Natural Selection or Social Selection: A Discussion on Degeneration of Human Ancestors’ Terminal Hair

新心 王

doi:10.12677/ma.2018.64005

The evolution of female sex pheromones

Current Zoology ◽

10.1093/czoolo/59.4.569 ◽

2013 ◽

Vol 59 (4) ◽

pp. 569-578 ◽

Cited By ~ 22

Author(s):

Ally R. Harari ◽

Hadass Steinitz

Keyword(s):

Sexual Selection ◽

Natural Selection ◽

Sex Pheromones ◽

Species Recognition ◽

Current Evidence ◽

Social Selection ◽

Breeding Sites ◽

Female Sex ◽

Breeding Resources

Abstract The role of female sex pheromones in natural selection, particularly as a means for species recognition to avoid the generation of hybrid offspring with low fitness, has been widely explored and is generally accepted by scholars. However, the significance of sex pheromones in shaping mate choice (sexual selection) and in competition over breeding resources (social selection) has been largely ignored. The effect of sexual selection on sex pheromones as a sexually dimorphic signaling trait has been discounted because the amount of pheromone released by females is typically minute, while the role of sex pheromones in competition over breeding resources (other than mates) has not yet been considered. As a result of natural selection, variation in sex pheromones among females is expected to be low, and males are not expected to choose their mates among phero-mone-releasing conspecific females. Sexual selection, on the other hand, should drive the increase in pheromone variance among females, and males are expected to choose females based on this variation. Moreover, social selection resulting from more general social interactions, for example competition among females for breeding sites and food, should also promote variance among female sex pheromones. Here, we review the current evidence for each of the three selection processes acting on sex pheromones of female moths as an advertising trait. We suggest that the three selection types are not mutually exclusive but rather act together to promote different fitness components in diverse ecological situations.

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Social Selection and the Evolution of Maladaptation

10.1101/2021.03.12.435141 ◽

2021 ◽

Author(s):

Joel W. McGlothlin ◽

David N. Fisher

Keyword(s):

Natural Selection ◽

Genetic Model ◽

Inclusive Fitness ◽

Empirical Work ◽

General Rule ◽

Social Selection ◽

Population Mean ◽

Individual Level ◽

Quantitative Genetic ◽

Mean Fitness

AbstractEvolution by natural selection is often viewed as a process that inevitably leads to adaptation, or an increase in population fitness over time. However, maladaptation, an evolved decrease in fitness, may also occur in response to natural selection under some conditions. Social effects on fitness (or social selection) have been identified as a potential cause of maladaptation, but we lack a general rule identifying when social selection should lead to a decrease in population mean fitness. Here we use a quantitative genetic model to develop such a rule. We show that maladaptation is most likely to occur when social selection is strong relative to the nonsocial component of selection and acts in an opposing direction. In this scenario, evolutionary increases in traits that impose fitness costs on others may outweigh evolved gains in fitness for the individual, leading to a net decrease in population mean fitness. Further, we find maladaptation may also sometimes occur when phenotypes of interacting individuals negatively covary. We outline the biological situations where maladaptation in response to social selection can be expected, provide both quantitative genetic and phenotypic versions of our derived result, and suggest what empirical work would be needed to test it. We also consider the effect of social selection on inclusive fitness and support previous work showing that inclusive fitness cannot suffer an evolutionary decrease. Taken together, our results show that social selection may decrease population mean fitness when it opposes individual-level selection, even as inclusive fitness increases.

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An examination of species limits in theAulacorhynchus“prasinus” toucanet complex (Aves: Ramphastidae)

PeerJ ◽

10.7717/peerj.2381 ◽

2016 ◽

Vol 4 ◽

pp. e2381 ◽

Cited By ~ 2

Author(s):

Kevin Winker

Keyword(s):

Gene Flow ◽

Natural Selection ◽

South America ◽

Multivariate Analyses ◽

Biological Species ◽

Past Century ◽

Social Selection ◽

Species Limits ◽

Color Changes ◽

The Past

The number of species recognized inAulacorhynchustoucanets has varied tremendously over the past century. Revisors seem to disagree on whether head and bill coloration are useful indicators of species limits, especially in theA.“prasinus” complex. Using morphometrics, I tested the hypothesis that the major color-based subspecific groups ofA.“prasinus”sensu latoare simply “cookie-cutter” (i.e., morphologically nearly identical) toucanets with different head and bill colorations. Univariate and multivariate analyses show that they are not simply morphological replicates of different colors: a complex array of morphometric similarities and dissimilarities occur between the major subspecific groups, and these variations differ between the sexes. Latitude and longitude had a small but significant association with female (but not male) PC1 and PC2. Hybridization and intergradation were also considered using plumage and bill characters as a surrogate to infer gene flow. Hybridization as indicated by phenotype appears to be substantial betweenA. “p.” cyanolaemusandA. “p.” atrogularisand nonexistent between other major groups, although from genetic evidence it is likely rare betweenA. “p.” albivittaandA. “p.” cyanolaemus. The congruence and complexities of the morphological and color changes occurring among these groups suggest that ecological adaptation (through natural selection) and social selection have co-occurred among these groups and that species limits are involved. Further, hybridization is not evident at key places, despite in many cases (hypothetical) opportunity for gene flow. Consequently, I recommend that this complex be recognized as comprising five biological species:A. wagleri, prasinus, caeruleogularis, albivitta,andatrogularis. Four of these also have valid subspecies within them, and additional work may eventually support elevation of some of these subspecies to full species. Species limits in South America especially need more study.

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