Niche Breadth
Mostrando 25-30 de 30 artigos, teses e dissertações.
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25. Influencia da variação fisionomica da vegetação sobre a composição de aves frugivoras na Mata Atlantica
Due to the alarming rate of deforestation in tropical forests, a better understanding on the organization of biological communities is needed, specifically regarding the interactions between birds and plants. Although this aspect is not often included among the top priorities for biodiversity conservation, it must be considered an important of effort in the
Publicado em: 2002
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26. Selection and Polygenic Characters*
A mathematical model is developed which describes the effect of selection on polygenic or continuously varying phenotypic characters. For the simplest case the standard deviation of a phenotypic character in a population cannot be greater than √2β where β is the expected deviation of the offspring from the average of the parents' types. This is found to
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27. Population Genetic Consequences of Feeding Habits in Some Forest Lepidoptera
By surveying variation at allozyme loci in several phytophagous lepidopteran species (Geometridae), we have tested two hypotheses about the relationship of genetic variation to environmental heterogeneity: (1) that allozyme polymorphisms may exist because of associations between genotypes and "niches" (different host plants, in this instance), and (2) that t
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28. Microbial diversity, producer-decomposer interactions and ecosystem processes: a theoretical model.
Interactions between the diversity of primary producers and that of decomposers--the two key functional groups that form the basis of all ecosystems--might have major consequences on the functioning of depauperate ecosystems. I present a simple ecosystem model in which primary producers (plants) and decomposers (microbes) are linked through material cycling.
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29. Predicting the risk of extinction from shared ecological characteristics
Understanding the ultimate causes of population declines and extinction is vital in our quest to stop the currently rampant biodiversity loss. Comparison of ecological characteristics between threatened and nonthreatened species may reveal these ultimate causes. Here, we report an analysis of ecological characteristics of 23 threatened and 72 nonthreatened b
National Academy of Sciences.
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30. Self-fertilization and monogenic strains in natural populations of terrestrial slugs
Electrophoretic studies of genetic variation in 14 species of terrestrial slugs of the families Arionidae, Philomycidae, and Limacidae in the eastern United States indicate that self-fertilization, either facultative or obligatory, is the normal breeding system in six of the species. Three of these six species are single monogenic strains; one consists of th