Sexual Selection In Animals
Mostrando 1-12 de 19 artigos, teses e dissertações.
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1. Avaliação da Proporção Sexual de Embriões Desenvolvidos In Vitro e de Progênie a Campo de Touros Jovens. / Evaluation of the Sex Ratio of Embryos Developed In Vitro and in Field Progeny of Young Sires.
Some of the main problems that affect the in vitro production of embryos is the variation among bulls in relation to fertility and the greater birth of male embryos. Many factors can change the ratio 1:1 between the genders, both in the in vitro production of embryos and in the method of artificial insemination. To try to change this sex ratio in vitro, we s
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 01/08/2011
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2. Disputas físicas e territorialidade da espécie de borboleta Actinote pellenea (Hubner, 1821) (Nymphalidae, Acraeinae) / Physical contests and territoriality in butterfly Actinote pellenea (Hubner, 1821) (Nymphalidae, Acraeinae)
Os machos de várias espécies de borboletas defendem territórios de acasalamentos contra rivais da mesma espécie por meio de intensas perseguições em espirais. Tais perseguições raramente apresentam contato físico, tornando incerto como residentes obtêm vantagem territorial. No sudeste do Brasil os machos da borboleta aposemática Actinote pellenea
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/02/2011
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3. Características vegetativas e reprodutivas das plantas e fatores abióticos do meio e suas relações com a alocação de biomassa floral e a seleção sexual em angiospermas / Vegetative and reproductive characteristics of plants and abiotic factors of the environment and their relations with floral biomass allocation and sexual selection in angiosperms
Plants are sessile organisms exposed to the effects of environmental stress. The flowers are fundamental structures in the evolution of angiosperms, because through them is sexual reproduction. For this, the flowers exhibit strategies that help the plant to achieve better reproductive success. Animals visit flowers in search of resources, however, to carry p
Publicado em: 2010
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4. Sistemas de acasalamento com defesa territorial : evolução, regras das disputas e seleção de territorios em satirineos neotropicais / Mating systems with territorial defense : evolution, contest rules and territory selection in neotropical satyrine Butterflies
Territorial conflicts in flying insects may be resolved through many different ways. In male butterflies, size, age and motivation are often reported as important determinants of the winning chances. However, the rules used when fighting, the biological context that affects the intensity of agonistic behaviors, and the functional role of male traits in the c
Publicado em: 2009
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5. Caracterização da freqüência de heterozigose em genes ligados à precocidade sexual em novilhas de corte compostas / Heterozigosity frequency characterization in genes related to sexual precocity in composite beef heifers
The luteinizing hormone receptor (LHR) and follicle-stimulating receptor (FSHR) genes, known for their influence on the onset of puberty were evaluated by PCR-RFLP analysis in a population of 370 European-Zebu composite beef heifers from different breed contributions. The objectives were to genetically characterize the investigated population using genotype
Publicado em: 2005
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6. Sexual selection in plants: pros and cons.
Sexual selection has long been regarded as a special mode of selection in animals. Various authors have argued in a growing number of publications since 1979 that sexual selection is also operative in plants, and consequently, two divergent concepts of sexual selection are now being stated in the literature, the original Darwinian concept and the new plant-c
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7. How cuckoldry can decrease the opportunity for sexual selection: Data and theory from a genetic parentage analysis of the sand goby, Pomatoschistus minutus
Alternative mating strategies are common in nature and are generally thought to increase the intensity of sexual selection. However, cuckoldry can theoretically decrease the opportunity for sexual selection, particularly in highly polygamous species. We address here the influence of sneaking (fertilization thievery) on the opportunity for sexual selection in
The National Academy of Sciences.
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8. How does breeding system variation modulate sexual antagonism?
The study of sexually antagonistic (SA) traits remains largely limited to dioecious (separate sex), mobile animals. However, the occurrence of sexual conflict is restricted neither by breeding system (the mode of sexual reproduction, e.g. dioecy or hermaphroditism) nor by sessility. Here, we synthesize how variation in breeding system can affect the evolutio
The Royal Society.
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9. Sex allocation and sexual conflict in simultaneously hermaphroditic animals
Links between sex allocation (SA) and sexual conflict in simultaneous hermaphrodites have been evident since Charnov's landmark paper published 30 years ago. We discuss two links, namely the potential for sexual conflict over SA between sperm donor and recipient, and the importance of post-copulatory sexual selection and the resulting sexual conflict for the
The Royal Society.
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10. Positive selection in the egg receptor for abalone sperm lysin
The mechanism of speciation is a central problem in evolutionary biology. In free-spawning animals with no complex mating behavior, prezygotic reproductive isolation (speciation) could result from the rapid divergence of genes coding for sperm and egg proteins that bind each other during fertilization. In abalone, sperm lysin evolves rapidly by positive Darw
The National Academy of Sciences.
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11. Sex and the nose: human pheromonal responses
The chemosensory functions of the human nose are underappreciated. Traditional teaching is that the sense of smell detects volatile compounds, which may then allow the identification of substances that may be beneficial or harmful—such as good versus putrefied food. However, increasing evidence from research in other animals suggests that olfaction may ser
The Royal Society of Medicine.
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12. Heterozygote Advantage and the Evolution of a Dominant Diploid Phase
The life cycle of eukaryotic, sexual species is divided into haploid and diploid phases. In multicellular animals and seed plants, the diploid phase is dominant, and the haploid phase is reduced to one, or a very few cells, which are dependent on the diploid form. In other eukaryotic species, however, the haploid phase may dominate or the phases may be equal