• Title/Summary/Keyword: sexual selection

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Sex and Population Differences in Intelligence Are Partly Caused by Sexual Selection: Hn Evolutionary Hypothesis

  • Piffer, Davide
    • Interdisciplinary Bio Central
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    • v.6 no.4
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    • pp.2.1-2.7
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    • 2014
  • Sexual dimorphism in intelligence suggests that this phenotype is a sexually selected trait. This view is supported by an overrepresentation (compared to the autosomal genome) of genes affecting cognition on the X chromosome. The aim of this study is to test the hypothesis that sexual selection can explain sex and country-level differences in performance on tests of fluid intelligence. Nationally representative samples from N = 44 countries were obtained from the Programme for International Student Assessment (PISA) Creative Problem Solving (CPS), which evaluates the core of intelligence, that is novel problem solving ability. Sexual selection has the double effect of increasing the prevalence of a favored phenotype and reducing genetic variation in sexually selected traits. Matching these predictions from evolutionary theory, the average country fluid intelligence is positively correlated to sexual dimorphism after partialling out per capita GDP and the latter in turn is inversely correlated to variance in intelligence scores within populations. Males have a higher variance than females but there is a negative correlation between male-female difference in variance and sexual dimorphism in intelligence, suggesting that selection reduces variance more in the selected sex. Average country male height is negatively correlated to sexual dimorphism in intelligence, a fact that supports the notion of a trade-off between physical and intellectual competition in the context of access to females. The results of this study, if replicated, imply that genome-wide association studies of cognition may benefit from a focus on sex chromosomes, which so far have been neglected. Another implication of this study is that intelligence has continued to evolve after different human populations migrated out of Africa and possibly up to the 19th century, as suggested by the substantial variability in sex differences even between neighbouring countries.

Evidence of Sexual Selection for Evening Orientation in Human Males: A Cross Cultural Study in Italy and Sri Lanka

  • Gunawardane, K.G. Chandrika;Custance, Deborah M.;Piffer, Davide
    • Interdisciplinary Bio Central
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    • v.3 no.4
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    • pp.13.1-13.8
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    • 2011
  • Previous research has established the existence of individual differences with regards to individuals' optimum time of well-functioning; specifically in terms of being either morning or evening oriented. An association has also emerged between being more evening, as opposed to morning, oriented and having a greater number of sexual partners. The aim of the present study was to investigate whether "eveningness" in males is an evolved sexually dimorphic trait consistent across different cultures. A sample of 179 male Sri Lankan men residing in two different cultural and economic settings, Italy and Sri Lanka, were administered the Morningness-Eveningness Questionnaire (MEQ) followed by assessing their sexual behavior history. The results robustly portrayed a highly significant main effect of MEQ types highlighting the twofold sexual success enjoyed by the evening individuals in both regional locations. Morning oriented individuals, showed a stronger preference for going out and partying than evening-types, suggesting that the higher mating success of evening types is not due to their different lifestyles allowing more opportunities to encounter females. However, evening types exhibited a preference for flirtatious behaviors in the later part of the day. Shoulder-to-hip and handgrip strength, as measures of testosterone levels, were not significantly associated with eveningness. The results are discussed in terms of sexual selection and its interplay with human cultural variation.

A Study on Mate Selection and Sexual Consciousness(I) -Investigation for Unmarried Japanese Women College Students- (배우자선택과 성의식에 관한 연구(I) -일본 여자대학생을 대상으로-)

  • 김혜선;김영희
    • Journal of Families and Better Life
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    • v.1 no.2
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    • pp.107-125
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    • 1983
  • This study aimed to clarify the attitude toward marriage, mate selection and sexual consciousness of japanese unmarried women students whom are believed in drastic change in a overall social value system and norm due to the introduction of western civilization, so as to provide some information of the same subject of our young women in similar situation. Survey was carried out for 177 unmarried Japanese women students of 3 Universities located in Osaka prefecture situation. Data were collected by means of Questionnaire and analyzed by SPSS BATCH SYSTEM. Result are as follows; 1) Pattern of mate selection- An increasing tendency of love match is recognized 2) Attitude to marriage-94.0% of correspondences want to marry and proper age of marriage, they think, is between 22-25 years. 3) Love-marriage relation- most correspondences answered that love is a prior condition for marriage, however, 32.8% of correspondences think, love can be built after the marriage. 4) Dating- most correspondences want free dating, however, they fell that they are lacking for opportunity and they are not confident in the selection of proper mate. 5) Premarital sexual intercourse-most correspondences show a very generous attitude toward premarital sexual intercourse if they are in love and this attitude becomes more remarkable among love match makers. 6) Equality of sexes-most correspondences answered that as women are different in physiological function from men, distinctive social roles of both sexes and the inequality of sexes are inevitable.

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EFFECT OF LONG TERM SELECTION ON GENETIC PARAMETERS OF ECONOMIC TRAITS IN WHITE LEGHORN

  • Sharma, D.;Johari, D.C.;Kataria, M.C.;Singh, B.P.;Singh, D.P.;Hazary, R.C.
    • Asian-Australasian Journal of Animal Sciences
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    • v.9 no.4
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    • pp.455-459
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    • 1996
  • The genetic parameters for various economic traits were estimated in a White Leghorn population selected for part period egg production over 16 generations. In early part of selection, egg number had moderate to high heritability (0.26 to 0.51) while age at sexual maturity, egg weight and body weight at 20 and 40 weeks of age had high heritability (0.54 to 0.83). The sire component heritability for all the traits except 20 week body weight declined in later periods of selection. Sex linked gene effects for egg number and age at sexual maturity were more important in early periods of selection in comparison to the later periods, while maternal effects remained important for 20 week body weight in all the periods. Egg number was negatively correlated with egg weight ($r_{G(S)}=-0.36$), age at sexual maturity ($r_{G(S)}=-0.84$) and 40 week body weight ($r_{G(S)}=-0.84$), while it was positively correlated with 20 week body weight ($r_{G(S)}=-0.34$) in base generation. The genetic association between egg number and 40 week body weight changed not only in magnitude but also in direction in later periods. The genetic correlation of egg number with egg weight as well as with age at sexual maturity also decreased in magnitude in later periods of selection.

Habitat selection in the lesser cuckoo, an avian brood parasite breeding on Jeju Island, Korea

  • Yun, Seongho;Lee, Jin-Won;Yoo, Jeong-Chil
    • Journal of Ecology and Environment
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    • v.44 no.2
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    • pp.106-114
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    • 2020
  • Background: Determining patterns of habitat use is key to understanding of animal ecology. Approximately 1% of bird species use brood parasitism for their breeding strategy, in which they exploit other species' (hosts) parental care by laying eggs in their nests. Brood parasitism may complicate the habitat requirement of brood parasites because they need habitats that support both their host and their own conditions for breeding. Brood parasitism, through changes in reproductive roles of sex or individual, may further diversify habitat use patterns among individuals. However, patterns of habitat use in avian brood parasites have rarely been characterized. In this study, we categorized the habitat preference of a population of brood parasitic lesser cuckoos (Cuculus poliocephalus) breeding on Jeju Island, Korea. By using compositional analyses together with radio-tracking and land cover data, we determined patterns of habitat use and their sexual and diurnal differences. Results: We found that the lesser cuckoo had a relatively large home range and its overall habitat composition (the second-order selection) was similar to those of the study area; open areas such as the field and grassland habitats accounted for 80% of the home range. Nonetheless, their habitat, comprised of 2.54 different habitats per hectare, could be characterized as a mosaic. We also found sexual differences in habitat composition and selection in the core-use area of home ranges (third-order selection). In particular, the forest habitat was preferentially utilized by females, while underutilized by males. However, there was no diurnal change in the pattern of habitat use. Both sexes preferred field habitats at the second-order selection. At the third-order selection, males preferred field habitats followed by grasslands and females preferred grasslands followed by forest habitats. Conclusions: We suggest that the field and grassland habitats represent the two most important areas for the lesser cuckoo on Jeju Island. Nevertheless, this study shows that habitat preference may differ between sexes, likely due to differences in sex roles, sex-based energy demands, and potential sexual conflict.

Sexual Reproduction Genetic Algorithms: The Effects of Multi-Selection & Diploidy on Search Performances (유성생식 유전알고리즘 : 다중선택과 이배성이 탐색성능에 미치는 영향)

  • Ryu, K.B.;Choi, Y.J.;Kim, C.E.;Lee, H.S.;Jung, C.K.
    • Proceedings of the KIEE Conference
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    • pp.1006-1010
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    • 1995
  • This paper describes Sexual Reproduction Genetic Algorithm(SRGA) for function optimization. In SRGA, each individual utilize a diploid chromosome structure. Sex cells(gametes) are produced through artificial meiosis in which crossover and mutation occur. The proposed method has two selection operators, one, individual selection which selects the individual to fertilize, and the other, gamete selection which makes zygote for offspring production. We consider the effects of multi-selection and diploidy on search performance. SRGA improves local and global search(exploitation and exploration) and show optimum tracking performance in nonstationary environments. Gray coding is incorporated to transforming the search space and Genic uniform distribution method is proposed to alleviate the problem of premature convergence.

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Relationship between Climacteric Symptoms and Sexual Satisfaction in Middle-aged Women (중년여성의 갱년기 증상과 성만족과의 관계 연구)

  • Cha Bo-Kyoung
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.10 no.3
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    • pp.283-291
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    • 2003
  • Purpose: This study was conducted to identify the relationship between climacteric symptoms and sexual satisfaction in middle-aged women. Method: Self-selection was used to recruit, for the study, 272 middle-aged women between 40 and 59 years of age from 2 metropolitan areas and 2 provinces in Korea. The questionnaire included information on demographic characteristics, climacteric symptoms and sexual satisfaction. Result: The results are as follows: 1. The mean/item climacteric symptom score was 1.91 and the mean sexual satisfaction score was 38.19.2. Climacteric symptoms were significantly influenced by age, education, economic status, frequency of abortions and menopausal status. Sexual satisfaction was influenced significantly by age, education, economic status and menopausal status. 3. There was a significant negative correlation between climacteric symptoms and sexual satisfaction (r=-.24, p =.0002). Conclusion: Sexuality should be considered when developing nursing strategies for middle-aged women, especially when dealing with climacteric symptoms.

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Genetic Parameters Estimated for Sexual Maturity and Weekly Live Weights of Japanese Quail (Coturnix coturnix japonica)

  • Sezer, Metin
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.1
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    • pp.19-24
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    • 2007
  • Covariance components and genetic parameters of weekly live body weight from hatching to six weeks of age and age of sexual maturation were estimated in a laying type Japanese quail line. The univariate and bivariate animal model analysis included hatching group and sex as fixed effects. Each trait was analysed with animal as random effect to fit the additive direct effect. Additional random effects incorporated in the models were changed according to the trait examined. The best model for a trait was chosen based on a likelihood ratio test, comparing the models with and without maternal additive genetic and maternal permanent environmental effects. Heritability estimates of live-weight at hatch and one to six weeks of age with their standard errors were 0.22${\pm}$0.088, 0.39${\pm}$0.099, 0.31${\pm}$0.086, 0.38${\pm}$0.056, 0.46${\pm}$0.055, 0.50${\pm}$0.059, and 0.56${\pm}$0.062, respectively. Direct heritability value of age of sexual maturation was moderate (0.24${\pm}$0.055). The variances due to permanent environmental effect of dam after one week of age and maternal genetic effect after two weeks of age were not important sources of variation. The correlations between direct and maternal genetic effects were negative and ranged from high to moderate values (-0.21 to -0.83). Among the weekly live weights, genetic correlations were generally high between not only successive but also early and late weightings. It suggests that selection for final weight may be based on early weight records. Genetic correlations between age of sexual maturation and live weights were low, favourable but had high standard errors. These results indicate that selection for high weight will potentially result in lower age of sexual maturation only with accurate determination of breeding values.

Integrative Review of Sexual Health Information Seeking Behaviors among Adolescents: Based on Qualitative Research (청소년의 성 건강정보 추구행동: 질적연구를 중심으로 한 통합적 문헌고찰)

  • Kim, Sookyung;Kim, Sanghee
    • Journal of the Korean Society of School Health
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    • v.34 no.1
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    • pp.42-52
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    • 2021
  • Purpose: With the development of media, the ways adolescents can obtain information related to sexual health have diversified. Prior quantitative research on adolescents' sexual health information seeking behaviors (HISB) has limitations in grasping the details, and sexual issues of adolescents have tended to be underreported in quantitative studies. It is necessary to explore sexual HISB through an integrative review of qualitative research. The aim of the study was to analyze the literature on sexual HISB among adolescents, focusing on qualitative research. Methods: An integrative review was undertaken to explore the studies conducted between 2009 and 2018 that addressed sexual HISB such as source preferences, perceived trustworthiness, and tendency according to age and gender among adolescents. Results: Seven studies met the selection criteria and were analyzed according different sexual HISB. It was identified that adolescents preferred trustworthy sources and had a pattern of reviewing and comparing the content among diverse sources to confirm the quality of the information. Female adolescents valued privacy and confidentiality, while male adolescents would like to earn information along with their peers and perceived it as an opportunity to exchange their experiences and thoughts. Late adolescents preferred to seek sexual health information from peers and on the internet such as websites and social platforms compared to early adolescents. Conclusion: This study is significant in that it provides evidence that can be applied when developing programs for promoting sexual health in adolescents. It is suggested that programs should focus on building trustworthiness and consider differences in age and gender to improve the use of sexual health information among adolescents.

Responses in Partial, Residual and Annual Egg Production Expected from Selection on Part Record in Synthetic White Leghorn flock (산란계의 합성종계통에 있어서 부분검정에 의한 선발효과 추정에 관한 연구)

  • 오봉국;이정구;이문연
    • Korean Journal of Poultry Science
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    • v.9 no.1
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    • pp.35-42
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    • 1982
  • Data pertaining to the first generation of a Synthetic White Leghorn flock were used to estimate the heritabilities of and genetic correlation between partial egg production(egg number or percentage) or diversely segmented part records and other traits such as age at sexual maturity, residual and annual egg production, and to compare the expected genetic gain from selection on partial egg number or partial percent production with correlated response in other traits. The estimated heritabilites for six measures of egg Production were ranged from 29 to 35, while heritability for age at sexual maturity (SM) was intermediate (48). Genetic correlations between partial egg number (P) and annual egg number. (A), and partial percent production (P') and annual percent production (A') were 51 and 72, respectively. Genetic correlation between P and SM was estimated largely negative (-.64), while correlation bettween P' and SM was positively intermediate(34). In comparing direct response from selection on partial production (P or P') with another response in correlated trait, selection on P would be 25% more efficient than selection of P' for improving A, while selection of P' would be 94% more efficient than selection P for improving A' For shortening SM selection of P would be 98% more efficient than selection on P'.

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