Sibling Competition
Mostrando 1-10 de 10 artigos, teses e dissertações.
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1. Do polyembryonic seeds of Carapa surinamensis (Meliaceae) have advantages for seedling development?
RESUMO Poliembrionia é a diferenciação e o desenvolvimento de múltiplos embriões em uma única semente. Esta característica pode proporcionar diversas vantagens, como aumentar o número de embriões produzidos com a mesma quantidade de recursos, e aumentar a probabilidade de estabelecimento de pelo menos uma plântula de uma única semente. Por outro l
Acta Amaz.. Publicado em: 06/05/2019
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2. Rivalidade fraterna na perspectiva dos progenitores : da gestação ao segundo ano de vida do segundo filho
O presente estudo teve como objetivo investigar a rivalidade fraterna desde a gestação até os 24 meses de vida do segundo filho em famílias com um primogênito em idade pré-escolar, a partir da perspectiva dos progenitores. De modo especial, buscou-se compreender como se manifesta e como se desenvolve a rivalidade fraterna ao longo dos 2 anos iniciais d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
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3. Life history consequences of mammal sibling rivalry
Mammal life history traits relating to growth and reproduction are extremely diverse. Sibling rivalry may contribute to selection pressures influencing this diversity, because individuals that are relatively large at birth typically have an advantage in competition for milk. However, selection for increased growth rate is likely to be constrained by kin sele
The National Academy of Sciences.
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4. Signaling of need, sibling competition, and the cost of honesty
Young birds and mammals frequently solicit food by means of extravagant and apparently costly begging displays. Much attention has been devoted to the idea that these displays are honest signals of need, and that their apparent cost serves to maintain their honesty. Recent analyses, however, have shown that the cost needed to maintain a fully informative, ho
The National Academy of Sciences.
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5. Skewed paternity and sex allocation in hermaphroditic plants and animals.
Models predict a reduced allocation to sperm when females preferentially use one of two males' sperm and the males do not know who is favoured. An analogous discounting occurs in plants when their paternity success is skewed by random, non-heritable factors such as location in the population and pollinator behaviour. We present a model that shows that skewed
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6. Sexually antagonistic chromosomal cuckoos
The two kinds of sex chromosomes in the heterogametic parent are transmitted to offspring with different sexes, causing opposite-sex siblings to be completely unrelated for genes located on these chromosomes. Just as the nest-parasitic cuckoo chick is selected to harm its unrelated nest-mates in order to garner more shared resources, sibling competition caus
The Royal Society.
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7. The evolution of begging: Signaling and sibling competition
In many species, young solicit food from their parents, which respond by feeding them. Because of the difference in genetic make-up between parents and their offspring and the consequent conflict, this interaction is often studied as a paradigm for the evolution of communication. Existent theoretical models demonstrate that chick signaling and parent re
The National Academy of Sciences of the USA.
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8. Competition between Mitochondrial Haplotypes in Distinct Nuclear Genetic Environments: Drosophila Pseudoobscura Vs. D. Persimilis
A test for coadaptation of nuclear and mitochondrial genomes was performed using the sibling species, Drosophila pseudoobscura and D. persimilis. Two lines of flies with ``disrupted'' cytonuclear genotypes were constructed by repeated backcrossing of males from one species to females carrying mitochondrial DNA (mtDNA) from the other species. Each ``disrupted
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9. Maternal yolk androgens stimulate territorial behaviour in black-headed gull chicks
Avian eggs contain substantial amounts of maternal androgens. The concentrations of these yolk androgens are affected by the maternal environment, such as the level of social competition, parasite exposure or food conditions. Since yolk androgens have been shown to affect a wide array of offspring traits, they may adjust the chicks to the expected post-hatch
The Royal Society.
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10. An Unusual Y Chromosome of Drosophila Simulans Carrying Amplified Rdna Spacer without Rrna Genes
The X and Y chromosomes of Drosophila melanogaster each contain a cluster of several hundred ribosomal RNA genes (rDNA). A nontranscribed spacer region separates adjacent rRNA genes and contains tandem copies of 240 bp repeats that include the initiation site for RNA polymerase I transcription. We show here that Drosophila simulans, a sibling species of D. m