Franck Courchamp, Ludek Berec, and Joanna Gascoigne
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780198570301
- eISBN:
- 9780191717642
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198570301.001.0001
- Subject:
- Biology, Biodiversity / Conservation Biology
Allee effects are broadly defined as a decline in individual fitness at low population size or density, that can result in critical population thresholds below which populations crash to extinction. ...
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Allee effects are broadly defined as a decline in individual fitness at low population size or density, that can result in critical population thresholds below which populations crash to extinction. As such, they are very relevant to many conservation programmes, where scientists and managers are often working with populations that have been reduced to low densities or small numbers. There are a variety of mechanisms that can create Allee effects, including mating systems, predation, environmental modification, and social interactions among others. The abrupt and unpredicted collapses of many exploited populations is just one illustration of the need to bring Allee effects to the forefront of conservation and management strategies. This book provides an overview of the topic, collating and integrating a widely dispersed literature from various fields: marine and terrestrial, plant and animal, theoretical and empirical, academic and applied. Less
Allee effects are broadly defined as a decline in individual fitness at low population size or density, that can result in critical population thresholds below which populations crash to extinction. As such, they are very relevant to many conservation programmes, where scientists and managers are often working with populations that have been reduced to low densities or small numbers. There are a variety of mechanisms that can create Allee effects, including mating systems, predation, environmental modification, and social interactions among others. The abrupt and unpredicted collapses of many exploited populations is just one illustration of the need to bring Allee effects to the forefront of conservation and management strategies. This book provides an overview of the topic, collating and integrating a widely dispersed literature from various fields: marine and terrestrial, plant and animal, theoretical and empirical, academic and applied.
Michael J. Wade
- Published in print:
- 2016
- Published Online:
- January 2017
- ISBN:
- 9780226129563
- eISBN:
- 9780226129877
- Item type:
- chapter
- Publisher:
- University of Chicago Press
- DOI:
- 10.7208/chicago/9780226129877.003.0010
- Subject:
- Biology, Evolutionary Biology / Genetics
This chapter presents the results of crosses between beetles from high and low reproducing populations in relation to the fitness landscape of flour beetle laboratory populations. The chapter ...
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This chapter presents the results of crosses between beetles from high and low reproducing populations in relation to the fitness landscape of flour beetle laboratory populations. The chapter presents the results of experimental studies of inbreeding to show that differences in inbreeding among the metapopulations were not responsible for the surprizing results of the Shifting Balance Experiment. The empirical differences between individual and population mean fitness are discussed and were estimated experimentally. The finding that the among-population genetic variation in fitness was 50-fold greater than predicted by standard theory is discussed in the context of empirical results. Lastly, the unique signature that among-group selection leaves on gene sequences is discussed and illustrated with genomic data. Suggestions for future research into metapopulation genomics are presented in conclusion.Less
This chapter presents the results of crosses between beetles from high and low reproducing populations in relation to the fitness landscape of flour beetle laboratory populations. The chapter presents the results of experimental studies of inbreeding to show that differences in inbreeding among the metapopulations were not responsible for the surprizing results of the Shifting Balance Experiment. The empirical differences between individual and population mean fitness are discussed and were estimated experimentally. The finding that the among-population genetic variation in fitness was 50-fold greater than predicted by standard theory is discussed in the context of empirical results. Lastly, the unique signature that among-group selection leaves on gene sequences is discussed and illustrated with genomic data. Suggestions for future research into metapopulation genomics are presented in conclusion.
Richard Mcelreath and Robert Boyd
- Published in print:
- 2007
- Published Online:
- February 2013
- ISBN:
- 9780226558264
- eISBN:
- 9780226558288
- Item type:
- chapter
- Publisher:
- University of Chicago Press
- DOI:
- 10.7208/chicago/9780226558288.003.0002
- Subject:
- Biology, Evolutionary Biology / Genetics
Resources are often scarce, and scarcity often leads to conflict. The form of conflict ranges from subtle supplants in which one animal departs at the other's approach to escalated fights in which ...
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Resources are often scarce, and scarcity often leads to conflict. The form of conflict ranges from subtle supplants in which one animal departs at the other's approach to escalated fights in which participants are seriously wounded. Interestingly, conflicts in a wide range of species are often resolved without dangerous escalation. In 1973, the eminent geneticist John Maynard Smith and an eccentric retired engineer named George Price explained why sometimes selection favored restraint, and why sometimes it didn't. This model, called the Hawk-Dove game, illustrates the power of simple models and changed the way biologists viewed animal contests. The Hawk-Dove game provides a simple introduction to a key feature of social behavior—individual fitness typically depends on the behavior of others. This chapter examines the Hawk-Dove game and some of its many descendants. It first introduces the basic ideas of evolutionary game theory and applies them to the understanding of the evolution of animal contests. It then discusses the results of the Hawk-Dove game for retaliation, evolutionary stable strategies, continuous stable strategies, ownership, resource holding power, and sequential play.Less
Resources are often scarce, and scarcity often leads to conflict. The form of conflict ranges from subtle supplants in which one animal departs at the other's approach to escalated fights in which participants are seriously wounded. Interestingly, conflicts in a wide range of species are often resolved without dangerous escalation. In 1973, the eminent geneticist John Maynard Smith and an eccentric retired engineer named George Price explained why sometimes selection favored restraint, and why sometimes it didn't. This model, called the Hawk-Dove game, illustrates the power of simple models and changed the way biologists viewed animal contests. The Hawk-Dove game provides a simple introduction to a key feature of social behavior—individual fitness typically depends on the behavior of others. This chapter examines the Hawk-Dove game and some of its many descendants. It first introduces the basic ideas of evolutionary game theory and applies them to the understanding of the evolution of animal contests. It then discusses the results of the Hawk-Dove game for retaliation, evolutionary stable strategies, continuous stable strategies, ownership, resource holding power, and sequential play.
Jan Komdeur
- Published in print:
- 2012
- Published Online:
- December 2013
- ISBN:
- 9780199692576
- eISBN:
- 9780191774737
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199692576.003.0010
- Subject:
- Biology, Evolutionary Biology / Genetics
This chapter reviews various social and ecological circumstances linked to parental care that could drive variation in adaptive sex allocation in of vertebrates. The most extreme and precise sex ...
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This chapter reviews various social and ecological circumstances linked to parental care that could drive variation in adaptive sex allocation in of vertebrates. The most extreme and precise sex ratio adjustments in relation to such social and environmental factors were found in species where the fitness benefits of facultative sex ratio adjustment are high and the apparent costs low. Furthermore, some studies report evidence for sex ratio bias, either at birth or at the end of the parental care period, while other studies do not, despite conditions predicted to favour adaptive sex ratio adjustments being satisfied. This discrepancy between studies conducted on different species, or even the same species, emphasizes the need for more robust predictions based on accurate estimates of potential fitness pay-offs. To this end, there is a need for better information on the long-term consequences of sex allocation on individual fitness. A major task for future work is to obtain more detailed information on the fitness functions of both parents and male and female offspring. Finally, theoretical models need to be developed that can predict the observed variation in the amount and precision of sex-ratio manipulation in response to the various factors that influence the selection pressure.Less
This chapter reviews various social and ecological circumstances linked to parental care that could drive variation in adaptive sex allocation in of vertebrates. The most extreme and precise sex ratio adjustments in relation to such social and environmental factors were found in species where the fitness benefits of facultative sex ratio adjustment are high and the apparent costs low. Furthermore, some studies report evidence for sex ratio bias, either at birth or at the end of the parental care period, while other studies do not, despite conditions predicted to favour adaptive sex ratio adjustments being satisfied. This discrepancy between studies conducted on different species, or even the same species, emphasizes the need for more robust predictions based on accurate estimates of potential fitness pay-offs. To this end, there is a need for better information on the long-term consequences of sex allocation on individual fitness. A major task for future work is to obtain more detailed information on the fitness functions of both parents and male and female offspring. Finally, theoretical models need to be developed that can predict the observed variation in the amount and precision of sex-ratio manipulation in response to the various factors that influence the selection pressure.
Josh Van Buskirk
- Published in print:
- 2012
- Published Online:
- May 2015
- ISBN:
- 9780199602568
- eISBN:
- 9780191810121
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:osobl/9780199602568.003.0011
- Subject:
- Biology, Animal Biology
This chapter considers the role of behavioural plasticity under rapid environmental change, including the kinds of changing conditions expected under anthropogenic climate change. It looks into how ...
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This chapter considers the role of behavioural plasticity under rapid environmental change, including the kinds of changing conditions expected under anthropogenic climate change. It looks into how this role arises as a result of behavioural modes of plasticity being common and permits relatively rapid and reversible responses to changing conditions. It discusses some key issues regarding the role of plasticity such as the degree to which behavioural plasticity improves individual fitness, and the impact that plasticity has on population persistence. It examines how behavioural plasticity accounts for most of the observed phenotypic response to environmental change, and also enumerates some population-level consequences of plasticity have enabled reduced population declines.Less
This chapter considers the role of behavioural plasticity under rapid environmental change, including the kinds of changing conditions expected under anthropogenic climate change. It looks into how this role arises as a result of behavioural modes of plasticity being common and permits relatively rapid and reversible responses to changing conditions. It discusses some key issues regarding the role of plasticity such as the degree to which behavioural plasticity improves individual fitness, and the impact that plasticity has on population persistence. It examines how behavioural plasticity accounts for most of the observed phenotypic response to environmental change, and also enumerates some population-level consequences of plasticity have enabled reduced population declines.
