; artificial group selection; and cultural evolution.Less
Selection is often generated by interaction with other organisms: neighbours, partners, or antagonists. The force and direction of selection in these social contexts is very generally influenced by the density and composition of the population. It may result in some degree of cooperation or helpfulness, rather than unrestricted competition among individuals. The first section here is called Selection within a single uniform population: density-dependent selection and details density regulation; density-dependent fitness; the principle of frugality; resource competition in continuous culture; r-K selection; r-K selection experiments; and selection in seasonal environments. The second section is called Selection within a single diverse population: frequency-dependent selection and describes GxG; frequency-dependent fitness; and also frequency-dependence in complex environments. The third section is about social behaviour and describes the phenotypic theory of aggression and exploitation; cross-feeding; selfish cooperation; the prisoners' dilemmas; intransitive social interactions; and time-lagged social interactions. The final section is called Kin selection and group selection and describes kin selection; kin proximity and kin choice; spite; group selection in structured populations; productivity and diversity; artificial group selection; and cultural evolution.
Michael Doebeli
- Published in print:
- 2011
- Published Online:
- October 2017
- ISBN:
- 9780691128931
- eISBN:
- 9781400838936
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691128931.003.0001
- Subject:
- Biology, Biodiversity / Conservation Biology
This introductory chapter provides an overview of frequency-dependent selection—the phenomenon that the evolving population is part of the changing environment determining the evolutionary ...
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This introductory chapter provides an overview of frequency-dependent selection—the phenomenon that the evolving population is part of the changing environment determining the evolutionary trajectory. Selection is frequency-dependent if the sign and magnitude of the correlations between heritable variation and reproductive variation change as a consequence of changes in the trait distribution that are themselves generated by such correlations. From the perspective of mathematical modeling, the realm of frequency dependence in evolution is larger than the realm of situations in which selection is not frequency dependent, because the absence of frequency dependence in a mathematical model of evolution essentially means that some parameters describing certain types of biological interactions are set to zero. Thus, in a suitable parameter space, frequency independence corresponds to the region around zero, while everything else corresponds to frequency dependence. In this way, frequency-dependent selection should therefore be considered the norm, not the exception, for evolutionary processes.Less
This introductory chapter provides an overview of frequency-dependent selection—the phenomenon that the evolving population is part of the changing environment determining the evolutionary trajectory. Selection is frequency-dependent if the sign and magnitude of the correlations between heritable variation and reproductive variation change as a consequence of changes in the trait distribution that are themselves generated by such correlations. From the perspective of mathematical modeling, the realm of frequency dependence in evolution is larger than the realm of situations in which selection is not frequency dependent, because the absence of frequency dependence in a mathematical model of evolution essentially means that some parameters describing certain types of biological interactions are set to zero. Thus, in a suitable parameter space, frequency independence corresponds to the region around zero, while everything else corresponds to frequency dependence. In this way, frequency-dependent selection should therefore be considered the norm, not the exception, for evolutionary processes.
Michael Doebeli
- Published in print:
- 2011
- Published Online:
- October 2017
- ISBN:
- 9780691128931
- eISBN:
- 9781400838936
- Item type:
- book
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691128931.001.0001
- Subject:
- Biology, Biodiversity / Conservation Biology
Understanding the mechanisms driving biological diversity remains a central problem in ecology and evolutionary biology. Traditional explanations assume that differences in selection pressures lead ...
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Understanding the mechanisms driving biological diversity remains a central problem in ecology and evolutionary biology. Traditional explanations assume that differences in selection pressures lead to different adaptations in geographically separated locations. This book takes a different approach and explores adaptive diversification—diversification rooted in ecological interactions and frequency-dependent selection. In any ecosystem, birth and death rates of individuals are affected by interactions with other individuals. What is an advantageous phenotype therefore depends on the phenotype of other individuals, and it may often be best to be ecologically different from the majority phenotype. Such rare-type advantage is a hallmark of frequency-dependent selection and opens the scope for processes of diversification that require ecological contact rather than geographical isolation. This book investigates adaptive diversification using the mathematical framework of adaptive dynamics. Evolutionary branching is a paradigmatic feature of adaptive dynamics that serves as a basic metaphor for adaptive diversification, and the book explores the scope of evolutionary branching in many different ecological scenarios, including models of coevolution, cooperation, and cultural evolution. It also uses alternative modeling approaches. Stochastic, individual-based models are particularly useful for studying adaptive speciation in sexual populations, and partial differential equation models confirm the pervasiveness of adaptive diversification. Showing that frequency-dependent interactions are an important driver of biological diversity, the book provides a comprehensive theoretical treatment of adaptive diversification.Less
Understanding the mechanisms driving biological diversity remains a central problem in ecology and evolutionary biology. Traditional explanations assume that differences in selection pressures lead to different adaptations in geographically separated locations. This book takes a different approach and explores adaptive diversification—diversification rooted in ecological interactions and frequency-dependent selection. In any ecosystem, birth and death rates of individuals are affected by interactions with other individuals. What is an advantageous phenotype therefore depends on the phenotype of other individuals, and it may often be best to be ecologically different from the majority phenotype. Such rare-type advantage is a hallmark of frequency-dependent selection and opens the scope for processes of diversification that require ecological contact rather than geographical isolation. This book investigates adaptive diversification using the mathematical framework of adaptive dynamics. Evolutionary branching is a paradigmatic feature of adaptive dynamics that serves as a basic metaphor for adaptive diversification, and the book explores the scope of evolutionary branching in many different ecological scenarios, including models of coevolution, cooperation, and cultural evolution. It also uses alternative modeling approaches. Stochastic, individual-based models are particularly useful for studying adaptive speciation in sexual populations, and partial differential equation models confirm the pervasiveness of adaptive diversification. Showing that frequency-dependent interactions are an important driver of biological diversity, the book provides a comprehensive theoretical treatment of adaptive diversification.
Glenn-Peter Sætre and Mark Ravinet
- Published in print:
- 2019
- Published Online:
- July 2019
- ISBN:
- 9780198830917
- eISBN:
- 9780191868993
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198830917.003.0004
- Subject:
- Biology, Evolutionary Biology / Genetics, Biomathematics / Statistics and Data Analysis / Complexity Studies
Natural selection is the scientific explanation for the evolution of adaptations. Wonders of the living world, such as the anatomy and physiology that grants the cheetah its unchallenged running ...
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Natural selection is the scientific explanation for the evolution of adaptations. Wonders of the living world, such as the anatomy and physiology that grants the cheetah its unchallenged running speed; the seductive colors and scents of a flower that are irresistible to its pollinators; and the accuracy and sophistication of sense organs such as the human eye are the ultimate results of this one creative force in evolution. This chapter investigates simple models of natural selection to explore its power in causing evolutionary change. Mathematical techniques including invasion fitness analysis and adaptive landscapes are powerful tools for analyzing such models and for identifying evolutionarily stable and unstable equilibria. The chapter further investigates frequency-dependent selection and evolutionary game theory. An important goal here is to show that selection can take many different forms and yield very different evolutionary outcomes.Less
Natural selection is the scientific explanation for the evolution of adaptations. Wonders of the living world, such as the anatomy and physiology that grants the cheetah its unchallenged running speed; the seductive colors and scents of a flower that are irresistible to its pollinators; and the accuracy and sophistication of sense organs such as the human eye are the ultimate results of this one creative force in evolution. This chapter investigates simple models of natural selection to explore its power in causing evolutionary change. Mathematical techniques including invasion fitness analysis and adaptive landscapes are powerful tools for analyzing such models and for identifying evolutionarily stable and unstable equilibria. The chapter further investigates frequency-dependent selection and evolutionary game theory. An important goal here is to show that selection can take many different forms and yield very different evolutionary outcomes.
Robert L. Perlman
- Published in print:
- 2013
- Published Online:
- December 2013
- ISBN:
- 9780199661718
- eISBN:
- 9780191774720
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199661718.003.0003
- Subject:
- Biology, Evolutionary Biology / Genetics
Evolution is often thought of in genetic terms, as a change in allele frequencies and in the phenotypes associated with these alleles in populations over time. Several evolutionary processes in ...
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Evolution is often thought of in genetic terms, as a change in allele frequencies and in the phenotypes associated with these alleles in populations over time. Several evolutionary processes in addition to selection — mutation, genetic drift, and gene flow — can change allele frequencies and increase the frequency of disease-associated alleles in populations. When they happen to be linked to beneficial alleles, deleterious or disease-associated alleles may also spread by genetic hitchhiking. Frequency dependent selection, heterozygote advantage, and environmental heterogeneity all contribute to the maintenance of genetic polymorphisms, the existence of multiple alleles of a gene. Most genes are pleiotropic; they have multiple phenotypic effects. The spread of alleles of pleiotropic genes depends upon the balance between their beneficial and deleterious effects. Epigenetic mechanisms, heritable changes in gene expression and therefore in phenotype that are not dependent on changes in DNA sequence, include DNA methylation, covalent modifications of histones, and expression of noncoding regulatory RNA molecules. The Hardy-Weinberg model is an idealized model that provides a starting point for thinking about the relationship between allele frequencies and genotype frequencies. The dramatic growth of the human population since the agricultural revolution has resulted in the production of many new, rare, alleles, some of which may be associated with disease. Contrary to what some people believe, the human population is subject to ongoing natural selection.Less
Evolution is often thought of in genetic terms, as a change in allele frequencies and in the phenotypes associated with these alleles in populations over time. Several evolutionary processes in addition to selection — mutation, genetic drift, and gene flow — can change allele frequencies and increase the frequency of disease-associated alleles in populations. When they happen to be linked to beneficial alleles, deleterious or disease-associated alleles may also spread by genetic hitchhiking. Frequency dependent selection, heterozygote advantage, and environmental heterogeneity all contribute to the maintenance of genetic polymorphisms, the existence of multiple alleles of a gene. Most genes are pleiotropic; they have multiple phenotypic effects. The spread of alleles of pleiotropic genes depends upon the balance between their beneficial and deleterious effects. Epigenetic mechanisms, heritable changes in gene expression and therefore in phenotype that are not dependent on changes in DNA sequence, include DNA methylation, covalent modifications of histones, and expression of noncoding regulatory RNA molecules. The Hardy-Weinberg model is an idealized model that provides a starting point for thinking about the relationship between allele frequencies and genotype frequencies. The dramatic growth of the human population since the agricultural revolution has resulted in the production of many new, rare, alleles, some of which may be associated with disease. Contrary to what some people believe, the human population is subject to ongoing natural selection.
Michael Doebeli
- Published in print:
- 2011
- Published Online:
- October 2017
- ISBN:
- 9780691128931
- eISBN:
- 9781400838936
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691128931.003.0010
- Subject:
- Biology, Biodiversity / Conservation Biology
This concluding chapter argues that experimental evolution with microbes has emerged as a very attractive alternative to overcome the problem of long time scales in empirical studies of evolution. ...
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This concluding chapter argues that experimental evolution with microbes has emerged as a very attractive alternative to overcome the problem of long time scales in empirical studies of evolution. This is exemplified by the long-term evolution experiments of Richard Lenski, whose experimental Escherichia coli lines have evolved for more than 40,000 generations to date. Lenski and his many collaborators convincingly argued that the diversified strains have coexisted over long time periods, and hence that this diversification represents a case of asexual speciation. The ecological mechanism for diversification in this case appears to be related to crossfeeding, a scenario in which one strain or species persists by scavenging on nutrients that accumulate in the environment as metabolic byproducts of the coexisting strain. With crossfeeding, polymorphisms can be maintained even in simple environments with a single limiting resource such as glucose. This is an excellent example of frequency-dependent selection, as the fitness of the crossfeeder depends on the presence or absence of the glucose specialist.Less
This concluding chapter argues that experimental evolution with microbes has emerged as a very attractive alternative to overcome the problem of long time scales in empirical studies of evolution. This is exemplified by the long-term evolution experiments of Richard Lenski, whose experimental Escherichia coli lines have evolved for more than 40,000 generations to date. Lenski and his many collaborators convincingly argued that the diversified strains have coexisted over long time periods, and hence that this diversification represents a case of asexual speciation. The ecological mechanism for diversification in this case appears to be related to crossfeeding, a scenario in which one strain or species persists by scavenging on nutrients that accumulate in the environment as metabolic byproducts of the coexisting strain. With crossfeeding, polymorphisms can be maintained even in simple environments with a single limiting resource such as glucose. This is an excellent example of frequency-dependent selection, as the fitness of the crossfeeder depends on the presence or absence of the glucose specialist.
Max Wolf, G. Sander Van Doorn, Olof Leimar, and Franz J. Weissing
- Published in print:
- 2013
- Published Online:
- September 2013
- ISBN:
- 9780226922058
- eISBN:
- 9780226922065
- Item type:
- chapter
- Publisher:
- University of Chicago Press
- DOI:
- 10.7208/chicago/9780226922065.003.0010
- Subject:
- Biology, Animal Behavior / Behavioral Ecology
This chapter focuses on evolutionary causes of animal personalities. First, it discusses the causes of variation within populations, and, in particular, describes how state differences, ...
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This chapter focuses on evolutionary causes of animal personalities. First, it discusses the causes of variation within populations, and, in particular, describes how state differences, frequency-dependent selection, spatiotemporal variation in the environment, and non-equilibrium dynamics can cause variation in behavior. The chapter also examines the role of the architecture of behavior, stable state variables, and social conventions in causing adaptive behavioral correlations.Less
This chapter focuses on evolutionary causes of animal personalities. First, it discusses the causes of variation within populations, and, in particular, describes how state differences, frequency-dependent selection, spatiotemporal variation in the environment, and non-equilibrium dynamics can cause variation in behavior. The chapter also examines the role of the architecture of behavior, stable state variables, and social conventions in causing adaptive behavioral correlations.
Robert L. Perlman
- Published in print:
- 2013
- Published Online:
- December 2013
- ISBN:
- 9780199661718
- eISBN:
- 9780191774720
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199661718.003.0007
- Subject:
- Biology, Evolutionary Biology / Genetics
Humans are home to a myriad of microorganisms that are known collectively as the human microbiome. Our bodies may also become infected by disease-causing organisms, or pathogens. Pathogens have ...
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Humans are home to a myriad of microorganisms that are known collectively as the human microbiome. Our bodies may also become infected by disease-causing organisms, or pathogens. Pathogens have complex life histories, which involve replication within an individual host and transmission among hosts. In general, pathogens evolve in ways that maximize their basic reproductive number, R0 , the number of secondary infections that would result from the introduction of one infectious host into a population of susceptible individuals. Pathogens do not necessarily evolve to be benign; instead, they evolve the level of virulence that optimizes their R0 . Because pathogens evolve to grow most efficiently in abundant host genotypes, they cause frequency-dependent selection of rare host genotypes. Hosts evolve in ways that minimize the fitness cost of pathogen infections. The manifestations of infectious diseases may be adaptations that benefit the hosts or manipulations of host physiology that enhance replication and transmission of the pathogens. The recent spread of methicillin-resistant Staphylococcus aureus (MRSA) is a reminder that evolution of antibiotic resistance remains a major challenge for medicine. Study of host-pathogen coevolution should help to guide medical and public health practices such as regimens of antibiotic therapy and immunization strategies.Less
Humans are home to a myriad of microorganisms that are known collectively as the human microbiome. Our bodies may also become infected by disease-causing organisms, or pathogens. Pathogens have complex life histories, which involve replication within an individual host and transmission among hosts. In general, pathogens evolve in ways that maximize their basic reproductive number, R0 , the number of secondary infections that would result from the introduction of one infectious host into a population of susceptible individuals. Pathogens do not necessarily evolve to be benign; instead, they evolve the level of virulence that optimizes their R0 . Because pathogens evolve to grow most efficiently in abundant host genotypes, they cause frequency-dependent selection of rare host genotypes. Hosts evolve in ways that minimize the fitness cost of pathogen infections. The manifestations of infectious diseases may be adaptations that benefit the hosts or manipulations of host physiology that enhance replication and transmission of the pathogens. The recent spread of methicillin-resistant Staphylococcus aureus (MRSA) is a reminder that evolution of antibiotic resistance remains a major challenge for medicine. Study of host-pathogen coevolution should help to guide medical and public health practices such as regimens of antibiotic therapy and immunization strategies.
- Published in print:
- 2013
- Published Online:
- September 2013
- ISBN:
- 9780199609543
- eISBN:
- 9780191747717
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199609543.003.0008
- Subject:
- Psychology, Evolutionary Psychology, Developmental Psychology
The early aim of evolutionary psychology was to explain human universals. Recently attention has turned to explaining individual differences which present a theoretical challenge. Differences in ...
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The early aim of evolutionary psychology was to explain human universals. Recently attention has turned to explaining individual differences which present a theoretical challenge. Differences in personality and intelligence are partially heritable: if evolution acts to select the most adaptive traits, why do we see differences in intelligence and personality? Why do we not all show the same “optimal” level of intelligence or emotional stability? This chapter examines how and why genetic and non-genetic sources make each of us unique.Less
The early aim of evolutionary psychology was to explain human universals. Recently attention has turned to explaining individual differences which present a theoretical challenge. Differences in personality and intelligence are partially heritable: if evolution acts to select the most adaptive traits, why do we see differences in intelligence and personality? Why do we not all show the same “optimal” level of intelligence or emotional stability? This chapter examines how and why genetic and non-genetic sources make each of us unique.
Liz Pásztor, Zoltán Botta-Dukát, Gabriella Magyar, Tamás Czárán, and Géza Meszéna
- Published in print:
- 2016
- Published Online:
- August 2016
- ISBN:
- 9780199577859
- eISBN:
- 9780191823787
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199577859.003.0009
- Subject:
- Biology, Ecology
The larger the difference between competing varieties in their method of growth regulation the more robust their coexistence. Stable coexistence assumes frequency-dependent fitness with the advantage ...
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The larger the difference between competing varieties in their method of growth regulation the more robust their coexistence. Stable coexistence assumes frequency-dependent fitness with the advantage of the rare variant, which is empirically demonstrated for alleles, clones, and species. This principle is demonstrated in the implicit Lotka–Volterra model and in the explicit resource competition model of Tilman, and is generalized for arbitrary density-dependence. The generalized competitive exclusion principle states that a necessary condition for stable coexistence is that there be at least as many regulating factors as variants. Asymmetric competition for space through colonization-competition trade-offs, and for light via the trade-off between the vertical growth of trees and the reproductive potential also provides opportunities for coexistence. Trophic interactions may lead to complex population dynamics, as demonstrated by chemostat examples and the Rosenzweig–MacArthur model. Discussion of the conditions for coexistence in the food web context closes the chapter.Less
The larger the difference between competing varieties in their method of growth regulation the more robust their coexistence. Stable coexistence assumes frequency-dependent fitness with the advantage of the rare variant, which is empirically demonstrated for alleles, clones, and species. This principle is demonstrated in the implicit Lotka–Volterra model and in the explicit resource competition model of Tilman, and is generalized for arbitrary density-dependence. The generalized competitive exclusion principle states that a necessary condition for stable coexistence is that there be at least as many regulating factors as variants. Asymmetric competition for space through colonization-competition trade-offs, and for light via the trade-off between the vertical growth of trees and the reproductive potential also provides opportunities for coexistence. Trophic interactions may lead to complex population dynamics, as demonstrated by chemostat examples and the Rosenzweig–MacArthur model. Discussion of the conditions for coexistence in the food web context closes the chapter.
Steven D. Johnson and Florian P. Schiestl
- Published in print:
- 2016
- Published Online:
- December 2016
- ISBN:
- 9780198732693
- eISBN:
- 9780191796975
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198732693.003.0003
- Subject:
- Biology, Plant Sciences and Forestry, Ecology
The majority of rewardless plant species are not specific mimics of the flowers of other species; instead, they deploy a generalized set of floral signals to attract pollinators. These generalized ...
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The majority of rewardless plant species are not specific mimics of the flowers of other species; instead, they deploy a generalized set of floral signals to attract pollinators. These generalized food-deceptive (GFD) species have a number of unique evolutionary and ecological properties that are discussed in this chapter. The success of GFD plants needs to be understood in light of the fact that flower-visiting animals regularly encounter reward-depleted flowers during their foraging bouts. The evolutionary strategy of GFD species succeeds because the process whereby flower visitors learn to avoid deceptive species is sometimes slow and uncertain and depends on a number of factors. Most of the known GFD species are orchids, but the principles outlined in this chapter apply broadly to other deceptive plant–pollinator interactions and underline the relative ease by which plants can manipulate food-seeking insects.Less
The majority of rewardless plant species are not specific mimics of the flowers of other species; instead, they deploy a generalized set of floral signals to attract pollinators. These generalized food-deceptive (GFD) species have a number of unique evolutionary and ecological properties that are discussed in this chapter. The success of GFD plants needs to be understood in light of the fact that flower-visiting animals regularly encounter reward-depleted flowers during their foraging bouts. The evolutionary strategy of GFD species succeeds because the process whereby flower visitors learn to avoid deceptive species is sometimes slow and uncertain and depends on a number of factors. Most of the known GFD species are orchids, but the principles outlined in this chapter apply broadly to other deceptive plant–pollinator interactions and underline the relative ease by which plants can manipulate food-seeking insects.
