1. The spatial structure of natural populations may profoundly influence their dynamics. Depending on the frequency of movements among local populations and the consequent balance between local and regional population processes, earlier work has attempted to classify metapopulations into clear-cut categories, ranging from patchy populations to sets of remnant populations. In an alternative, dic...

BACKGROUND Many of the processes affecting genetic diversity act on local populations. However, studies of plant nucleotide diversity have largely ignored local sampling, making it difficult to infer the demographic history of populations and to assess the importance of local adaptation. Arabidopsis lyrata, a self-incompatible, perennial species with a circumpolar distribution, is an excellent ...

Natural selection is widely noted to drive divergence of phenotypic traits. Predation pressure can facilitate morphological divergence, for example the evolution of both cryptic and conspicuous coloration in animals. In this context Dendrobatid frogs have been used to study evolutionary forces inducing diversity in protective coloration. The polytypic strawberry poison frog (Oophaga pumilio) sh...

In many species, individuals discriminate among sexual signals of conspecific populations in the contexts of mate choice and male-male competition. Differences in signals among populations (geographical variation) are in part the result of signal evolution within populations (temporal variation). Understanding the relative effect of temporal and geographical signal variation on signal salience ...

the taxonomic affinity of six species of crocus (c, cancellatus subsp. damascenus c. almehensis, c. gilanicus, c. sativus, c.pallassi subsp. haussknechtii,c. speciosus subsp. speciosus) from iran were studied usingdifferent electrophoresis techniques. the similarity index of the species was computed by comparison of protein bands of - corm and seed tissues, and the related dendrogms of affinity...

Local adaptation arises as a result of selection by the local environment favoring phenotypes that enhance fitness. Geographic patterns of phenotypic variation are in part due to this selective process. Classically, the genetic basis of those phenotypes has been studied in plant populations using a quantitative genetic approach in which plants from different source populations are grown in comm...

Understanding the historical processes that generated current patterns of phenotypic diversity in nature is particularly challenging in subdivided populations. Populations often exhibit heritable genetic differences that correlate with environmental variables, but the non-independence among neighbouring populations complicates statistical inference of adaptation. To understand the relative infl...

We analyzed the statistical distribution of intra-specific local abundances for a set North American breeding bird species. We constructed frequency plots for every species and found that they showed long-tail power-law behavior, truncated at an upper abundance cut-off value. Based on finite size scaling arguments, we investigated whether frequency curves may be considered scaled copies of each...