نتایج جستجو برای: dispersal barrier
تعداد نتایج: 109429 فیلتر نتایج به سال:
Dispersal is a key demographic process, ultimately responsible for genetic connectivity among populations. Despite its importance, quantifying dispersal within and between populations has proven difficult for many taxa. Even in passerines, which are among the most intensely studied, individual movement and its relation to gene flow remains poorly understood. In this study we used two parallel g...
Dispersal is a critically important process in ecology, but robust predictive models of animal dispersal remain elusive. We identify a potentially ubiquitous component of variation in animal dispersal that has been largely overlooked until now: the influence of mate encounters on settlement probability. We use an individual-based model to simulate dispersal in sexually-reproducing organisms tha...
conclusions the influences of various facilities and barriers were different in the physical activity of elderly in kashan. the promotion of active life style should be a part of health care planning in elderly. background the supplements and decreasing the limitations are important for suitable physical activity. these factors are different in various environments. objectives the current study...
Dispersal influences both the ecological and evolutionary dynamics of range expansion. While some studies have demonstrated a role for human-mediated dispersal during invasion, the genetic effects of such dispersal remain to be understood, particularly in terrestrial range expansions. In this study, we investigated multimodal dispersal during the range expansion of the invasive gecko Hemidactyl...
Seed dispersal can be advantageous (1) in escape from densityor distance-dependent seed and seedling mortality, (2) by colonization of suitable sites unpredictable in space and time, and (3) by directed dispersal to particular sites with a relatively high probability of survival. Most previous research on the consequences of seed dispersal has focused on escape and colonization because adaptati...
Dispersal is a crucial factor in natural evolution, since it determines the habitat experienced by any population and defines the spatial scale of interactions between individuals. There is compelling evidence for systematic differences in dispersal characteristics within the same population, i.e., genotype-dependent dispersal. The consequences of genotype-dependent dispersal on other evolution...
Phylogenetic and paleontological analyses are combined to reveal patterns of species origination and divergence and to define the significance of potential and actual barriers to dispersal in Conus, a species-rich genus of predatory gastropods distributed throughout the world's tropical oceans. Species-level phylogenetic hypotheses are based on nucleotide sequences from the nuclear calmodulin a...
While evidence is mounting that larval reef fish are active participants in the process of dispersal and settlement, the sensory and behavioural mechanisms by which these fishes disperse and return from their oceanic phase to the reefs remain unknown. On One Tree Island (Great Barrier Reef, Australia), we tested freshly collected animals in a large choice-flume on the shore. Here, we present th...
Tropical leaf-cutter ants cultivate the fungus Attamyces bromatificus in a many-to-one, diffuse coevolutionary relationship where ant and fungal partners re-associate frequently over time. To evaluate whether ant-Attamyces coevolution is more specific (tighter) in peripheral populations, we characterized the host-specificities of Attamyces genotypes at their northern, subtropical range limits (...
Movements and spatial distribution of host populations are expected to shape the genetic structure of their parasite populations. Comparing the genetic patterns of both interacting species may improve our understanding of their evolutionary history. Moreover, genetic analyses of parasites with horizontal transmission may serve as indicators of historical events or current demographic processes ...
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