997 resultados para Möller, Heinrich Ferdinand, 1745-1798.
Resumo:
r/K theory classically predicts that offspring size should increase under density-dependent selection. However, this is questionable, being based on implicit rather than explicit assumption (the logistic model does not include offsring size as a parameter). From recent models of optimal offspring size (Sibly & Calow, 1983; Taylor & Williams, 1984) it can be shown that density should select for larger offspring if density-dependence in the per capita rate of increase is mainly due to a reduction of the juvenile growth rate or survivorship. In contrast, density should select for smaller offspring if such density-dependence is mainly due to a reduction of adult fecundity or survivorship. Therfore, the outcome of selection cannot be predicted without precise knowledge of the density-dependence of age-specific reproduction and mortality rates. To test the above models, genetically identical individuals of Simocephalus vetulus (Müller) were reared in a density gradient; density-dependence in the per capita rate of increase was shown to be mainly due to a reduction of the juvenile growth rate, thereby selecting for larger offspring; offspring size at birth appeared to be phenotypically plastic and to increase with density. Models were therefore qualitatively supported. However, a discrepancy occurred in quantitative predictions; offspring were produced larger than predicted. Field and laboratory studies are suggested to address this.
Resumo:
Enregistrement : Paris, Université de Paris, La Sorbonne, 03-01-1912
Resumo:
Two new species of Marilia Müller (Odontoceridae), M. aiuruoca sp. nov. and M. huamantincoae sp. nov., are described and figured from Itatiaia massif, Mantiqueira mountain range, southeastern Brazil. The female of M. major Müller, 1880 is described and the species is recorded for the first time from Rio de Janeiro state.
Resumo:
Comprend : Catalogue descriptif des ouvrages de Ferdinand de Saint-Urbain et de Claude-Augustin de Saint-Urbain
