scholarly journals The evolution of sexual dichromatism in a large radiation of landfowls: re-examining the female-biased selection in Wallace's model

2022 ◽  
Author(s):  
Zheng Li ◽  
De Chen ◽  
Lu Dong
Keyword(s):  
Natural Selection ◽  
Evolutionary Rates ◽  
Sexual Dichromatism ◽  
Colour Difference ◽  
Evolutionary Forces ◽  
Worldwide Distribution ◽  
Terrestrial Habitats ◽  
Males And Females ◽  
The Relationship

Sexual dichromatism, the colour difference between males and females, has been particularly important for studying the interplay between sexual and natural selection. However, previous studies on the evolutionary forces of sexual dichromatism examing the Darwin's and Wallace's model have produced mixed results. Phasianidae is a species-rich family with worldwide distribution, occupancy in nearly all terrestrial habitats, and a wide diversity of plumage patterns and colourations. Here, we use phylogenetic comparative methods to test the relationship between sexual dichromatism and colour complexity of males and females on both evolutionary direction and tempo including all species in Phasianidae. We show that the evolutionary direction of sexual dichromatism is negatively correlated with colour complexity in females but not males, and the evolutionary rates of sexual dichromatism are positively correlated with the evolutionary rates of colour complexity in both sexes. These results highlight the important role of female colour evolution in shaping sexual dichromatism in the pheasant family, and provide strong empirical supports for Wallace's hypothesis via a mosaic of sexual and natural selection in both sexes.

scholarly journals Evolution of gene regulatory networks by means of selection and random genetic drift

2018 ◽  
Author(s):  
Antonios Kioukis ◽  
Pavlos Pavlidis
Keyword(s):  
Natural Selection ◽  
Positive Selection ◽  
Genetic Drift ◽  
Regulatory Networks ◽  
Fitness Landscape ◽  
Random Genetic Drift ◽  
Maturation Period ◽  
Evolutionary Forces ◽  
Gene Regulatory

The evolution of a population by means of genetic drift and natural selection operating on a gene regulatory network (GRN) of an individual has not been scrutinized in depth. Thus, the relative importance of various evolutionary forces and processes on shaping genetic variability in GRNs is understudied. Furthermore, it is not known if existing tools that identify recent and strong positive selection from genomic sequences, in simple models of evolution, can detect recent positive selection when it operates on GRNs. Here, we propose a simulation framework, called EvoNET, that simulates forward-in-time the evolution of GRNs in a population. Since the population size is finite, random genetic drift is explicitly applied. The fitness of a mutation is not constant, but we evaluate the fitness of each individual by measuring its genetic distance from an optimal genotype. Mutations and recombination may take place from generation to generation, modifying the genotypic composition of the population. Each individual goes through a maturation period, where its GRN reaches equilibrium. At the next step, individuals compete to produce the next generation. As time progresses, the beneficial genotypes push the population higher in the fitness landscape. We examine properties of the GRN evolution such as robustness against the deleterious effect of mutations and the role of genetic drift. We confirm classical results from Andreas Wagner’s work that GRNs show robustness against mutations and we provide new results regarding the interplay between random genetic drift and natural selection.

scholarly journals Role of Peers Pressure and Self-Esteem on the General Secondary Students’ Aggression

2017 ◽  
Vol 9 (2) ◽  
pp. 89
Author(s):  
Fadel Ali Falah Al-Zoubi ◽  
Ibrahim El-Zraigat
Keyword(s):  
Secondary Students ◽  
Self Esteem ◽  
Limiting Factors ◽  
Cognitive Behavioural ◽  
The Family ◽  
Social Difficulties ◽  
Males And Females ◽  
Vital Matter ◽  
The Relationship

The objective of study was examining impacts of peers’ pressure, and the variable of self-esteem on levels of aggression at general secondary students, males and females. Aggression is known as any type of behavior meant to hurt others. Aggression always merges in the context of dealing among individuals (such as emotional and social difficulties, fewness of self-esteem, peers-discarding, and studying failure), environing character is tice (such as poverty, weakness of family supervisors, limited social support, and conflicts with the family) limiting factors that cause aggression are considered a vital matter to specify precautions of it. This qualitative rational research aims at examining impacts of variables of peers’ pressure, and self-esteem on prediction with levels of aggression at general secondary students. The sample of study consisted of 411 male and female students and they have been randomly chosen from 720 students and the general secondary students in Jerash governorate. The participants answered the questionnaire of aggression and scale of peers’-pressure, and scale of self-esteem in their classes during periods of research. Date had been analyzed by using hierarchy method analysis of using hierarchy method analyzing the multi-declension. It was pin-pointed that peers’ pressure was an effective predictor in explaining levels of aggression relative to hierarchy of analyzing the multi-declension of the general secondary students, males and females. Moreover, it was pin-pointed that self-esteem was in the second rank from part of the relationship with aggression amongst the general secondary students, males and females. It was clear that peers’ pressure had an impact indicative to the general secondary students’ aggression in the deeds connected with prevention of aggression, and it is necessary to teach the general secondary students how to adapt with pressure, and how to say “no”. Leaning on these results, we recommend that schools to students how to prevent violence and aggression. In addition to that, we recommend to use cognitive behavioural technicalities to raise the level of the general secondary students’ awareness with non-beneficial behaviour and motivating to aggression so that they can amend such behaviour.

scholarly journals Evolutionary antagonisms and the progress of three categories of traits

BJHS Themes ◽  
2021 ◽  
pp. 1-22
Author(s):  
Nasser Zakariya
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Intellectual Development ◽  
Thomas Henry Huxley ◽  
Alfred Russel Wallace ◽  
Different Types ◽  
The Relationship ◽  
Descent Of Man ◽  
Ethical Systems

Abstract Darwin in The Descent of Man deliberates over the question of progress in relation to three categories of traits – aesthetic, moral and intellectual – attending to their interplay. The later formulations of Thomas Henry Huxley and Alfred Russel Wallace shift and reframe the terms for weighing together progress and the relationship across these traits, downplaying the role of aesthetic assessments. Huxley and Wallace invoke ‘antagonisms’ countering, respectively, ‘ethical progress’ and ‘cosmic process’, ‘humanity – the essentially human emotion’ and ‘physical and even intellectual race-improvement’. Thereafter, evolutionary antagonisms reappear – whether to endorse, dismiss or overcome them – and they remain relevant in evolutionary arguments, whether made explicit or left implicit. Following a thread of ongoing appeals to this interplay of traits and corresponding antagonisms invoking Huxley's 1893 lecture ‘Evolution and ethics’, implicit differences appear in the treatment of aesthetic, moral and intellectual development. These treatments maintain the progress that their own ethical systems represented, even while granting moral variation and conceding independent/alternative notions of the beautiful. They generally took as granted the uniformity of intellectual judgements, where evolutionary progress was both ethical and intellectual/scientific, even when speculating on the development of different types of mind. As characteristic of future-oriented visions of progress by the first decades of the twentieth century, sexual selection was subsumed under natural selection.

scholarly journals Sex chromosomes, sex ratios and sex gaps in longevity in plants

2021 ◽  
Author(s):  
Gabriel AB Marais ◽  
Jean-Francois Lemaitre
Keyword(s):  
Sex Chromosomes ◽  
Statistical Power ◽  
Sex Chromosome ◽  
Sex Ratios ◽  
Y Chromosomes ◽  
Adult Sex Ratio ◽  
Female Longevity ◽  
Males And Females ◽  
The Relationship

In animals, males and females can display markedly different longevity (also called sex gap in longevity, SGLs). Recent work has revealed that sex chromosomes contribute to establishing these SGLs. X-hemizygosity and toxicity of the Y chromosomes are two mechanisms that have been suggested to reduce male longevity (Z-hemizygosity and W toxicity in females in ZW systems). In plants, SGLs are known to exist but the role of sex chromosomes remains to be established. Here, by using adult sex ratio as a proxy for measuring SGLs, we explored the relationship between sex chromosome and SGLs across 43 plant species. Based on the knowledge recently accumulated in animals, we specifically asked whether: (i) species with XY systems tend to have female-biased sex ratios (reduced male longevity) and species with ZW ones tend to have male-biased sex ratios (reduced female longevity), and (ii) this patterns was stronger in heteromorphic systems compared to homomorphic ones. Our results tend to support these predictions although we lack statistical power because of a small number of ZW systems and the absence of any heteromorphic ZW system in the dataset. We discuss the implications of these findings, which we hope will stimulate further research on sex-differences in lifespan and ageing across plants.

scholarly journals It's a Boy Thing: The Role of the Internet in Young People's Psychological Wellbeing

2004 ◽  
Vol 21 (2) ◽  
pp. 76-89 ◽  
Author(s):  
Lauren Donchi ◽  
Susan Moore
Keyword(s):  
Self Esteem ◽  
Relative Strength ◽  
Psychological Wellbeing ◽  
The Internet ◽  
Friendship Networks ◽  
Face To Face ◽  
Males And Females ◽  
University Population ◽  
The Relationship

AbstractThe aim of this study was to assess the relationship between psychological wellbeing and Internet use among adolescents, focussing not only on time spent on the Internet, but also on the relative strength/importance of both face-to-face and Internet friendship networks. A sample of 336 young people aged between 15 and 21 years from a secondary school and a university population were surveyed. Results indicated that females with more online friends were higher on selfesteem and lower on loneliness than females with fewer online friends, but the opposite was true for males. A higher number of online regular friendships seemed to militate against self-esteem and was related to greater loneliness for males. For face-to-face friendships, the effects on wellbeing were in the same direction for males and females, but stronger for males. Those with more face-to-face friendships were higher on self-esteem and less lonely. In addition, young men who rated their online friendship networks as very important were more likely to have lower self-esteem and to be lonely. Actual time spent on the Internet was not a predictor of wellbeing for either sex when online and offline friendship factors were included in the regression equation.

scholarly journals Reproductive barriers as a byproduct of gene network evolution

2020 ◽  
Author(s):  
Chia-Hung Yang ◽  
Samuel V. Scarpino
Keyword(s):  
Natural Selection ◽  
Reproductive Isolation ◽  
Gene Networks ◽  
Regulatory Networks ◽  
Network Evolution ◽  
Genetic Interactions ◽  
Reproductive Barriers ◽  
Evolutionary Forces ◽  
Functional Representation

AbstractMolecular analyses of closely related taxa have increasingly revealed the importance of higher-order genetic interactions in explaining the observed pattern of reproductive isolation between populations. Indeed, both empirical and theoretical studies have linked the process of speciation to complex genetic interactions. Gene Regulatory Networks (GRNs) capture the inter-dependencies of gene expression and encode information about an individual’s phenotype and development at the molecular level. As a result, GRNs can–in principle–evolve via natural selection and play a role in non-selective, evolutionary forces. Here, we develop a network-based model, termed the pathway framework, that considers GRNs as a functional representation of coding sequences. We then simulated the dynamics of GRNs using a simple model that included natural selection, genetic drift, and sexual reproduction and found that reproductive barriers can develop rapidly between allopatric populations experiencing identical selection pressure. Further, we show that alleles involved in reproductive isolation can predate the allopatric separation of populations and that the number of interacting loci involved in genetic incompatibilities, i.e., the order, is often high simply as a by-product of the networked structure of GRNs. Finally, we discuss how results from the pathway framework are consistent with observed empirical patterns for genes putatively involved in post-zygotic isolation. Taken together, this study adds support for the central role of gene networks in speciation and in evolution more broadly.

scholarly journals Behavioural changes controlled by catecholaminergic systems explain recurrent loss of pigmentation in cavefish

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180243 ◽  
Author(s):  
Helena Bilandžija ◽  
Lindsey Abraham ◽  
Li Ma ◽  
Kenneth J. Renner ◽  
William R. Jeffery
Keyword(s):  
Natural Selection ◽  
Loss Of Function ◽  
Melanin Pigmentation ◽  
Trade Off ◽  
Catecholamine Synthesis ◽  
Astyanax Mexicanus ◽  
Adaptive Behaviours ◽  
The Relationship ◽  
Insight Into

Multiple cave populations of the teleost Astyanax mexicanus have repeatedly reduced or lost eye and body pigmentation during adaptation to dark caves. Albinism, the complete absence of melanin pigmentation, is controlled by loss-of-function mutations in the oca2 gene. The mutation is accompanied by an increase in the melanin synthesis precursor l -tyrosine, which is also a precursor for catecholamine synthesis. In this study, we show a relationship between pigmentation loss, enhanced catecholamine synthesis and responsiveness to anaesthesia, determined as a proxy for catecholamine-related behaviours. We demonstrate that anaesthesia resistance (AR) is enhanced in multiple depigmented and albino cavefish (CF), inversely proportional to the degree of pigmentation loss, controlled by the oca2 gene, and can be modulated by experimental manipulations of l -tyrosine or the catecholamine norepinephrine (NE). Moreover, NE is increased in the brains of multiple albino and depigmented CF relative to surface fish. The results provide new insights into the evolution of pigment modification because NE controls a suite of adaptive behaviours similar to AR that may represent a target of natural selection. Thus, understanding the relationship between loss of pigmentation and AR may provide insight into the role of natural selection in the evolution of albinism via a melanin–catecholamine trade-off.

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