Yet the new forecast from the US-based Population Reference Bureau attracted no comment from our government, which has barely begun to shape a population policy, as distinct from an immigration policy, which it says sets "no upper limits".
Although natural selection is often viewed as a slow pruning process, a dramatic new field study suggests it can sometimes shape a population as fast as a chain saw can rip through a sapling.
The role of individual variation in shaping a population's niche was first articulated as a component of Van Valen's [5] niche variation hypothesis.
Understanding how social determinants of health interact to ultimately shape a population's pattern of disease is a daunting task, full of methodological complexity and theoretical uncertainty.
In fact, the increased susceptibility of GOUNDRY to malaria parasite infection (Riehle et al. 2011) could be explained by such a mechanism, under the hypothesis that a change of ecological niche in this population has shaped a new pattern of selection in the immune genes.
To compare curve shapes, a population of slopes was calculated from biological and statistical replicates.
Second, there is discordance between the genetic constitution and the prevailing leaf shape of a population; genetic clustering does not predict leaf shape genotype frequencies for populations.
Based on 37 measurements--ranging from the length of the cranium to the height of the eye sockets--the team reports this week in Nature that the worldwide pattern of skull shapes closely matches the genetic data: The diversity of cranial shape within a population falls off the farther it is from Africa.
The age and sex structure of the population determines the ultimate shape of a population pyramid, such that the representation may take the form of a pyramid, have a columnar shape (with vertical sides rather than sloped sides), or have an irregular profile.
Analytical results are derived for single-shape landscapes, in particular, simple expressions are obtained for the mean fraction of master shapes in a population and for phenotypic error thresholds.
