Large seasonal variation in the rate of change in girth of tropical rain-forest tree species has been described, but its origin is still under debate. We tested whether this variation might be related ...

Recruitment variation is believed to be an important mechanism of species coexistence in variable environments. This mechanism, however, is a composite of two other mechanisms: the storage effect, and ...

Most populations have some degree of variation in their gene pools. By measuring the amount of genetic variation in a population, scientists can begin to make predictions about how genetic variation ...

Evidence from twelve species of passerine birds points to higher heart ratios in high-altitude populations. Such variation in relative heart size, which might be expected on physiological grounds, ...