scholarly journals Mechanisms of Cultural Evolution in the Songs of Wild Bird Populations

2021 ◽  
Vol 12 ◽  
Author(s):  
Heather Williams
Keyword(s):  
Sexual Selection ◽  
Cultural Evolution ◽  
Mean Value ◽  
Directional Selection ◽  
Specific Reference ◽  
Wild Populations ◽  
Rare Form ◽  
Savannah Sparrow ◽  
Savannah Sparrows ◽  
Over Time

Young songbirds draw the source material for their learned songs from parents, peers, and unrelated adults, as well as from innovation. These learned songs are used for intraspecific communication, and have well-documented roles for such functions as territory maintenance and mate attraction. The songs of wild populations differ, forming local “dialects” that may shift over time, suggesting that cultural evolution is at work. Recent work has focused on the mechanisms responsible for the cultural evolution of bird songs within a population, including drift, learning biases (such as conformity and rare-form copying), and selection (including sexual selection). In many songs or song repertoires, variability is partitioned, with some songs or song segments being stable and consistent, while others vary within the population and across time, and still others undergo population-wide transitions over time. This review explores the different mechanisms that shape the cultural evolution of songs in wild populations, with specific reference to a long-term investigation of a single population of philopatric Savannah sparrows. Males learn a single four-segment song during their 1st year and sing the same song thereafter. Within this song, the buzz segment is a population marker, and may be stable for decades – variant forms occur but eventually disappear. In contrast, the middle segment is highly variable both within the population and over time; changes in relative prevalence of different forms may be due to cultural drift or a rare-form learning bias. Within the introductory segment, a high note cluster was replaced by a click train between 1982 and 2010, following an S-shaped trajectory characteristic of both selective sweeps in population genetics and the replacement of one form by another in human language. In the case of the Savannah sparrows, this replacement may have been due to sexual selection. In subsequent generations, the number of clicks within trains increased, a form of cultural directional selection. In contrast to the narrowing of a trait's range during directional selection in genetic systems, variation in the number of clicks in a train increased as the mean value shifted because improvisation during song learning allowed the range of the trait to expand. Thus, in the single short song of the Savannah sparrow, at least four different mechanisms appear to contribute to three different types of cultural evolutionary outcomes. In the future, it will be import to explore the conditions that favor the application of specific (and perhaps conditional) learning rules, and studies such as the ongoing song seeding experiment in the Kent Island Savannah sparrow population will help in understanding the mechanisms that promote or repress changes in a population's song.

Sexual dimorphism in two savannah sparrow populations

1980 ◽  
Vol 58 (3) ◽  
pp. 412-415 ◽  
Author(s):  
Patrick J. Weatherhead
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Stabilizing Selection ◽  
Sexually Dimorphic ◽  
Mainland Population ◽  
Savannah Sparrow ◽  
Savannah Sparrows ◽  
Insular Population

Contrary to predictions, a monogamous, mainland population of savannah sparrows was found to be more sexually dimorphic than a polygynous, insular population. When only trophic characters were considered, the insular population fit the prediction of greater sexual dimorphism. Several explanations for increased sexual selection or decreased stabilizing selection in the more dimorphic population are considered. While none of the explanations seem readily applicable from the available evidence, further avenues of investigation are suggested.

Song characters as reliable indicators of male reproductive quality in the Savannah Sparrow (Passerculus sandwichensis)

2020 ◽  
Vol 98 (1) ◽  
pp. 32-38
Author(s):  
Ha-Cheol Sung ◽  
Paul Handford
Keyword(s):  
Sexual Selection ◽  
Reproductive Performance ◽  
Territory Size ◽  
Male Mating ◽  
Combined Effects ◽  
Male Quality ◽  
Passerculus Sandwichensis ◽  
Song Variation ◽  
Savannah Sparrow ◽  
Savannah Sparrows

Bird song may provide female birds with signals of male quality. To investigate this potential for sexual selection via female choice, we assessed the relationships between male song variation and male mating and reproductive success of the Savannah Sparrow (Passerculus sandwichensis (J.F. Gmelin, 1789)) over 3 years (2001–2003) in a population of Savannah Sparrows near London, Ontario, Canada. We measured song rate, as well as temporal and frequency attributes of song structure, as possible predictors of male quality, and then related these measures to attributes of male reproductive performance (mating and breeding success and territory size of males). We found significant correlations between male reproductive performance and several song features, such that the combined effects of two trill sections could potentially play an important role: males possessing such songs arrived and paired earlier and had higher fledging success. The results suggested that the trill segments of the song may signal important aspects of male quality. Possible reasons for significant roles of such songs in open-habitat birds are discussed.

Social transmission bias and the cultural evolution of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
David Hirshleifer ◽  
Siew Hong Teoh
Keyword(s):  
Cultural Evolution ◽  
Social Transmission ◽  
Cognitive Approach ◽  
Economic Problems ◽  
Economic Attitudes ◽  
The Social ◽  
Economic Beliefs ◽  
Over Time

AbstractEvolved dispositions influence, but do not determine, how people think about economic problems. The evolutionary cognitive approach offers important insights but underweights the social transmission of ideas as a level of explanation. The need for asocialexplanation for the evolution of economic attitudes is evidenced, for example, by immense variations in folk-economic beliefs over time and across individuals.

scholarly journals Structural Health Monitoring for cultural heritage constructions: a resilience perspective

2019 ◽  
Author(s):  
Maria Pina Limongelli ◽  
Zehra Irem Turksezer ◽  
Pier Francesco Giordano
Keyword(s):  
Structural Health Monitoring ◽  
Cultural Heritage ◽  
Health Monitoring ◽  
Social Value ◽  
Specific Reference ◽  
Structural Health ◽  
Heritage Constructions ◽  
The Impact ◽  
Support Decision Making ◽  
Over Time

<p>Disturbances or disruptive events may induce reductions of functionality of the built environment. For Cultural Heritage (CH) structures, functionalities may range from technical, to economic ones linked to touristic activities, up to intangible functionalities related to the cultural and social value of these constructions. Resilience can be defined as the capability of a system overcome a disturbance with the minimum total loss of functionality over time. Structural Health Monitoring (SHM) may enhance resilience by providing information that can support decision making, aiming to reduce the impact of the disturbances. In this paper, the benefits of SHM systems as means for improving resilience of CH structures are addressed and discussed with specific reference to the three different decision situations; before, during and after events of disturbances. Examples of real applications of SHM for CH structures and its effect on the resilience of the system conclude the paper.</p>

scholarly journals The Uses and Abuses of Tree Thinking in Cultural Evolution

2021 ◽  
Author(s):  
Cara Evans ◽  
Simon J. Greenhill ◽  
Joseph Watts ◽  
Johann-Mattis List ◽  
Carlos A. Botero ◽  
...  
Keyword(s):  
Best Practices ◽  
Cultural Evolution ◽  
Cross Cultural ◽  
Tree Thinking ◽  
Phylogenetic Methods ◽  
Cultural Research ◽  
Cross Cultural Research ◽  
Cultural Traits ◽  
Lines Of Evidence ◽  
Over Time

Modern phylogenetic methods are increasingly being used to address questions about macro-level patterns in cultural evolution. These methods can illuminate the unobservable histories of cultural traits and identify the evolutionary drivers of trait-change over time, but their application is not without pitfalls. Here we outline the current scope of research in cultural tree thinking, highlighting a toolkit of best practices to navigate and avoid the pitfalls and ‘abuses’ associated with their application. We emphasise two principles that support the appropriate application of phylogenetic methodologies in cross-cultural research: researchers should (1) draw on multiple lines of evidence when deciding if and which types of phylogenetic methods and models are suitable for their cross-cultural data, and (2) carefully consider how different cultural traits might have different evolutionary histories across space and time. When used appropriately phylogenetic methods can provide powerful insights into the processes of evolutionary change that have shaped the broad patterns of human history.

scholarly journals Veld management with specific reference to game ranching in the grassland and savanna areas of South Africa

Koedoe ◽  
1990 ◽  
Vol 33 (2) ◽  
Author(s):  
W.S.W. Trollope
Keyword(s):  
South Africa ◽  
Land Use ◽  
Nature Conservation ◽  
National Parks ◽  
Management Practices ◽  
Wide Spectrum ◽  
Management Program ◽  
Specific Reference ◽  
Game Ranching ◽  
Over Time

Veld management refers to the management of natural vegetation for specific objectives related to different forms of land use. In the wildlife context a wide spectrum of different forms of land use are practised ranging from pure nature conservation in large national parks through to smaller areas used for game farming. Consequently the products useable to society emanating from these areas vary greatly, and therefore the management of veld stocked with wildlife is extremely complex and must be adapted to the particular form of land use that is being practised. A generally accepted principle is that the smaller the area being used for wildlife the more intensively it must be managed, particularly game ranches. A prerequisite for the development of an effective veld management program is a comprehensive assessment of the condition of the veld upon which realistic veld management practices can be formulated. These practices will include stocking the veld with the appropriate species and numbers of animals, grazing and browsing management, veld burning and the provision of watering points. Finally a programme for monitoring veld condition over time is a prerequisite for sound veld management.

scholarly journals The evolution of high-fidelity social learning

2020 ◽  
Vol 287 (1928) ◽  
pp. 20200090
Author(s):  
Marcel Montrey ◽  
Thomas R. Shultz
Keyword(s):  
Social Learning ◽  
Cultural Evolution ◽  
Bayesian Model ◽  
Individual Learning ◽  
High Fidelity ◽  
Human Culture ◽  
Cumulative Cultural Evolution ◽  
Over Time

A defining feature of human culture is that knowledge and technology continually improve over time. Such cumulative cultural evolution (CCE) probably depends far more heavily on how reliably information is preserved than on how efficiently it is refined. Therefore, one possible reason that CCE appears diminished or absent in other species is that it requires accurate but specialized forms of social learning at which humans are uniquely adept. Here, we develop a Bayesian model to contrast the evolution of high-fidelity social learning, which supports CCE, against low-fidelity social learning, which does not. We find that high-fidelity transmission evolves when (1) social and (2) individual learning are inexpensive, (3) traits are complex, (4) individual learning is abundant, (5) adaptive problems are difficult and (6) behaviour is flexible. Low-fidelity transmission differs in many respects. It not only evolves when (2) individual learning is costly and (4) infrequent but also proves more robust when (3) traits are simple and (5) adaptive problems are easy. If conditions favouring the evolution of high-fidelity transmission are stricter (3 and 5) or harder to meet (2 and 4), this could explain why social learning is common, but CCE is rare.

Navigating Diffuse Jurisdictions

2019 ◽  
pp. 98-120
Author(s):  
Helen Quane
Keyword(s):  
Legal System ◽  
Legal Pluralism ◽  
Customary Law ◽  
Specific Reference ◽  
State Law ◽  
System P ◽  
The Status ◽  
Over Time

This chapter studies the jurisdictional boundaries between state and non-state law with specific reference to religious, or customary, law. The determination of these regulatory forms as state law depends on the extent to which they perform prescriptive, adjudicative, or enforcement functions. Indeed, the boundaries between state and non-state law are not as stable as they may appear, as they are liable to shift according to circumstances and over time. The chapter then argues that the issue of classification acquires resonance in cases where legal pluralism occurs as the character and scope of a state’s exercise of jurisdiction becomes far more ambiguous in such situations. This can create uncertainty about the jurisdiction of the respective systems, the status of norms from one system that are given effect in another, and how these norms should be interpreted and applied given their concurrent existence within more than one legal system.

scholarly journals Secular trends in weight, height and weight for height among children under 7 years in nine cities of China, 1975–2015: results from five repeated cross-sectional surveys

BMJ Open ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. e029201 ◽  
Author(s):  
Ya Qin Zhang ◽  
Hui Li ◽  
Hua Hong Wu ◽  
Xin Nan Zong
Keyword(s):  
Outcome Measures ◽  
Mean Value ◽  
Secular Trends ◽  
Healthy Children ◽  
Sample Sizes ◽  
Older Children ◽  
Cross Sectional ◽  
The Mean ◽  
Increasing Trends ◽  
Over Time

ObjectiveTo analyse the secular trends in mean value and distribution of weight, height and weight for height in children under 7 years in developed regions in China.DesignFive repeated cross-sectional surveys were conducted using the same methods at the same sites during 1975–2015.SettingNine cities in northern, central and southern regions of China.PopulationHealthy children under 7 years; the sample sizes were 94 496 in 1975, 79 177 in 1985, 79 152 in 1995, 69 760 in 2005 and 83 583 in 2015.Main outcome measuresWeight and height were measured by the same methods in the five surveys.ResultsThe increasing trends in the mean value of weight, height and weight for height were observed and their distribution was found to have shifted upwards. There were unbalanced increments in various centiles and the relative increments in the 3rd centile of height for children under 7 years were larger than those in the 50th and 97th centiles. Although the relative increments in the 3rd centile of weight for children under 2 years were larger than those in the 50th and 97th centiles, the increments in the 97th centile for children older than 2 years became the largest compared with other centiles. The changes in each centile of weight for height were similar with those of weight. The annual increments of height and weight increased over time and were more significant between birth and 2 years of age for height and between ages 4 years and 6 years for weight. The per-decade increments in 1975–1985, 1985–1995 and 1995–2005 became larger, while those in 2005–2015 slowed down.ConclusionsThe rapid increasing trends of weight, height and weight for height had slowed down since 2005 in developed regions of China. The relative increments in the low centile of height were more significant, while the high centile of weight and weight for height increased more significantly in older children.

scholarly journals Evidence for differing trajectories of songs in urban and rural populations

2019 ◽  
Vol 30 (6) ◽  
pp. 1734-1742
Author(s):  
Dana L Moseley ◽  
Jennifer N Phillips ◽  
Elizabeth P Derryberry ◽  
David A Luther
Keyword(s):  
San Francisco ◽  
Cultural Evolution ◽  
Foraging Strategies ◽  
Vocal Performance ◽  
Communication Signals ◽  
Performance Constraints ◽  
Urban Males ◽  
Alternative Means ◽  
Display Performance ◽  
Over Time

Abstract Learned traits, such as foraging strategies and communication signals, can change over time via cultural evolution. Using historical recordings, we investigate the cultural evolution of birdsong over nearly a 50-year period. Specifically, we examine the parts of white-crowned sparrow (Zonotrichia leucophrys nuttalli) songs used for mate attraction and territorial defense. We compared historical (early 1970s) recordings with contemporary (mid-2010s) recordings from populations within and near San Francisco, CA and assessed the vocal performance of these songs. Because birds exposed to anthropogenic noise tend to sing at higher minimum frequencies with narrower frequency bandwidths, potentially reducing one measure of song performance, we hypothesized that other song features, such as syllable complexity, might be exaggerated, as an alternative means to display performance capabilities. We found that vocal performance increased between historical and contemporary songs, with a larger effect size for urban songs, and that syllable complexity, measured as the number of frequency modulations per syllable, was historically low for urban males but increased significantly in urban songs. We interpret these results as evidence for males increasing song complexity and trilled performance over time in urban habitats, despite performance constraints from urban noise, and suggest a new line of inquiry into how environments alter vocal performance over time.

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